- Email: [email protected]
Spotlight on obstetrics
SPOTLIGHT ON OBSTETRICS Morton A. Stenchever, MD Editor
Management of Term PROM With Oral Misoprostol
ACOG CLINICAL REVIEW Morton A. Stenchever, MD Editor
Ralph W. Hale, MD Associate Editor Nancy Rowe
Managing Editor ● ● ●
Journals Surveyed Include: Acta Obstetricia et Gynecologica Scandinavica ● American Journal of Obstetrics and Gynecology ● Annals of Internal Medicine ● Australian and New Zealand Journal of Obstetrics and Gynaecology BMJ ● British Journal of Obstetrics and Gynaecology Canadian Medical Association Journal ● Cancer ● European Journal of Obstetrics, Gynecology, and Reproductive Biology Fertility and Sterility International Urogynecology Journal JAMA ● Journal of Ultrasound in Medicine ● Lancet ● Military Medicine ● New England Journal of Medicine ● Obstetrics and Gynecology ● Pediatrics ● ● ● Copyright © 2003 by the American College of Obstetricians and Gynecologists. Published by Elsevier Inc. ACOG Clinical Review is issued bimonthly by Elsevier Inc., 360 Park Avenue South, New York, NY 10010-1710. Subscription prices per year: For customers in the United States: Institutional rate: $235.00, personal rate: $119.00, Nurses rate: $31.00. For customers in Europe and the CIS: Institutional rate: EUR 210.00, personal rate: EUR 106.00. For customers in Japan: Institutional rate: JPY 27,800.00, personal rate: JPY 14,700.00. Prices include postage and are subject to change without notice. For additional information, contact Elsevier Customer Support Department, P.O. Box 945, New York, NY 10010, Tel: (212) 633-3730. Toll free (for customers in North America): 1-888-4ES-INFO, Fax: (212) 633-3680, E-mail: [email protected]. Address advertising inquiries to Pharmaceutical Media Inc., 30 East 33rd St., New York, NY 10016. Periodicals postage paid at New York, NY, and at additional mailing offices. Postmaster: Send address changes to ACOG Clinical Review, Elsevier Inc., 360 Park Avenue South, New York, NY 10010-1710. No responsibility is assumed by the publisher or the American College of Obstetricians and Gynecologists for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. Because of rapid advances in the medical sciences, independent verification of diagnoses and drug dosages should be made. Discussions, views, and recommendations as to medical procedures, choice of drugs, and drug dosages are the responsibility of the authors. The appearance of advertising in publications of the American College of Obstetricians and Gynecologists (and/or in exhibits at meetings of the College) does not constitute a guarantee or endorsement of the quality or value of such product or of the claims made for it by its manufacturer. The fact that a product, service, or company is advertised in a publication or exhibited at a meeting of the College shall not be referred to by the manufacturer in advertising.
2
●
ACOG CLINICAL REVIEW
●
June 2003
Shetty A, Stewart K, Stewart G, Rice P, Danielian P, Templeton A. Active management of term prelabour rupture of membranes with oral misoprostol. BJOG 2002; 109:1354 – 8.
Synopsis: The authors compared the active management of term prelabor rupture of membranes with oral misoprostol with conservative management followed by induction with oxytocin or prostaglandin E2 gel. The study was a nonblinded, randomized, controlled trial, and included 61 women with confirmed prelabor rupture of membranes who were at ⱖ36 weeks’ gestation. The women randomized to the active group received 50 g misoprostol orally repeated every 4 hours as required to a maximum of five doses. The control group received an induction of labor at 24 hours if labor had not begun spontaneously. Of the group managed actively, 93.3% were in spontaneous labor within 24 hours compared with 54.8% of the conservatively managed group. Of women achieving a vaginal delivery, 72% of the active group did so within 24 hours of prelabor rupture of membranes compared with 26.9% of the conservative group. No differences were found in neonatal or maternal outcomes or in the cesarean delivery rate, which was 16.7% in the active group and 16.2% in the conservative group. Satisfaction rates were comparable in the two groups (83% versus 76%, P⫽.8). Level I. ● ● ●
Commentary: Whereas the authors demonstrated that active treatment with prostaglandin ripening of the cervix during the first 24 hours after rupture of the membranes resulted in a shorter prelabor to delivery time, no differences were seen in the mode of delivery or the neonatal or maternal outcomes. However, their sample size
was not large enough to address these issues adequately. Thus they demonstrated that using oral misoprostol could speed the process, but did not demonstrate any particular medical advantage or potential harm from one approach over the other, at least within the sample size that they used.
Risk for Uterine Rupture Shipp TD, Zelop C, Cohen A, Repke JT, Lieberman E. Post-cesarean delivery fever and uterine rupture in a subsequent trial of labor. Obstet Gynecol 2003;101:136 –9.
Synopsis: The authors conducted a nested, case-control study in a cohort of women undergoing a trial of labor after cesarean delivery over a 12-year period. Four controls who had had a cesarean delivery at the same institution were matched to each case by year of delivery, number of previous cesarean deliveries, prior vaginal delivery, and induction in the index pregnancy. Fever was defined as temperature above 38°C. Twenty-one cases of uterine rupture were recorded, and the rate of fever after the previous cesarean delivery was 38% (8 of 21) among the cases and 15% (13 of 84) in the control group (P⫽.03), with an odds ratio of 4.0 for rupture occurring with postpartum fever. Level II-1. ● ● ●
Commentary: Whereas the total numbers in this study were small, the information is interesting because recent findings demonstrated that the risk for uterine rupture was increased when patients who had had a previous cesarean delivery experienced a trial of labor. Perhaps the history of fever and probable postpartum infection after the previous cesarean delivery should be taken into consideration when determining if a woman should attempt a trial of labor. If women who have a previous cesarean delivery are to attempt a trial of labor, it will be increasingly important for obstetricians to identify and consider potential risk factors when making such a decision.
