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Premature Separation of the Normally Implanted Placenta
Premature Separation of the Normally Implanted Placenta STANLEY M. BYSSHE, M.D., F.A.C.S.*
separation of the normally implanted placenta represents a serious complication of pregnancy endangering the life of both mother and baby. Rigby,! in 1776, first defined this development as an accidental hemorrhage, in contradistinction to the unavoidable hemorrhage noted in cases of placenta previa. "Abruptio placentae," "ablatio placentae" and "accidental hemorrhage" have all been used in the past as terms for premature separation of the normally implanted placenta. Today "abruptio placentae" is usually reserved for the most severe type of placental separation, while "premature separation of the normally implanted placenta" is accepted as the all-inclusive term for all types of this pregnancy mishap. When properly handled this complication should not carry the risk to maternal life cited in the past. There is still much room for improvement in treatment, aimed at reduction of fetal loss, in premature separation of the placenta of the normally implanted placenta. PREMATURE
ETIOLOGICAL CONSIDERATIONS
The etiological factor for all premature separations of the normally implanted placenta is not completely understood. While the cases of true abruptio placentae are associated with pregnancy toxemia about 40 per cent of the time, the placental abruptions of lesser severity are more commonly seen resulting from mechanical factors and other unexplained causes. In any case, degeneration and necrosis of the trophoblasticdecidual junction seems to represent the underlying pathologic process, while the other mechanical factors are merely contributing causes. At the Sloane Hospital for Women2 an associated pregnancy toxemia has been noted in 24.4 per cent of all of the cases of premature separation of the placenta. In the same period analyzed, toxemia was seen in only 12.4 per cent of all deliveries. It has been concluded that not only is pregnancy toxemia an important precursor in premature separation of
* Associate Professor of Clinical Obstetrics and Gynecology, CoUege of Physicians and Surgeons, Columbia University; Associate Attending Obstetrician and Gynecologist, Sloane Hospital for Women, Columbia-Presbyterian Medical Center, New York, N. Y. 393
Stanley M. Bysshe the placenta, but the degree of placental separation increases with the severity of the pregnancy toxemia as well. The incidence of premature separation of the placenta in nontoxemia patients was 1 in 135, while this complication rose to 1 in 51 in all toxemia patients. Toxemia of pregnancy is found in a ratio of 1 in 2.6 of the cases of severe placental abruption. One can hypothesize that separation of placenta may represent one facet of the toxemia picture, manifesting itself as a vascular accident at the site of placental attachment. Many times, in the emergency handling of a case of abruptio placentae, the blood pressure is low as a result of shock, and the diagnosis of pregnancy toxemia is not apparent until many hours after the shock picture has been relieved. External trauma was seen as a predisposing cause of placental separation in only 3 per cent of these cases. Umbilical cord complications, with a true or relative shortening of the cord, were found in 8.2 per cent of cases. Hydramnios, multiple pregnancy, previous incision in the uterine musculature, and fibromyomata uteri were each noted in no more than about 2 per cent of cases. Fetal presentation was in no way altered in premature separation of the placenta. The simple forces of labor undoubtedly give rise to premature separation of the placenta in the largest number of cases. Separation may occur late in first stage, but more often in the second stage of labor. The separation may be quite mild, yet it always represents a serious accident for the fetus. Nearly all mild placental abruptions are to be seen in this group, and only the most careful surveillance of labor will detect this mishap before the baby may be lost. ASSOCIATED CLINICAL FINDINGS
Premature separation of the normally implanted placenta may be described as a pregnancy complication occurring after 28 weeks of pregnancy, and thus the babies delivered all fall into the viable premature (1000 gm.) or term period. The age, parity and color of the mother are of no significance here. One finds, however, more toxemia patients among older patients. Vaginal bleeding may be noted in 17.1 per cent of these patients at any time in pregnancy before the final episode or onset of labor, yet this is only comparable to the incidence of antepartum bleeding in all antepartum patients who fail to abort and go on successfully to term. Nevertheless, approximately one-third of placental separations do manifest themselves in bleeding in the last trimester of pregnancy, and 50 per cent have vaginal bleeding just prior to the onset of labor. Bleeding late in pregnancy is also common in placenta previa, but this condition is found only one-half as often as premature separation of the placenta. Repetition of a placental separation has been found to occur in a subsequent pregnancy in 4.4 per cent of placental abruptions. It is of utmost importance to realize that premature separation of the normally implanted placenta is an accident of pregnancy occurring as
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often in the premature period of pregnancy, before 37 weeks of gestation, as in the term gestations. The prognosis for the fetus will vary, therefore, according to the date of delivery. With up-to-date premature nursery care, the baby of 2000 grams has a 95 per cent chance of survival, while 80 per cent of the 1500 gram babies should be salvaged. Even the still smaller babies make a healthy survival in a reasonable number of cases. The gross mortality in all cases of premature separation may be as high as 35.6 per cent. It is important to realize that the fetal deaths fall equally into losses before labor, intrapartum deaths, and neonatal deaths. The infant mortality arises from prematurity in two-thirds of the cases, while fetal anoxia and fetal shock from fetal blood loss are contributing factors in all cases. CLINICAL PICTURE
In their discussions of premature separation of the placenta, most essayists attempt to classify it according to the clinical picture of the severity of the accident. Such an approach is plausible, since one can then formulate definite steps in the course of therapy. Any classification, of necessity, pictures an overlapping of the etiological factors present. The simplest grading is that of mild, moderate and severe placental separation. In the years 1933-1955, at the Sloane Hospital for Women, the incidence of premature separation of the normally implanted placenta was 1 in 131 of the 69,150 deliveries reviewed. Mild Placental Separation
Here the condition is seldom recognized before delivery and the diagnosis is based on the eventual examination of the placenta. There may be minimal vaginal bleeding, and uterine pain is seldom noted by the patient. There is, therefore, no sign of uterine tetany and no maternal shock. Signs of fetal distress should be apparent during labor in at least a few of these cases. The placenta will exhibit adherent blood clot involving no more than one-sixth of its surface. Total bleeding is less than 400 cc., and is not of the concealed type. Mild placental separations are found in two-thirds of all separations, and are noted once in 204 deliveries. The patient is almost invariably in labor, and she is no more likely to be toxemic than any other pregnant patient. Fetal mortality for mild separations is 19.1 per cent. The bleeding in many of these cases represents an exodus of blood from the rupture of the marginal veins of the placenta-the so-called marginal sinus. Douglas3 and his co-workers prefer to call this a "marginal separation" of the placenta. He has described the condition as occurring in 23.2 per cent of placental abruptions, and emphasizes the fact that the fetal mortality here is six or seven times that of the general clinic loss. Premature separation of the normally implanted placenta and cases of bleeding from the marginal sinus are clinically indistinguishable as separate entities in labor.
