Treatment Options for the Fetus With Alloimmune Hemolytic Disease

Treatment Options for the Fetus With AlIoimmune Hemolytic Disease J.M. Bowman

R LOUIS DIAMOND, in 1932, coined the name erythroblastosis fetalis for hemolytie disease of the fetus and newbom.! He recognized that hydrops fetalis and kernieterus were different spectra of the same disorder, whieh was characterized by fetal red cell hemolysis, extramedullary erythropoiesis, and the outpouring of nucleated erythrocytes (erythroblasts) , into the fetal circulation (Fig 1). He had no idea what was causing the hemolysis. Such knowledge had to await the discovery of the Rh blood group system by Landsteiner and Wiener in 1940. 2 Levine et al, in 1941, determined that the etiology of hemolytic disease was the development of an Rh(D) antibody in an Rh(D) negative woman following exposure to Rh(D) positive red cells. The Rh antibody, predominantly immunoglobulin G (IgG) , traverses the placenta, coats the fetal Rh(D) positive red cells, and causes their destruction. 3 Wiener's 1948 postulate, that Rh alloimmunization was caused by the transplacental passage of Rh positive fetal red cells into the Rh negative mother's circulation, composed of small amounts during pregnancy and larger amounts at the time of delivery,4 was proven by Chown in 1954. 5 The development of the Kleihauer acid elution fetal red cell test, 6 which can detect one fetal red cell in 200,000 adult red cells, allowed the determination of the prevalence of fetomatemal transplacental hemorrhages (Table 1), 3% in the first trimester, 12% in the second trimester, 45% in the third trimester, and 64% immediately after birth; in 24% of pregnant women, no fetal red cells were found at any time. 7 As one might expect, there is a wide spectrum of severity of hemolytic disease (Table 2). About 50% of affected fetuses are so mildly affected that they survive intact after birth without treatment, as they did in the early 1940s before any treatment was available. Of the remainder, about one half (25% of the total) will be bom alive at or near term in good condition. However, unless they are treated promptly after birth, they will develop kernieterus. Ninety percent will die; the surviving 10% will be left with severe neurologie damage, neurosensory deafness, spastic choreoathetosis, and some degree of mental retardation. The re-

D

Transfusion Medicine Reviews, Vol IV, No 3 (July), 1990: pp 191·207

maining 25% will become hydropic and die in utero: about one half between 18 weeks' and 34 weeks' gestation, the other half after 34 weeks' gestation. Although hydrops was once considered to be due to anemie hypervolemic fetal heart failure, in most instances, heart failure is a secondary factor, developing after delivery and treatment. 8 The primary cause is hepatic: extreme hepatosplenomegaly, portal hypertension with the development of ascites, and hepatocellular damage producing hypoalbuminemia and generalized anasarca. MATERNAL RED CELL ALLOANTIBODIES CAUSING FETAL HEMOLYTIC DISEASE

Since 1968, the ability to prevent Rh immunization through the administration of Rh immune globulin (RhIG)9 has produced a striking reduction in the prevalence of Rh alloimmunization (88% reduction in Manitoba by 1988). Although Rh hemolytic disease will never be completely eradicated, as a result of this decrease in prevalence, the experience of perinatal management teams (immunohematologists, obstetricians, and neonatologists) with Rh(D) hemolytic disease has diminished considerably. The relative prevalence of non-Rh(D) alloimmunization is becoming greater. Because some non-Rh(D) alloantibodies have the same hemolytic disease potential as Rh(D) antibodies and others do not, the perinatal management team must be able to determine the significance of differing alloantibodies. In Manitoba, (population l million), the mean annual prevalence of Rh(D) alloimmunization in pregnant women (Table 3) dropped from 194 in the 5-year period ending October 31, 1967 to 28 in the 6-year period ending October 31, 1988. In the From the Department oJ Pediatrics and Child Health. De· partment oJ Obstetrics. Gynecology, and Reproductive Sciences, Faculty oJMedicine, University oJManitoba; and the Rh Laboratory, Women's Hospital, Health Sciences Centre, Winnipeg, Manitoba. Canada. Address reprint requests to J.M. Bowman. MD, Women's Hospital, Health Sciences Centre, 735 Notre Dame Ave, Winnipeg, Manitoba, R3E OLB, Canada. © 1990 W.B. Saunders Company. 0887·796319010403·0003$03.()()IO 191

192

J.M. BOWMAN

Fig 1. Cord blood of a baby with severe Rh erythroblastosis fetalis who required multiple fetal transfusions and exchange transfusions. Smear treated by Kleihauer technique and Wright's stain. Note adult donor ghost red cells, dark fetaI red cells, and early fetaI erythroid series from erythroblasts to normoblasts. Reprinted with permission.'A

same two periods, the mean annual prevalence of detected non-anti-D alloimmunization in pregnant women (excluding ABO alloimmunization) increased from 14 to 88. This increase is partially due to the increased screening of pregnant Rh positive women, but is also due to a real increase in the prevalence of non-anti-D alloimmunization because of the increased frequency of blood transfusions (transfused blood being only ABO and Rh(D) compatible). The true increase in prevalence of non-anti-D

Table 1. Prevalence of Fetal Transplacental Hemorrhage (TPHI in 33 Women Delivering ABO-eompatible Babies No. With

No. Without

Gestation

TPH (%)

TPH (%)

First trimester Second trimester Third trimester Post delivery At any time during pregnancy and delivery

1( 3) 4 (12) 15 (45) 21 (64)

32 (97) 29 (88) 18 (55) 12 (36)

25 (76)

8 (24)

alloimmunization is ref1ected in the changing ratio of anti-D versus non-anti-D alloimmunization in pregnant patients who live outside Manitoba and were referred to the Rh Laboratory for fetal treatment (Table 4). Although those with anti-D stiU pre-

Table 2. Classificetion of Severity Degree ot Severity Mild

ot Rh

Hemolylic Disease Incidence

Description

%

Indirect bilirubin does not exceed 280-340 ....mol/L. Minimai anemia. No treatment needed.

45-50

Moderate

Fetal hydrops does not develop. Moderate anemia. Severe jaundice with risk of kernicterus unless treated after birth.

25-30

Severe

Feta I hydrops develops in utero. Before 34 weeks' gestation. After 34 weeks' gestation.