Two-Year Outcome of Low Birth Weight Infants Sweet MP, Hodgman JE, Pena I, Barton L, Pavlova Z, Ramanathan R. Two-year outcome of infants weighing 600 grams or less at ©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
birth and born 1994 through 1998. Obstet Gynecol 2003;101:18 –23.
Synopsis: The authors assessed the neurologic and developmental outcomes at 2 years of age in preterm infants with birth weights 600 g or less. The study was retrospective from January 1994 through December 1998 and considered placental histopathology, maternal factors, neonatal intensive care unit course, growth, neurologic/special sense status, and development at 2 years of age corrected for prematurity. Of 104 neonates in this weight class, 24 survived to nursery discharge (23%), two of whom died of chronic lung disease after discharge. Of the remaining infants, 21 of 22 returned for follow-up. Acute inflammation of the placenta was found in 67% and other placental abnormalities occurred in 76%. Mean birth weight was 537 g (430 – 600 g) and mean gestational age was 24 weeks (22–27 weeks). At nursery discharge and 2 years of age, 94% of the infants were below the 10% percentile for weight, length, and head circumference. Among these infants, 19 (90%) were abnormal on neurodevelopment follow-up with major problems including cerebral palsy (76%), blindness (38%), impaired vision (24%), feeding problems (62%), need for gastrostomy tubes (29%), chronic lung disease (86%), and need for ventriculoperitoneal shunts (29%). Level II-2. ● ● ●
Commentary: In the past, the philosophy on most tertiary care units has tended to be to resuscitate all living infants energetically regardless of birth weight or gestational age. This philosophy was reasonable as no data existed pertaining to infant outcome as a result of this resuscitation. However, the results of this study and other similar studies have demonstrated that such a philosophy may be inappropriate. We must ask ourselves which is the lesser tragedy: to allow very immature newborn to die or to commit them and their families to a life of very poor quality? The effect of maintaining severely damaged infants can be devastating to a mother and a family unit, and extremely costly financially to society. A life of good quality ap©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
pears to be just about impossible for such infants. The major problem is how to establish a policy for resuscitation for these infants. Certainly the facts developed by this study, and by similar studies, should be carefully discussed with the mother and her significant other so that their input is included in the decision-making process. In the case of the institution reporting this study (University of Southern California Medical Center), guidelines have been instituted to routinely resuscitate infants weighing ⱖ500 g or of ⱖ24 weeks’ gestation.
Magnesium Sulfate More Effective Than Nimodipine for Preventing Eclampsia Belfort MA, Anthony J, Saade GR, Allen JC Jr, for the Nimodipine Study Group. A comparison of magnesium sulfate and nimodipine for the prevention of eclampsia. N Engl J Med 2003;348:304 –11.
Synopsis: The authors speculated that as magnesium sulfate is effective, at least in part, in preventing eclampsia by reducing cerebral vasoconstriction and ischemia, a calcium channel blocker, nimodipine, which has a specific cerebral vasodilator effect, might also be useful in preventing eclampsia. They therefore performed a study at 14 sites in eight nations of 1650 women with severe preeclampsia who were randomized to receive nimodipine (n⫽819) and magnesium sulfate (n⫽831). Although the study was not blinded, it was randomized and the primary outcome was eclampsia. Secondary outcome measurements, including blood pressure (BP) control, complications of adverse drug effects, complications of labor and delivery, and indication of fetal and neonatal condition, were also studied. Among the 819 women who received nimodipine, 21 (2.6%) had a seizure compared with seven (0.8%) of the 831 women who received magnesium sulfate. This difference was statistically significant (P⫽.01). Thus, the adjusted risk ratio for eclampsia was 3.2 (95% confidence interval 1.1, 9.1). Whereas the antepartum seizure rate did not differ significantly between the groups, a higher rate of postpartum seizure was observed in the nimodipine group. No significant differences were noted in neonatal outcome
between the groups, but more women in the magnesium sulfate group required BP control using hydralazine, and there was a somewhat increased risk of postpartum hemorrhage in the magnesium sulfate group. Level I. ● ● ●
Commentary: Investigating the hypothesis that a calcium channel blocker might be effective in preventing eclampsia, was a reasonable and worthwhile research endeavor. However, once again a new therapeutic approach did not measure up to the benefits of magnesium sulfate in preventing eclampsia. Magnesium sulfate has been the primary therapy used to treat or prevent eclampsia in the United States since 1925, but has been used for this purpose in the rest of the world only recently. Despite the development of newer agents, magnesium sulfate continues to be the best treatment available. Magnesium sulfate radically reduces the effects of preeclampsia and eclampsia on morbidity and mortality, and despite the limitations of a slight increase in postpartum hemorrhage and occasional respiratory distress, it continues to be our leading therapy for this condition.
Value of Midterm Genetic Sonograms Among High-Risk Pregnancies Hobbins JC, Lezotte DC, Persutte WH, et al. An 8-center study to evaluate the utility of midterm genetic sonograms among highrisk pregnancies. J Ultrasound Med 2003; 22:33– 8.
