When Has an Induction Failed?

OBJECTIVE

To evaluate the length of the latent phase that, during labor inductions in nulliparous women, is associated with significantly decreased chance of vaginal delivery and increased risk of maternal and neonatal morbidity.

METHODS

All inductions of labor during a 6-month period were identified. Only those women who were nulliparous with a pregnancy of 36 weeks or more of gestation underwent further data analysis. Demographic data, intrapartum course, and maternal and neonatal outcomes were abstracted from the medical record. The latent phase was defined as beginning after oxytocin had been initiated and amniotomy performed and continuing until either 4 cm cervical dilation and 80% effacement or 5 cm cervical dilation regardless of effacement.

RESULTS

A total of 397 nulliparous women, 32% of whom underwent cervical ripening, presented during the study period. Only 8 women (2%) never achieved active phase labor before cesarean, and the overall cesarean rate was 26.0%. A longer latent phase was associated with a greater rate of cesarean delivery, although only after 18 hours did a majority of induced labors result in cesarean. Chorioamnionitis and postpartum hemorrhage were more frequent with latent phases of labor greater than 18 hours (16% and 26%, respectively), although these diagnoses did not translate into greater risk of transfusion, hysterectomy, or prolonged hospitalization. Neonatal outcomes, including meconium passage, fetal acidemia, neonatal intensive care unit admission, or other morbidity did not increase in conjunction with longer latent phases.

CONCLUSION

A latent phase of as long as 18 hours during induction of labor in nulliparous women allows the majority of these women to achieve a vaginal delivery without being subject to a significantly increased risk of significant maternal or neonatal morbidity.

LEVEL OF EVIDENCE

II-2.

Routine hepatitis C virus screening in pregnancy: a cost-effectiveness analysis

OBJECTIVE

The purpose of this study was to determine whether routine hepatitis C virus screening in pregnancy is cost-effective.

STUDY DESIGN

A decision tree with Markov analysis was developed to compare 3 approaches to asymptomatic hepatitis C virus infection in low-risk pregnant women: (1) no hepatitis C virus screening, (2) hepatitis C virus screening and subsequent treatment for progressive disease, and (3) hepatitis C virus screening, subsequent treatment for progressive disease, and elective cesarean delivery to avert perinatal transmission. Lifetime costs and quality-adjusted life years were evaluated for mother and child.

RESULTS

In our base case, hepatitis C virus screening and subsequent treatment of progressive disease was dominated (more costly and less effective) by no screening, with an incremental cost of 108 US dollars and a decreased incremental effectiveness of 0.00011 quality-adjusted life years. When compared with no screening, the marginal cost and effectiveness of screening, treatment, and cesarean delivery was 117 US dollars and 0.00010 quality-adjusted life years, respectively, which yields a cost-effectiveness ratio of 1,170,000 US dollars per quality-adjusted life year.

CONCLUSION

The screening of asymptomatic pregnant women for hepatitis C virus infection is not cost-effective.

The association of echogenic fetal lungs with trisomy 21

OBJECTIVE

To evaluate the association between echogenic appearing lungs on ultrasonographic examination of the fetus and aneuploidy.

METHODS

Cases in which echogenic lungs were prospectively identified on ultrasonographic examination were collected. Other abnormal ultrasonographic findings were documented, as were patient data pertinent to the risk of aneuploidy, such as maternal age and results of serum screening. The chromosomal complement of each identified case is reported.

RESULTS

Five fetuses were identified with diffusely echogenic lungs on ultrasound examination over a two-year period. In three of the five cases, there were other ultrasound abnormalities, although in only one of these was a major congenital abnormality detected. In all three of these cases, the fetal chromosomal complement showed trisomy 21. In 1 of the 2 cases in which the echogenic lungs were an isolated finding, the fetus also was found to have trisomy 21.

CONCLUSIONS

Bilateral and diffusely echogenic lungs appear to have an association with fetal trisomy 21.

Neurodevelopmental outcome of very low birth weight infants after multiple courses of antenatal corticosteroids

OBJECTIVE

To determine if two or more courses of antenatal corticosteroids are associated with neurodevelopmental impairment.