20-25 10-12 10-12

FETAL TREATMENT OPTIONS IN HEMOLYTIC DISEASE

193

Table 3. Pałtern ot Maternal Alloimmunization Manitoba 11/1/62-10/31/88: Mean Annuallncidence ot D and Non·D Antibodies

Period

Mean Anti-D Incidence

Affected

1111/62-10/31/67 11/1167·10/31n2 11/1/72·10/31m 11/107-10/31/82 1111182-10/31188

194 141 69 33 28

149 89 37 15.4 12.5

dominate, the number of patients referred with non-anti-D alIoimmunization had increased from zero in the 5-year period ending December 31, 1968 to 13 in the 5-year period ending December 31, 1980. The non-anti-D alIoantibodies observed in Manitoba pregnant women in the 26-year period ending October 31, 1988 are set out in Tables 5 and 6. Although anti-E and anti-KelI were by far the most cornmon (350 and 337, respectively), only 13 of the 108 affected babies (cord red celIs direct antiglobulin positive) due to anti-E and only two ofthe eight affected babies due to anti-KelI required exchange transfusion and/or phototherapy. None of them were severely affected. Anti-c was the only non-anti-D alIoantibody in Manitoba pregnant patients with the same severity of hemolytic disease potential as anti-D. Anti-c, when present, was more likely to cause hemolytic disease (65% v 31 % and 2.4% for anti-E and anti-KelI), in those affected, and was more likely to cause disease requiring exchange transfusion and/or phototherapy (29% v 12% and 25% for anti-E and KelI). It was also the only non-anti-D alIoantibody in Manitoba women that caused hemolytic disease so severe that it ended in hydropic stillbirth, fetuses requiring intrauterine transfusions, or babies bom with cord hemoglobin levels less than 60 g/L.

labie 4. Non·Manitoba Patients Referred to the Winnipeg Rh Laboratory With Severe Fetal Hemolytic Disease 1/1/64· 12131/88: Antibody Specificity

5-Year Period

No. ot Anti-D Patients

No. ot Nonanti-D Patients (%1

1964-1968 1969-1973 1974-1978 1979-1983 1984-1988

57 59 24 23 60

O 2( 3.3) 1( 4.0) 6(20.7) 13(17.8)

Non-anti-D Speciticity

lK,lE lK lK,4e,lFy· 6K, 3e, 1k, 1eE, lJk·, lCCw

Deaths (%1

Mean Non-anti-D Incidence

Affeeted

Deaths (%)

20(13.4) 6(6.7) 1.2(3.2) 0.6(3.9) 0.7(5.4)

14 44 57 87 88

10 8 10 15 17

0.4(4.0) 0.2(2.5) 0.2(2.0)

Anti-C, -Ce, _Cw, _Kpa, ok, _Fya, and -S (Table 5) on rare occasions caused hemolytic disease severe enough to require treatment after birth, but in no instance was disease so severe that hydrops developed or fetal transfusions were required. Other blood group antibodies in pregnant Manitoba patients (Table 6) produced either no clinical disease (Table 6, column 1), or mild clinical disease, which did not require treatment (Table 6, column 2). The experience of the Rh Laboratory over the past 25 years with pregnant non-anti-D alloirnmunized women referred from outside Manitoba (22 in number), a highly selected group with very severely affected fetuses, drawn from a much greater population base, is somewhat different (Table 7). In these referred women, there were examples of the folIowing antibodies: anti-KelI (nine), anti-c (seven), anti-k, anti-Jka, anti-Fya, anti-CC w, and anti-E (one each), which produced hemolytic disease so severe that intrauterine treatment was required. Pregnant women with the non-anti-D alloantibodies listed in Tables 5 and 7 should be managed in the same way as pregnant women with anti-D. If their antibody titres are 2::16 in albumin or 2::32 to 64 by indirect antiglobulin, investigative and treatment measures (if indicated) should be carried out. Those with alIoantibodies listed in Table 6, column l, may be disregarded since these antibodies never produce hemolytic disease. Those with alIoantibodies listed in Table 6, column 2, rarely, if ever, have significantly affected fetuses. Nevertheless, if titres are high (2::64 by indirect antiglobulin), investigative measures should be carried out. This role also applies if a pregnant woman has a high titre alIoantibody of unknown disease potential (unlisted in the above tables). There are isolated case reports of alIoantibodies, usualIy benign, causing severe hemolytic disease (antiKpblO, anti-M l1 , etc).

194

J.M. BOWMAN

Table 5. Severity of Hemolytic Disease: Manitoba-26 Years (11/1/62·10/31/881 Except for Anti-D (11/1175-10/31/881

% No

Alloantibody 5pecificity

No.of Patien!s

Affected

D(13yrs) E c,cE C,Ce,Cw Kell Kp" k Fy" S

420 350 183 108 337 6 1 23 14

201 (48) 108(31) 119 (65) 34 (321 8(2.4) 2 (33) 1(1001 5 (22) 8 (571

Treatment Required

("lo)

49 88 62 79 88 50 80 75

% Phototherapy and/or Exchange Transfusjon Required

32 12 29 21 12 50 100 20 25

"Io5B, Hydropic, or Hgb <60 g/L 19 9*

Abbreviation: SB, stillborn. *Anti-c, other than D, was the only cause of hydrops fetalis in Manitoba patients.

DETERMINATION OF SEVERITY OF FETAL HEMOLYTIC DISEASE

The central problem with carrying out investigative and treatment measures in alloimmunized pregnant women is the risk to the fetus. It is therefore essential that severity of fetal disease be determined as accurately as possible and that investigative measures be restricted to pregnancies in which the fetus is at risk and that treatment measures be confined to fetuses who require them in order to survive. Parameters Predicting Severity oj Fetal Hemolytic Disease Past pregnancy history. Up to 1961, the only parameters available to assess severity of hemolytic disease were the degree of severity of hemolytic disease in previous pregnancies and maternal antiTabla 6. Antibodias Associated with No Traatment Required or No Clinical Disaase-Manitoba Not Affeeted Lu" LUb

p Le"(leb ) Wr" Multiple/rare Nonspecific or high incidence Affected but no treatment required Fyb Jk" Jkb

s M LW Auto

15

1 25 88 18

11 11 10f 3 40f 7 lof 2 lof 2 2 of 82 10f 2 3 of 27

body titres (Table 8). Although it is generally correct that the severity of hemolytic disease remains the same or increases in severity during subsequently affected pregnancies, occasionally disease is less severe. With a past history of hydrops, a subsequently affected fetus has a better than 90%, but not 100%, likelihood ofbecoming hydropic. If hydrops is going to develop, it usually does so at the same gestation period or earlier, but occasionally it may not appear until later. With a prior history of hydrops and a husband heterozygous for the offending antigen, the physician is in a quandary. The fetus may be antigen negative and unaffected or antigen positive and very severely affected. In a first Rh(D) sensitized pregnancy in which there is no history, there is an 8% to 10% risk of hydrops developing. Maternal alloantibody titres. Similarly, although antibody titrations carried out in the same laboratory, by the same experienced personnel, using the same methods, and test cells are reproducible and do give the physician some indication of risk, they are not of sufficient accuracy by themselves to allow potentially hazardous fetal treatment measures to be undertaken. In an 8-year period, 1954 to 1961, in which 426 Rh alloimmunized women came to delivery at the Winnipeg General Hospital (now the Health Sciences Centre) (Table 9), 54 were salvaged only because they were induced and delivered early. Sixty-seven perinatal deaths occurred. Of the 67 deaths, 34 were potentially salvagable using the management measures available at that time, if the degree of severity of disease had only been known with greater accuracy (26 with earlier delivery, 8 with later delivery). When we assessed these 121 most

FETAL TREATMENT OPTIONS IN HEMOLYTIC DISEASE

195

Table 7. Twenty·two Non·anti·D Out ot Province Referrals to Rh Laboratory Present Pregnancy Alloantibody Specificity

No. ot Patients

AntigenNegative

Hydrops in Pregnancy

Hydropic Deaths

lUT Traumatic Deaths

Kell

9

C

7 1 1 1 1 1 1

1 O O O O O O O

8 1 O O 1 Ot O; Ot

4* O O O O O O O

O 2* O O O O O 1

cE Fy' Jk'

cew k E

*Three Kell and 1 c death not treated in Winnipeg. tPrior hydropic death. ;Hgb 60 giL.

