Comparison of transverse and vertical skin incision for emergency cesarean delivery

OBJECTIVE

To compare incision-to-delivery intervals and related maternal and neonatal outcomes by skin incision in primary and repeat emergent cesarean deliveries.

METHODS

From 1999 to 2000, a prospective cohort study of all cesarean deliveries was conducted at 13 hospitals comprising the Eunice Kennedy Shriver National Institute of Child Health and Human Development's Maternal-Fetal Medicine Units Network. This secondary analysis was limited to emergent procedures, defined as those performed for cord prolapse, abruption, placenta previa with hemorrhage, nonreassuring fetal heart rate tracing, or uterine rupture. Incision-to-delivery intervals, incision-to-closure intervals, and maternal outcomes were compared by skin-incision type (transverse compared with vertical) after stratifying for primary compared with repeat singleton cesarean delivery. Neonatal outcomes were compared by skin-incision type.

RESULTS

Of the 37,112 live singleton cesarean deliveries, 3,525 (9.5%) were performed for emergent indications of which 2,498 (70.9%) were performed by transverse and the remaining 1,027 (29.1%) by vertical incision. Vertical skin incision shortened median incision-to-delivery intervals by 1 minute (3 compared with 4 minutes, P<.001) in primary and 2 minutes (3 compared with 5 minutes, P<.001) in repeat cesarean deliveries. Total median operative time was longer after vertical skin incision by 3 minutes in primary (46 compared with 43 minutes, P<.001) and 4 minutes in repeat cesarean deliveries (56 compared with 52 minutes, P<.001). Neonates delivered through a vertical incision were more likely to have an umbilical artery pH of less than 7.0 (10% compared with 7%, P=.02), to be intubated in the delivery room (17% compared with 13%, P=.001), or to be diagnosed with hypoxic ischemic encephalopathy (3% compared with 1%, P<.001).

CONCLUSION

In emergency cesarean deliveries, neonatal delivery occurred more quickly after a vertical skin incision, but this was not associated with improved neonatal outcomes.

LEVEL OF EVIDENCE

II.

Vitamins C and E to prevent complications of pregnancy-associated hypertension

BACKGROUND

Oxidative stress has been proposed as a mechanism linking the poor placental perfusion characteristic of preeclampsia with the clinical manifestations of the disorder. We assessed the effects of antioxidant supplementation with vitamins C and E, initiated early in pregnancy, on the risk of serious adverse maternal, fetal, and neonatal outcomes related to pregnancy-associated hypertension.

METHODS

We conducted a multicenter, randomized, double-blind trial involving nulliparous women who were at low risk for preeclampsia. Women were randomly assigned to begin daily supplementation with 1000 mg of vitamin C and 400 IU of vitamin E or matching placebo between the 9th and 16th weeks of pregnancy. The primary outcome was severe pregnancy-associated hypertension alone or severe or mild hypertension with elevated liver-enzyme levels, thrombocytopenia, elevated serum creatinine levels, eclamptic seizure, medically indicated preterm birth, fetal-growth restriction, or perinatal death.

RESULTS

A total of 10,154 women underwent randomization. The two groups were similar with respect to baseline characteristics and adherence to the study drug. Outcome data were available for 9969 women. There was no significant difference between the vitamin and placebo groups in the rates of the primary outcome (6.1% and 5.7%, respectively; relative risk in the vitamin group, 1.07; 95% confidence interval [CI], 0.91 to 1.25) or in the rates of preeclampsia (7.2% and 6.7%, respectively; relative risk, 1.07; 95% CI, 0.93 to 1.24). Rates of adverse perinatal outcomes did not differ significantly between the groups.

CONCLUSIONS

Vitamin C and E supplementation initiated in the 9th to 16th week of pregnancy in an unselected cohort of low-risk, nulliparous women did not reduce the rate of adverse maternal or perinatal outcomes related to pregnancy-associated hypertension (ClinicalTrials.gov number, NCT00135707).

The effect of maternal body mass index on neonatal outcome in women receiving a single course of antenatal corticosteroids

OBJECTIVE

The aim of this study was to determine the effect of maternal body mass index on the incidence of neonatal prematurity morbidities in those who receive corticosteroids.

STUDY DESIGN

This was a secondary analysis of a trial of corticosteroids in women at risk for preterm birth. Women receiving a single course of corticosteroids were classified by their prepregnancy body mass index (<25 and > or = 25) and compared on a composite outcome comprised of several neonatal morbidities and on each individual outcome.

RESULTS

Of 183 eligible women, 96 (52.5%) had a body mass index of <25 and 87 (47.5%) had a body mass index of > or = 25. The composite outcome occurred more frequently in the body mass index of > or = 2 5 group (28.7%), compared with those with a body mass index of <25 (18.8%), although this was not statistically significant (odds ratio, 1.75; 95% confidence interval, 0.83-3.72). Body mass index was not associated with outcomes after adjusting for confounding.

