Cervical funneling or intra-amniotic debris and preterm birth in nulliparous women with midtrimester cervical length less than 30 mm.

OBJECTIVE: To evaluate whether the presence of cervical funneling or intra-amniotic debris identified in the second trimester is associated with a higher rate of preterm birth (PTB) in asymptomatic nulliparous pregnant women with a midtrimester cervical length (CL) less than 30 mm (i.e. below the 10th percentile). METHODS: This was a secondary cohort analysis of data from a multicenter trial in nulliparous women between 16 and 22 weeks' gestation with a singleton gestation and CL less than 30 mm on transvaginal ultrasound, randomized to treatment with either 17-alpha-hydroxyprogesterone caproate or placebo. Sonographers were centrally certified in CL measurement, as well as in identification of intra-amniotic debris and cervical funneling. Univariable and multivariable analysis was performed to assess the associations of cervical funneling and intra-amniotic debris with PTB. RESULTS: Of the 657 women randomized, 112 (17%) had cervical funneling only, 33 (5%) had intra-amniotic debris only and 45 (7%) had both on second-trimester ultrasound. Women with either of these findings had a shorter median CL than those without (21.0 mm vs 26.4 mm; P < 0.001). PTB prior to 37 weeks was more likely in women with cervical funneling (37% vs 21%; odds ratio (OR), 2.2 (95% CI, 1.5-3.3)) or intra-amniotic debris (35% vs 23%; OR, 1.7 (95% CI, 1.1-2.9)). Results were similar for PTB before 34 and before 32 weeks' gestation. After multivariable adjustment that included CL, PTB < 34 and < 32 weeks continued to be associated with the presence of intra-amniotic debris (adjusted OR (aOR), 1.85 (95% CI, 1.00-3.44) and aOR, 2.78 (95% CI, 1.42-5.45), respectively), but not cervical funneling (aOR, 1.17 (95% CI, 0.63-2.17) and aOR, 1.45 (95% CI, 0.71-2.96), respectively). CONCLUSIONS: Among asymptomatic nulliparous women with midtrimester CL less than 30 mm, the presence of intra-amniotic debris, but not cervical funneling, is associated with an increased risk for PTB before 34 and 32 weeks' gestation, independently of CL. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Neonatal Genetic Variation in Steroid Metabolism and Key Respiratory Function Genes and Perinatal Outcomes in Single and Multiple Courses of Corticosteroids.

OBJECTIVE: The aim of the study is to evaluate the association of steroid metabolism and respiratory gene polymorphisms in neonates exposed to antenatal corticosteroids (ACS) with respiratory outcomes, small for gestational age (SGA), and response to repeat ACS. STUDY DESIGN: This candidate gene study is a secondary analysis of women enrolled in a randomized controlled trial of single versus weekly courses of ACS. Nineteen single nucleotide polymorphisms (SNPs) in 13 steroid metabolism and respiratory function genes were evaluated. DNA was extracted from placenta or fetal cord serum and analyzed with TaqMan genotyping. Each SNP was evaluated for association via logistic regression with respiratory distress syndrome (RDS), continuous positive airway pressure (CPAP)/ventilator use (CPV), and SGA. RESULTS: CRHBP, CRH, and CRHR1 minor alleles were associated with an increased risk of SGA. HSD11B1 and SCNN1B minor alleles were associated with an increased likelihood of RDS. Carriage of minor alleles in SerpinA6 was associated with an increased risk of CPV. CRH and CRHR1 minor alleles were associated with a decreased likelihood of CPV. CONCLUSION: Steroid metabolism and respiratory gene SNPs are associated with respiratory outcomes and SGA in patients exposed to ACS. Risks for respiratory outcomes are affected by minor allele carriage as well as by treatment with multiple ACS.

Neuraxial analgesia effects on labour progression: facts, fallacies, uncertainties and the future.