severely affected pregnancies, it was apparent that our accuracy of prediction of severity of hemolytic disease rate was onIy 62%.12 Amniotic fluid spectrophotometry. This state of affairs changed dramaticalIy in 1961 when Liley introduced amniotic fluid spectrophotometry, 13 as a means of more accurately determining severity of hemolytic disease. Although not the first to use spectrophotometry, he was the first to develop a method of measurement, the deviation from linearity at 450 nm, the absorption spectrum of bilirubin, ie, the ~OD 450 reading, which alIowed communication from one center to another of an easily interpreted reading, readily giving an accurate determination of severity of hemolytic disease. Readings falling into zone III (Fig 2) indicate severe disease and hydrops present or developing within 7 to 10 days; readings falling into zone I indicate either no disease or no anemia but a 10% chance of requiring exchange transfusion; readings in zone II indicate moderate disease, becoming more severe as the zone III boundary is approached. The overall arnniotic fluid accuracy of prediction of hemolytic disease severity is 95%, a great improvement over our previous 62% rate, but this accuracy can only be achieved with serial ~OD 450 measurements. Amniotic fluid ~OD 450 readings reflect severity of disease more accurately in Table 8. Parameters Predicting Severity ot Fetal Hemolytic Disease 1. Maternal history of prior severity ot hemolytic disease 2. Maternal alloantibody titres 3. Amniotic fluid spectrophotometry 4. Fetal ultrasonography 5. Percutaneous fetal blood sampling

the third trimester than they do in the second trimester. 14,15 In the second trimester, the actual zone boundaries have not been as accurately determined, again pointing out the need for serial measurements (often weekly for several weeks). Final readings falling in zone I and zone III have an accuracy of prediction rate of 98%, but final readings falling in zone II have an accuracy of prediction rate of only 90%. Amniocentesis is not without hazard. In the preultrasound era, there was a 10% risk of placental trauma,16 placing blood in the arnniotic fluid and producing 580, 540, and 405 nm oxyhemoglobin peaks (Fig 3),17A completely obscuring the 450 nm peak and rendering the fluid worthless from the standpoint of predicting severity of hemolytic disease. What is even more serious, placental trauma carries a great likelihood of producing a fetomaternal transplacental hemorrhage, exposing the mother to more fetal red celI antigen, increasing her alIoantibody level, and increasing Table 9. Rh Erythroblastosis Births at the Winnipeg General Hospital 1954-1961 (Total 426) Stillbirths and neonatal deaths Hopeless (stillborn or hydropic deaths <33 weeks gestationl Probabie survival with early induction (",,32 weeks gestation) Probabie survival it bom later Deaths due to faults in management after birth Survivors Survivors who lived only because of early delivery

67 (16%1

25 26* 8*

8 359 54 (13%1

*Deaths probably preventable by early induetion or later or no induetion, 34.

196

J.M. BOWMAN 1.00

.80 .60

M

--------1-----::.-.-.

>- .20

~

0.256

-.-.

;;;

J __ ...Jl

-- -

3

-.-.......-.

2

-.-

Z

~ ~

V

~ .10

0. 08

.06 Fig 2. Amniotic fluid optical density increase at 450 nm 0.256 (zone III) in this example. The furtherincrease at 405 to 410 nm represents either oxyhemoglobin (traumatic contaminant) or heme (severe disease). This fetus subsequently underwent a 34.5-week induction and deliv· ery resulting in a prehydropic. edematous neonate with a cord hemoglobin of 50 giL. Four exchange transfusions were done and the child is currently alive and wel!. Reprinted with permission.'2

.04

-. ....... ....... -.

-- -

-.

-.-.

.02

....

1

o ---t,,,,--,,,--,,,u~--""I''''--''U~--''I''''--''

WAVIUNGTH (mil)

Pi

GESTATlON

27

(weeks)

the severity of fetal hemolytic disease. With the advent of ultrasound placentallocalization, the risk of placental trauma at amniocentesis has been sharply reduced but not removed altogether (residual incidence 2%17). Perinatal ultrasonography. The introduction of ultrasound imaging techniques in the late 1970s has been a major advance in the management of matemal blood group alloimmunization. 18 Ultrasound allows an estimation of placental and hepatic size and the presence or absence of edema, ascites, and other effusions, (ie, the presence or absence of hydrops fetalis), (Fig 4), and has been of great help in the assessment of fetal well-being (measuring the fetal biophysical profile). It has increased the accuracy of placental localization and has sharply reduced the incidence of placental trauma at amniocentesis. Ultrasound is essential in directing the transfusion needle with the least possible hazard in both intraperitoneal and intravascular transfusions. Following intraperitoneal transfusion, ultrasound examination confirms the presence of blood in the fetal peritoneal cavity, and serial examinations monitor its absorption. At the time of direct fetal intravascular transfusion, ultra~

550

31

450

350

35

sound observation of characteristic turbulence within the fetal umbilical blood vessel, as the blood is injected, confrrms that it is being transfused into the fetal circulation. Unfortunately, although ultrasound makes the diagnosis of the presence of hydrops with great accuracy, it may not make the diagnosis of impending hydrops until hydrops has developed. However, after fetal transfusions, ultrasound biophysical profile scoring provides an accurate assessment of fetal well-being and notes whether improvement OT deterioration is occurring. Percutaneous umbilical blood sampling. With the development of sophisticated ultrasound equipment and the availability of perinatologists skilled in its use, percutaneous fetal umbilical blood sampling became feasible in the mid-1980s. 19 This procedure allows the direct measurement of all blood parameters that can be measured after birth (hemoglobin, hematocrit, blood groups, direct antiglobulin testing, serum bilirubin levels, plate1et and leucocyte counts, serum protein levels, and fetal blood gases). Fetal blood sampling is by far the most accurate means of determining the degree of severity of fetal hemolytic. disease (in the ab-

FETAL TREATMENT OPTIONS IN HEMOLYTIC DISEASE

197

415

BlOOOY AMNlonc FLUID

0.40 0.30

--------------------

0.20

l:

Oń

...Z O

• V

~

2

0.10 O.
---------

O

0.06 0.04

--------

0.03 0.02

Fig 3. Spectrophotometric curve (Liley methodl of amniotic fluid grossly contaminated with blood. Note sharp peaks at 580. 540. and 415 nm. which obscure the 450-nm increase. Reprinted with permission. 17A

----- ------------

------

0.01

WAVElENGTH GESTATlON

700 27

sence of hydrops) and the need for fetal treatment measures. Fetal blood sampling is a relatively benign procedure carrying with it a traumatic fetal mortality rate of a fraction of 1%.19 Since it carries with it a very high ńsk of fetomatemai hemorrhage, its use is recommended only (1) when seńal amniotic fluid aOD 450 readings ńse to the upper 75% level of zone II, and (2) when an anteńor placenta cannot be avoided at amniocentesis, and matemai pregnancy history and/or maternal alIoantibody titres place the fetus at ńsk. Fetal blood sampling may be possible as early as 18 weeks' gestation; it usually is feasible by 20 to 21 weeks' gestation. The preferred sampling site is from the umbilical vessel (preferably the vein) at its insertion into the placenta. For this reason, the procedure is technica1ly easier if the placenta is implanted on the anteńor uteńne wall. THE MANAGEMENT Of MATERNAL ALLOIMMUNIZATION