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Moderate Placental Separation
The moderate type of premature separation of the placenta may be seen either as a more marked degree of mild separation or possibly the initial picture of the true abruptio placentae. This type can be expected to progress to serious complications before delivery in some of the cases. There is usually !!lome tetany of the uterine wall along with pain and tenderness in the uterus. Vaginal bleeding is noted in variable amounts, but can be concealed. There is usually no maternal shock here. In this type, fetal distress is more frequently noted, and fetal death occurs during labor more often than in the mild cases. Adherent blood clot may be noted involving more than one-sixth but less than two-thirds of the placental surface. Bleeding is more than 400 cc., but is not hemorrhagic. Moderate placental separation is found once in 532 deliveries. In cases of this degree of separation, pregnancy toxemia is also present one-third of the time. This moderate degree of premature separation of the placenta should be diagnosed routinely before delivery. The patient mayor may not be in labor at the time of the accident. Fetal mortality in placental separations of moderate degree is 45.1 per cent. Severe Placental Separation
In the past, the severe type of premature separation of the placenta, or true "abruptio placentae," was the only degree of separation recognized clinically. Here the patient has a. sudden accident characterized by acute and severe pain in the uterus along with variable amounts of vaginal bleeding. In nearly 50 per cent of the cases there is an associated pregnancy toxemia of a moderate or severe type. This accident appears without warning signs or symptoms. The patient is usually close to term and is seldom in labor. The bleeding exhibited vaginally may be alarming, while in those cases with little or no manifest bleeding the hemorrhage may be excessive, yet entirely concealed. Such cases exhibit shock out of proportion to the manifest bleeding and are proverbially the most serious from the point of view of maternal survival. The uterus in severe placental separations becomes hard and tetanically contracted. Mter an hour or two the uterus may be noted to have increased in size as a result of the increasing intrauterine hemorrhage. The initial bleeding is in the form of a centrally located hemorrhage behind the placenta, often referred to as "uteroplacental apoplexy." The blood can dissect the membranes free from their attachment throughout the uterus, and the placenta can "prolapse" into the region of the cervix. In some instances the hemorrhage ruptures into the sac. Membranes or presenting part may seal off the vaginal escape of blood. With prolonged intrauterine tension, blood becomes extravasated into the myometrium and to the serosal surface of the uterus, and in the severest type blood may gain access into the peritoneal cavity from actual rents in the serosa of the
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uterus. The tubes, ovaries and broad ligaments may be congested with blood. In this picture the uterus exhibits blotchy ecchymoses on its surface and becomes copper colored or darkest purple, as originally described by Couvelaire. Such a picture of the Couvelaire uterus occurs in 44.4 per cent of severe placental abruptions. Abruptio placentae occurs once in 1192 deliveries and the fetal mortality is as high as 67.4 per cent. Since this accident comes on so abruptly and since the placenta is completely or almost completely separated, the baby stands little chance of survival. The patient is rarely in labor, at least of an advanced degree, and delivery cannot be expedited sufficiently before the fetus succumbs in utero. In severe placental abruptiolls there are definite associated complications for the mother. The picture of shock deepens and must be relieved before it becomes irreversible. Shock cannot be safely evaluated and adequately treated until the uterus is emptied. The generalized vasospasm seen in hypertension, shock, and overdistention of the uterus is a likely cause here of lower nephron sclerosis and renal cortical necrosis. Renal failure may be fatal and not infrequently the surviving patients have a relative kidney shutdown for at least two or more days. It has been thought, previously, that the hemorrhage seen after delivery in severe premature separation of the placenta was due to the presence of a Couvelaire uterus. This is not true, for the Couvelaire uterus will contract physiologically after it is emptied. The degree of hemorrhagic discoloration of the uterus seen at laparotomy has no bearing on the ability of the myometrium to contract effectively. If, however, the case of abruptio placentae is allowed to go along for hours without relief for the tetantically contracted and overdistended uterus, then uterine atony may be seen postpartum and undue hemorrhage can result therefrom. Afibrinogenemia
Maternal deaths in severe cases of placental abruption have, in years past, been attributed to hemorrhage and shock resulting from the poorly contracting Couvelaire uterus. Such a deduction for the cause of excessive bleeding is now considered to be faulty. In 1901, DeLee noted hemorrhage and a faulty blood clotting mechanism to be present in some cases of abruptio placentae. This he described as a temporary hemophilia. In the last two decades, many workers have described the association of an acquired afibrinogenemia in severe placental separations. The etiology of the syndrome remains controversial. In general, it may be said that tissue thromboplastin from damaged placenta or decidua can readily enter the open maternal venous sinuses in cases of placental separation. Such a picture initiates the sensitive blood coagulation mechanism and causes extensive intravascular clotting. Microscopic thrombin emboli are formed and a resultant defibrination of the blood
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occurs. The bulk of the thromboplastin has been shown to end up in the liver and lungs. Occasionally this process may stimulatf' the protective fibrinolysin system to keep the circulation free of clots. Thus the picture of hypofibrinogenemia may result mainly from depletion of fibrinogen in clots and occasionally through destruction of fibrinogen by a fibrinolysin. The diagnosis of afibrinogenemia may be carried out through laboratory studies of the circulating fibrinogen noted in a sample of blood. Such studies are time-consuming, and in many emergencies this loss of time may be dangerous for the patient. Page 4 and his associates have outlined a rapid method for the determination of plasma fibrinogen. For practical purposes, however, the simple clot observation test is an adequate guide to therapy. Failure of a freshly drawn sample of venous blood to clot in a test tube incubated at 37° C. in half an hour, or poor retraction of a normally formed clot and evidence of gross hemolysis in the serum is felt to be sufficient evidence that the circulating plasma fibrinogen is reduced to a serious level. The normal fibrinogen level at delivery is at least 325 mg. per 100 cc. When fibrinogen falls to 100 mg. per 100 cc., or less, a critical level is reached, usually requiring replacement of fibrinogen for the safety of the mother. Critically low levels of fibrinogen are noted in some cases where the blood