Approximately 60% of women who labour in the USA receive some form of neuraxial analgesia, but concerns have been raised regarding whether it negatively impacts the labour and delivery process. In this review, we attempt to clarify what has been established as truths, falsities and uncertainties regarding the effects of this form of pain relief on labour progression, negative and/or positive. Additionally, although the term 'epidural' has become synonymous with neuraxial analgesia, we discuss two other techniques, combined spinal-epidural and continuous spinal analgesia, that are gaining popularity, as well as their effects on labour progression.

Prenatal vitamin C and E supplementation in smokers is associated with reduced placental abruption and preterm birth: a secondary analysis.

OBJECTIVE: Smoking and pre-eclampsia (PE) are associated with increases in preterm birth, placental abruption and low birthweight. We evaluated the relationship between prenatal vitamin C and E (C/E) supplementation and perinatal outcomes by maternal self-reported smoking status focusing on outcomes known to be impacted by maternal smoking. DESIGN/SETTING/POPULATION: A secondary analysis of a multi-centre trial of vitamin C/E supplementation starting at 9-16 weeks in low-risk nulliparous women with singleton gestations. METHODS: We examined the effect of vitamin C/E by smoking status at randomisation using the Breslow-Day test for interaction. MAIN OUTCOME MEASURES: The trial's primary outcomes were PE and a composite outcome of pregnancy-associated hypertension (PAH) with serious adverse outcomes. Perinatal outcomes included preterm birth and abruption. RESULTS: There were no differences in baseline characteristics within subgroups (smokers versus nonsmokers) by vitamin supplementation status. The effect of prenatal vitamin C/E on the risk of PE (P = 0.66) or PAH composite outcome (P = 0.86) did not differ by smoking status. Vitamin C/E was protective for placental abruption in smokers (relative risk [RR] 0.09; 95% CI 0.00-0.87], but not in nonsmokers (RR 0.92; 95% CI 0.52-1.62) (P = 0.01), and for preterm birth in smokers (RR 0.76; 95% CI 0.58-0.99) but not in nonsmokers (RR 1.03; 95% CI 0.90-1.17) (P = 0.046). CONCLUSION: In this cohort of women, smoking was not associated with a reduction in PE or the composite outcome of PAH. Vitamin C/E supplementation appears to be associated with a reduction in placental abruption and preterm birth among smokers.

A randomized trial of the effects of coached vs uncoached maternal pushing during the second stage of labor on postpartum pelvic floor structure and function.

OBJECTIVE: The purpose of this study was to determine if refraining from coached pushing during the second stage of labor affects postpartum urogynecologic measures of pelvic floor structure and function. STUDY DESIGN: Nulliparous women at term were randomized to coached (n = 67) vs uncoached (n = 61) pushing. At 3 months' postpartum women underwent urodynamic testing, pelvic organ prolapse examination (POPQ), and pelvic floor neuromuscular assessment. RESULTS: Urodynamic testing revealed decreased bladder capacity (427 mL vs 482 mL, P = .051) and decreased first urge to void (160 mL vs 202 mL, P = .025) in the coached group. Detrusor overactivity increased 2-fold in the coached group (16% vs 8%), although this difference was not statistically significant (P = .17). Urodynamic stress incontinence was diagnosed in the coached group in 11/67 (16%) vs 7/61 (12%) in the uncoached group (P = .42). CONCLUSION: Coached pushing in the second stage of labor significantly affected urodynamic indices, and was associated with a trend towards increased detrusor overactivity.

Onset and persistence of postpartum depression in an inner-city maternal health clinic system.