Suppression oj Rh Alloimmunization Since the mid-1980s, attempts have been made to suppress the strength of already developed maternal red celI immunization. Rh hapten20 has no value. The benefit of Rh positive red celI stroma,

650 29

600

31

550 33

500

35

450 37

400 39

3SO 41

advocated by Bierme et al,21 has been refuted by Gold et al. 22 The value of administration of promethazine hydrochlońde put forward by Gusdon et al,23 has not been confirmed by others, including ourselves. Simi1arly, administration of Rh immune globulin, of great value in Rh prevention, has been shown to be quite ineffective in suppressing Rh immunization, no matter how weak, once Rh immunization has begun. 24 ,25 The two suppressive modalities of some benefit in reducing matemai antibody levels are (1) intensive plasma exchange,26,27 and (2) the administration of intravenous immune serum globulin IGIV. 28 ,29 With intensive plasma exchange (10 to 20 L weekly), a1loantibody can be reduced as much as 75%. In the author's expeńence, after 6 to 8 weeks, even with continued plasma exchange, antibody levels tend to rebound. Venous access often becomes a problem with the need for placement of arteńal venous shunts. The plasma removed must be replaced, at least partially, with blood fractions (albumin and IGIV) in order to reduce antibody feedback rebound and to keep matemai serum albumin and IgG at adequate leveIs (:::::30 giL and :::::3 giL, respectively). Plasma exchange is tedious, cost1y, and uncomfortable. It is not without some risk to the mother, inc1uding bacterial sepsis, particularly if arteńal venous

198

J.M. BOWMAN

Fig 4. Ultrasound examination of fetus with hydrops fetalis. Fetal abdomen encloses a large volume of ascitic fluid (under white arrowl and a large Iiver with a dilated ductus venosus. Reprinted with permismission.'8A

shunts have been implanted. Our only expectation with the use of intensive plasma exchange is that fetal treatment measures may be delayed until the fetus is at greater than 22 to 24 weeks' gestation. The institution of plasma exchange should never preclude or delay the use of definitive investigative procedures such as amniocentesis and/or fetal blood sampling. We reserve plasma exchange for the mother with a husband homozygous for the antigen to which she is immunized and a prior history of hydrops at or before 24 to 26 weeks' gestation. In this situation, intensive plasma exchange should be begun at 10 to 12 weeks' gestation when transfer of matemai IgG is beginning, with initial amniocentesis at 18 weeks' gestation

and/or fetal blood sampling at 19 to 22 weeks' gestation. There have been reports of the benefits of highdose IGłV administration in the severely alloimmunized pregnant woman. 28 ,29 The author's experience is that, with doses of 2 glkg matemai body weight, circulating matemal alloantibody levels can indeed be reduced by as much as 50%, primarily due to the negative feedback produced by totał circulating matemai IgG levels of 25 to 30 g/L, readily achieved by a dose of 2 glkg body weight. Further benefits of IGIV therapy may be due to interference with transfer of matemai antibody across the placenta by trophoblastic FC receptor saturation and, similarly, reduction of IgG coated

FETAL TREATMENT OPTIONS IN HEMOLYTIC DISEASE

fetal red cell hemolysis by fetal reticuloendothelial FC receptor saturation with the injected IGIY. If IGłY therapy is considered, it should only be used in the same situation as intensive plasma exchange, again beginning at 10 to 12 weeks' gestation. The recommended dose is 400 mg/kg maternal body weight for 5 days repeated at 3- to 6week intervals, depending upon amniotic fluid and/or fetal blood sampling assessment of fetal disease and the need for definitive fetal therapy. This form of therapy, again in the author's expeńence, has been of transient or minimaI benefit for the fetuses of very severely alloimmunized women. The relative ineffectiveness of both intensive plasma exchange and administration of IGłY is typified by the author's expeńence with E.M., an extremely severely Rh-immunized patient. Following two hydropic fetal deaths, the second one at 25 weeks' gestation, she had two further affected pregnancies. Oespite institution of both treatment modalities at 6 and 10 weeks' gestation, respectively, hydrops was present at 23V2 weeks' gestation in the first with survival only because of multiple intravascular transfusions; hydrops was averted in the second pregnancy only by the initiation of fetal intravascular transfusions at 20V2 weeks' gestation. MANAGEMENT OF THE INFANT WITH HEMOLYTIC DISEASE

Initial treatment measures in the 1940s were entirely directed towards the close-to-term, livebom infant, who was not hydropic yet doomed to die of kernicterus. Simple transfusion of antigennegative red cells was ineffective because hyperbilirubinemia, the cause of kemicterus, was not prevented. With the introduction of exchange transfusion by Wallerstein at Jewish Memońal Hospital in New York in 1945,30 the replacement of the infant's antibody-coated hemolysing antigen-positive red cells with antigen-negative red cells, which maintained hemoglobin levels and removed the source of bilirubin, kemicterus became preventable, and peńnatal mortality from hemolytic disease was reduced from 50% to 25%. Other postdelivery therapeutic measures, introduced since 1945 (phototherapy, phenobarbital, and albumin infusion), have reduced the need for exchange transfusion. More sophisticated laboratory methods (albumin saturation indices, reserve

199

albumin binding capacity measurements, free indirect bilirubin measurements) have been developed to define more accurately the ńsk of kemicterus and thereby confine the use of exchange transfusions to infants more clearly determined to be at ńsk. Nevertheless, exchange transfusion has been the keystone in the treatment of the livebom infant with hemolytic disease, and it is exchange transfusion, first carried out 45 years ago, that halved the mortality from hemolytic disease in the late 1940s and early 1950s. MANAGEMENT OF THE FETUS WITH HEMOLYTIC DISEASE

Early Delivery for Hemolytic Disease

The pńmary problem, since 1945, has been the development of methods of management of the fetus destined to become hydropic in utero. In 1952, Chown reasoned that induced early delivery might be the solution for the fetus doomed to become hydropic after 32 to 34 weeks' gestation (50% of all hydrops); that is, accept the considerable ńsk from prematuńty instead of the much greater risk from hemolytic disease. He was proven brilliantly correct. 31 BY 1961, the perinatal mortality from hemolytic disease in Manitoba was 16%. The family in the following experience is a case in point. The mother, after anormaI birth in 1949, had three hydropic fetal deaths, the last in 1952 at 32 weeks' gestation. Her next baby, a gid, was induced and delivered in 1954 at 32 weeks' gestation. She had a cord hemoglobin level of 67 giL, a cord serum bilirubin level of 120 mcmollL (7 mgl dL), and required four exchange transfusions. Her brother, induced and delivered in 1956 at the same gestation, with the same cord blood findings, also did well following multiple exchange transfusions. The mother, following a move from Winnipeg, completed her pregnancy cycle in 1965 with a hydropic fetal death at 27 weeks' gestation. If she had lived in Winnipeg in 1965, we might have salvaged that fetus as well. Until 1961, our major problem with induced early delivery was our inability to predict severity of hemolytic disease accurately based upon history and titre alone. With the introduction of amniotic fluid aoo 450 measurements by Liley, 13 this problem was for the most part resolved. By 1964, the perinatal mortality from Rh hemolytic disease in Manitoba had been lowered to 13%.