Synopsis: In this study, eight centers provided data on 176 pregnancies with known fetal Down syndrome. Of these pregnancies, 134 were considered high risk because of advanced maternal age, and 42 because of abnormal triple screen results. An abnormal long bone length (femur, humerus, or both), a major structural abnormality, or Down syndrome marker (sandal gap or nuchal skin fold thickness) was present in 125 fetuses (71.0%). Combined diagnostic sensitivity was 71.6% (range 63.6 – 80%) for the eight centers. Level II-2. ● ● ●
June 2003
●
ACOG CLINICAL REVIEW
●
3
Commentary: The authors concluded that as the results of this study and other published studies placed the sensitivity for genetic sonograms at about 70%, this study could be used to better adjust the Down syndrome risk among high-risk patients. Positive findings could alleviate the need for amniocentesis if the specificity of the test is proven to be high. However, as a fairly large percentage of fetuses (about 30%) test negative but still have Down syndrome, avoiding amniocentesis does not seem possible if the genetic sonogram is negative. The work presented is strictly appropriate for high-risk pregnancies. Applying it to the general population may not be prudent; however, it does offer an alternate approach for couples who do not wish to undergo amniocentesis.
Cesarean Delivery Does Not Prevent Anal Incontinence Lal M, Mann CH, Callender R, Radley S. Does cesarean delivery prevent anal incontinence? Obstet Gynecol 2003;101:305–12.
Synopsis: The authors compared the incidence and severity of anal incontinence in primiparas after cesarean delivery with that noted after spontaneous vaginal delivery. Using a comprehensive bowel function questionnaire, interviews were conducted 8 –12 months postpartum with 184 primiparas who were delivered by cesarean (104 emergency, 80 elective) and 100 women who were delivered vaginally. Bowel-specific questions pertained to bowel habits, laxative use, urgency, flatus, urge and passive incontinence, soiling, and pad use, before and during pregnancy and postpartum. The authors noted that anal incontinence was first present in nine mothers (5%) after cesarean delivery and eight (8%) after vaginal delivery. The difference was not statistically significant. Severe symptoms necessitating pad use were observed in two women who underwent cesarean delivery and one who underwent vaginal delivery. Five of 22 women who sustained a second-degree tear had new anal incontinence compared with only one of 40 mothers who had an intact perineum after vaginal delivery. Level II-2. 4
●
ACOG CLINICAL REVIEW
●
June 2003
● ● ●
Commentary: The important takehome message from this study is that cesarean delivery did not necessarily protect against the subsequent development of anal incontinence, and that the incidence was not that different in primigravidas delivered by cesarean or vaginally. Perhaps the damage to the nerves controlling anal incontinence occurs in the last part of pregnancy or during labor because of head pressure on the pelvic nerves, as has been suggested by previous authors. Also of interest is the finding that women with perineal tears were more likely to experience anal incontinence; these tears may be considered another measure of increased pressure on the pelvic floor. In any event, the authors demonstrated, as have other researchers, that performing a cesarean delivery did not necessarily protect against the development of anal incontinence.
of preterm birth in many women, and strategies that reduce the risk by treating potential infection early would seem warranted. However, the proof of the value of any strategy, it seems to this reviewer, would be a reduction in the incidence of LBW and VLBW infants.
Fetal Asphyxia in Preterm Pregnancies Low JA, Killen H, Derrick EJ. Antepartum fetal asphyxia in the preterm pregnancy. Am J Obstet Gynecol 2003;188:461–5.
Synopsis: The authors performed a randomized, double-blind, placebocontrolled, study in three centers in the United Kingdom. They randomized 409 women with abnormal genital tract flora on Gram stain qualifying as bacterial vaginosis at 13–20 weeks’ gestation to receive a 3-day course of clindamycin 2% vaginal cream or placebo. If the flora was still abnormal after 3 weeks, a 7-day course of the same medication was used. The incidence of preterm birth in the clindamycin group was 4% compared with 10% in the placebo group (P ⬍ .03). Level I.
Synopsis: The authors sought to demonstrate the frequency and characteristics of antepartum fetal asphyxia in pregnancies delivered preterm. The study population was derived from 1182 pregnancies delivered preterm between 1984 and 1996 in the authors’ unit in Kingston, Ontario, Canada. Fetal asphyxia occurred in 86 pregnancies as expressed by umbilical artery base deficit of ⬎ 12 mmol/L at delivery. Thirty pregnancies were delivered by cesarean before the onset of labor (the antepartum asphyxia group), and 56 after the onset of labor. Antepartum fetal asphyxia accounted for at least 34% of fetal asphyxia in preterm deliveries. There was a 50% incidence of moderate-to-severe asphyxia in the antepartum preterm pregnancies compared with 15% in term pregnancies as reported in previous publications. Abnormal fetal assessment tests were valuable in predicting antepartum fetal asphyxia. The authors concluded that the increased frequency of moderate and severe fetal asphyxia in a pregnancy delivered preterm implied a greater likelihood of long-term morbidity and death, as nine of the moderate-to-severe cases of asphyxia ended in early neonatal death. Level II-3.
● ● ●
● ● ●
Commentary: Although the authors demonstrated a significant decrease in preterm delivery based on gestational age, no real effect was noted on the number of low birth weight (LBW) infants or very low birth weight (VLBW) infants. Therefore, the clinical significance of this study remains to be seen. Infection is clearly a cause
Commentary: The authors demonstrated that a significant percentage of asphyxiated fetuses delivered preterm were affected before labor, as 30 of their fetuses were delivered before labor. They also demonstrated that antepartum fetal assessment was useful in determining which of the fetuses were suffering from metabolic acido-
Reducing Preterm Birth Lamont RF, Duncan SLB, Mandal D, Bassett P. Intravaginal clindamycin to reduce preterm birth in women with abnormal genital tract flora. Obstet Gynecol 2003;101: 516 –22.