METHODS

All infants born at Northwestern Memorial Hospital between 1995 and 1998, who met the following criteria, were identified: birth weight < or = 1500 g, gestational age between 24 and 34 weeks, recipient of antenatal corticosteroids, and subsequent neurodevelopmental evaluation in multidisciplinary developmental evaluation clinic. The outcomes of these infants were compared according to degree of corticosteroid exposure. This study had 80% power to detect a difference in the mental development index score of 10% or a relative risk of neurodevelopmental delay of 2.5 in the group receiving at least two courses of corticosteroids.

RESULTS

Ninety-three infants were exposed to less than two full courses and 33 infants were exposed to at least two full courses of corticosteroids. The mean duration of follow-up was similar in the two groups (25 months vs 30 months, respectively, P >.05). The two groups had similar neonatal outcomes, and had no differences in any measures of neurodevelopmental outcome on follow-up.

CONCLUSION

Repeated courses of antenatal corticosteroids are not associated with increased incidence of abnormalities on subsequent neurodevelopmental outcome measures.

The cost-effectiveness of routine antenatal screening for maternal herpes simplex virus-1 and -2 antibodies

OBJECTIVE

The purpose of this study was to determine the cost-effectiveness of routine antenatal screening for herpes simplex virus 1 and 2 in women without a known history of genital herpes.

STUDY DESIGN

Decision analysis was used to compare 3 treatment strategies to prevent neonatal herpes infection in women without a known history of genital herpes simplex virus: (1) the current standard of care (no herpes simplex virus screening), (2) antepartum herpes simplex virus-1 and -2 antibody screening of the pregnant woman and her male partner with appropriate counseling, and (3) antepartum herpes simplex virus-1 and -2 antibody screening with appropriate counseling and acyclovir prophylaxis at 36 weeks of gestation in seropositive women.

RESULTS

Our model predicts that using current guidelines, 1 of 5469 women will have a herpes-infected neonate. Strategy 2 and 3 cost $5,812,819 and $4,130,297, respectively, for every significant neurologic sequela or death prevented. The cost-effectiveness of these strategies, expressed as cost per quality life-year gained, was $219,513 and $155,988 respectively. These results were robust in the sensitivity analysis.

CONCLUSION

Routine herpes simplex virus screening in pregnancy is not cost-effective.

The thrombogenic effect of an inflammatory cytokine on trophoblasts from women with preeclampsia

OBJECTIVE

This study was undertaken to investigate whether the increased thrombogenic potential of cytotrophoblastic cells of women with preeclampsia can be accounted for by increased rates of apoptosis.

STUDY DESIGN

Cytotrophoblasts were isolated from the placenta of (a) nulliparous women without hypertensive disease who were delivered at term and (b) nulliparous women with preeclampsia. The cytotrophoblasts were identified by morphology, and cytokeratin and gonadotropin-releasing hormone positivity. The inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) was added to cytotrophoblasts in vitro and incubated for 24 hours. Tissue factor antigen, activity, and amount of apoptosis were evaluated both before and after TNF-alpha stimulation.

RESULTS

TNF-alpha simulation significantly increased tissue factor activity both in the cytotrophoblasts of women with (0.08 +/- 0.04 pmol/min/10 6 cells to 0.53 +/- 0.19 pmol/min/10 6 cells) and without (0.07 +/- 0.04 pmol/min/10 6 cells to 0.30 +/- 0.16 pmol/min/10 6 cells) preeclampsia. TNF-alpha stimulation of the cytotrophoblasts also significantly increased tissue factor antigen in the cytotrophoblasts of both groups of women (3.6 +/- 0.9 fmol/10 6 cells to 34.0 +/- 7.5 fmol/10 6 cells, and 7.5 +/- 1.4 fmol/10 6 cells to 25.4 +/- 2.2 fmol/10 6 cells, respectively). For both tissue factor antigen and activity, the magnitude of increase after stimulation was significantly greater in the preeclamptic cytotrophoblasts. In contrast, both normal and preeclamptic cytotrophoblasts showed similar increases in their apoptotic indices (approximately 2-fold) after induction by TNF-alpha.