200

J.M. BOWMAN

INTRAUTERINE TRANSFUSIONS FOR FETAL HEMOLYTIC DISEASE

Intraperitonea! Feta! Transfusion In 1961, induced early de1ivery cou1d not be carried out ear1ier than 31 to 32 weeks' gestation without encountering prohibitive mortality from prematurity and severe Rh disease. Eight percent of fetuses become hydropic before 32 weeks' gestation. The introduction of intraperitonea1 feta1 transfusion (IPT)32 by Li1ey in 1963 comp1ete1y altered the out1ook for these most severe1y affected of all fetuses. It has been known since the tum of the century that red celIs placed in the peritoneal cavity will be absorbed and will function normally. At one time IPT was a favorite method of transfusing chi1dren with thalassemia. It was abandoned in favor of vascular transfusions because of the severe discomfort that it caused. Absorption is via the subdiaphragmatic Iymphatic lacunae, up the right Iymphatic duct, into the venous circulation. Diaphragmatic movements are necessary for absorption to occur. 33 In the absence of hydrops, 10% to 12% of infused red cells are absorbed daily. The presence of ascites per se does not prevent absorption,34 although the rate of absorption is more variable. If the hydropic fetus is moribund and not breathing, no absorption of red cells will 33 OCCUr.

B!ood for Intrauterine Transfusion Group 0, Rh negative, and Kell-negative red cells are used for IPT if the alloantibody is anti-D. If the alloantibody is non-anti-D in the Rh system, group 0, Kell-negative, c-negative, C-negative, and E-negative red cells, as the case may be, are used. If the alloantibody is outside the Rh system, group 0, Rh negative, Kell-negative red cells, missing the offending antigen to which the mother is alloimmunized, are used. The blood ideally shou1d have been drawn from the donor within 48 to 72 hours of the transfusion. The donor red cells are very carefully crossmatched against matemai serum; these women are prolific antibody producers, some having as many as four to six alloantibodies other than their primary antibody. In such circumstances, the finding of a compatible donor may be difficult. Before the transfusion, the unit is tight1y packed, all plasma and buffy coat being removed. Immediately before the intrauterine

transfusion, 10 to 15 mL of sterile, isotonic saline is added, so that the hemoglobin and hematocrit of the packed red cells are 270 to 300 g/L and 0.85 to 0.90, respectively. In many centers, the red cells are irradiated before use to prevent donor Iymphocyte engraftment and the development of graft-versus-host disease. In the belief that the normal human fetus can reject donor 1ymphocyte engraftment as early as 20 weeks' gestation, we have never irradiated donor red celIs before fetal transfusion. None of our 275 survivors following intrauterine transfusion to date (October 30, 1989) have developed graft-versushost disease.

The Intrauterine Transfusion Team The number of candidates for intrauterine fetal transfusion (IUT) is decreasing as the number of immunized Rh negative women declines because of the success of Rh prophylaxis. Intrauterine transfusion technique either intraperitonea1 or its successor, direct intravascular, appears simple, but it is not. Complete management of the immunized mother and baby before and after birth requires not onIy an experienced obstetrician but also neonatal, ultrasound, and 1aboratory personnel and services of the highest order. Procedures shou1d be carried out only in a tertiary leve1 perinatal center. A team approach is essential. As a minimum, each center in which feta1 transfusions are performed should deal with four or five fetuses annually on whom 12 to 16 transfusions are carried out. To reach this volume of patients, the lUT team must have all transfusion candidate referrals from a population base of 2 million (25,000 to 30,000 deliveries per year). Only under such circumstances will the team's expertise in lUT and overall management of the severely affected fetus and infant with hemolytic disease be maintained.

Technique of Intraperitonea! Feta! Transfusion The mother is heavily premedicated with an analgesic and muscle re1axant, but is not anesthetized. The target, the feta1 abdomen, is localized by ultrasound. After aseptic skin preparation, infiltration of the matemai skin with local anesthetic. Using cap, mask, gown, and sterile glove technique, and under u1trasound guidance, a 16-gauge, 18-cm Tuohy needle is directed into the fetal abdomen (Fig 5). Usually, as the IPT needle reaches the feta1 ab-

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of Manitoba and Rh Laboratory does not inject blood into the peritoneal cavity directly down the needle and very strongly recommends against this method of intraperitoneal transfusion. The epidural catheter transfusion technique pioneered by Liley is safer and more reliable than the direct-needle transfusion technique. Prior to the ultrasound era (before 1978), visualization of the contrast diffusing into a large volume of ascitic fluid (Fig 7) was often the way the initial diagnosis of the presence of hydrops fetalis was made. Intraperitoneal Fetal Transfusion Volumes and Intervals Fig 5. IPT dilgrlm. Tuohy needle inserted Icross the mlternel ebelomine' well Ind uterine well into the fetal peritoneel cevity; the epidurll cetheter is threeded into the periton8l1 cevity of the fetus. The sefest position for the fetus It IPl is not with his Ibdomen enterior (IS shown in this dilgrem), beceuse the umbilicel fetal v_ls then Iie in the center of the terget eree. Reprinted with permission.'A

domen, it can, by ultrasound, be seen indenting the abdomen and then penetrating it. At the same time, frequently, the obstetrician feels resistance as the needle tip indents the abdomen, which disappears as the tip enters the peritoneal cavity. An epidural catheter is then threaded down the needle. Frequently, the tip of the catheter, as it is threaded, can be seen by ultrasonography moving around the peritoneal cavity. The needle is then withdrawn to lie on the matemai abdomen. Although, in the past 3 years with the development of highly sophisticated ultrasound equipment, we have confirmed the proper placement of the catheter tip-free in the feta! peritoneal cavity-by the injection of one mL of aerated sterile saline and the observation by ultrasound of the bubble rising to the top of the fetal abdomen, this method has led on one recent occasion, to a rnistaken diagnosis of proper placement of the catheter tip when in fact it was in fetal bowel. For this reason, although x-ray arnniograms and preliminary x-rays have been rendered obsolete by ultrasound, we believe it to be essential that the proper placement of the catheter tip be confrrmed radiographically following the injection of l to 1.5 mL of radiopaque contrast medium (Fig 6). It is for this reason, and because of the additional risk of trauma and needle dislodgement, that the intrauterine transfusion team of the University

The volume of packed red cells transfused is lirnited by the size of the feta! peritoneal cavity. If the volume transfused is so great that intraperitoneal pressure exceeds umbilical venous pressure, blood flow from the placenta to the fetus will stop and the fetus will die. 35 As a general rule, a volume transfused according to the formula gestation in weeks - 20 x 10 mL (ie, 50 mL at 25 weeks) is well tolerated. 36 Since the aim is to increase the circulating hemoglobin concentration to at least 160 g/L, a second IPT is carried out in about 10 days followed by further procedures at 3 V2- to 4week intervals, the last one being at 30 to 32 weeks' gestation to allow delivery no earlier than 33V2 to 34 weeks' gestation. Salvage Rates Witk Intraperitoneal Fetal Transfusion

aur overall salvage rate with IPT from January 2, 1964 to October 21, 1986 (the last date that a fetus was given IPT alone) was 63% (222 of 353 fetuses transfused 862 times). Survival rates in the modem ultrasound era (Table 10, colurnn l) are very much better: 76% overall, 87% for nonhydrops, 60% for hydrops. If the moribund nonbreathing, hydropic fetuses, none of whom survived, are removed, our nonmoribund hydropic survival rate is 82%, a rate only modestly less than our nonhydropic feta! survival rate. Careful follow-up of our IPT survivors indicates that the quality of survival is very good. Most are completely normal. aur oldest survivor (age 25) obtained his University Masters Degree in 1988 and married that same year.