©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
sis, and that the presence of moderateto-severe asphyxia was related to a high percentage of neonatal death, thus demonstrating the sensitivity of the fetal brain to acidosis. In many cases of preterm birth, the fetus is already damaged before labor occurs, and utilization of fetal assessment studies in pregnancies at high risk of preterm labor should be vigorously used.
Maternal Morbidity After Repeat Caesarean Delivery Lynch CM, Kearney R, Turner MJ. Maternal morbidity after elective repeat caesarean section after two or more previous procedures. Eur J Obstet Gynecol Reprod Biol 2003;106:10 –3.
Synopsis: The authors of this Irish study identified 250 women who had had two or more previous cesarean deliveries out of a total of 67,097 deliveries of infants weighing ⬎ 500 g. Eighty women were having a third cesarean delivery, 131 women were having a fourth cesarean delivery, and 39 had five or more cesarean deliveries. The study was performed from 1990 to 1999. Placenta previa was seen in 12 women (4.8%), four of whom required transfusion and two a hysterectomy. Wound infection occurred in 6.3% of the women and urinary tract infection occurred in 11.2%. No cases of thromboembolism or maternal deaths were recorded. Level II-3. ● ● ●
Commentary: The authors proved once again that most women with a history of previous cesarean delivery can have subsequent cesarean deliveries with a relatively low risk for morbidity. However, the rate of placenta previa (4.8%) was greatly increased from the normal rate of about 0.5%, and can, as was shown in this study, be of a higher stage, such as placenta accreta. The two patients who required hysterectomy had had four and six previous cesarean deliveries, respectively. Clearly, if a grand multipara has had multiple previous cesarean deliveries, she is best managed by a repeat cesarean delivery. However, as the authors pointed out, performing ultrasound to detect placenta previa and planning the elective cesarean delivery ©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
at a time when optimal staff is available would be prudent. The authors correctly pointed out that the risk of maternal mortality could not be measured in this study because of the relatively small numbers. However, when dealing with grand multiparas and the potential for placenta accreta, mortality is certainly a possibility that must be kept in mind and all precautions taken to avoid it.
SPOTLIGHT ON GYNECOLOGY Morton A. Stenchever, MD Editor
Value of ASCUS Interpretation on Papanicolaou Smear Pitman MB, Cibas ES, Powers CN, Renshaw AA, Frable WJ. Reducing or eliminating use of the category of atypical squamous cells of undetermined significance decreases the diagnostic accuracy of the Papanicolaou smear. Cancer 2002;96:128 –34.
Synopsis: The authors reviewed 100 cervical Papanicolaou smears originally diagnosed as atypical squamous cells of undetermined significance (ASCUS), all of which had histologic follow-up. One reviewer re-reviewed the material blindly and reclassified the smears as negative (within normal limits/benign cellular changes), lowgrade squamous intraepithelial lesions (SIL) or high-grade SIL, thereby eliminating ASCUS as a diagnostic possibility. The second reviewer reinterpreted the cases, but attempted to use the ASCUS diagnosis (favor reactive or favor dysplasia) sparingly. After all histologic diagnoses were reviewed, an adjudicated final diagnosis was established. Histologically confirmed SIL was found in 38 women (21 lowgrade SIL, 17 high-grade SIL) including one endocervical adenocarcinoma. Of these 38 cases, 31 were classified originally as ASCUS, not otherwise specified. One case was classified as ASCUS favor reactive and six cases were categorized as ASCUS favor dysplasia. The reviewer who used the ASCUS diagnosis sparingly reclassified the smears as negative (62 cases), ASCUS favor reactive (three cas-
es), ASCUS favor dysplasia (13 cases), low-grade SIL (19 cases), and highgrade SIL (three cases). The reviewer who eliminated the ASCUS category reclassified the smears as negative (59 cases), low-grade SIL (29 cases), and high-grade SIL (12 cases). The rate of SIL/high-grade SIL in those cases interpreted as abnormal was 38% compared with 17% originally, with 42% compared with 24% with reduced ASCUS interpretation, and 37% compared with 17% when the ASCUS category was eliminated. In those ASCUS smears that were reclassified as negative, the SIL/high-grade SIL rate was 35% compared with 13% with a reduced ASCUS interpretation, and 39% compared with 17% when the ASCUS category was eliminated. The sensitivity for detecting SIL/high-grade SIL was reduced from 100% for the original ASCUS interpretation to 42% compared with 53% for the reduced ASCUS interpretation, and 39% compared with 41% with the elimination of the ASCUS interpretation. The authors concluded that eliminating the ASCUS diagnosis appeared to decrease the sensitivity of the Papanicolaou smear significantly, and was no better than chance at predicting a diagnosis of SIL on biopsy including high-grade SIL. Level II-1. ● ● ●
Commentary: The authors believed that an attempt to reduce or eliminate the ASCUS interpretation would not increase the positive predictive value of an abnormal diagnosis for either SIL or high-grade SIL, and resulted in a consistent and significant decrease in the overall sensitivity of both SIL and high-grade SIL. They demonstrated that even with several years experience, they were unable to predict which ASCUS cases would be associated with subsequent SIL or highgrade SIL on biopsy. They did not believe that the new Bethesda System recommendations to eliminate ASCUS favor reactive and stratify ASCUS into either ASCUS not otherwise specified or ASCUS favor highgrade SIL would change the outcome of the current study significantly, because only five cases were diagnosed originally and three reclassified as ASCUS favor reactivity. June 2003
●
ACOG CLINICAL REVIEW
●
5
Management of Term PROM With Oral Misoprostol
ACOG CLINICAL REVIEW Morton A. Stenchever, MD Editor
Ralph W. Hale, MD Associate Editor Nancy Rowe