CONCLUSION

Maternal body mass index did not affect neonatal prematurity morbidities in those receiving corticosteroids.

Influence of maternal asthma and asthma severity on newborn morphometry

OBJECTIVE

To determine if maternal asthma or asthma severity affects newborn morphometry.

STUDY DESIGN

A secondary analysis was performed on data collected in a multicenter prospective observational cohort study of asthma in pregnancy. Patients enrolled included women with asthma stratified by severity of disease and controls. Asthma severity was defined according to the classification proposed by the National Asthma Education Program (NAEP) Report of the Working Group on Asthma and Pregnancy, modified to include medication requirements. Newborn morphometry measurements included birth weight (BW) and multiples of the median birth weight (BW-MOM), head circumference (HC), length (L), HC:BW ratio, and ponderal index (PI).

RESULTS

Of 2480 patients there were 828 nonasthmatic controls, 828 with mild, 775 with moderate, and 49 with severe disease. Comparing all groups, there were statistically significant differences in maternal age (p < .001), race (p = .005), parity (p = .006), prepregnancy weight (p = .028), and medical care source (p = .001), with the severe asthma group having the highest mean maternal age (25.7 years), and proportion of African Americans (71.4%), proportion of multiparous patients (63.3%), and proportion of patients receiving government assistance (85.7%). When the control group was excluded from the comparisons, differences in prepregnancy weight and medical care source were no longer significant. BW-MOM and L did not differ between groups. The HC:BW ratio increased with asthma severity (p = .029) and was increased compared to controls (p = .010). This remained significant after controlling for confounding variables (both p <.001). HC was statistically significantly different between all groups (p = .032), as well as among women with varying degrees of asthma severity (p = .013), which was not clinically significant. After covariates adjustment, HC was not significantly different among all groups (p = .228), nor the asthma groups (p = .144).

CONCLUSION

Asthma severity is associated with an increased HC:BW ratio. Severity was not found to impact HC, BW-MOM, L, or PI independently. However, the magnitudes of the effects were too small to suggest a clinically significant effect of asthma on neonatal morphometry in this large prospectively studied sample.

The relationship of asthma-specific quality of life during pregnancy to subsequent asthma and perinatal morbidity

OBJECTIVE

To determine whether asthma-specific quality of life during pregnancy is related to asthma exacerbations and to perinatal outcomes.

METHODS

This was a secondary analysis of data from a randomized controlled trial of inhaled beclomethasone versus theophylline in the treatment of moderate asthma during pregnancy. The Juniper Asthma Quality of Life Questionnaire (AQLQ) was administered to patients at enrollment. Exacerbations were defined as asthma symptoms requiring a hospitalization, unscheduled medical visit, or oral corticosteroid course.

RESULTS

Quality of life assessments were provided by 310 of the 385 participants who completed the study. There was more than a 25% decrease in the odds of a subsequent asthma exacerbation for every 1-point increase in AQLQ score for the overall score (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.55-0.96), emotion domain (OR 0.72, 95% CI 0.59-0.88), and symptoms domain (OR 0.73, 95% CI 0.57-0.94). These relationships were not significantly influenced by initial symptom frequency or forced expiratory volume in 1 s (FEV(1)). No significant relationships were demonstrated between enrollment AQLQ scores and preeclampsia, preterm birth, low birth weight, or small for gestational age.

CONCLUSION

Asthma-specific quality of life in early pregnancy is related to subsequent asthma morbidity during pregnancy but not to perinatal outcomes.

White's classification of maternal diabetes and vaginal birth after cesarean delivery success in women undergoing a trial of labor

OBJECTIVE

To estimate the rate of vaginal birth after cesarean delivery (VBAC) success in diabetic women based on White's Classification.

METHODS

This is a secondary analysis of an observational study conducted at 19 medical centers of women attempting VBAC. Diabetic women with singleton gestations, one prior cesarean delivery, and cephalic presentation who underwent a trial of labor were included. Vaginal birth after cesarean delivery success rates and maternal and neonatal complications were compared based on White's Classification.

RESULTS

Of 11,856 women who underwent trial of labor, 624 met all study criteria (class A1, 356; A2, 169; B, 70; C, 21; D/R/F, 8). Vaginal birth after cesarean delivery success in each group was: A1, 68.5% (95% confidence interval [CI] 63.4-73.3%); A2, 55% (95% CI 47.2-62.7%); B, 70% (95% CI 57.9-80.4%); C, 47.6% (95% CI 25.7-70.2%); and D/F/R, 12.5% (95% CI 0.3-52.7%). Maternal and neonatal complications were rare and not found to be different among groups.