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Fig 6. Successful catheterization of the fetaI peritoneal cavity, as shown by radiopaque contrast agent in the fetal peritoneal cavity, outlining negative shadow of Iiver and negative shadows of smali bowel.

Problems With Intraperitoneal Fetal Transfusion

Although IPT represented a major advance in the management of severe erythroblastosis fetalis, it has some serious problems. The procedure is of no value for the nonbreathing moribund hydropic fetus. In this situation, red cells are not absorbed, and the fetus dies. Also, if the placenta is implanted on the anterior uterine wall and must be transfixed by the Tuohy needle in order to enter the fetal peritoneal cavity, the traumatic death rate per procedure, in our hands, has been 7%. Moreover, following IPT, there is a 30% spontaneous labor rate per patient with delivery earlier than otherwise planned; fortunately most of such deliveries occur after 30 weeks' gestation. Seventy percent of fetuses bom following spontaneous labor survive. Finally, although serial amniotic fluid dOD 450 measurements very materially increase the accuracy of prediction of severity of hemolytic disease, inaccuracies do occur: the occasional only moderately affected fetus despite a zone III reading, and

less commonly, hydrops despite only a moderate (60%) zone II reading. Direction Intravascular Fetal Transfusion

Pioneering attempts at direct intravascular transfusions (IVT), either into a fetalor placental vessel, approached via a hysterotomy incision, were attempted in the mid_1960s. 37•39 The results were abysmal because the women almost invariably went into labor. Rodeck, in 1981, introduced direct transfusion through a fetoscope. 4O Few others have achieved his skill with the fetoscope. Blood, meconium, or turbidity in the arnniotic fluid make fetoscopic visualization of the fetal blood vessels impossible. With the advent of fetal blood sampling by the early to mid-1980s, 19 it became possible to follow the sampling procedure with direct intravascular fetal transfusions (IVT). 41-45 Under ultrasound guidance, the tip of a 22- or 20-gauge spinal needle is introduced into an umbilical blood vessel, preferably the vein, occasionally the artery , at its in-

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Fig 7. Hydrops fetalis at intrauterine transfusions. Note radiopaque eonu8st medium infusing into a large volume of fluid in the feta I abelomen at both transfusions. The fetus, hydropie at birth with a cord hemoglobin of 9 g/100 mL and all donor red cells, survived.

Table 10. Salvage Rates With Intrauterine Transfusion (Ultrasound Era) 240 IVT* 5186-'0189

2041PT 7180-'0186

Fetuses Survivors Nonhydrops Survivors Hydrops Survivors Nonmoribund hydrops Survivors Moribund hydrops Survivors lUT per fetus Traumatic deaths Risk per lUT Risk when placenta anterior

75

67* 55 (87%)

57 (76%) 45

41 39 (87%)

30

39t (95%) 22

18 (60%)

16* (73%) 14

22 18(82%)

11

5 (63%)

O( 0%)

2.7 7

(79%)

8

8

(10.0%) 3.5% 7.0%

3.7 2

( 3%) 0.8% 0.0%

* Four in utero awaiting further IVT. t Two nonhydropic deaths not due to IVT, one neonatal death after eleetive delivery at 36 weeks' gestation; one abruptio placentae at 35 weeks' gestation, 6 days after seventh IVT. Three of the six hydropic deaths were at 19 to 22 weeks' gestation in intravenous drug abusers; two were in dying moribund fetuses, one was exsanguination of a hydropic fetus at 22 weeks' gestation.

*

sertion into the placenta, but rarely at its insertion into the fetal abdomen_

The Advantages oj Fetal Blood Sampling and Intravascular Fetal Transfusion As stated earlier, in the absence of hydrops, the direct measurement of fetal blood parameters is by far the most accurate method of determining severity of hemolytic disease, far more accurate than amniotic fluid AOD 450 measurements and ultrasonographic assessments. The latter two parameters, however, combined with past history and matemal antibody titres, serve to indicate the fetus at risk who requires a fetal blood sampling procedure. Direct intravascular transfusion, as a method of transfusing the severeiy affected fetus, does not rely upon diaphragmatic movement to increase hemoglobin levels. Therefore, it is capable of salvaging the moribund nonbreathing fetus, provided that the fetus still has umbilical blood flow. AIso, direct IVT raises circulating hemoglobin levels in the

204

fetus immediately, rather than in the 8 to 10 days required for rPT. Technique oj lntravascular Fetal Transfusion

Packed red celIs used for rYT are of the same hemoglobin and matemal crossmatch compatibility as those used for IPT. The obstetric ultrasonographer (Dr C.R. Harmon, Department of Obstetrics, Gynecology, and Reproductive Sciences, Faculty of Medicine, University of Manitoba, Canada) upon whose skill and experience the success of the procedure depends, takes great care in identifying the cord vessel insertion into the placenta (Fig 8) (rarely into the fetal abdomen), the target for the rYT needle. The obstetrician venepuncturist (Dr F.A. Manning and Dr S. Menticoglou, Department of Obstetrics, Gynecology, and Reproductive Sciences, Faculty of Medicine, University of Manitoba, Canada) under real time ultrasound guidance, directs a 22- or 20-gauge spinal puncture needle toward the target vessel. The transducer is positioned in such a pIane that there is simultaneous identification of the target vessel and needle tipo As the needle tip is being advanced in a three-dimensional pIane, under ultrasound, a

Fig 8. Ultrasound photograph of the insertion of the umbilical vein into the placenta (arrowl, the target area for insertion of the needle at direct intravascular transfusion. Reprinted with permission. 45A

J.M. BOWMAN

two-dimensional medium, repeated smalI delicate corrections of needle direction are necessary to insert the needle tip into the fetal vessel. In most instances, the needle tip can be seen indenting and then puncturing the fetal vessel. Once the needle tip appears to be in the vessel, blood is aspirated, which is deterrnined to be fetal by a rapid alkaline denaturation test. The correct position of the needle tip is confirrned by the observation of characteristic turbulence coursing down the vessel folIowing injection of 0.5 mL of isotonic saline. An immediate hemoglobin measurement is carried out. Subsequently, complete investigation of the fetal blood sample is carried out in the Rh Laboratory. If the stat hemoglobin reading is below 110 giL, the rYT proceeds. If fetal movements are likely to disturb the needle insertion (posterior cord insertion), the fetus is paralysed by the intravenous injection of pancuronium. While the obstetrician venepuncturist holds the needle hub and the blood transfusion tubing connector very fmnly, and the obstetrician ultrasonographer watches the blood flow turbulence in the fetal blood vessel continualIy, the transfusionist (the third member of the