Managing Editor ● ● ●
Journals Surveyed Include: Acta Obstetricia et Gynecologica Scandinavica ● American Journal of Obstetrics and Gynecology ● Annals of Internal Medicine ● Australian and New Zealand Journal of Obstetrics and Gynaecology BMJ ● British Journal of Obstetrics and Gynaecology Canadian Medical Association Journal ● Cancer ● European Journal of Obstetrics, Gynecology, and Reproductive Biology Fertility and Sterility International Urogynecology Journal JAMA ● Journal of Ultrasound in Medicine ● Lancet ● Military Medicine ● New England Journal of Medicine ● Obstetrics and Gynecology ● Pediatrics ● ● ● Copyright © 2003 by the American College of Obstetricians and Gynecologists. Published by Elsevier Inc. ACOG Clinical Review is issued bimonthly by Elsevier Inc., 360 Park Avenue South, New York, NY 10010-1710. Subscription prices per year: For customers in the United States: Institutional rate: $235.00, personal rate: $119.00, Nurses rate: $31.00. For customers in Europe and the CIS: Institutional rate: EUR 210.00, personal rate: EUR 106.00. For customers in Japan: Institutional rate: JPY 27,800.00, personal rate: JPY 14,700.00. Prices include postage and are subject to change without notice. For additional information, contact Elsevier Customer Support Department, P.O. Box 945, New York, NY 10010, Tel: (212) 633-3730. Toll free (for customers in North America): 1-888-4ES-INFO, Fax: (212) 633-3680, E-mail: [email protected]. Address advertising inquiries to Pharmaceutical Media Inc., 30 East 33rd St., New York, NY 10016. Periodicals postage paid at New York, NY, and at additional mailing offices. Postmaster: Send address changes to ACOG Clinical Review, Elsevier Inc., 360 Park Avenue South, New York, NY 10010-1710. No responsibility is assumed by the publisher or the American College of Obstetricians and Gynecologists for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. Because of rapid advances in the medical sciences, independent verification of diagnoses and drug dosages should be made. Discussions, views, and recommendations as to medical procedures, choice of drugs, and drug dosages are the responsibility of the authors. The appearance of advertising in publications of the American College of Obstetricians and Gynecologists (and/or in exhibits at meetings of the College) does not constitute a guarantee or endorsement of the quality or value of such product or of the claims made for it by its manufacturer. The fact that a product, service, or company is advertised in a publication or exhibited at a meeting of the College shall not be referred to by the manufacturer in advertising.
2
●
ACOG CLINICAL REVIEW
●
June 2003
Shetty A, Stewart K, Stewart G, Rice P, Danielian P, Templeton A. Active management of term prelabour rupture of membranes with oral misoprostol. BJOG 2002; 109:1354 – 8.
Synopsis: The authors compared the active management of term prelabor rupture of membranes with oral misoprostol with conservative management followed by induction with oxytocin or prostaglandin E2 gel. The study was a nonblinded, randomized, controlled trial, and included 61 women with confirmed prelabor rupture of membranes who were at ⱖ36 weeks’ gestation. The women randomized to the active group received 50 g misoprostol orally repeated every 4 hours as required to a maximum of five doses. The control group received an induction of labor at 24 hours if labor had not begun spontaneously. Of the group managed actively, 93.3% were in spontaneous labor within 24 hours compared with 54.8% of the conservatively managed group. Of women achieving a vaginal delivery, 72% of the active group did so within 24 hours of prelabor rupture of membranes compared with 26.9% of the conservative group. No differences were found in neonatal or maternal outcomes or in the cesarean delivery rate, which was 16.7% in the active group and 16.2% in the conservative group. Satisfaction rates were comparable in the two groups (83% versus 76%, P⫽.8). Level I. ● ● ●
Commentary: Whereas the authors demonstrated that active treatment with prostaglandin ripening of the cervix during the first 24 hours after rupture of the membranes resulted in a shorter prelabor to delivery time, no differences were seen in the mode of delivery or the neonatal or maternal outcomes. However, their sample size
was not large enough to address these issues adequately. Thus they demonstrated that using oral misoprostol could speed the process, but did not demonstrate any particular medical advantage or potential harm from one approach over the other, at least within the sample size that they used.
Risk for Uterine Rupture Shipp TD, Zelop C, Cohen A, Repke JT, Lieberman E. Post-cesarean delivery fever and uterine rupture in a subsequent trial of labor. Obstet Gynecol 2003;101:136 –9.
Synopsis: The authors conducted a nested, case-control study in a cohort of women undergoing a trial of labor after cesarean delivery over a 12-year period. Four controls who had had a cesarean delivery at the same institution were matched to each case by year of delivery, number of previous cesarean deliveries, prior vaginal delivery, and induction in the index pregnancy. Fever was defined as temperature above 38°C. Twenty-one cases of uterine rupture were recorded, and the rate of fever after the previous cesarean delivery was 38% (8 of 21) among the cases and 15% (13 of 84) in the control group (P⫽.03), with an odds ratio of 4.0 for rupture occurring with postpartum fever. Level II-1. ● ● ●
Commentary: Whereas the total numbers in this study were small, the information is interesting because recent findings demonstrated that the risk for uterine rupture was increased when patients who had had a previous cesarean delivery experienced a trial of labor. Perhaps the history of fever and probable postpartum infection after the previous cesarean delivery should be taken into consideration when determining if a woman should attempt a trial of labor. If women who have a previous cesarean delivery are to attempt a trial of labor, it will be increasingly important for obstetricians to identify and consider potential risk factors when making such a decision.