CONCLUSION

Our study provides estimates for VBAC success based on White's classification and indicates a relatively low rate of perinatal complications after VBAC attempt for diabetic women.

LEVEL OF EVIDENCE

III.

Does information available at admission for delivery improve prediction of vaginal birth after cesarean?

We sought to construct a predictive model for vaginal birth after cesarean (VBAC) that combines factors that can be ascertained only as the pregnancy progresses with those known at initiation of prenatal care. Using multivariable modeling, we constructed a predictive model for VBAC that included patient factors known at the initial prenatal visit as well as those that only become evident as the pregnancy progresses to the admission for delivery. We analyzed 9616 women. The regression equation for VBAC success included multiple factors that could not be known at the first prenatal visit. The area under the curve for this model was significantly greater ( P < 0.001) than that of a model that included only factors available at the first prenatal visit. A prediction model for VBAC success, which incorporates factors that can be ascertained only as the pregnancy progresses, adds to the predictive accuracy of a model that uses only factors available at a first prenatal visit.

Failed operative vaginal delivery

OBJECTIVE

To compare maternal and neonatal outcomes in women undergoing second-stage cesarean delivery after a trial of operative vaginal delivery with those in women undergoing second-stage cesarean delivery without such an attempt.

METHODS

This study is a secondary analysis of the women who underwent second-stage cesarean delivery. The maternal outcomes examined included blood transfusion, endometritis, wound complication, anesthesia use, and maternal death. Neonatal outcomes examined included umbilical artery pH less than 7.0, Apgar score of 3 or less at 5 minutes, seizures within 24 hours of birth, hypoxic ischemic encephalopathy, stillbirth, skull fracture, and neonatal death.

RESULTS

Of 3,189 women who underwent second-stage cesarean delivery, operative vaginal delivery was attempted in 640. Labor characteristics were similar in the two groups, with the exception of the admission-to-delivery time and cesarean indication. Those with an attempted operative vaginal delivery were more likely to undergo cesarean delivery for a nonreassuring fetal heart rate tracing (18.0% compared with 13.9%, P=.01), have a wound complication (2.7% compared with 1.0%, odds ratio [OR] 2.65, 95% confidence interval [CI] 1.43-4.91), and require general anesthesia (8.0% compared with 4.1%, OR 2.05, 95% CI 1.44-2.91). Neonatal outcomes, including umbilical artery pH less than 7.0, Apgar score of 3 or less at 5 minutes, and hypoxic ischemic encephalopathy, were more common for those with an attempted operative vaginal delivery. This was not significant when cases with a nonreassuring fetal heart rate tracing were removed.

CONCLUSION

Cesarean delivery after an attempt at operative vaginal delivery was not associated with adverse neonatal outcomes in the absence of a nonreassuring fetal heart rate tracing.

LEVEL OF EVIDENCE

II.

The frequency and complication rates of hysterectomy accompanying cesarean delivery

OBJECTIVE

To estimate the frequency, indications, and complications of cesarean hysterectomy.

METHODS

This was a prospective, 2-year observational study at 13 academic medical centers conducted between January 1, 1999, and December 31, 2000, on all women who underwent a hysterectomy at the time of cesarean delivery. Data were abstracted from the medical record by study nurses. The outcomes included procedure frequency, indications, and complications.

RESULTS

A total of 186 cesarean hysterectomies (0.5%) were performed from a cohort of 39,244 women who underwent cesarean delivery. The leading indications for hysterectomy were placenta accreta (38%) and uterine atony (34%). Of the hysterectomy cases with a diagnosis recorded as accreta, 18% accompanied a primary cesarean delivery, and 82% had a prior procedure (P<.001). Of the hysterectomy cases with atony recorded as a diagnosis, 59% complicated primary cesarean delivery, whereas 41% had a prior cesarean (P<.001). Major maternal complications of cesarean hysterectomy included transfusion of red blood cells (84%) and other blood products (34%), fever (11%), subsequent laparotomy (4%), ureteral injury (3%), and death (1.6%). Accreta hysterectomy cases were more likely than atony hysterectomy cases to require ureteral stents (14% compared with 3%, P=.03) and to instill sterile milk into the bladder (23% compared with 8%, P=.02).

CONCLUSION

The rate of cesarean hysterectomy has declined modestly in the past decade. Despite the use of effective therapies and procedures to control hemorrhage at cesarean delivery, a small proportion of women continue to require hysterectomy to control hemorrhage from both uterine atony and placenta accreta.

LEVEL OF EVIDENCE

II.

Bone metabolism in fetuses of pregnant women exposed to single and multiple courses of corticosteroids

OBJECTIVE

To estimate the effect of single and recurrent doses of antenatal corticosteroids on fetal bone metabolism.