205

FETAL TREATMENT OPTION5 IN HEMOLYTIC DI5EA5E

team) transfuses the packed red cells in 10 mL aliquots, each aliquot being transfused in 1 to 2 minutes until the desired transfusion volume is attained (mean, 50 mLlkg estimated nonhydropic fetal weight). It is due to the expansile placental vascular bed that such large red cell volumes transfused so rapidly are tolerated. The ultrasonographer monitors fetal heart rate and cardiac ventricular size. If there is evidence of significant bradycardia or marked ventricular dilation (a rare event), the transfusion is discontinued before the full volume is administered. Since the aim is to shut off erythropoiesis so that hepatosplenomegaly will diminish and hydrops be prevented or if present be reversed, a second procedure is carried out as soon as it is estimated that the total circulating hemoglobin concentration has dropped into the 100 g/L range. The average donor hemoglobin attrition rate is 4 g/Llday. Subsequent IVT are usually required every 3 to 4 weeks again when the estimated residual circulating hemoglobin concentration has dropped into the 90 to 100 g/L range.

Intravascular Fetal Transfusion Survival Rates IVT survival rates (Table 10, column 2) are superior to IPT survival rates in every category. The two nonhydropic deaths were unrelated to IVT: abruptio placentae at 34Y2 weeks' gestation, 6 days after an uneventful fifth IVT, and a neonatal intensive care nursery death at 36 weeks' gestation due to a procedure misadventure. Of the five deaths in hydropic fetuses, two occurred in dying fetuses with no umbilical blood flow (referred too late) , one occurred in a substance abuser shortly after self-administration of a large amount of cocaine; oniy two were related to IVT: (1) exsanguination of a severely hydropic, non-moribund, 22 weeks' gestation fetus with a pretransfusion hemoglobin concentration of 30 g/L and a posterior cord insertion in which the needle tip could not be maintained in the vessel long enough for the IVT to be carried out, and (2) inadvertent partial injection of RBC outside the vein lumen producing a vessel wall hematoma, obstructing umbilical blood flow at a second IVT again in a severely hydropic fetus at 21 weeks' gestation. aur final perinatal death occurred in a 19-week, 2-day gestation moribund hydropic fetus whose mother was also a drug abuser. Neither an umbilical vessel nor a cardiac

chamber could be successfully entered to carry out a transfusion. It should be noted that almost 1Y2 times as many IVT as IPT are required per patient. The reasons for the increased number are that (1) IVT are being carried out earlier in gestation, (2) perinatal mortality per procedure is less, allowing multiple procedures in more patients, and (3) because of somewhat smaller IVT volumes, intervals between IVT are modestly shorter.

The Pros and Cons of Intravascular Fetal Transfusion Versus Intraperitoneal Fetal Transfusion There can be no doubt that in 1990 IVT, if feasible, is the procedure of choice. Oniy through IVT can the moribund, nonbreathing, hydropic fetus be salvaged; five of eight (63%) survived (Table lO). What is gratifying is the much lower overall risk with IVT versus IPT (0.8% v 3.5% per procedure). This is even more dramatically illustrated when the placenta is anterior (0% risk to date for IVT v 7% risk for IPT). Although the risk of IVT is very materially less, this low risk can only be achieved when the obstetrician ultrasonographer and the obstetrician venepuncturist colleagues have great skill and experience with the procedure. Otherwise, there are hazards that will increase the risk of IVT: (1) overtransfusion with cardiac failure (not observed in our series), (2) exsanguination (a problem, particulady if the fetus is hydropic thrombocytopenic and the cord insertion is posterior46 ), and (3) inadvertent injection of blood into the cord around the vein, producing a cord hematoma, compressing and interfering with umbilical blood flow. This third hazard is a very real one, which caused one of our fetal deaths. It can only be prevented by an alert experienced ultrasonographer. The fourth hazard, of no consequence to the fetus being transfused, but a potential consequence to a subsequent fetus, is the inevitable transplacental hemorrhage produced by fetal blood sampling and IVT, with consequent increase in severity of matemai alloimmunization. Despite the great advantages of IVT, there are two situations in which IPT may still be necessary, and therefore the need for skill in carrying out IPT must be maintained. One is the rare situation, early

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J.M. BOWMAN

in pregnancy (before 20 to 21 weeks' gestation), in which the cord vessels may be too smalI for a successful venepuncture; the second is the more common situation in which Iater in pregnancy (after 30 weeks' gestation), after several successful IVTs, increasing fetal size totally obscures a posterior cord vessel insertion making venepuncture impossible. In the 24-month period ending October 31, 1989 in which 174 IVTs were carried out, one IPT was carried out for the first reason and six for the second. Over the past 45 years, we have witnessed a

reduction of alIoimnlline hemolytic disease perinatal mortality in Manitoba from 50% to 25% with exchange transfusion, from 25% to 16% with induced earIy deIivery, from 16% to 13% with the introduction of amniocentesis, and now in the past 7 years, with ultrasound, IPT, fetal blood sarnpling, and IVT, the perinatal mortality has been reduced to 3%. It is hoped that with increased experience with intravascuIar transfusion and universal earIy referral of severeIy affected fetuses the perinatal mortality from fetal hemolytic disease may be reduced to 1% or a fraction thereof.

REFERENCES 1. Diamond LK, Blackfan KD, Baty JM: Erythroblastosis fetalis and its association with universal edema of the fetus, ictems gravis neonatomm and anemia of the newborn. J Pediatr 1:269, 1932 lA. Bowman JM: Blood-group incompatibilities, in Iffy L, Karninetzky HA (eds): Principles and Practice of Obstetrics and Perinatology, vol 70. New York, NY, Wiley, 1981, pp 11931239 2. Landsteiner K, Weiner AS: An agglutinable factor in human blood recognized by immune sera for rhesus blood. Proc Soc Exp Biol MOO 43:223, 1940 3. Levine P, Katzin EM, Bumham L: lsoimmunization in pregnancy: lts possible bearing on the etiology of erythroblastosis fetalis. JAMA 116:825-827, 1941 4. Wiener AS: Diagnosis and treatment of anemia of the newborn caused by occult placental hemorrhage. Aro J Obstet Gynecol 56:717-722, 1948 5. Chown B: Anemia from bleeding of the fetus into the mother's circulation. Lancet 1:1213-1215, 1954 6. Kleihauer E, Braun H, Betke K: Demonstration, von fetalem haemoglobin in den erythrozyten eines blutausstriches. Klin Wochenschr 35:637-638, 1957 7. Bowman IM, Pollock IM, Penston LE: Fetomatemai transplacental hemorrhage, during pregnancy and after deIivery. Vox Sang 51:117-121, 1986 8. James LS: Shock in the newborn in relation to hydrops, in Robertson JG, Dambrosio F (eds): International Symposium on the Management of the Rh Problem. Ann Ostet Ginec Special Number:193-195, 1970 9. Freda VJ, Gorman JG, Pollack W: Successful prevention of experimental Rh sensitization in man with an anti-Rh gamma 2-globulin antibody preparation: A prelirninary report. Transfusion 4:26-32, 1964 10. Dacus]V, Spinnato JA: Severe erythroblastosis fetalis secondary to anti-Kpb sensitization. Am J Obstet Gynecol 150:888-889, 1984 11. MacPherson CR, Christiansen MI, Newton WA, et al: Anti-M antibody as a cause of intrauterine death. Am J Clin Pathol 35:31-35, 1961 12. Bowman JM, Pollock IM: Aroniotic fluid spectrophotometry and early delivery in the management of erythroblastosis fetalis. Pediatrics 35:815-835, 1965