Two-Year Outcome of Low Birth Weight Infants Sweet MP, Hodgman JE, Pena I, Barton L, Pavlova Z, Ramanathan R. Two-year outcome of infants weighing 600 grams or less at ©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
birth and born 1994 through 1998. Obstet Gynecol 2003;101:18 –23.
Synopsis: The authors assessed the neurologic and developmental outcomes at 2 years of age in preterm infants with birth weights 600 g or less. The study was retrospective from January 1994 through December 1998 and considered placental histopathology, maternal factors, neonatal intensive care unit course, growth, neurologic/special sense status, and development at 2 years of age corrected for prematurity. Of 104 neonates in this weight class, 24 survived to nursery discharge (23%), two of whom died of chronic lung disease after discharge. Of the remaining infants, 21 of 22 returned for follow-up. Acute inflammation of the placenta was found in 67% and other placental abnormalities occurred in 76%. Mean birth weight was 537 g (430 – 600 g) and mean gestational age was 24 weeks (22–27 weeks). At nursery discharge and 2 years of age, 94% of the infants were below the 10% percentile for weight, length, and head circumference. Among these infants, 19 (90%) were abnormal on neurodevelopment follow-up with major problems including cerebral palsy (76%), blindness (38%), impaired vision (24%), feeding problems (62%), need for gastrostomy tubes (29%), chronic lung disease (86%), and need for ventriculoperitoneal shunts (29%). Level II-2. ● ● ●
Commentary: In the past, the philosophy on most tertiary care units has tended to be to resuscitate all living infants energetically regardless of birth weight or gestational age. This philosophy was reasonable as no data existed pertaining to infant outcome as a result of this resuscitation. However, the results of this study and other similar studies have demonstrated that such a philosophy may be inappropriate. We must ask ourselves which is the lesser tragedy: to allow very immature newborn to die or to commit them and their families to a life of very poor quality? The effect of maintaining severely damaged infants can be devastating to a mother and a family unit, and extremely costly financially to society. A life of good quality ap©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
pears to be just about impossible for such infants. The major problem is how to establish a policy for resuscitation for these infants. Certainly the facts developed by this study, and by similar studies, should be carefully discussed with the mother and her significant other so that their input is included in the decision-making process. In the case of the institution reporting this study (University of Southern California Medical Center), guidelines have been instituted to routinely resuscitate infants weighing ⱖ500 g or of ⱖ24 weeks’ gestation.
Magnesium Sulfate More Effective Than Nimodipine for Preventing Eclampsia Belfort MA, Anthony J, Saade GR, Allen JC Jr, for the Nimodipine Study Group. A comparison of magnesium sulfate and nimodipine for the prevention of eclampsia. N Engl J Med 2003;348:304 –11.
Synopsis: The authors speculated that as magnesium sulfate is effective, at least in part, in preventing eclampsia by reducing cerebral vasoconstriction and ischemia, a calcium channel blocker, nimodipine, which has a specific cerebral vasodilator effect, might also be useful in preventing eclampsia. They therefore performed a study at 14 sites in eight nations of 1650 women with severe preeclampsia who were randomized to receive nimodipine (n⫽819) and magnesium sulfate (n⫽831). Although the study was not blinded, it was randomized and the primary outcome was eclampsia. Secondary outcome measurements, including blood pressure (BP) control, complications of adverse drug effects, complications of labor and delivery, and indication of fetal and neonatal condition, were also studied. Among the 819 women who received nimodipine, 21 (2.6%) had a seizure compared with seven (0.8%) of the 831 women who received magnesium sulfate. This difference was statistically significant (P⫽.01). Thus, the adjusted risk ratio for eclampsia was 3.2 (95% confidence interval 1.1, 9.1). Whereas the antepartum seizure rate did not differ significantly between the groups, a higher rate of postpartum seizure was observed in the nimodipine group. No significant differences were noted in neonatal outcome
between the groups, but more women in the magnesium sulfate group required BP control using hydralazine, and there was a somewhat increased risk of postpartum hemorrhage in the magnesium sulfate group. Level I. ● ● ●
Commentary: Investigating the hypothesis that a calcium channel blocker might be effective in preventing eclampsia, was a reasonable and worthwhile research endeavor. However, once again a new therapeutic approach did not measure up to the benefits of magnesium sulfate in preventing eclampsia. Magnesium sulfate has been the primary therapy used to treat or prevent eclampsia in the United States since 1925, but has been used for this purpose in the rest of the world only recently. Despite the development of newer agents, magnesium sulfate continues to be the best treatment available. Magnesium sulfate radically reduces the effects of preeclampsia and eclampsia on morbidity and mortality, and despite the limitations of a slight increase in postpartum hemorrhage and occasional respiratory distress, it continues to be our leading therapy for this condition.
Value of Midterm Genetic Sonograms Among High-Risk Pregnancies Hobbins JC, Lezotte DC, Persutte WH, et al. An 8-center study to evaluate the utility of midterm genetic sonograms among highrisk pregnancies. J Ultrasound Med 2003; 22:33– 8.