METHODS

This was a secondary analysis of a cohort of pregnant women from a previously reported randomized, placebo-controlled, multicenter trial of women at risk for preterm delivery who received weekly courses of betamethasone (active) or placebo after an initial course of corticosteroids. Umbilical cord serum levels of carboxy-terminal carboxy-terminal propeptide of type I procollagen and cross-linked carboxy-terminal telopeptide of type I procollagen were measured to assess the rate of fetal bone formation and resorption, respectively. Analysis was stratified according to number of repeat antenatal study courses of betamethasone or placebo (one to three compared with at least four courses, not including the initial course).

RESULTS

Of the 251 umbilical cord serum samples, the median serum carboxy-terminal telopeptide of type I procollagen levels, but not carboxy-terminal propeptide of type I procollagen levels, was significantly lower with repeat betamethasone exposure (55.0 compared with 57.9 micrograms/L, P=.01). In the fetuses exposed to at least four repeat study courses, there was a significant decrease in median carboxy-terminal telopeptide of type-I procollagen levels between repeat betamethasone exposure and placebo (53.4 compared with 58.6 micrograms/L, respectively, P=.04), but there was no difference between groups in the fetuses exposed to 1-3 repeat study courses (57.4 compared with 56.7 micrograms/L, respectively, P=.29).

CONCLUSION

Levels of umbilical cord serum markers of bone resorption but not formation are reduced in fetuses exposed to repeat courses of antenatal betamethasone. Up to four courses of antenatal betamethasone do not seem to affect fetal bone metabolism.

LEVEL OF EVIDENCE

II.

Timing of elective repeat cesarean delivery at term and neonatal outcomes

BACKGROUND

Because of increased rates of respiratory complications, elective cesarean delivery is discouraged before 39 weeks of gestation unless there is evidence of fetal lung maturity. We assessed associations between elective cesarean delivery at term (37 weeks of gestation or longer) but before 39 weeks of gestation and neonatal outcomes.

METHODS

We studied a cohort of consecutive patients undergoing repeat cesarean sections performed at 19 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network from 1999 through 2002. Women with viable singleton pregnancies delivered electively (i.e., before the onset of labor and without any recognized indications for delivery before 39 weeks of gestation) were included. The primary outcome was the composite of neonatal death and any of several adverse events, including respiratory complications, treated hypoglycemia, newborn sepsis, and admission to the neonatal intensive care unit (ICU).

RESULTS

Of 24,077 repeat cesarean deliveries at term, 13,258 were performed electively; of these, 35.8% were performed before 39 completed weeks of gestation (6.3% at 37 weeks and 29.5% at 38 weeks) and 49.1% at 39 weeks of gestation. One neonatal death occurred. As compared with births at 39 weeks, births at 37 weeks and at 38 weeks were associated with an increased risk of the primary outcome (adjusted odds ratio for births at 37 weeks, 2.1; 95% confidence interval [CI], 1.7 to 2.5; adjusted odds ratio for births at 38 weeks, 1.5; 95% CI, 1.3 to 1.7; P for trend <0.001). The rates of adverse respiratory outcomes, mechanical ventilation, newborn sepsis, hypoglycemia, admission to the neonatal ICU, and hospitalization for 5 days or more were increased by a factor of 1.8 to 4.2 for births at 37 weeks and 1.3 to 2.1 for births at 38 weeks.

CONCLUSIONS

Elective repeat cesarean delivery before 39 weeks of gestation is common and is associated with respiratory and other adverse neonatal outcomes.

Can a prediction model for vaginal birth after cesarean also predict the probability of morbidity related to a trial of labor?

OBJECTIVE

The objective of the study was to determine whether a model for predicting vaginal birth after cesarean (VBAC) can also predict the probabilty of morbidity associated with a trial of labor (TOL).

STUDY DESIGN

Using a previously published prediction model, we categorized women with 1 prior cesarean by chance of VBAC. Prevalence of maternal and neonatal morbidity was stratfied by probability of VBAC success and delivery approach.

RESULTS

Morbidity became less frequent as the predicted chance of VBAC increased among women who underwent TOL (P < .001) but not elective repeat cesarean section (ERCS) (P > .05). When the predicted chance of VBAC was less than 70%, women undergoing a TOL were more likely to have maternal morbidity (relative risk [RR], 2.2; 95% confidence interval [CI], 1.5-3.1) than those who underwent an ERCS; when the predicted chance of VBAC was at least 70%, total maternal morbidity was not different between the 2 groups (RR, 0.8; 95% CI, 0.5-1.2). The results were similar for neonatal morbidity.

CONCLUSION

A prediction model for VBAC provides information regarding the chance of TOL-related morbidity and suggests that maternal morbidity is not greater for those women who undergo TOL than those who undergo ERCS if the chance of VBAC is at least 70%.