CONCLUSION

The greater response of tissue factor activity and antigen to TNF-alpha by preeclamptic cytotrophoblasts cannot be accounted for by the increase in apoptosis. These data suggest that preeclamptic cytotrophoblasts are inherently more thrombogenic and more sensitive to TNF-alpha stimulation.

Elective cesarean delivery to prevent perinatal transmission of hepatitis C virus: a cost-effectiveness analysis

OBJECTIVE

This study was undertaken to determine whether elective cesarean delivery to avert perinatal hepatitis C virus (HCV) transmission is cost-effective.

STUDY DESIGN

Using decision analysis, we compared 2 approaches: (1) offering elective cesarean delivery to avert perinatal HCV transmission, (2) performing a cesarean delivery only for obstetric indications. Lifetime cost and quality-adjusted-life-years (QALYs) for HCV-infected neonates were evaluated with Markov analysis. We assumed elective cesarean delivery reduces perinatal HCV transmission, and we varied both the risk reduction caused by elective cesarean delivery and the background risk of perinatal HCV infection.

RESULTS

When elective cesarean section prevents all perinatal HCV transmission, 18 elective cesarean deliveries are necessary to avert 1 neonatal infection with a cost-effectiveness ratio of 34,812 dollars/QALY. At a background perinatal transmission rate of 7.7% elective cesarean deliveries is cost-effective only if it reduces the risk of perinatal transmission by more than 77%.

CONCLUSION

Elective cesarean delivery is cost-effective only if it substantially reduces the risk of perinatal HCV transmission.

Does fetal fibronectin use in the diagnosis of preterm labor affect physician behavior and health care costs? A randomized trial

OBJECTIVE

The purpose of this study was to determine whether a knowledge of fetal fibronectin results affects patient treatment and health care costs.

STUDY DESIGN

Women between 24 and 34 weeks of gestation with a singleton pregnancy and preterm uterine contractions were eligible for enrollment. Once informed consent was given, a fetal fibronectin specimen was obtained, and women were assigned randomly into 2 groups. In 1 group, results of the fetal fibronectin test were available; in the other group, results were not available. The use of inpatient and outpatient health care resources subsequent to enrollment was ascertained through the use of medical records, hospital billing data, and patient interviews. This study was powered to allow the detection in the fetal fibronectin group of a 20% reduction in total health care-related costs.

RESULTS

The 2 groups were similar with respect to maternal age, parity, race, cervical examination at admission, and estimated gestational age at enrollment and at delivery. Women who did not have fetal fibronectin results available were no different than those women who did with respect to initial length of labor and delivery observation (median, 4 hours vs 3 hours), hospital admission (28% vs 26%), tocolysis (18% vs 16%), cessation of work (27% vs 26%), or total health care-related costs (log mean +/- SD, 7.6 +/- 1.2 vs 7.5 +/- 1.1).

CONCLUSION

In this study population, the use of fetal fibronectin did not affect physician behavior or health care costs related to preterm contractions.

Induction of labor after one prior cesarean: predictors of vaginal delivery

OBJECTIVE

To estimate the characteristics most associated with vaginal birth in patients undergoing induction of labor after 1 prior cesarean delivery.

METHODS

All patients who presented for induction of labor from 1996 to 2001 with a history of 1 prior cesarean delivery were identified. Relevant demographic and obstetric data were abstracted from the charts. Univariate analysis was used to identify predictive factors associated with vaginal birth after cesarean. Binary logistic regression was further used to identify which factors were independently associated with the outcome measure.

RESULTS

Of the 429 women included in the study, 334 (77.9%) had a successful trial of labor. In the final binary logistic regression equation, prior vaginal delivery (odds ratio [OR] 3.75; 95% confidence interval [CI] 1.96, 7.18) remained independently associated with an increased chance of a vaginal delivery after a trial of labor. Conversely, prior cesarean delivery for dystocia (OR 0.46; 95% CI 0.27, 0.79), induction on or past the estimated date of delivery (OR 0.46; 95% CI 0.27, 0.78), need for cervical ripening (OR 0.35; 95% CI 0.20, 0.61), and maternal gestational or preexisting diabetes (OR 0.16; 95% CI 0.06, 0.40) were all factors associated with a decreased likelihood of achieving a successful trial of labor.