OBJECTIVE: Postpartum depressive disorders lead to maternal disability and disturbed mother-infant relationships, but information regarding the rates of major depressive disorder in minority women is noticeably lacking. The goal of this study was to determine whether the risk factors for and rate of postpartum major depressive disorder in a predominantly African American and Hispanic clinic population would be similar to those reported for Caucasian women. METHOD: Investigators systematically screened all women scheduled for their first postpartum visit on selected days at four publicly funded inner-city community maternal health clinics in Dallas County (N=802). A multistage screening process included the Edinburgh Postnatal Depression Scale, the Inventory of Depressive Symptomatology, and the Structured Clinical Interview for DSM-IV for a maximum of three assessments during the initial 3-5-week postpartum period. RESULTS: The estimated rate of major depressive disorder during the postpartum period among women in this setting was between 6.5% and 8.5%. Only 50% of the depressed women reported onset following birth. Bottle-feeding and not living with one's spouse or significant other were associated with depression at the first evaluation; persistent depressive symptoms were linked with the presence of other young children at home. Greater severity of depressive symptoms at first contact predicted major depressive disorder several weeks later. CONCLUSIONS: Rates of postpartum depression among Latina and African American postpartum women are similar to epidemiologic rates for Caucasian postpartum and nonpostpartum women. As previously shown for Caucasian women, major depressive disorder in many Latina and African American postpartum women begins before delivery, revealing the need to screen pregnant women for depression.

A randomized trial of labor analgesia in women with pregnancy-induced hypertension.

OBJECTIVE: The purpose of this study was to compare the peripartum and perinatal effects of epidural with intravenous labor analgesia in women with pregnancy-induced hypertension. STUDY DESIGN: Women with pregnancy-induced hypertension who had consented to participate were randomized to receive either epidural or intravenous analgesia for labor pain. Both methods were given according to standardized protocols. All women received magnesium sulfate seizure prophylaxis. Obstetric and neonatal outcomes were compared according to intent-to-treat allocation. RESULTS: Seven hundred thirty-eight women were randomized: 372 women were given epidural analgesia, and 366 women were given intravenous analgesia. Maternal characteristics were similar, including the severity of hypertension. Epidural analgesia was associated with a significantly prolonged second-stage labor, an increase in forceps deliveries, and an increase in chorioamnionitis. Cesarean delivery rates and neonatal outcomes were similar. Pain relief was superior with the epidural method. Hypotension required treatment in 11% of women in the epidural group. CONCLUSION: Epidural labor analgesia provides superior pain relief but no additional therapeutic benefit to women with pregnancy-induced hypertension.

Recurrence of preterm birth in singleton and twin pregnancies.

OBJECTIVE: To assess recurrence of preterm birth and its impact on an obstetric population. METHODS: Women with consecutive births at our hospital beginning with their first pregnancy were identified (n = 15,945). The first pregnancy was categorized as delivered between 24 and 34 weeks' gestation or 35 weeks or beyond, singleton or twin, and spontaneous or induced. The risk of preterm delivery in these same women during subsequent pregnancies was then analyzed. RESULTS: Compared with women who delivered a singleton at or beyond 35 weeks' gestation in their first pregnancy, those who delivered a singleton before 35 weeks were at a significant increased risk for recurrence (odds ratio [OR] 5.6, 95% confidence interval [CI] 4.5, 7.0), whereas those who delivered twins were not (OR 1.9, 95% CI 0.46, 8.14). The OR for recurrent spontaneous preterm birth presenting with intact membranes was 7.9 (95% CI 5.6, 11.3) compared with 5.5 (95% CI 3.2, 9.4) with ruptured membranes. Of those women with a recurrent preterm birth, 49% delivered within 1 week of the gestational age of their first delivery and 70% delivered within 2 weeks. Among 15,863 nulliparous women with singleton births at their first delivery, a history of preterm birth in that pregnancy could predict only 10% of the preterm births that ultimately occurred in the entire obstetric population. CONCLUSION: In a population-based study at our hospital, women who initially delivered preterm and thus were identified to be at risk for recurrence ultimately accounted for only 10% of the prematurity problem in the cohort.

Failure of metronidazole to prevent preterm delivery among pregnant women with asymptomatic Trichomonas vaginalis infection.