Salivary progesterone and estriol among pregnant women treated with 17-alpha-hydroxyprogesterone caproate or placebo

OBJECTIVE

The objectives of the study was to determine whether salivary progesterone (P) or estriol (E3) concentration at 16-20 weeks' gestation predicts preterm birth or the response to 17alpha-hydroxyprogesterone caproate (17OHPC) and whether 17OHPC treatment affected the trajectory of salivary P and E3 as pregnancy progressed.

STUDY DESIGN

This was a secondary analysis of a clinical trial of 17OHPC to prevent preterm birth. Baseline saliva was assayed for P and E3. Weekly salivary samples were obtained from 40 women who received 17OHPC and 40 who received placebo in a multicenter randomized trial of 17OHPC to prevent recurrent preterm delivery.

RESULTS

Both low and high baseline saliva P and E3 were associated with a slightly increased risk of preterm birth. However, 17OHPC prevented preterm birth comparably, regardless of baseline salivary hormone concentrations. 17OHPC did not alter the trajectory of salivary P over pregnancy, but it significantly blunted the rise in salivary E3 as well as the rise in the E3/P ratio.

CONCLUSION

17OHPC flattened the trajectory of E3 in the second half of pregnancy, suggesting that the drug influences the fetoplacental unit.

Cesarean delivery for the second twin

OBJECTIVE

To examine maternal and infant outcomes after a vaginal delivery of twin A and a cesarean delivery of twin B, and to identify whether the second twin experienced increased short-term morbidity as part of a combined route of delivery.

METHODS

Between January 1, 1999, and December 31, 2000, a prospective cohort study of all cesarean deliveries was conducted at 13 university centers. This secondary analysis was limited to women with twin gestations who experienced labor and underwent cesarean delivery. We compared outcomes of the second twin in women who had vaginal delivery of the first twin and a cesarean delivery of the second twin to those who had cesarean delivery of both twins.

RESULTS

One thousand twenty-eight twin pregnancies experienced labor and underwent cesarean delivery; 179 (17%) had a combined vaginal/cesarean delivery. Gestational age at delivery was 34.6 weeks in both groups (P=.97). The rupture of membranes to delivery interval was longer in the combined group (3.2 compared with 2.3 hours, P<.001). Endometritis and culture-proven sepsis in the second twin were more common in the combined group, respectively (n=24, odds ratio 1.6, 95% confidence interval, 1.0-2.7; n=15, odds ratio 1.8, 95% confidence interval, 1.0-3.4). These differences were not significant after logistic regression analysis. There were no statistically significant differences in an arterial cord pH of less than 7.0, Apgar score less than or equal to 3 at 5 minutes, seizures, grade III or IV intraventricular hemorrhage, hypoxic ischemic encephalopathy, or neonatal death.

CONCLUSION

Combined twin delivery may be associated with endometritis and neonatal sepsis when compared with a twin delivery where both are delivered by cesarean in twin pregnancies experiencing labor. More serious neonatal sequelae, including hypoxic ischemic encephalopathy and death, were not affected by the route of delivery of the second twin.

Prediction of uterine rupture associated with attempted vaginal birth after cesarean delivery

OBJECTIVE

The purpose of this study was to develop a model that predicts individual-specific risk of uterine rupture during an attempted vaginal birth after cesarean delivery.

STUDY DESIGN

Women with 1 previous low-transverse cesarean delivery who underwent a trial of labor with a term singleton were identified in a concurrently collected database of deliveries that occurred at 19 academic centers during a 4-year period. We analyzed different classification techniques in an effort to develop an accurate prediction model for uterine rupture.

RESULTS

Of the 11,855 women who were available for analysis, 83 women (0.7%) had had a uterine rupture. The optimal final prediction model, which was based on a logistic regression, included 2 variables: any previous vaginal delivery (odds ratio, 0.44; 95% CI, 0.27-0.71) and induction of labor (odds ratio, 1.73; 95% CI, 1.11-2.69). This model, with a c-statistic of 0.627, had poor discriminating ability and did not allow the determination of a clinically useful estimate of the probability of uterine rupture for an individual patient.

CONCLUSION

Factors that were available before or at admission for delivery cannot be used to predict accurately the relatively small proportion of women at term who will experience a uterine rupture during an attempted vaginal birth after cesarean delivery.

Bone metabolism in pregnant women exposed to single compared with multiple courses of corticosteroids

OBJECTIVE

To compare markers of maternal bone metabolism between women who received a single compared with multiple courses of antenatal corticosteroids.

METHODS

This is an analysis of serum samples from a previously reported randomized, placebo-controlled, multicenter trial. Women at risk for preterm delivery after an initial course of corticosteroids were randomly assigned to weekly courses of betamethasone (active) or placebo. Serum levels of carboxy terminal propeptide of type I procollagen (PICP) and cross-linked carboxy terminal telopeptide of type I collagen (ICTP) were measured to assess the rate of bone formation and resorption, respectively, at three time points. The placebo group (n=93) was compared with the active group, receiving four or more courses of betamethasone (n=112).