is apparently clotting adequately. In cases of abruptio placentae, the afibrinogenemia continues to increase in direct relation to the length of time the fetus and placenta remain undelivered. Where low levels of fibrinogen have existed, normal levels are physiologically restored within a matter of 12 to 24 hours after delivery, when the source of thromboplastin is removed. In the relief of afibrinogenemia the replacement of all blood lost by the patient must be carried out expeditiously. Whole fresh blood is to be used by choice, for stored bank blood is low in fibrinogen. With actual blood coagulation difficulties sufficient fibrinogen cannot be replaced through transfusions alone. Commerical fibrinogen dissolved in dextrose in water can be administered intravenously to patients whose fibrinogen levels are less than 100 mg. per 100 cc., and whose blood fails to clot well. One must be ever mindful of the fact that fibrinogen thus given carries the danger of transmitting the virus of homologous serum jaundice. Thus fibrinogen administration is to be used only as a life-saving measure. On rare occasions transfusion and fibrinogen therapy fail to restore the normal blood clotting mechanism. The intravenous use of toluid;ne blue has been suggested to neutralize fibrinolytic substances through its antiheparin-like quality. Today, maternal deaths resulting from abruptio placentae should be considered preventable. Only the rare case, seen too late in the complication, need succumb to this accident. The loss of time before delivery is precious. Delay encourages uterine atony and resulting hemorrhage. Inadequately treated shock may lead to lower nephron nephrosis. renal
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cortical necrosis and anterior pituitary necrosis. While the patient remains undelivered she is in constant and increasing danger of developing afibrinogenemia. TREATMENT As with ether complications of pregnancy and labor, the treatment of premature separation of the placenta begins in the early antepartum period. One must see that a proper diet is eaten by the patient, that all anemia is adequately treated, and that proper care is taken of pregnancy toxemia. Such prophylaxis should allow the mother to arrive at her confinement in the best of physical condition. The occurrence of abruptio placentae should be diminished, and perhaps prevented, by the careful handling of pregnancy toxemia. When the patient is in good physical condition, she is less likely to deliver in the premature period and she should withstand an accidental hemorrhage when it occurs, whether or not there is an associated toxemia present. Treatment of Mild Placental Separation
Here the patient is invariably in labor, which has usually advanced to the second stage. Mild placental abruption may be anticipated where there has been a rapid and forceful labor, in the presence of toxemia, after rapid evacuation of a large amount of amniotic fluid, and after the delivery of the first of twins. Since the only outward sign is that of excessive vaginal bleeding, undue bloody show is always suspect. Marginal placenta previa enters into the differential diagnosis here. Careful and repeated auscultation of the fetal heart should be made, and whenever signs of fetal distress are present, preparations for immediate delivery are made. Administration of oxygen to the mother with an anesthesia mask will help to prevent hypoxia in the fetus. If the membranes are intact, amniotomy should be performed. Forceps delivery is indicated as soon as full cervical dilatation is reached. Many cases are not diagnosed until a stillborn fetus is delivered and the placenta has been examined. The routine use of prophylactic low forceps has strong backing here, for an occasional baby may be salvaged where an unsuspected placental separation exists. Afibrinogenemia is never a factor in these mild cases, yet preparation for transfusion and the clot observation test are indicated if the bleeding is unusual. In the rare case with fetal distress, where delivery is not imminent, cesarean section should be considered. This might be true in the case of an elderly primigravida, in severe toxemia, or with the failure of labor to ensue after amniotomy. Treatment of Moderate Placental Separation
Cases of moderate separation of the placenta represent those in which a diagnosis can be made before delivery, and most important, before the separation becomes too serious. Such cases may be seen before labor or
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at its onset. Since many of these cases may be followed in labor for hours, blood for transfusion is readied, fibrinogen tests are made, and the operating room is alerted for a cesarean section. The patient must now be examined under sterile precautions. Placenta previa is ruled out. No matter what the dilatation of the cervix, amniotomy must be performed in hope of preventing a tetanically contracted uterus and the associated entrance of tissue extractives, from the placental site, into the maternal circulation. Where delivery cannot be anticipated within a very few hours, cesarean section should be elected. Such expeditious treatment avoids possible shock in the mother and the development of afibrinogenemia. This seemingly radical treatment alone will save a high percentage of babies, especially those estimated to weigh over 2000 grams. When the baby is thought to be dead in utero or too small for reasonable hope of survival, then vaginal delivery should be planned. Fortunately in these cases labor after amniotomy is usually rapid. All estimated blood loss is replaced as the blood is lost, thus keeping ahead of shock. Should blood coagulation difficulties arise, 2 grams of fibrinogen should be given. Blood and fibrinogen administration is repeated as needed. Delivery is completed with prophylactic forceps as soon as the cervix is fully dilated. At any point where labor lags and bleeding increases, cesarean section still may be done if the condition of the cervix precludes early delivery. Since some cases of moderate placental separation seem to advance to a severe type of separation, early emptying of the uterus is all-important. No serious shock or afibrinogenemia will develop from such a course. In the interests of the fetus, cesarean section alone will save the baby, where very early delivery cannot be anticipated. Douglas3 has pointed out that some babies are shocked from loss of their own blood, and these can be saved through umbilical cord transfusion immediately after birth. As with the mild placental abruptions, signs of fetal distress warrant immediate cesarean section whenever vaginal delivery is not immediately feasible. The secondary indications for cesarean section mentioned under the treatment of mild placental separation are all used more broadly in the moderate type of abruption. Treatlllent of Severe Placental Separation
Here we are dealing with the picture of true "abruptio placentae." It is in these cases that maternal deaths may occur. Nearly one-half of the patients have an associated toxemia of moderate or severe degree. Since this accident occurs suddenly, precious time is often lost before the patient is hospitalized. There is always the picture of true or impending shock. One must not be misled by minimal vaginal bleeding, when there may be a thousand or more cubic centimeters of blood concealed in the uterus.