Synopsis: In this study, eight centers provided data on 176 pregnancies with known fetal Down syndrome. Of these pregnancies, 134 were considered high risk because of advanced maternal age, and 42 because of abnormal triple screen results. An abnormal long bone length (femur, humerus, or both), a major structural abnormality, or Down syndrome marker (sandal gap or nuchal skin fold thickness) was present in 125 fetuses (71.0%). Combined diagnostic sensitivity was 71.6% (range 63.6 – 80%) for the eight centers. Level II-2. ● ● ●
June 2003
●
ACOG CLINICAL REVIEW
●
3
Commentary: The authors concluded that as the results of this study and other published studies placed the sensitivity for genetic sonograms at about 70%, this study could be used to better adjust the Down syndrome risk among high-risk patients. Positive findings could alleviate the need for amniocentesis if the specificity of the test is proven to be high. However, as a fairly large percentage of fetuses (about 30%) test negative but still have Down syndrome, avoiding amniocentesis does not seem possible if the genetic sonogram is negative. The work presented is strictly appropriate for high-risk pregnancies. Applying it to the general population may not be prudent; however, it does offer an alternate approach for couples who do not wish to undergo amniocentesis.
Cesarean Delivery Does Not Prevent Anal Incontinence Lal M, Mann CH, Callender R, Radley S. Does cesarean delivery prevent anal incontinence? Obstet Gynecol 2003;101:305–12.
Synopsis: The authors compared the incidence and severity of anal incontinence in primiparas after cesarean delivery with that noted after spontaneous vaginal delivery. Using a comprehensive bowel function questionnaire, interviews were conducted 8 –12 months postpartum with 184 primiparas who were delivered by cesarean (104 emergency, 80 elective) and 100 women who were delivered vaginally. Bowel-specific questions pertained to bowel habits, laxative use, urgency, flatus, urge and passive incontinence, soiling, and pad use, before and during pregnancy and postpartum. The authors noted that anal incontinence was first present in nine mothers (5%) after cesarean delivery and eight (8%) after vaginal delivery. The difference was not statistically significant. Severe symptoms necessitating pad use were observed in two women who underwent cesarean delivery and one who underwent vaginal delivery. Five of 22 women who sustained a second-degree tear had new anal incontinence compared with only one of 40 mothers who had an intact perineum after vaginal delivery. Level II-2. 4
●
ACOG CLINICAL REVIEW
●
June 2003
● ● ●
Commentary: The important takehome message from this study is that cesarean delivery did not necessarily protect against the subsequent development of anal incontinence, and that the incidence was not that different in primigravidas delivered by cesarean or vaginally. Perhaps the damage to the nerves controlling anal incontinence occurs in the last part of pregnancy or during labor because of head pressure on the pelvic nerves, as has been suggested by previous authors. Also of interest is the finding that women with perineal tears were more likely to experience anal incontinence; these tears may be considered another measure of increased pressure on the pelvic floor. In any event, the authors demonstrated, as have other researchers, that performing a cesarean delivery did not necessarily protect against the development of anal incontinence.
of preterm birth in many women, and strategies that reduce the risk by treating potential infection early would seem warranted. However, the proof of the value of any strategy, it seems to this reviewer, would be a reduction in the incidence of LBW and VLBW infants.
Fetal Asphyxia in Preterm Pregnancies Low JA, Killen H, Derrick EJ. Antepartum fetal asphyxia in the preterm pregnancy. Am J Obstet Gynecol 2003;188:461–5.
Synopsis: The authors performed a randomized, double-blind, placebocontrolled, study in three centers in the United Kingdom. They randomized 409 women with abnormal genital tract flora on Gram stain qualifying as bacterial vaginosis at 13–20 weeks’ gestation to receive a 3-day course of clindamycin 2% vaginal cream or placebo. If the flora was still abnormal after 3 weeks, a 7-day course of the same medication was used. The incidence of preterm birth in the clindamycin group was 4% compared with 10% in the placebo group (P ⬍ .03). Level I.
Synopsis: The authors sought to demonstrate the frequency and characteristics of antepartum fetal asphyxia in pregnancies delivered preterm. The study population was derived from 1182 pregnancies delivered preterm between 1984 and 1996 in the authors’ unit in Kingston, Ontario, Canada. Fetal asphyxia occurred in 86 pregnancies as expressed by umbilical artery base deficit of ⬎ 12 mmol/L at delivery. Thirty pregnancies were delivered by cesarean before the onset of labor (the antepartum asphyxia group), and 56 after the onset of labor. Antepartum fetal asphyxia accounted for at least 34% of fetal asphyxia in preterm deliveries. There was a 50% incidence of moderate-to-severe asphyxia in the antepartum preterm pregnancies compared with 15% in term pregnancies as reported in previous publications. Abnormal fetal assessment tests were valuable in predicting antepartum fetal asphyxia. The authors concluded that the increased frequency of moderate and severe fetal asphyxia in a pregnancy delivered preterm implied a greater likelihood of long-term morbidity and death, as nine of the moderate-to-severe cases of asphyxia ended in early neonatal death. Level II-3.
● ● ●
● ● ●
Commentary: Although the authors demonstrated a significant decrease in preterm delivery based on gestational age, no real effect was noted on the number of low birth weight (LBW) infants or very low birth weight (VLBW) infants. Therefore, the clinical significance of this study remains to be seen. Infection is clearly a cause
Commentary: The authors demonstrated that a significant percentage of asphyxiated fetuses delivered preterm were affected before labor, as 30 of their fetuses were delivered before labor. They also demonstrated that antepartum fetal assessment was useful in determining which of the fetuses were suffering from metabolic acido-
Reducing Preterm Birth Lamont RF, Duncan SLB, Mandal D, Bassett P. Intravaginal clindamycin to reduce preterm birth in women with abnormal genital tract flora. Obstet Gynecol 2003;101: 516 –22.