RESULTS

There were significant (P<.001) increases in PICP and ICTP between baseline and delivery in both groups. Cross-linked carboxy terminal telopeptide of type I collagen, but not PICP, was lower with corticosteroid exposure immediately before administration of the fourth study course (P<.001). No significant differences in PICP and ICTP were seen between groups at delivery.

CONCLUSION

Increasing levels of PICP and ICTP with advancing gestation are consistent with physiologic changes in maternal bone metabolism. Multiple courses of corticosteroids for fetal maturation are not associated with persistent or cumulative effects on maternal bone metabolism as measured by PICP and ICTP.

LEVEL OF EVIDENCE

II.

The effect of body mass index on therapeutic response to bacterial vaginosis in pregnancy

Our objective was to determine the effect of body mass index (BMI) on response to bacterial vaginosis (BV) treatment. A secondary analysis was conducted of two multicenter trials of therapy for BV and TRICHOMONAS VAGINALIS. Gravida were screened for BV between 8 and 22 weeks and randomized between 16 and 23 weeks to metronidazole or placebo. Of 1497 gravida with asymptomatic BV and preconceptional BMI, 738 were randomized to metronidazole; BMI was divided into categories: < 25, 25 to 29.9, and > or = 30. Rates of BV persistence at follow-up were compared using the Mantel-Haenszel chi square. Multiple logistic regression was used to evaluate the effect of BMI on BV persistence at follow-up, adjusting for potential confounders. No association was identified between BMI and BV rate at follow-up ( P = 0.21). BMI was associated with maternal age, smoking, marital status, and black race. Compared with women with BMI of < 25, adjusted odds ratio (OR) of BV at follow-up were BMI 25 to 29.9: OR, 0.66, 95% CI 0.43 to 1.02; BMI > or = 30: OR, 0.83, 95% CI 0.54 to 1.26. We concluded that the persistence of BV after treatment was not related to BMI.

Diet-treated gestational diabetes mellitus: comparison of early vs routine diagnosis

OBJECTIVE

The purpose of this study was to compare pregnancy outcomes in women with diet-treated gestational diabetes mellitus (GDM) that was diagnosed at < 24 weeks of gestation to those women who received the diagnosis at > or = 24 weeks of gestation.

STUDY DESIGN

This was a retrospective cohort study of 2596 women with diet-treated GDM who delivered between December 1999 and June 2005 at Parkland Hospital. Women with risk factors for GDM underwent immediate glucose screening; women without risk factors underwent universal glucose screening between 24 and 28 weeks of gestation. Women with diet-treated GDM that was diagnosed at < 24 weeks of gestation (n = 339; 13.1%) were compared with those women who received the diagnosis at > or = 24 weeks of gestation.

RESULTS

Women with an earlier diagnosis of diet-treated GDM were at increased risk of preeclampsia and the delivery of large infants. Even after adjustment for differences in maternal characteristics and glycemic control, the risk of preeclampsia persisted (odds ratio, 2.4; 95% CI, 1.5, 3.8).

CONCLUSION

Women with an early diagnosis of diet-treated GDM have a 2-fold increased risk of preeclampsia.

Predicting macrosomia

OBJECTIVE

The purpose of this study was to evaluate the prediction of fetal macrosomia based on ultrasound estimates of fetal weight and amniotic fluid volume combined with clinical risk factors.

METHODS

A retrospective cohort study of women undergoing indicated obstetric ultrasound examinations within 7 days of delivery was conducted.

RESULTS

A total of 3115 women gave birth within 7 days of ultrasound examinations that included an estimated fetal weight (EFW) and an amniotic fluid index (AFI). Clinical risk factors were associated with an 8% positive predictive value for a birth weight of 4000 g or higher. Adding an ultrasound EFW of 4000 g or higher increased the positive predictive value to 62%. Adding an AFI of 20 cm or higher to the clinical risk factors and the ultrasound EFW further increased the positive predictive value to 71%.

CONCLUSIONS

An ultrasound EFW of 4000 g or higher within 1 week of delivery combined with clinical risk factors and an increased AFI is associated with macrosomia at birth in 71% of cases.

The relationship between resolution of asymptomatic bacterial vaginosis and spontaneous preterm birth in fetal fibronectin-positive women

OBJECTIVE

The purpose of this study was to determine the impact of persistent bacterial vaginosis (BV) on the occurrence of spontaneous preterm birth (SPB) in women who test positive for fetal fibronectin.