BACKGROUND: Infection with Trichomonas vaginalis during pregnancy has been associated with preterm delivery. It is uncertain whether treatment of asymptomatic trichomoniasis in pregnant women reduces the occurrence of preterm delivery. METHODS: We screened pregnant women for trichomoniasis by culture of vaginal secretions. We randomly assigned 617 women with asymptomatic trichomoniasis who were 16 to 23 weeks pregnant to receive two 2-g doses of metronidazole (320 women) or placebo (297 women) 48 hours apart. We treated women again with the same two-dose regimen at 24 to 29 weeks of gestation. The primary outcome was delivery before 37 weeks of gestation. RESULTS: Between randomization and follow-up, trichomoniasis resolved in 249 of 269 women for whom follow-up cultures were available in the metronidazole group (92.6 percent) and 92 of 260 women with follow-up cultures in the placebo group (35.4 percent). Data on the time and characteristics of delivery were available for 315 women in the metronidazole group and 289 women in the placebo group. Delivery occurred before 37 weeks of gestation in 60 women in the metronidazole group (19.0 percent) and 31 women in the placebo group (10.7 percent) (relative risk, 1.8; 95 percent confidence interval, 1.2 to 2.7; P=0.004). The difference was attributable primarily to an increase in preterm delivery resulting from spontaneous preterm labor (10.2 percent vs. 3.5 percent; relative risk, 3.0; 95 percent confidence interval, 1.5 to 5.9). CONCLUSIONS: Treatment of pregnant women with asymptomatic trichomoniasis does not prevent preterm delivery. Routine screening and treatment of asymptomatic pregnant women for this condition cannot be recommended.

Prolonged pregnancy: induction of labor and cesarean births.

OBJECTIVE: To determine the effects of labor induction on cesarean delivery in post-date pregnancies. MATERIALS AND METHODS: A total of 1325 women who reached 41 weeks' gestation between December 1, 1997, and April 4, 2000, and who were scheduled for induction of labor at 42 weeks were included in this prospective observational study. Cesarean delivery rates were compared between those women who entered spontaneous labor and those who underwent induction. Women with any medical or obstetric risk factors were excluded. A power analysis was performed to determine how many patients would be required to show no effect of labor induction on cesarean delivery with a beta of.8 and an alpha of.05. Approximately 5200 patients would be required, taking an estimated 28 years to accrue at our institution. RESULTS: Admission to delivery was longer (5.7 compared with 11.1 hours, P =.001) and more likely to extend beyond 10 hours (55 compared with 24%, P =.001) in the induction group. Cesarean deliveries were increased in the induced group (19 compared with 14%, P <.001) due to cesarean for failure to progress (14 compared with 8%, P <.001). Independent risk factors for cesarean delivery included nulliparity, undilated cervix prior to labor, and epidural analgesia. Correction for these risk factors using logistic regression analysis revealed that it was the risk factors, and not induction of labor per se, that increased cesarean delivery. CONCLUSION: Risk factors intrinsic to the patient, rather than labor induction itself, are the cause of excess cesarean deliveries in women with prolonged pregnancies.

Intensity of labor pain and cesarean delivery.

Some authors have suggested that the intensity of labor pain may be related to labor dystocia. We performed a secondary analysis of a previously published randomized investigation of the effects of epidural analgesia during labor compared with patient-controlled IV meperidine on cesarean delivery. Two-hundred-fifty-nine women who received patient-controlled IV meperidine were identified for analysis. All women were in spontaneous labor with a singleton, term gestation. Women requiring 50 mg or more of meperidine per hour during labor were compared with those who required <50 mg/h. In addition, their pain scores (visual analog scale) were compared before and after analgesia administration. Pain scores were significantly higher in women requiring 50 mg/h of meperidine (8.7 vs 8.0, P = 0.05), and their labors tended to be longer (9 vs 5 h, P = 0.09). More cesarean deliveries for obstructed labor were performed in women requiring >50 mg/h of meperidine (14% vs 1.4%, P = 0.001). Neonatal outcomes were similar in the two groups.

Outcomes among term infants when two-hour postnatal pH is compared with pH at delivery.