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In the patients with abruptio placentae hypofibrinogenemia increases with the hours following abruption. Renal failure from lower nephron nephrosis and renal cortical necrosis are directly related to the degree and prolongation of the shock picture. The same is true of the cases that go on to develop anterior pituitary necrosis. It would seem quite obvious that the whole rationale of treatment should be focused on emptying the uterus as expeditiously and safely as possible in order to prevent the development or continuation of the above-cited complications. First, ample blood for transfusion is made available and fibrinogen determinations are done. Infusions of glucose or dextran may be started until the blood is ready. Meanwhile the operating room should be set up for a cesarean section. The patient is then examined vaginally and, no matter what the dilatation of the cervix may be, amniotomy is done. Such a step relieves intrauterine tension and will usually induce labor. Shock must be corrected with ample blood replacement and fibrinogen given as indicated. In severe cases four or more units of blood may be necessary, and occasionally 6 to 8 grams of fibrinogen are administered in 2 gram doses. Rarely does the fetus survive the massive separation of the placenta, but fetal heart sounds can be masked by the difficulty in auscultation of a tetanically contracted uterus. With severe placental separation, cesarean section is mandatory when the baby is still alive and the maternal shock picture is under control. With a dead baby in utero, vaginal delivery can be planned for those cases in which the cervix is thin, soft, and at least two fingers dilated. As has been mentioned before, these patients can be expected to have an efficient labor after stimulation by amniotomy. The use of the Pitocin infusion here, to stimulate labor, may be considered only after careful appraisal. One may produce violent contractions of the uterus, or even a tetanic contraction, and thus encourage the escape of thromboplastic substances into the maternal blood stream. One may continue expectantly in the plan for vaginal delivery where ample blood replacement and necessary fibrinogen are given and the vital signs and blood coagulation remain normal. If, however, adequate labor fails to ensue and the cervix is not approaching full dilatation after eight to ten hours, cesarean section must be done. Initially, cesarean section may be elected where the condition of the cervix is such that early delivery is unlikely. In any case, cesarean section is not done until shock is relieved and fibrinogen deficiency has been corrected. After a vaginal delivery no undue hemorrhage should ensue if the plasma fibrinogen picture is normal. On rare occasions, there may be uterine atony following prolonged overdistention of the uterus; for these cases hysterectomy may become necessary to control postpartum bleeding. In brief, the treatment of severe premature separation of the placenta is aimed at the early emptying of uterus. In only those cases that should deliver vaginally within a very few hours can one delay in doing a cesar-
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ean section. When cesarian section is done for abruptio placentae, the low-flap type of procedure seems to be indicated. Thus the remaining placental attachment may be avoided in the interests of the baby. Then, too, one may avoid cutting through the site of placental attachment and prevent unnecessary uterine bleeding. Some degree of the Couvelaire type of uterus will be encountered at cesarean section in 44.4 per cent of the cases of abruptio placentae. This uterus will contract efficiently in a few minutes with administration of oxytoxics and the application of warm packs to the fundus. Removal of the uterus for the Couvelaire picture should never be necessary. Hysterectomy has been resorted to only once at the time of cesarean section for abruptio placentae in the 100 laparotomies done in the last 23 years at the Sloane Hospital for Women. Discussion of TreatnlCnt
At the Sloane Hospital for Women the radical (cesarean section) treatment of the severe, and some moderate, cases of premature separation of placenta has been favored since 1933. Before 1950, this course of therapy was aimed solely at saving the mother. In 69,150 deliveries since 1933, there has been recorded a total of 526 placental separations of all degrees, there being 58 cases (11 per cent) of abruptio placentae. Two maternal deaths occurred in severe cases seen over 14 years ago; death resulted in one from pneumonia and in the other from shock. These patients died before the advent of antibiotics and the establishment of a blood bank. Since 1950, consideration of plasma fibrinogen has been made, and ten cases with levels under 100 mg. per 100 cc. were encountered. Seven of these cases were treated with 2 to 4 grams of fibrinogen, and in each case gross blood coagulation difficulties were noted. Many patients do have low levels of plasma fibrinogen, but when there is no lack of blood clotting and blood is amply replaced, they can be expected to restore their own fibrinogen to normal levels within approximately 24 hours after delivery. Prior to 1950 one-third of all fetal deaths encountered in premature separation of placenta were observed during labor and another onethird of the fetal losses were noted neonatally. In recent years care of the premature newborn has been so improved that many more premature babies should be salvaged. Since 1950, the cesarean section rate in premature separation of the placenta has risen from a previous figure of 12.9 per cent to 30 per cent. Admittedly the election of operative delivery has been made on much more lenient indications aimed at saving the baby. The previous fetal mortality rate in premature separation of the placenta of 35.6 per cent has dropped to 23.6 per cent. Now only one-tenth of the fetal deaths are intrapartum and one-quarter of the fetal losses are neonatal. With the improved care of the many premature babies encountered, our more lenient indications for cesarean section seem to be justified.
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SUMMARY
1. Premature separation of the normally implanted placenta remains a serious complication of the latter one-third of pregnancy, endangering the life of both mother and baby. 2. Maternal deaths are preventable when the patient is properly treated early in this accident. 3. Abruptio placentae and severe pregnancy toxemia are closely associated. 4. The degree of shock and afibrinogenemia noted in the mother are directly related to the length of time the patient remains undelivered after the accident occurs. 5. Administration of fibrinogen to the mother with afibrinogenemia should be reserved for those patients showing blood clotting difficulties and then used as a last resort. 6. Improvement in fetal salvage in this complication in recent years is largely due to the improved care of the premature newborn. 7. Only radical treatment (cesarean section) will reduce the too frequent intrapartum and neonatal fetal deaths. REFERENCES 1. Rigby, E.: An Essay on Internal Hemorrhages. 1st Ed. London, Burke and Kennebrook, 1776. 2. Bysshe, S. M.: Premature Separation of the Normally Implanted Placenta. Am. J. Obst. & Gynec. 62:38-51 (July), 1951. 3. Douglas, R. G., Buchman, M. I. and Macdonald, F. A.: Premature Separation of the Normally Implanted Placenta. J. Obst. & Gynec., Brit. Emp. 62:710, (Oct.), 1955. 4. Glendenning, M. B., Olson, L. and Page, E. W.: Rapid Determination of Plasma Fibrinogen. Am. J. Obst. & Gynec. 70:655-56 (Sept.), 1955. 180 Fort Washington Avenue New York 32, N. Y.