STUDY DESIGN

This is a secondary analysis of a subset of pregnant women who tested positive for BV and fetal fibronectin between 16(0/7) and 25(6/7) weeks of gestation and who participated in randomized placebo controlled trials of antibiotic therapy. Nugent's criteria were used for the diagnosis of BV. Patients were reassessed for the presence of BV after treatment. The rate of SPB at <34 weeks of gestation was analyzed on the basis of treatment mode and BV status at the follow-up visit.

RESULTS

The primary studies included a total of 3285 women. A subset of 215 women met the criteria for this analysis. Seventy-seven of 100 patients (77%) in the antibiotics group vs 33 of the 115 patients (28.7%) in the placebo group became BV negative (P < .0001). The rate of SPB at <34 weeks of gestation was lower for BV resolution compared with persistent BV (0 vs 5.7%, respectively; P = .01).

CONCLUSION

In women who tested positive for fetal fibronectin and BV, resolution of BV is associated with less SPB before 34 weeks of gestation.

Risk of Uterine Rupture and Adverse Perinatal Outcome at Term After Cesarean Delivery

OBJECTIVE

Current information on the risk of uterine rupture after cesarean delivery has generally compared the risk after trial of labor to that occurring with an elective cesarean delivery without labor. Because antepartum counseling cannot account for whether a woman will develop an indication requiring a repeat cesarean delivery or whether labor will occur before scheduled cesarean delivery, the purpose of this analysis was to provide clinically useful information regarding the risks of uterine rupture and adverse perinatal outcome for women at term with a history of prior cesarean delivery.

METHODS

Women with a term singleton gestation and prior cesarean delivery were studied over 4 years at 19 centers. For this analysis, outcomes from five groups were studied: trial of labor, elective repeat with no labor, elective repeat with labor (women presenting in early labor who subsequently underwent cesarean delivery), indicated repeat with labor, and indicated repeat without labor. All cases of uterine rupture were reviewed centrally to assure accuracy of diagnosis.

RESULTS

A total of 39,117 women were studied. In term pregnant women with a prior cesarean delivery, the overall risk for uterine rupture was 0.32% (125 of 39,117), and the overall risk for serious adverse perinatal outcome (stillbirth, hypoxic ischemic encephalopathy, neonatal death) was 106 of 39,049 (0.27%). The uterine rupture risk for indicated repeat cesarean delivery (labor or without labor) was 7 of 6,080 (0.12%); the risk for elective (no indication) repeat cesarean delivery (labor or without labor) was 4 of 17,714 (0.02%). Indicated repeat cesarean delivery increased the risk of uterine rupture by a factor of 5 (odds ratio 5.1, 95% confidence interval 1.49-17.44). In the absence of an indication, the presence of labor also increased the risk of uterine rupture (4 of 2,721 [0.15%] compared with 0 of 14,993, P<.01). The highest rate of uterine rupture occurred in women undergoing trial of labor (0.74%, 114 of 15,323).

CONCLUSION

At term, the risk of uterine rupture and adverse perinatal outcome for women with a singleton and prior cesarean delivery is low regardless of mode of delivery, occurring in 3 per 1,000 women. Maternal complications occurred in 3-8% of women within the five delivery groups.

Trial of Labor After One Previous Cesarean Delivery for Multifetal Gestation

OBJECTIVE

To estimate success rates and risks with a trial of labor after one previous cesarean delivery for multifetal gestation compared with one previous cesarean delivery for a singleton pregnancy.

METHODS

Patients from the National Institute of Child Health and Human Development Maternal Fetal Medicine Units Network Cesarean Registry with one previous cesarean delivery and a current term singleton pregnancy were identified. Cases had one previous cesarean delivery for a multifetal pregnancy. Controls had one previous cesarean delivery for a singleton pregnancy.

RESULTS

Of cases, 556 of 944 (58.9%) attempted a trial of labor. Of controls, 13,923 of 29,329 (47.5%) attempted a trial of labor. The trial of labor success rate was 85.6% among cases and 73.1% among controls (odds ratio 2.19, 95% confidence interval 1.72-2.78). Compared with trial of labor controls, cases had no statistically increased risk of transfusion, endometritis, intensive care unit admissions, uterine rupture, or perinatal complications. Cases in this analysis with a successful trial of labor were more likely to have previously had a successful vaginal birth after cesarean (37.1% compared with 14.1%, P<.001).

CONCLUSION

Women with one previous cesarean delivery for a multifetal gestation have high trial of labor success rates and low complication rates.

Long-term outcomes after repeat doses of antenatal corticosteroids

BACKGROUND

Previous trials have shown that repeat courses of antenatal corticosteroids improve some neonatal outcomes in preterm infants but reduce birth weight and increase the risk of intrauterine growth restriction. We report long-term follow-up results of children enrolled in a randomized trial comparing single and repeat courses of antenatal corticosteroids.