OBJECTIVE: This study was undertaken to measure infant outcomes when pH at birth was compared with neonatal pH determined within 2 hours of age. STUDY DESIGN: We retrospectively studied term infants born between January 1, 1988, and August 31, 1998, who had umbilical artery blood pH measured at birth and again from the radial artery or umbilical artery within 2 hours after birth. Statistical significance was determined with the chi2 test. Odds ratios and 95% confidence intervals were calculated by means of the Mantel-Haenszel method. RESULTS: Data from a total of 1691 infants were analyzed: 178 (11%) had acidemia at birth (pH of <7.20) that persisted through the first 2 hours after birth; 110 (6%) had development of acidemia after birth; and 594 (35%) were born with a cord pH of <7.20 that improved after delivery. The remaining 809 infants (48%) did not have acidemia either at birth or during the neonatal period, and these served as the reference group. Seizures during the first 24 hours after birth were more likely among those infants with persistent acidemia (odds ratio, 13.0; 95% confidence interval, 6.3-26.7). The odds ratio for seizures among infants in whom acidemia developed after birth was 5.7 (95% confidence interval, 2.2-14.5). Other than the reference group, the infants who were born with acidemia that was corrected by 2 hours after birth had the lowest risk of seizures (odds ratio, 2.5; 95% confidence interval, 1.2-5.3). Significant differences in neonatal outcomes persisted after correction for anomalies. CONCLUSION: The direction of pH change from birth to the immediate neonatal period was significantly related to morbidity and mortality among term infants who were ill at birth or became ill shortly thereafter.

Antenatal dexamethasone and decreased birth weight.

OBJECTIVE: To test the hypothesis that antenatal dexamethasone treatment to promote fetal lung maturation results in decreased birth weight corrected for gestational age. METHODS: The birth weights of all dexamethasone-treated, singleton, live-born infants delivered at our hospital were compared with our overall obstetric population; a group of untreated infants frequency matched approximately 3:1 according to maternal race, infant sex, and gestational age at delivery; and an historical cohort of infants with an indication for dexamethasone but delivered in the 12 months before the introduction of corticosteroid therapy at our hospital. RESULTS: Dexamethasone-treated infants (n = 961), when compared with either the overall population (n = 122,629) or matched controls (n = 2808), had significantly lower birth weights after adjustment for week of gestation (P <.001). Compared with the historical cohort of infants, the average birth weight of dexamethasone-treated infants was smaller by 12 g at 24-26 weeks, 63 g at 27-29 weeks, 161 g at 30-32 weeks, and 80 g at 33-34 weeks' gestation. CONCLUSION: Antenatal dexamethasone administered to promote fetal maturation is associated with diminished birth weight.

The continuing value of the Apgar score for the assessment of newborn infants.

BACKGROUND: The 10-point Apgar score has been used to assess the condition and prognosis of newborn infants throughout the world for almost 50 years. Some investigators have proposed that measurement of pH in umbilical-artery blood is a more objective method of assessing newborn infants. METHODS: We carried out a retrospective cohort analysis of 151,891 live-born singleton infants without malformations who were delivered at 26 weeks of gestation or later at an inner-city public hospital between January 1988 and December 1998. Paired Apgar scores and umbilical-artery blood pH values were determined for 145,627 infants to assess which test best predicted neonatal death during the first 28 days after birth. RESULTS: For 13,399 infants born before term (at 26 to 36 weeks of gestation), the neonatal mortality rate was 315 per 1000 for infants with five-minute Apgar scores of 0 to 3, as compared with 5 per 1000 for infants with five-minute Apgar scores of 7 to 10. For 132,228 infants born at term (37 weeks of gestation or later), the mortality rate was 244 per 1000 for infants with five-minute Apgar scores of 0 to 3, as compared with 0.2 per 1000 for infants with five-minute Apgar scores of 7 to 10. The risk of neonatal death in term infants with five-minute Apgar scores of 0 to 3 (relative risk, 1460; 95 percent confidence interval, 835 to 2555) was eight times the risk in term infants with umbilical-artery blood pH values of 7.0 or less (180; 95 percent confidence interval, 97 to 334). CONCLUSIONS: The Apgar scoring system remains as relevant for the prediction of neonatal survival today as it was almost 50 years ago.