separation of the normally implanted placenta represents a serious complication of pregnancy endangering the life of both mother and baby. Rigby,! in 1776, first defined this development as an accidental hemorrhage, in contradistinction to the unavoidable hemorrhage noted in cases of placenta previa. "Abruptio placentae," "ablatio placentae" and "accidental hemorrhage" have all been used in the past as terms for premature separation of the normally implanted placenta. Today "abruptio placentae" is usually reserved for the most severe type of placental separation, while "premature separation of the normally implanted placenta" is accepted as the all-inclusive term for all types of this pregnancy mishap. When properly handled this complication should not carry the risk to maternal life cited in the past. There is still much room for improvement in treatment, aimed at reduction of fetal loss, in premature separation of the placenta of the normally implanted placenta. PREMATURE
ETIOLOGICAL CONSIDERATIONS
The etiological factor for all premature separations of the normally implanted placenta is not completely understood. While the cases of true abruptio placentae are associated with pregnancy toxemia about 40 per cent of the time, the placental abruptions of lesser severity are more commonly seen resulting from mechanical factors and other unexplained causes. In any case, degeneration and necrosis of the trophoblasticdecidual junction seems to represent the underlying pathologic process, while the other mechanical factors are merely contributing causes. At the Sloane Hospital for Women2 an associated pregnancy toxemia has been noted in 24.4 per cent of all of the cases of premature separation of the placenta. In the same period analyzed, toxemia was seen in only 12.4 per cent of all deliveries. It has been concluded that not only is pregnancy toxemia an important precursor in premature separation of
* Associate Professor of Clinical Obstetrics and Gynecology, CoUege of Physicians and Surgeons, Columbia University; Associate Attending Obstetrician and Gynecologist, Sloane Hospital for Women, Columbia-Presbyterian Medical Center, New York, N. Y. 393
Stanley M. Bysshe the placenta, but the degree of placental separation increases with the severity of the pregnancy toxemia as well. The incidence of premature separation of the placenta in nontoxemia patients was 1 in 135, while this complication rose to 1 in 51 in all toxemia patients. Toxemia of pregnancy is found in a ratio of 1 in 2.6 of the cases of severe placental abruption. One can hypothesize that separation of placenta may represent one facet of the toxemia picture, manifesting itself as a vascular accident at the site of placental attachment. Many times, in the emergency handling of a case of abruptio placentae, the blood pressure is low as a result of shock, and the diagnosis of pregnancy toxemia is not apparent until many hours after the shock picture has been relieved. External trauma was seen as a predisposing cause of placental separation in only 3 per cent of these cases. Umbilical cord complications, with a true or relative shortening of the cord, were found in 8.2 per cent of cases. Hydramnios, multiple pregnancy, previous incision in the uterine musculature, and fibromyomata uteri were each noted in no more than about 2 per cent of cases. Fetal presentation was in no way altered in premature separation of the placenta. The simple forces of labor undoubtedly give rise to premature separation of the placenta in the largest number of cases. Separation may occur late in first stage, but more often in the second stage of labor. The separation may be quite mild, yet it always represents a serious accident for the fetus. Nearly all mild placental abruptions are to be seen in this group, and only the most careful surveillance of labor will detect this mishap before the baby may be lost. ASSOCIATED CLINICAL FINDINGS
Premature separation of the normally implanted placenta may be described as a pregnancy complication occurring after 28 weeks of pregnancy, and thus the babies delivered all fall into the viable premature (1000 gm.) or term period. The age, parity and color of the mother are of no significance here. One finds, however, more toxemia patients among older patients. Vaginal bleeding may be noted in 17.1 per cent of these patients at any time in pregnancy before the final episode or onset of labor, yet this is only comparable to the incidence of antepartum bleeding in all antepartum patients who fail to abort and go on successfully to term. Nevertheless, approximately one-third of placental separations do manifest themselves in bleeding in the last trimester of pregnancy, and 50 per cent have vaginal bleeding just prior to the onset of labor. Bleeding late in pregnancy is also common in placenta previa, but this condition is found only one-half as often as premature separation of the placenta. Repetition of a placental separation has been found to occur in a subsequent pregnancy in 4.4 per cent of placental abruptions. It is of utmost importance to realize that premature separation of the normally implanted placenta is an accident of pregnancy occurring as
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often in the premature period of pregnancy, before 37 weeks of gestation, as in the term gestations. The prognosis for the fetus will vary, therefore, according to the date of delivery. With up-to-date premature nursery care, the baby of 2000 grams has a 95 per cent chance of survival, while 80 per cent of the 1500 gram babies should be salvaged. Even the still smaller babies make a healthy survival in a reasonable number of cases. The gross mortality in all cases of premature separation may be as high as 35.6 per cent. It is important to realize that the fetal deaths fall equally into losses before labor, intrapartum deaths, and neonatal deaths. The infant mortality arises from prematurity in two-thirds of the cases, while fetal anoxia and fetal shock from fetal blood loss are contributing factors in all cases. CLINICAL PICTURE
In their discussions of premature separation of the placenta, most essayists attempt to classify it according to the clinical picture of the severity of the accident. Such an approach is plausible, since one can then formulate definite steps in the course of therapy. Any classification, of necessity, pictures an overlapping of the etiological factors present. The simplest grading is that of mild, moderate and severe placental separation. In the years 1933-1955, at the Sloane Hospital for Women, the incidence of premature separation of the normally implanted placenta was 1 in 131 of the 69,150 deliveries reviewed. Mild Placental Separation
Here the condition is seldom recognized before delivery and the diagnosis is based on the eventual examination of the placenta. There may be minimal vaginal bleeding, and uterine pain is seldom noted by the patient. There is, therefore, no sign of uterine tetany and no maternal shock. Signs of fetal distress should be apparent during labor in at least a few of these cases. The placenta will exhibit adherent blood clot involving no more than one-sixth of its surface. Total bleeding is less than 400 cc., and is not of the concealed type. Mild placental separations are found in two-thirds of all separations, and are noted once in 204 deliveries. The patient is almost invariably in labor, and she is no more likely to be toxemic than any other pregnant patient. Fetal mortality for mild separations is 19.1 per cent. The bleeding in many of these cases represents an exodus of blood from the rupture of the marginal veins of the placenta-the so-called marginal sinus. Douglas3 and his co-workers prefer to call this a "marginal separation" of the placenta. He has described the condition as occurring in 23.2 per cent of placental abruptions, and emphasizes the fact that the fetal mortality here is six or seven times that of the general clinic loss. Premature separation of the normally implanted placenta and cases of bleeding from the marginal sinus are clinically indistinguishable as separate entities in labor.