CONCLUSION

Several factors are available which may assist in identifying patients with the best chance of vaginal delivery after an induction of labor in the presence of a prior low-transverse cesarean scar.

LEVEL OF EVIDENCE

II-2

Isolated low second-trimester maternal serum β-human chorionic gonadotropin is not associated with adverse pregnancy outcome

OBJECTIVE

We investigated whether low human chorionic gonadotropin from maternal serum screening is associated with adverse pregnancy outcome.

STUDY DESIGN

Women between 15 and 20 completed weeks of gestation who had a maternal serum screen performed from June 1999 to November 2001 were studied. Cases included women with human chorionic gonadotropin values of <or=0.5 multiples of the median, alpha-fetoprotein values of >0.5 and <2.0 multiples of the median, and estriol values of >0.6 and <2.0 multiples of the median. Control subjects were selected randomly from the population of women with normal values for all three analytes.

RESULTS

There were 146 case subjects and 292 control subjects. There was no increased risk in the study group compared with the control subjects for preterm delivery, intrauterine fetal death, low birth weight, abruptio placentae, preeclampsia, or preterm premature rupture of membranes.

CONCLUSION

An isolated low human chorionic gonadotropin level from second-trimester maternal serum screening is not associated with adverse pregnancy outcome.

Infertility patients and their partners: differences in the desire for twin gestations

OBJECTIVE

To explore how the individuals within an infertile couple differ from one another in their attitudes toward the conception of twin gestations.

METHODS

From November 1999 through February 2000, consecutive couples undergoing treatment at a university-based infertility clinic were invited to participate in a face-to-face interview that ascertained their individual desires for singleton and twin gestations and their perception of the risks associated with these pregnancies.

RESULTS

Of the 94 couples approached, 90 (96%) agreed to participate in the study. Patients estimated the incidence of prematurity, low birth weight, preeclampsia, and postpartum depression in twin gestations to be significantly greater than their partners did (27% versus 17%, 26% versus 17%, 22% versus 16%, and 21% versus 16%, respectively). Despite these higher estimates, the desire for a twin gestation was similar. In 19 couples (21%), the patient and partner did not agree whether a singleton or twin pregnancy was the most preferred outcome. No predictive factor for this discordance could be identified.

CONCLUSION

Women undergoing infertility treatment are less risk averse than their partners. Additionally, a sizeable portion of couples do not align in their preference for a twin gestation. These differences should be recognized and addressed during the preconceptional period.

Management of the second stage of labor in nulliparas with continuous epidural analgesia

OBJECTIVE

To determine if waiting for a strong urge to push in nulliparas with continuous low-concentration epidural analgesia shortens the pushing duration in the second stage.

METHODS

Nulliparas with standardized patient-controlled epidural analgesia (0.0625% bupivacaine with fentanyl 2 microg/mL) were randomly assigned to pushing immediately upon complete cervical dilatation (n = 85) or waiting for a strong urge to push (n = 117). Urge to push and patient satisfaction were quantified on 100-mm visual analogue scales. Duration of pushing and total duration of the second stage were analyzed as survival time data.

RESULTS

Women who delayed pushing and those who pushed immediately were similar with respect to maternal characteristics. Women who delayed pushing had a stronger urge to push (P <.01) and a longer second stage (P <.05) than women who pushed immediately. There was no significant difference in the time spent pushing (median 57 versus 62 minutes, respectively) or the median level of patient satisfaction (80 mm for both groups). There were no significant differences in the overall rates of cesarean delivery (6% versus 12%, respectively), cesarean delivery during the second stage (2% in each group), spontaneous vaginal delivery (70% versus 69%, respectively), or neonatal or maternal morbidity.

CONCLUSION

In nulliparas with continuous low-concentration epidural analgesia, delaying pushing until a strong urge is felt does not reduce the duration of pushing in the second stage of labor.