Impact of head-to-abdominal circumference asymmetry on outcomes in growth-discordant twins.

OBJECTIVE: Our aim was to evaluate head-to-abdominal circumference asymmetry as a marker for adverse outcomes in growth-discordant twins. STUDY DESIGN: We conducted a retrospective cohort study of asymmetric and symmetric twins with > or =25% growth discordance, comparing their outcomes with those in concordant symmetric twins. Growth was termed asymmetric on the basis of a head circumference/abdominal circumference ratio at > or =95th percentile on ultrasonography performed < or =4 weeks before delivery. RESULTS: We evaluated 572 twin pairs. Asymmetric discordant twins were more likely than symmetric concordant twins to be delivered at < or =34 weeks' gestation (57% vs. 27%), to require intubation (36% vs. 7%), to remain in intensive care >1 week (36% vs 3%), and to have an outcome composite that included respiratory morbidity, intraventricular hemorrhage, sepsis, or neonatal death (29% vs 6%), all P<.05. Symmetric discordant and symmetric concordant twins had similar outcomes. CONCLUSIONS: Discordant twins with head-to-abdominal circumference asymmetry have an increased risk of morbidity. Moreover, in the absence of asymmetry, outcomes are comparable among discordant and concordant twins.

Maternal age and malformations in singleton births.

OBJECTIVE: To examine the effect of maternal age on incidence of nonchromosomal fetal malformations. METHODS: Malformations detected at birth or in the newborn nursery were catalogued prospectively for 102,728 pregnancies, including abortions, stillbirths, and live births, from January 1, 1988 to December 31, 1994. Maternal age was divided into seven epochs. Relative risks (RRs) were used to compare demographic variables and specific malformations. The Mantel-Haenszel chi(2) statistic was used to compare age-specific anomalies. Multiple logistic regression analysis was used to adjust for parity. RESULTS: Abnormal karyotypes were significantly more frequent in older women. After excluding infants with chromosomal abnormalities, the incidence of structurally malformed infants also was increased significantly and progressively in women 25 years of age or older. The additional age-related risk of nonchromosomal malformations was approximately 1% in women 35 years of age or older. The odds ratio for cardiac defects was 3.95 in infants of women 40 years of age or older (95% CI 1.70, 9.17) compared with women aged 20-24 years. The risks of clubfoot and diaphragmatic hernia also increased as maternal age increased. CONCLUSION: Advanced maternal age beyond 25 years was associated with significantly increased risk of fetuses having congenital malformations not caused by aneuploidy.

Effects of symmetric and asymmetric fetal growth on pregnancy outcomes.

OBJECTIVE: To assess the prevalence of head circumference to abdomen circumference (HC/AC) asymmetry among small for gestational age (SGA) fetuses, and to determine the likelihood of adverse outcomes among asymmetric and symmetric SGA infants compared with their appropriate for gestational age (AGA) counterparts. METHODS: In a retrospective cohort study, we analyzed consecutive live-born singletons of women who had antepartum sonography within 4 weeks of delivery and delivered between January 1, 1989 and September 30, 1996. A gestational age-specific HC/AC nomogram was derived from our sonographic database of 33,740 nonanomalous live-born singletons. Asymmetric HC/AC was defined as greater than or equal to the 95th percentile for gestational age. RESULTS: Among 1364 SGA infants, 20% had asymmetric HC/AC and 80% were symmetric. Asymmetric SGA infants were more likely to have major anomalies than symmetric SGA infants or AGA infants (14% versus 4% versus 3%, respectively; P <.001). After exclusion of anomalous infants, pregnancy-induced hypertension at or before 32 weeks' gestation and cesarean delivery for nonreassuring fetal heart rate were more common in the asymmetric SGA than the AGA group (7% versus 1% and 15% versus 3%, respectively; both P <.001). A neonatal outcome composite, including one or more of respiratory distress, intraventricular hemorrhage, sepsis, or neonatal death, was more frequent among asymmetric SGA than AGA infants (14% versus 5%, P =.001). Symmetric SGA infants were not at increased risk of morbidity compared with AGA infants. CONCLUSION: The minority of SGA fetuses with HC/AC asymmetry are at increased risk for intrapartum and neonatal complications.