METHODS

Women at 23 through 31 weeks of gestation who remained pregnant 7 days after an initial course of corticosteroids were randomly assigned to weekly courses of betamethasone, consisting of 12 mg given intramuscularly and repeated once at 24 hours, or an identical-appearing placebo. We studied the children who were born after these treatments when they were between 2 and 3 years of corrected age. Prespecified outcomes included scores on the Bayley Scales of Infant Development, anthropometric measurements, and the presence of cerebral palsy.

RESULTS

A total of 556 infants were available for follow-up; 486 children (87.4%) underwent physical examination and 465 (83.6%) underwent Bayley testing at a mean (+/-SD) corrected age of 29.3+/-4.6 months. There were no significant differences in Bayley results or anthropometric measurements. Six children (2.9% of pregnancies) in the repeat-corticosteroid group had cerebral palsy as compared with one child (0.5% of pregnancies) in the placebo group (relative risk, 5.7; 95% confidence interval, 0.7 to 46.7; P=0.12).

CONCLUSIONS

Children who had been exposed to repeat as compared with single courses of antenatal corticosteroids did not differ significantly in physical or neurocognitive measures. Although the difference was not statistically significant, the higher rate of cerebral palsy among children who had been exposed to repeat doses of corticosteroids is of concern and warrants further study. (ClinicalTrials.gov number, NCT00015002 [ClinicalTrials.gov].).

Uterine Contractions Preceding Labor

OBJECTIVE

To evaluate whether 12 contractions in 1 hour is a meaningful signal that spontaneous labor has begun or is imminent.

METHODS

This prospective observational cohort study includes all women reporting contractions who presented to a labor and delivery triage unit between August 1 and October 31, 2006, who met the following criteria: 1) 36 0/7 to 41 6/7 weeks of gestation, 2) cervical dilation less than 4 cm, 3) intact membranes, and 4) no other medical or obstetric complications that might influence admission. Each woman received external fetal monitoring for a minimum of 1 hour. Women were discharged home if cervical dilation did not advance and the fetal heart rate pattern was reassuring. Women who progressed to a cervical dilation of 4 cm were admitted with the diagnosis of labor.

RESULTS

Among 768 women studied, labor was diagnosed within 24 hours in 268 (76%) with 12 or more contractions per hour compared with 216 (52%) of 416 women with fewer than 12 contractions per hour, P<.001. Cervical condition and fetal station were more advanced on presentation in women with 12 or more contractions per hour.

CONCLUSION

Twelve contractions or more per hour at term is a meaningful signal that true labor has either begun or is imminent.

LEVEL OF EVIDENCE

II.

The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network Beneficial Effects of Antenatal Repeated Steroids study: impact of repeated doses of antenatal corticosteroids on placental growth and histologic findings

OBJECTIVE

In utero exposure to repeated doses of antenatal corticosteroids (ACSs) has been shown to reduce fetal growth. Our goal was to evaluate whether weekly betamethasone (R-ACS) alters placental growth and histologic findings.

STUDY DESIGN

In a multicenter randomized controlled trial of R-ACS vs a single course of ACS followed by weekly placebo (S-ACS), placentas were weighed after removal of the membranes and umbilical cord. A single pathologist who was masked to study group and pregnancy outcomes performed histologic evaluation for placental calcifications, infarction, fibrin deposition, and hemorrhage or thrombus formation, acute and chronic chorioamnionitis, fibromuscular vascular hyperplasia, nucleated red blood cells, and villous crowding, edema, fibrosis, or fibrinoid necrosis. Findings were compared between study groups and according to the number of courses of ACS.

RESULTS

One hundred ninety-four placentas were available for evaluation. Univariable analyses revealed no differences between study groups in any of the 19 evaluated histologic parameters between R-ACS and S-ACS groups overall or in analyses that were restricted to deliveries at < 32 or > or = 32 weeks of gestation. Calcifications were more common (P = .045) in the R-ACS group after controlling for other factors. Multivariable analysis revealed increasing gestational age at delivery, but not increasing ACS courses, to be associated with decreasing chorionic inflammation, villous edema, and fibrosis and with increasing villus crowding, fibrin deposition, and calcifications. Ninety-three placentas were weighed before formalin fixation. After controlling for delivery gestation and infant gender, placental weight was significantly lower in the R-ACS group (P = .017) and was related inversely to the number of ACS courses (P = .037). This finding was confirmed only for deliveries at > or = 32 weeks of gestation (525 vs 441 g for R-ACS and S-ACS group, respectively; P = .036).

CONCLUSION

Repeated antenatal corticosteroid treatments in pregnancy are associated with decreased placental growth in a dose-dependent fashion, but not with evident differences in histologic markers of placental inflammation, ischemia, or infarction. Histologic placental abnormalities should not be attributed to repeated courses of corticosteroids.