Factors associated with success of emergent second-trimester cerclage

OBJECTIVE

To assess the factors associated with delivery greater than or equal to 28 weeks' gestation after placement of an emergent cerclage in women with singleton gestations.

METHODS

All women who underwent emergent cerclage, defined as any cerclage placed between 16 and 24 6/7 weeks' gestation in response to documented cervical change on physical examination, at Northwestern Memorial Hospital from 1980 to 2000 were identified. Univariable and multivariable analyses were used to determine the factors most associated with achieving at least 28 weeks' gestation.

RESULTS

One hundred sixteen women were eligible for analysis. Maternal age, race, and operative variables such as suture type and use of antibiotics were not associated with differences in the frequency of delivery at or after 28 weeks. Cerclage placement at or after 22 weeks' gestation increased the likelihood of reaching 28 weeks, whereas several cervical examination findings (dilatation greater than 3 cm, cervical length less than 0.5 cm, and membranes prolapsing beyond the external cervical os) as well as need for placement in a nullipara significantly reduced the likelihood of reaching 28 weeks. In multivariable analysis, nulliparity (odds ratio 0.31, 95% confidence interval 0.1, 0.8) and membranes prolapsing beyond the external cervical os (odds ratio 0.24, 95% confidence interval 0.1, 0.4) continued to be associated with delivery before 28 weeks, whereas cerclage placement at or after 22 weeks (odds ratio 3.2, 95% confidence interval 1.2, 8.6) increased the chance of achieving at least 28 weeks' gestation.

CONCLUSION

Nulliparity, the presence of membranes prolapsing beyond the external cervical os, and gestational age less than 22 weeks at cerclage placement are associated with decreased chance of delivery at or after 28 weeks after emergent cerclage; these factors may be used to help counsel patients considering the procedure.

Preference assessment of prenatal diagnosis for Down syndrome: is 35 years a rational cutoff?

OBJECTIVE

To compare the perceptions of miscarriage and birth of a child with Down syndrome among pregnant women and to evaluate the implications of these preferences for the traditional 35-year old maternal age risk boundary.

METHODS

An interviewer-administered survey was given to 186 pregnant women receiving antepartum care at a university hospital. Preferences, as reflected by utilities, for birth of a child with Down syndrome and pregnancy miscarriage, stratified by patient characteristics, were assessed.

RESULTS

The utility for the birth of a child with Down syndrome decreased (p < 0.001) as clinical severity increased from mild (0.78) to severe (0.65). Miscarriage of a pregnancy had a mean utility of 0.76 +/- 0.31. Women who desired prenatal diagnosis had a utility value for miscarriage (0.79 +/- 0.28) that was significantly higher than for the birth of a child with Down syndrome of unknown severity (0.73 +/- 0.27). In multivariable logistic regression, desire for prenatal diagnosis was the only factor associated with a preference of miscarriage over birth of an affected child (odds ratio 2.26, 95% confidence interval 1.03, 4.96).

CONCLUSION

Women who desire prenatal diagnosis do not perceive the birth of a child with Down syndrome and a pregnancy miscarriage to be equivalent health states. This finding calls into question the rationale of the 35-year-old maternal age criterion and suggests that actual patient preferences should be better incorporated into the decision to offer definitive prenatal diagnosis.

Patient perceptions of multiple gestations: an assessment of knowledge and risk aversion

OBJECTIVE

To determine whether knowledge of the increased risk of certain pregnancy complications affects a woman's desire to achieve a multifetal gestation.

STUDY DESIGN

Women who attended an infertility clinic were given an interviewer-administered survey that ascertained how intensely they desired a multifetal pregnancy and how accurately they perceived the risks of multifetal complications. In addition, 5-point Likert scales were used to assess how different perceptions of risk affected the desire for gestations of different plurality.

RESULTS

Most respondents (67%) expressed the desire to conceive a twin pregnancy, although they could not accurately estimate the probability of risks associated with this type of pregnancy. Nevertheless, their desire was affected by perceptions of pregnancy-associated risk. On the basis of ordinal regression, desire for twins was more likely after in vitro fertilization (P <.01) but less likely as a woman's estimation of the risk of pregnancy complications increased (P <.05). When women were presented with scenarios of differing pregnancy-associated risk magnitudes, their desire for twin pregnancy decreased as risk magnitudes increased (median Likert score decrease from 4 to 3 to 2, P <.01). After being confronted with the actual probabilities of specified perinatal complications associated with a twin pregnancy, women were less desirous of having a twin pregnancy (median Likert score decrease from 4 to 3, P <.001) than they had originally expressed.