Vaginal fetal fibronectin measurements from 8 to 22 weeks' gestation and subsequent spontaneous preterm birth.

OBJECTIVE: We sought to determine the range of fetal fibronectin values in the vagina from 8 to 22 weeks' gestation, the factors associated with both low and high values, and whether high values are associated with gestational age at birth. STUDY DESIGN: Vaginal fetal fibronectin was quantitatively determined in a prospective cohort study of 13,360 women being evaluated for participation in the National Institute of Child Health and Human Development Maternal-Fetal Medicine Unit treatment trials for bacterial vaginosis and Trichomonas vaginalis. Fetal fibronectin values were correlated with gestational age at screening, race, the presence of bacterial vaginosis and Trichomonas vaginalis, and gestational age at delivery. RESULTS: Vaginal fetal fibronectin values at each gestational age ranged from unmeasurable to >1000 ng/mL, with median values always being <10 ng/mL. Fetal fibronectin values declined progressively with increasing gestational age at sampling. Bacterial vaginosis and black race were associated with higher values, whereas nulliparity was associated with lower values. High values after 13 weeks' gestation were associated with a 2- to 3-fold increased risk of subsequent spontaneous preterm birth overall and a 4-fold increased risk of very early preterm birth. CONCLUSION: Elevated vaginal fetal fibronectin levels from 13 to 22 weeks' gestation are associated with a significantly increased risk of spontaneous preterm birth.

Forty weeks and beyond: pregnancy outcomes by week of gestation.

OBJECTIVE: To assess pregnancy outcomes at 40, 41, and 42 weeks' gestation when labor induction is done routinely at 42 but not 41 weeks. METHODS: We reviewed all singleton pregnancies delivered at 40 or more weeks' gestation between 1988 and 1998 at Parkland Memorial Hospital, Dallas, Texas. We excluded women with hypertension, prior cesarean, diabetes, malformations, breech presentation, and placenta previa. Labor characteristics and neonatal outcomes of pregnancies at 41 and 42 weeks' gestation were compared with pregnancies that ended at 40 weeks. Women with certain dating criteria had induction of labor at 42 weeks. Gestational age was calculated from the last menstrual period (LMP), sonography when available, and clinical examination. If the fundal height between 18 and 30 weeks was within 2 cm of gestational age, the reported LMP was accepted as correct. Sonogram was used to calculate gestational age if a discrepancy was identified. Statistical analysis consisted of chi(2) and analysis of variance. RESULTS: We studied 56,317 pregnancies: 29,136 at 40 weeks, 16,386 at 41 weeks, and 10,795 at 42 weeks. Labor complications increased from 40 to 42 weeks, including oxytocin induction (2% versus 35%, P <.001), length of labor (5.5 +/- 4.9 versus 8.8 +/- 6. 5 hours, P <.001), prolonged second stage of labor (2% versus 4%, P <.001), forceps use (6% versus 9%, P <.001), and cesarean delivery (7% versus 14%, P <.001). Neonatal outcomes were similar in the three groups, including 5-minute Apgar score less than 4, admission to the neonatal intensive care unit (NICU), umbilical artery pH less than 7, seizures, and perinatal mortality. Sepsis was more frequent in the 42-week group than the other groups (0.1 versus 0.3%, P =. 001), as was admission to the NICU (0.4 versus 0.6%, P =.008). CONCLUSION: Routine labor induction at 41 weeks likely increases labor complications and operative delivery without significantly improving neonatal outcomes.