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Moderate Placental Separation
The moderate type of premature separation of the placenta may be seen either as a more marked degree of mild separation or possibly the initial picture of the true abruptio placentae. This type can be expected to progress to serious complications before delivery in some of the cases. There is usually !!lome tetany of the uterine wall along with pain and tenderness in the uterus. Vaginal bleeding is noted in variable amounts, but can be concealed. There is usually no maternal shock here. In this type, fetal distress is more frequently noted, and fetal death occurs during labor more often than in the mild cases. Adherent blood clot may be noted involving more than one-sixth but less than two-thirds of the placental surface. Bleeding is more than 400 cc., but is not hemorrhagic. Moderate placental separation is found once in 532 deliveries. In cases of this degree of separation, pregnancy toxemia is also present one-third of the time. This moderate degree of premature separation of the placenta should be diagnosed routinely before delivery. The patient mayor may not be in labor at the time of the accident. Fetal mortality in placental separations of moderate degree is 45.1 per cent. Severe Placental Separation
In the past, the severe type of premature separation of the placenta, or true "abruptio placentae," was the only degree of separation recognized clinically. Here the patient has a. sudden accident characterized by acute and severe pain in the uterus along with variable amounts of vaginal bleeding. In nearly 50 per cent of the cases there is an associated pregnancy toxemia of a moderate or severe type. This accident appears without warning signs or symptoms. The patient is usually close to term and is seldom in labor. The bleeding exhibited vaginally may be alarming, while in those cases with little or no manifest bleeding the hemorrhage may be excessive, yet entirely concealed. Such cases exhibit shock out of proportion to the manifest bleeding and are proverbially the most serious from the point of view of maternal survival. The uterus in severe placental separations becomes hard and tetanically contracted. Mter an hour or two the uterus may be noted to have increased in size as a result of the increasing intrauterine hemorrhage. The initial bleeding is in the form of a centrally located hemorrhage behind the placenta, often referred to as "uteroplacental apoplexy." The blood can dissect the membranes free from their attachment throughout the uterus, and the placenta can "prolapse" into the region of the cervix. In some instances the hemorrhage ruptures into the sac. Membranes or presenting part may seal off the vaginal escape of blood. With prolonged intrauterine tension, blood becomes extravasated into the myometrium and to the serosal surface of the uterus, and in the severest type blood may gain access into the peritoneal cavity from actual rents in the serosa of the
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uterus. The tubes, ovaries and broad ligaments may be congested with blood. In this picture the uterus exhibits blotchy ecchymoses on its surface and becomes copper colored or darkest purple, as originally described by Couvelaire. Such a picture of the Couvelaire uterus occurs in 44.4 per cent of severe placental abruptions. Abruptio placentae occurs once in 1192 deliveries and the fetal mortality is as high as 67.4 per cent. Since this accident comes on so abruptly and since the placenta is completely or almost completely separated, the baby stands little chance of survival. The patient is rarely in labor, at least of an advanced degree, and delivery cannot be expedited sufficiently before the fetus succumbs in utero. In severe placental abruptiolls there are definite associated complications for the mother. The picture of shock deepens and must be relieved before it becomes irreversible. Shock cannot be safely evaluated and adequately treated until the uterus is emptied. The generalized vasospasm seen in hypertension, shock, and overdistention of the uterus is a likely cause here of lower nephron sclerosis and renal cortical necrosis. Renal failure may be fatal and not infrequently the surviving patients have a relative kidney shutdown for at least two or more days. It has been thought, previously, that the hemorrhage seen after delivery in severe premature separation of the placenta was due to the presence of a Couvelaire uterus. This is not true, for the Couvelaire uterus will contract physiologically after it is emptied. The degree of hemorrhagic discoloration of the uterus seen at laparotomy has no bearing on the ability of the myometrium to contract effectively. If, however, the case of abruptio placentae is allowed to go along for hours without relief for the tetantically contracted and overdistended uterus, then uterine atony may be seen postpartum and undue hemorrhage can result therefrom. Afibrinogenemia
Maternal deaths in severe cases of placental abruption have, in years past, been attributed to hemorrhage and shock resulting from the poorly contracting Couvelaire uterus. Such a deduction for the cause of excessive bleeding is now considered to be faulty. In 1901, DeLee noted hemorrhage and a faulty blood clotting mechanism to be present in some cases of abruptio placentae. This he described as a temporary hemophilia. In the last two decades, many workers have described the association of an acquired afibrinogenemia in severe placental separations. The etiology of the syndrome remains controversial. In general, it may be said that tissue thromboplastin from damaged placenta or decidua can readily enter the open maternal venous sinuses in cases of placental separation. Such a picture initiates the sensitive blood coagulation mechanism and causes extensive intravascular clotting. Microscopic thrombin emboli are formed and a resultant defibrination of the blood
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occurs. The bulk of the thromboplastin has been shown to end up in the liver and lungs. Occasionally this process may stimulatf' the protective fibrinolysin system to keep the circulation free of clots. Thus the picture of hypofibrinogenemia may result mainly from depletion of fibrinogen in clots and occasionally through destruction of fibrinogen by a fibrinolysin. The diagnosis of afibrinogenemia may be carried out through laboratory studies of the circulating fibrinogen noted in a sample of blood. Such studies are time-consuming, and in many emergencies this loss of time may be dangerous for the patient. Page 4 and his associates have outlined a rapid method for the determination of plasma fibrinogen. For practical purposes, however, the simple clot observation test is an adequate guide to therapy. Failure of a freshly drawn sample of venous blood to clot in a test tube incubated at 37° C. in half an hour, or poor retraction of a normally formed clot and evidence of gross hemolysis in the serum is felt to be sufficient evidence that the circulating plasma fibrinogen is reduced to a serious level. The normal fibrinogen level at delivery is at least 325 mg. per 100 cc. When fibrinogen falls to 100 mg. per 100 cc., or less, a critical level is reached, usually requiring replacement of fibrinogen for the safety of the mother. Critically low levels of fibrinogen are noted in some cases where the blood