CONCLUSION

Women who undergo treatment for infertility are not well aware of the risks of perinatal complications associated with multiple gestations. Moreover, these women are risk sensitive and change their desires on the basis of their perception of overall risk.

Indomethacin tocolysis and intraventricular hemorrhage

OBJECTIVE

To determine the association between indomethacin tocolysis and neonatal intraventricular hemorrhage.

METHODS

Fifty-six preterm neonates with intraventricular hemorrhage were matched by gestational age with neonates (n = 224) without this morbidity. Maternal and neonatal charts were reviewed to ascertain the type of tocolytic exposure experienced by the neonate. Other maternal and neonatal demographic and outcome data were also abstracted. Results were analyzed using the Student t test, chi(2) analysis, and multivariable logistic regression. The number of studied subjects provided 80% power to determine if antenatal exposure to indomethacin was twice as likely among infants with intraventricular hemorrhage.

RESULTS

Univariate analysis revealed that there were no significant differences between the study and control groups with respect to maternal age, parity, or betamethasone exposure. Infants with intraventricular hemorrhage were significantly more likely to be born at an earlier gestational age, a lower birth weight, after maternal chorioamnionitis, after vaginal delivery, and after exposure to either indomethacin alone or a combination of indomethacin and magnesium. Additionally, their neonatal course was significantly more likely to be complicated by sepsis and respiratory distress syndrome. In a multivariable logistic model, only gestational age, chorioamnionitis, vaginal delivery, and respiratory distress syndrome continued to be significantly associated with intraventricular hemorrhage. Indomethacin exposure, either as single-agent (adjusted odds ratio 1.3, 95% confidence interval 0.5, 3.3) or combination tocolytic therapy (adjusted odds ratio 2.0, 95% confidence interval 0.8, 4.8), was not significantly associated with intraventricular hemorrhage.

CONCLUSION

Indomethacin tocolysis is not associated with an increased risk of intraventricular hemorrhage.

Serum insulin, insulin-like growth factor-I, and insulin-like growth factor binding protein-1 in women who develop preeclampsia

OBJECTIVE

To determine whether second-trimester serum concentrations of insulin, insulin-like growth factor-I (IGF-I), and insulin-like growth factor binding protein-1 (IGFBP-1) were altered in women before they developed clinical signs of preeclampsia.

METHODS

A nested case-control study used serum obtained during second-trimester pregnancies from 12 women who developed preeclampsia matched with 24 controls who remained normotensive. Nine preeclamptic subjects and 18 controls were necessary to have 80% power to discern a 20% difference between groups with regard to the analytes under consideration.

RESULTS

There were no significant differences between cases and controls with respect to many demographic factors. Women who developed preeclampsia had insulin concentrations that were not significantly different from controls, but serum concentrations of IGF-I were significantly higher and IGFBP-1 were significantly lower than those of the controls. The IGF-I/IGFBP-1 ratio helped to identify those at risk for developing preeclampsia.

CONCLUSIONS

Serum concentrations of IGF-I and IGFBP-1 were abnormal long before women manifested clinical evidence of preeclampsia in this study. These alterations might be related to abnormalities in trophoblastic invasion and prove useful as potential markers for the identification of women who are at high risk of developing preeclampsia.

Serum levels of activin A and inhibin A and the subsequent development of preeclampsia

OBJECTIVE

To determine whether serum levels of activin A and inhibin A are altered in patients before development of preeclampsia.

METHODS

Blood samples were collected from patients during the second trimester of prenatal care. We identified patients who subsequently developed preeclampsia and matched them with patients who had no evidence of preeclampsia during their gestation. Matching criteria included gestational age at blood sampling, gestational age at delivery, and birth weight. Assays were then performed to assess the levels of activin A and inhibin A in the control and study groups. A power calculation determined that 12 patients who subsequently developed preeclampsia, if matched with controls in a 1:2 ratio, would allow the detection of differences in analyte levels that were 60% as large as those previously reported between patients already diagnosed with preeclampsia and matched controls.