13. Liley AW: Liquor aronii analysis in management of pregnancy complicated by rhesus immunization. Am J Obstet GynecoI82:1359-1371, 1961 14. Nicolaides KH, Rodeck CH, Mibashan MD, et al: Have Liley charts outlived their usefulness? Am J Obstet Gynecol 155:90-94, 1986 15. Ananth U, Queenan JT: Does midtrimester aOD 450 of anrniotic fluid reflect severity of Rh disease? Am J Obstet Gynecol, 161:47-49, 1989 16. Peddle LJ: lncrease of antibody titer following amniocentesis. Am J Obstet Gynecol 100:567-569, 1968 17. Bowman JM, Pollock JM: Transplacental fetal hemorrhage after anrniocentesis. Obstet Gynecol 66:749-754, 1985 17A. Bowman JM: Hemolytic disease of the newborn, in Conn HF, Conn RB (eds): Current Diagnosis (eds). Philadel· phia, PA, Saunders, 1977, pp 1098-1110 18. Chitkara U, Wilkins l, Lynch L, et al: The role of sonography in assessing severity of fetal anemia in Rh- and Kellisoimmunized pregnancies. Obstet Gynecol 71:393-398, 1988 18A. Bowman JM: Maternal blood group immunization, in Creasy RK, Resnik R (OOs): Maternal·Fetal Medicine: Princi· pIes and Practice. Philadelphia, PA, Saunders, 1984, chapter 17 19. Daffos F, Capella-Pavlovsky M, Forestier F: Fetal blood sampling during pregnancy with use of a needle guided by ultrasound: A study of 606 consecutive cases. Am J Obstet Gynecol 153:655-660, 1985 20. Carter BB: Preliminary report on a substance which inhibits anti-Rh semm. Aro JClin Pathol 17:646-649, 1947 21. Bierm~ SJ, Blanc M, Abbal M, et al: Oral Rh treatrnent for severely immunized mothers. Lancet 1:604-605, 1979 22. Gold WR Jr, Queenan JT, Woody J, et al: Oral desensitization in Rh disease. Am J Obstet Gynecol 146:980-981, 1983 23. Gusdon JP Jr, Caudle MR, Herbst GA, et al: Phagocytosis and erythroblastosis: 1. Modification of the neonatal response by promethazine hydrochloride. Aro J Obstet Gynecol 125:224-226, 1976 24. Bowman JM, PolIock JM: Reversal of Rh alloimmunization. Faet or faney? Vox Sang 47:209-215, 1984 25. De Silva M, Contreras M, Mollison PL: Failure of pas-

FETAL TREATMENT OPTIONS IN HEMOLYTIC DISEASE

sively administered anti-Rh to prevent secondary Rh immune responses. Vox Sang 48:178-180, 1985 26. Graham-Pole J, Barr W, Willoughby MLN: Continuous flow plasmapheresis in management of severe Rhesus disease. Br Med J 1:1185-1188, 1977 27. Robinson EAE, Tovey LAD: Intensive plasma exchange in the management ofsevere Rh disease. Br JHaematoI45:621631, 1980 28. Berlin G, Selbing A, Ryden G: Rhesus haemolytic disease treated with high-dose intravenous immunoglobulin. Lancet 1:1153, 1985 (letter) 29. de la Camara C, Arrieta R, Gonzalez A, et al: High-dose intravenous immunoglobulin as the sole prenatal treatment for severe Rh immunization. New Engl J Med 318:519-520, 1988 30. Wallerstein H: Treatment of severe erythroblastosis by simultaneous removal and replacement of blood of the newbom. Science 103:583-584, 1946 31. Chown B, Bowman WD: The place of early delivery in the prevention of foetal death from erythroblastosis. Pediatr Clin NA 5:279-285, 1958 32. Liley AW: Intrauterine transfusion of fetus in haemolytic disease. Br Med J 2:1107-1109, 1963 33. Menticoglou SM, Harman CR, Manning FA, et al: Intraperitoneal fetal transfusion: Paralysis inhibits red celI absorption. Feta! Therapy 2:154-159, 1987 34. Lewis M, Bowman JM, Pollock JM, et al: Absorption of red cells from the peritoneal cavity of an hydropic twin. Transfusion 13:37-40, 1973 35. Crosby WM, Brobmann GF, Chang ACK: Intrauterine transfusion and fetaI death: Relationship of intraperitoneal pressure to umbilical vein flow. Am J Obstet Gynecol 108: 135, 1970 36. Bowman JM: The management of Rh-Isoimmunization. Obstet GynecoI52:1-16, 1978 37. Adamsons K Jr, Freda VJ, James LS, et al: Prenatal

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treatment of erythroblastosis fetalis folIowing hysterotomy. Pediatrics 35:848-855, 1965 38. Asensio SH, Figueroa-Longo JG, Pelegrina A: Intrauterine exchange transfusion. Am J Obstet Gynecol 95: 1129-1133, 1966 39. Seelen J, Van Kessel H, Eskes T, et al: A new method of exchange transfusion in utero: Cannulation of vessels on the feta! side of the human placenta. Aro J Obstet Gynecol 95:872876, 1966 40. Rodeck CH, Holman CA, Kamicki J, et al: Direct intravascular fetal blood transfusion by fetoscopy in severe rhesus isoimmunisation. Lancet 1:625-627, 1981 41. De Crespigny LC, Robinson HP, Quinn M, et al: Ultrasound-guided blood transfusion for severe rhesus isoimmunization. Obstet Gynecol 66:529-532, 1985 42. Berkowitz RL. Chitkara U, Goldberg m, et al: Intrauterine intravascular transfusions for severe red blood cell isoimmunization: Ultrasound-guided percutaneous approach. Am J Obstet GynecoI155:574-581, 1986 43. Nicolaides KH, Soothill PW, Clewell W, et al: Rh Disease: Intravascular fetal blood transfusion by cordocentesis. Fetal Therapy 1:185-192, 1986 44. Seeds JW, Bowes WA: Ultrasound-guided intravascular transfusion in severe rhesus immunization. Am J Obstet Gynecol 154:1105-1107, 1986 45. Grannum PAT, Copel JA, Moya FR, et al: The reversal of hydrops fetalis by intravascular intrauterine transfusion in severe isoimmune fetal anemia. Am J Obstet GynecoI158:914919, 1988 45A. Bowman JM: Matemal blood group immunization, in Creasy RK, Resnik R (eds): Maternal-Fetal Medicine: Principies and Practice (ed 2). Philadelphia, PA, Saunders, 1989, chapter 35 46. Harman CR, Bowman JM, Menticoglou SM, et al: Profound fetal thrombocytopenia in Rhesus disease: Serious hazard at intravascular transfusion. Lancet 2:741-742, 1988