is apparently clotting adequately. In cases of abruptio placentae, the afibrinogenemia continues to increase in direct relation to the length of time the fetus and placenta remain undelivered. Where low levels of fibrinogen have existed, normal levels are physiologically restored within a matter of 12 to 24 hours after delivery, when the source of thromboplastin is removed. In the relief of afibrinogenemia the replacement of all blood lost by the patient must be carried out expeditiously. Whole fresh blood is to be used by choice, for stored bank blood is low in fibrinogen. With actual blood coagulation difficulties sufficient fibrinogen cannot be replaced through transfusions alone. Commerical fibrinogen dissolved in dextrose in water can be administered intravenously to patients whose fibrinogen levels are less than 100 mg. per 100 cc., and whose blood fails to clot well. One must be ever mindful of the fact that fibrinogen thus given carries the danger of transmitting the virus of homologous serum jaundice. Thus fibrinogen administration is to be used only as a life-saving measure. On rare occasions transfusion and fibrinogen therapy fail to restore the normal blood clotting mechanism. The intravenous use of toluid;ne blue has been suggested to neutralize fibrinolytic substances through its antiheparin-like quality. Today, maternal deaths resulting from abruptio placentae should be considered preventable. Only the rare case, seen too late in the complication, need succumb to this accident. The loss of time before delivery is precious. Delay encourages uterine atony and resulting hemorrhage. Inadequately treated shock may lead to lower nephron nephrosis. renal
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cortical necrosis and anterior pituitary necrosis. While the patient remains undelivered she is in constant and increasing danger of developing afibrinogenemia. TREATMENT As with ether complications of pregnancy and labor, the treatment of premature separation of the placenta begins in the early antepartum period. One must see that a proper diet is eaten by the patient, that all anemia is adequately treated, and that proper care is taken of pregnancy toxemia. Such prophylaxis should allow the mother to arrive at her confinement in the best of physical condition. The occurrence of abruptio placentae should be diminished, and perhaps prevented, by the careful handling of pregnancy toxemia. When the patient is in good physical condition, she is less likely to deliver in the premature period and she should withstand an accidental hemorrhage when it occurs, whether or not there is an associated toxemia present. Treatment of Mild Placental Separation
Here the patient is invariably in labor, which has usually advanced to the second stage. Mild placental abruption may be anticipated where there has been a rapid and forceful labor, in the presence of toxemia, after rapid evacuation of a large amount of amniotic fluid, and after the delivery of the first of twins. Since the only outward sign is that of excessive vaginal bleeding, undue bloody show is always suspect. Marginal placenta previa enters into the differential diagnosis here. Careful and repeated auscultation of the fetal heart should be made, and whenever signs of fetal distress are present, preparations for immediate delivery are made. Administration of oxygen to the mother with an anesthesia mask will help to prevent hypoxia in the fetus. If the membranes are intact, amniotomy should be performed. Forceps delivery is indicated as soon as full cervical dilatation is reached. Many cases are not diagnosed until a stillborn fetus is delivered and the placenta has been examined. The routine use of prophylactic low forceps has strong backing here, for an occasional baby may be salvaged where an unsuspected placental separation exists. Afibrinogenemia is never a factor in these mild cases, yet preparation for transfusion and the clot observation test are indicated if the bleeding is unusual. In the rare case with fetal distress, where delivery is not imminent, cesarean section should be considered. This might be true in the case of an elderly primigravida, in severe toxemia, or with the failure of labor to ensue after amniotomy. Treatment of Moderate Placental Separation
Cases of moderate separation of the placenta represent those in which a diagnosis can be made before delivery, and most important, before the separation becomes too serious. Such cases may be seen before labor or
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at its onset. Since many of these cases may be followed in labor for hours, blood for transfusion is readied, fibrinogen tests are made, and the operating room is alerted for a cesarean section. The patient must now be examined under sterile precautions. Placenta previa is ruled out. No matter what the dilatation of the cervix, amniotomy must be performed in hope of preventing a tetanically contracted uterus and the associated entrance of tissue extractives, from the placental site, into the maternal circulation. Where delivery cannot be anticipated within a very few hours, cesarean section should be elected. Such expeditious treatment avoids possible shock in the mother and the development of afibrinogenemia. This seemingly radical treatment alone will save a high percentage of babies, especially those estimated to weigh over 2000 grams. When the baby is thought to be dead in utero or too small for reasonable hope of survival, then vaginal delivery should be planned. Fortunately in these cases labor after amniotomy is usually rapid. All estimated blood loss is replaced as the blood is lost, thus keeping ahead of shock. Should blood coagulation difficulties arise, 2 grams of fibrinogen should be given. Blood and fibrinogen administration is repeated as needed. Delivery is completed with prophylactic forceps as soon as the cervix is fully dilated. At any point where labor lags and bleeding increases, cesarean section still may be done if the condition of the cervix precludes early delivery. Since some cases of moderate placental separation seem to advance to a severe type of separation, early emptying of the uterus is all-important. No serious shock or afibrinogenemia will develop from such a course. In the interests of the fetus, cesarean section alone will save the baby, where very early delivery cannot be anticipated. Douglas3 has pointed out that some babies are shocked from loss of their own blood, and these can be saved through umbilical cord transfusion immediately after birth. As with the mild placental abruptions, signs of fetal distress warrant immediate cesarean section whenever vaginal delivery is not immediately feasible. The secondary indications for cesarean section mentioned under the treatment of mild placental separation are all used more broadly in the moderate type of abruption. Treatlllent of Severe Placental Separation
Here we are dealing with the picture of true "abruptio placentae." It is in these cases that maternal deaths may occur. Nearly one-half of the patients have an associated toxemia of moderate or severe degree. Since this accident occurs suddenly, precious time is often lost before the patient is hospitalized. There is always the picture of true or impending shock. One must not be misled by minimal vaginal bleeding, when there may be a thousand or more cubic centimeters of blood concealed in the uterus.