RESULTS

Twelve patients with preeclampsia were identified and matched with 24 controls. No differences in serum levels of activin A or inhibin A were detected between the two groups. Because of the significant overlap of analyte levels between the two groups, no cutpoint that would allow identification of patients destined to become preeclamptic could be determined.

CONCLUSION

These data suggest that activin A and inhibin A cannot be used as markers for later development of preeclampsia in a low-risk population.

Comparison of active phase labor between triplet, twin, and singleton gestations

OBJECTIVE

To characterize the active phase of labor in triplet pregnancies and compare it with gestational age-matched twins and singletons.

METHODS

Active phase rates were calculated beginning at 5 cm of dilation for women with triplet gestations longer than 24 weeks who labored and reached the second stage. Twin and singleton cohorts that also completed the first stage of labor were matched for gestational age at delivery (+/-1 week), parity, and epidural use. Intrapartum variables included oxytocin use (induction or augmentation, duration of infusion, and maximum dosage), cervical dilation at membrane rupture, and active phase dilation rate.

RESULTS

Thirty-two triplet pregnancies met inclusion criteria between January 1994 and September 1998 and were each compared with twin and singleton cases in a 1:2 ratio. Triplet and twin active phase rates, while similar (1.8 versus 1.7 cm/hour, respectively), were significantly lower than the mean singleton dilation rate (2.3 cm/hour, P =.02). No other intrapartum variables differed between the three groups. Despite controlling for gestational age at delivery, mean birth weights were significantly higher in singletons and correspondingly lower in twins and triplets (2,493 versus 2,112 and 1,968 g, respectively; P =.001). An analysis of active phase dilation rates as a function of the cumulative birth weight per pregnancy demonstrated an inverse correlation, with slower progress in active labor associated with increasing total fetal weight (R = -.24; P =.002).

CONCLUSIONS

Triplet and twin active phase dilation proceeds at a slower rate than that observed in singleton pregnancies. The rate of active phase dilation is inversely correlated to total fetal weight.

Indomethacin tocolysis and risk of necrotizing enterocolitis

OBJECTIVE

To investigate the possible association of indomethacin tocolysis with neonatal necrotizing enterocolitis.

METHODS

A case-control study was performed for the period November 1, 1997, through May 1, 1999. All cases of proven necrotizing enterocolitis were ascertained, and four controls for each case were randomly identified from all Special Care Nursery admissions before 37 weeks' gestation without necrotizing enterocolitis during that same period.

RESULTS

During the 18-month period there were 24 cases of necrotizing enterocolitis out of 10,200 deliveries. Infants with necrotizing enterocolitis were more preterm (29.7 +/- 3.9 compared with 32.7 +/- 6.0 weeks; P =.03) and had lower birth weights (1453 +/- 777 compared with 1820 +/- 678 g; P =.02) compared with controls (n = 96). Respiratory distress syndrome (RDS) and sepsis were both significantly associated with an increased risk of necrotizing enterocolitis: 16 of 24 cases compared with 40 of 96 controls had RDS (odds ratio [OR] 2.8, 95% confidence interval [CI] 1.0, 8.3) and 14 of 24 cases compared with 11 of 96 controls were septic (OR 10.8, 3.4, 95% CI 34.2). Indomethacin as a single agent was not associated with necrotizing enterocolitis (OR 1.0, 95% CI 0.2, 4.8). Using a logistic regression model, necrotizing enterocolitis was strongly associated with sepsis (adjusted OR 8.5, 95% CI 2.2, 32.5). When sepsis was removed from the model, double-agent tocolytic therapy was significantly associated with necrotizing enterocolitis (adjusted OR 6.9, 95% CI 1.1, 43.6).

CONCLUSION

Tocolysis with indomethacin as a single agent was not associated with necrotizing enterocolitis in this case-control study. Combination tocolytic therapy may be a marker for subclinical infection and not causally related to necrotizing enterocolitis.