©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
sis, and that the presence of moderateto-severe asphyxia was related to a high percentage of neonatal death, thus demonstrating the sensitivity of the fetal brain to acidosis. In many cases of preterm birth, the fetus is already damaged before labor occurs, and utilization of fetal assessment studies in pregnancies at high risk of preterm labor should be vigorously used.
Maternal Morbidity After Repeat Caesarean Delivery Lynch CM, Kearney R, Turner MJ. Maternal morbidity after elective repeat caesarean section after two or more previous procedures. Eur J Obstet Gynecol Reprod Biol 2003;106:10 –3.
Synopsis: The authors of this Irish study identified 250 women who had had two or more previous cesarean deliveries out of a total of 67,097 deliveries of infants weighing ⬎ 500 g. Eighty women were having a third cesarean delivery, 131 women were having a fourth cesarean delivery, and 39 had five or more cesarean deliveries. The study was performed from 1990 to 1999. Placenta previa was seen in 12 women (4.8%), four of whom required transfusion and two a hysterectomy. Wound infection occurred in 6.3% of the women and urinary tract infection occurred in 11.2%. No cases of thromboembolism or maternal deaths were recorded. Level II-3. ● ● ●
Commentary: The authors proved once again that most women with a history of previous cesarean delivery can have subsequent cesarean deliveries with a relatively low risk for morbidity. However, the rate of placenta previa (4.8%) was greatly increased from the normal rate of about 0.5%, and can, as was shown in this study, be of a higher stage, such as placenta accreta. The two patients who required hysterectomy had had four and six previous cesarean deliveries, respectively. Clearly, if a grand multipara has had multiple previous cesarean deliveries, she is best managed by a repeat cesarean delivery. However, as the authors pointed out, performing ultrasound to detect placenta previa and planning the elective cesarean delivery ©2003 by the American College of Obstetricians and Gynecologists Published by Elsevier Inc. 1085-6862/03/$6.00
at a time when optimal staff is available would be prudent. The authors correctly pointed out that the risk of maternal mortality could not be measured in this study because of the relatively small numbers. However, when dealing with grand multiparas and the potential for placenta accreta, mortality is certainly a possibility that must be kept in mind and all precautions taken to avoid it.
SPOTLIGHT ON GYNECOLOGY Morton A. Stenchever, MD Editor
Value of ASCUS Interpretation on Papanicolaou Smear Pitman MB, Cibas ES, Powers CN, Renshaw AA, Frable WJ. Reducing or eliminating use of the category of atypical squamous cells of undetermined significance decreases the diagnostic accuracy of the Papanicolaou smear. Cancer 2002;96:128 –34.
Synopsis: The authors reviewed 100 cervical Papanicolaou smears originally diagnosed as atypical squamous cells of undetermined significance (ASCUS), all of which had histologic follow-up. One reviewer re-reviewed the material blindly and reclassified the smears as negative (within normal limits/benign cellular changes), lowgrade squamous intraepithelial lesions (SIL) or high-grade SIL, thereby eliminating ASCUS as a diagnostic possibility. The second reviewer reinterpreted the cases, but attempted to use the ASCUS diagnosis (favor reactive or favor dysplasia) sparingly. After all histologic diagnoses were reviewed, an adjudicated final diagnosis was established. Histologically confirmed SIL was found in 38 women (21 lowgrade SIL, 17 high-grade SIL) including one endocervical adenocarcinoma. Of these 38 cases, 31 were classified originally as ASCUS, not otherwise specified. One case was classified as ASCUS favor reactive and six cases were categorized as ASCUS favor dysplasia. The reviewer who used the ASCUS diagnosis sparingly reclassified the smears as negative (62 cases), ASCUS favor reactive (three cas-
es), ASCUS favor dysplasia (13 cases), low-grade SIL (19 cases), and highgrade SIL (three cases). The reviewer who eliminated the ASCUS category reclassified the smears as negative (59 cases), low-grade SIL (29 cases), and high-grade SIL (12 cases). The rate of SIL/high-grade SIL in those cases interpreted as abnormal was 38% compared with 17% originally, with 42% compared with 24% with reduced ASCUS interpretation, and 37% compared with 17% when the ASCUS category was eliminated. In those ASCUS smears that were reclassified as negative, the SIL/high-grade SIL rate was 35% compared with 13% with a reduced ASCUS interpretation, and 39% compared with 17% when the ASCUS category was eliminated. The sensitivity for detecting SIL/high-grade SIL was reduced from 100% for the original ASCUS interpretation to 42% compared with 53% for the reduced ASCUS interpretation, and 39% compared with 41% with the elimination of the ASCUS interpretation. The authors concluded that eliminating the ASCUS diagnosis appeared to decrease the sensitivity of the Papanicolaou smear significantly, and was no better than chance at predicting a diagnosis of SIL on biopsy including high-grade SIL. Level II-1. ● ● ●
Commentary: The authors believed that an attempt to reduce or eliminate the ASCUS interpretation would not increase the positive predictive value of an abnormal diagnosis for either SIL or high-grade SIL, and resulted in a consistent and significant decrease in the overall sensitivity of both SIL and high-grade SIL. They demonstrated that even with several years experience, they were unable to predict which ASCUS cases would be associated with subsequent SIL or highgrade SIL on biopsy. They did not believe that the new Bethesda System recommendations to eliminate ASCUS favor reactive and stratify ASCUS into either ASCUS not otherwise specified or ASCUS favor highgrade SIL would change the outcome of the current study significantly, because only five cases were diagnosed originally and three reclassified as ASCUS favor reactivity. June 2003
●
ACOG CLINICAL REVIEW
●
5