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In the patients with abruptio placentae hypofibrinogenemia increases with the hours following abruption. Renal failure from lower nephron nephrosis and renal cortical necrosis are directly related to the degree and prolongation of the shock picture. The same is true of the cases that go on to develop anterior pituitary necrosis. It would seem quite obvious that the whole rationale of treatment should be focused on emptying the uterus as expeditiously and safely as possible in order to prevent the development or continuation of the above-cited complications. First, ample blood for transfusion is made available and fibrinogen determinations are done. Infusions of glucose or dextran may be started until the blood is ready. Meanwhile the operating room should be set up for a cesarean section. The patient is then examined vaginally and, no matter what the dilatation of the cervix may be, amniotomy is done. Such a step relieves intrauterine tension and will usually induce labor. Shock must be corrected with ample blood replacement and fibrinogen given as indicated. In severe cases four or more units of blood may be necessary, and occasionally 6 to 8 grams of fibrinogen are administered in 2 gram doses. Rarely does the fetus survive the massive separation of the placenta, but fetal heart sounds can be masked by the difficulty in auscultation of a tetanically contracted uterus. With severe placental separation, cesarean section is mandatory when the baby is still alive and the maternal shock picture is under control. With a dead baby in utero, vaginal delivery can be planned for those cases in which the cervix is thin, soft, and at least two fingers dilated. As has been mentioned before, these patients can be expected to have an efficient labor after stimulation by amniotomy. The use of the Pitocin infusion here, to stimulate labor, may be considered only after careful appraisal. One may produce violent contractions of the uterus, or even a tetanic contraction, and thus encourage the escape of thromboplastic substances into the maternal blood stream. One may continue expectantly in the plan for vaginal delivery where ample blood replacement and necessary fibrinogen are given and the vital signs and blood coagulation remain normal. If, however, adequate labor fails to ensue and the cervix is not approaching full dilatation after eight to ten hours, cesarean section must be done. Initially, cesarean section may be elected where the condition of the cervix is such that early delivery is unlikely. In any case, cesarean section is not done until shock is relieved and fibrinogen deficiency has been corrected. After a vaginal delivery no undue hemorrhage should ensue if the plasma fibrinogen picture is normal. On rare occasions, there may be uterine atony following prolonged overdistention of the uterus; for these cases hysterectomy may become necessary to control postpartum bleeding. In brief, the treatment of severe premature separation of the placenta is aimed at the early emptying of uterus. In only those cases that should deliver vaginally within a very few hours can one delay in doing a cesar-
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ean section. When cesarian section is done for abruptio placentae, the low-flap type of procedure seems to be indicated. Thus the remaining placental attachment may be avoided in the interests of the baby. Then, too, one may avoid cutting through the site of placental attachment and prevent unnecessary uterine bleeding. Some degree of the Couvelaire type of uterus will be encountered at cesarean section in 44.4 per cent of the cases of abruptio placentae. This uterus will contract efficiently in a few minutes with administration of oxytoxics and the application of warm packs to the fundus. Removal of the uterus for the Couvelaire picture should never be necessary. Hysterectomy has been resorted to only once at the time of cesarean section for abruptio placentae in the 100 laparotomies done in the last 23 years at the Sloane Hospital for Women. Discussion of TreatnlCnt
At the Sloane Hospital for Women the radical (cesarean section) treatment of the severe, and some moderate, cases of premature separation of placenta has been favored since 1933. Before 1950, this course of therapy was aimed solely at saving the mother. In 69,150 deliveries since 1933, there has been recorded a total of 526 placental separations of all degrees, there being 58 cases (11 per cent) of abruptio placentae. Two maternal deaths occurred in severe cases seen over 14 years ago; death resulted in one from pneumonia and in the other from shock. These patients died before the advent of antibiotics and the establishment of a blood bank. Since 1950, consideration of plasma fibrinogen has been made, and ten cases with levels under 100 mg. per 100 cc. were encountered. Seven of these cases were treated with 2 to 4 grams of fibrinogen, and in each case gross blood coagulation difficulties were noted. Many patients do have low levels of plasma fibrinogen, but when there is no lack of blood clotting and blood is amply replaced, they can be expected to restore their own fibrinogen to normal levels within approximately 24 hours after delivery. Prior to 1950 one-third of all fetal deaths encountered in premature separation of placenta were observed during labor and another onethird of the fetal losses were noted neonatally. In recent years care of the premature newborn has been so improved that many more premature babies should be salvaged. Since 1950, the cesarean section rate in premature separation of the placenta has risen from a previous figure of 12.9 per cent to 30 per cent. Admittedly the election of operative delivery has been made on much more lenient indications aimed at saving the baby. The previous fetal mortality rate in premature separation of the placenta of 35.6 per cent has dropped to 23.6 per cent. Now only one-tenth of the fetal deaths are intrapartum and one-quarter of the fetal losses are neonatal. With the improved care of the many premature babies encountered, our more lenient indications for cesarean section seem to be justified.
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SUMMARY
1. Premature separation of the normally implanted placenta remains a serious complication of the latter one-third of pregnancy, endangering the life of both mother and baby. 2. Maternal deaths are preventable when the patient is properly treated early in this accident. 3. Abruptio placentae and severe pregnancy toxemia are closely associated. 4. The degree of shock and afibrinogenemia noted in the mother are directly related to the length of time the patient remains undelivered after the accident occurs. 5. Administration of fibrinogen to the mother with afibrinogenemia should be reserved for those patients showing blood clotting difficulties and then used as a last resort. 6. Improvement in fetal salvage in this complication in recent years is largely due to the improved care of the premature newborn. 7. Only radical treatment (cesarean section) will reduce the too frequent intrapartum and neonatal fetal deaths. REFERENCES 1. Rigby, E.: An Essay on Internal Hemorrhages. 1st Ed. London, Burke and Kennebrook, 1776. 2. Bysshe, S. M.: Premature Separation of the Normally Implanted Placenta. Am. J. Obst. & Gynec. 62:38-51 (July), 1951. 3. Douglas, R. G., Buchman, M. I. and Macdonald, F. A.: Premature Separation of the Normally Implanted Placenta. J. Obst. & Gynec., Brit. Emp. 62:710, (Oct.), 1955. 4. Glendenning, M. B., Olson, L. and Page, E. W.: Rapid Determination of Plasma Fibrinogen. Am. J. Obst. & Gynec. 70:655-56 (Sept.), 1955. 180 Fort Washington Avenue New York 32, N. Y.