Cost-effectiveness of elective cesarean delivery after one prior low transverse cesarean

OBJECTIVE

This analysis was undertaken to better understand the costs and health consequences of a trial of labor after cesarean when compared with a policy of routine elective repeat cesarean delivery.

METHODS

A decision-tree model incorporating a Markov analysis was used to examine the reproductive life of a hypothetical cohort of 100,000 pregnant women whose only prior pregnancy was delivered through a low transverse cesarean incision. Using this model, the policy of performing routine elective cesarean delivery was compared with a policy of allowing a trial of labor. Main outcome measures were maternal and neonatal morbidity and mortality, total costs to the health care system, and cost per major neonatal complication avoided (death or permanent neurologic sequelae).

RESULTS

The consequences of routine elective cesarean delivery for a second birth are significant, with an additional 117,748 cesarean deliveries, 5500 maternal morbid events, and $179 million incurred during the reproductive life of 100,000 women. The prevention of one major adverse neonatal outcome requires 1591 cesarean deliveries and $2.4 million. Sensitivity analysis confirms the robustness of the analysis.

CONCLUSION

Routine elective cesarean for a second delivery for women with a prior low transverse cesarean incision results in an excess of maternal morbidity and mortality and a high cost to the medical system.

The cost-effectiveness of voluntary intrapartum rapid human immunodeficiency virus testing for women without adequate prenatal care

OBJECTIVES

We sought to determine the health and economic consequences of voluntary rapid human immunodeficiency testing during labor for women who have not received adequate prenatal care.

STUDY DESIGN

A decision-tree model was used to assess the number of pediatric human immunodeficiency virus cases that would be averted if women who were unable to determine their human immunodeficiency virus serostatus antenatally were offered an intrapartum rapid human immunodeficiency virus test. Medical costs associated with the introduction of this policy were also determined. Probability and cost estimates entered into the model are based on data in the published literature.

RESULTS

Under the base-case assumptions, a policy of intrapartum voluntary rapid human immunodeficiency virus testing decreases the number of cases of perinatal human immunodeficiency virus from 407 to 339 per 100,000 women without adequate prenatal care per year, with a corresponding cost savings of $6 million. Sensitivity analysis demonstrates that these cost savings are maintained across a wide range of assumptions and that even conservative scenarios still result in a cost-effective policy.

CONCLUSIONS

In the absence of adequate prenatal care, a voluntary rapid human immunodeficiency virus test not only allows patients to fully explore their options with regard to testing and treatment but also has the potential to provide significant health benefits to women and children and economic benefits to the medical system.

Positive predictive value of suspected growth aberration in twin gestations

OBJECTIVE

Our purpose was to determine the positive predictive value of ultrasonographic surveillance for growth abnormalities in twin gestations as a function of gestational age.

STUDY DESIGN

Women with twin gestations and delivery between January 1992 and March 1998 who had a 20- to 24-week sonogram with normal fetal anatomic findings and who had at least 1 sonogram showing abnormal growth were identified. Abnormal growth on ultrasonography was defined as an estimated fetal weight <10th percentile, abdominal circumference <5th percentile, or twin discordance (>20% difference in twin weights as a function of the heavier twin). Birth weights were then assessed for evidence of twin discordance or growth restriction.

RESULTS

The positive predictive value for the occurrence of a growth abnormality at birth, after an abnormal growth finding on ultrasonography at any time during gestation, was 47.7%. The positive predictive value was greatest (85%) when suspected growth restriction was first documented at 20 to 24 weeks of gestation and decreased with increasing gestational age. Even though sonograms were obtained at a mean interval of 4.4 +/- 2.0 weeks, those gestations with normal growth at 20 to 24 weeks had an elapsed time of 10.3 +/- 3.9 weeks until a growth abnormality was subsequently detected.

CONCLUSION

In twin gestations the positive predictive value of a sonogram for a growth abnormality at birth is significantly decreased after normal findings on a 20- to 24-week sonogram. This finding suggests that a routine 2- to 4-week interval between sonograms for all twin gestations may be unwarranted.