Gestational Weight Gain: Association with Adverse Pregnancy Outcomes

Background It is unclear how adherence to the Institute of Medicine's (IOM) guidelines for weight gain affects pregnancy outcomes. Objective We investigated how weight gain outside the IOM's recommendations affects the risks of adverse pregnancy outcomes. Study Design We performed a secondary analysis of a prospective cohort study including singleton, nonanomalous fetuses. The risks of small for gestational age (SGA), macrosomia, preeclampsia, cesarean delivery, gestational diabetes, or preterm birth were calculated for patients who gained weight below or above the IOM's recommendations based on body mass index category. A time-to-event analysis was performed to account for gestational age at delivery. A Cox proportional model was fit to estimate hazard ratios accounting for possible confounders. Results Women who gained weight below recommendations were 2.5 times more likely to deliver SGA and twice as likely to deliver preterm. Normal-weight patients who gained below recommendations were 2.5 times more likely to deliver SGA and twice as likely to deliver preterm. Obese patients who gained inadequate weight were 2.5 times more likely to deliver SGA. Conclusion Among normal-weight patients, adhering to IOM recommendations may prevent growth abnormalities and preterm delivery. Among obese patients, a minimum weight gain requirement may prevent SGA infants.

Maternal Marijuana Use and Adverse Neonatal Outcomes: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate whether marijuana use in pregnancy increases risks for adverse neonatal outcomes and clarify if any increased risk is attributable to marijuana use itself or to confounding factors such as tobacco use.

DATA SOURCES

Two authors performed a search of the data through August 2015 utilizing PubMed, Embase, Scopus, Cochrane reviews, ClinicalTrials.gov, and Cumulative Index to Nursing and Allied Health.

METHODS OF STUDY SELECTION

We looked at observational studies that compared rates of prespecified adverse neonatal outcomes in women who used marijuana during pregnancy with women who did not.

TABULATION, INTEGRATION, AND RESULTS

Two authors independently extracted data from the selected studies. Primary outcomes were low birth weight (less than 2,500 g) and preterm delivery at less than 37 weeks of gestation. Secondary outcomes were birth weight, gestational age at delivery, small for gestational age, level II or greater nursery admission, stillbirth, spontaneous abortion, low Apgar score, placental abruption, and perinatal death. DerSimonian-Laird random-effects models were used. We assessed heterogeneity using the Q test and I statistic. Stratified analyses were performed for the primary outcomes and pooled adjusted estimates were calculated. We included 31 studies that assessed the effects of maternal marijuana use on adverse neonatal outcomes. Based on pooled unadjusted data, marijuana use during pregnancy was associated with an increased risk of low birth weight (15.4% compared with 10.4%, pooled relative risk [RR] 1.43, 95% confidence interval [CI] 1.27-1.62) and preterm delivery (15.3% compared with 9.6%, pooled RR 1.32, 95% CI 1.14-1.54). However, pooled data adjusted for tobacco use and other confounding factors showed no statistically significant increased risk for low birth weight (pooled RR 1.16, 95% CI 0.98-1.37) or preterm delivery (pooled RR 1.08, 95% CI 0.82-1.43).

CONCLUSION

Maternal marijuana use during pregnancy is not an independent risk factor for adverse neonatal outcomes after adjusting for confounding factors. Thus, the association between maternal marijuana use and adverse outcomes appears attributable to concomitant tobacco use and other confounding factors.

Utility of the Simplified Bishop Score in Spontaneous Labor

Objective The objective of this study was to evaluate the relationship between the simplified Bishop score (SBS) on admission for labor and subsequent labor outcomes to identify women at higher risk for cesareans. Study Design This was a secondary analysis of a prospective cohort study of 4,733 singleton pregnancies. Adjusted odds ratios (aOR) were calculated comparing outcomes in women with an unfavorable SBS ≤ 5 to women with a favorable SBS > 5. A favorable SBS was compared with the individual parameters of dilation, effacement, and station. The primary outcome was vaginal delivery. Secondary outcomes were prolonged first stage, completion of first stage, oxytocin augmentation, and prolonged second stage. Results 47.8% of the patients admitted in labor had an unfavorable SBS. Nulliparous and multiparous patients with a favorable SBS were more likely to have a vaginal delivery (aOR 1.96, 95% confidence intervals [CI] 1.49-2.57; aOR 1.91, 95% CI 1.44-2.53) and less likely to require oxytocin augmentation (aOR 0.34, 95% CI 0.28-0.42; aOR 0.26, 95% CI 0.22-0.30. Compared with dilation alone, the SBS in its entirety was associated with a higher likelihood of vaginal delivery in nulliparous. Conclusion An unfavorable SBS on admission for labor is associated with a decreased likelihood of having a vaginal delivery.

Three-Versus Two-Dimensional Sonographic Biometry for Predicting Birth Weight and Macrosomia in Diabetic Pregnancies

OBJECTIVES

The purpose of this study was to test the hypothesis that a formula incorporating 3-dimensional (3D) fractional thigh volume would be superior to the conventional 2-dimensional (2D) formula of Hadlock et al (Am J Obstet Gynecol 1985; 151:333-337) for predicting birth weight and macrosomia.

METHODS

We conducted a prospective cohort study of pregnancies complicated by pregestational or gestational diabetes and delivered after 38 weeks. Two-dimensional and 3D sonographic examinations were performed for fetal biometry and factional thigh volumes at 34 to 37 weeks. Fetal weight was estimated by Hadlock's 2D formula IV, which uses only 2D biometry, and formula 6 from Lee et al (Ultrasound Obstet Gynecol 2009; 34:556-565), which incorporates 3D fractional thigh volume and 2D biometry. The gestation-adjusted projection method was used to estimate predicted birth weights from 2D and 3D estimates. The primary outcome was fetal macrosomia, which was defined as birth weight of 4000 g or higher.

RESULTS

A total of 115 women with diabetes met inclusion criteria, and 17 (14.8%) delivered macrosomic neonates. The mean percentage error was significantly lower for the 2D than the 3D projected estimate (1.0% versus 12.0%; P < .01). The standard deviation of the mean percentage error was also significantly lower for the 2D projected estimate (10.2% versus 17.2%; P< .01). Two-dimensional biometry was overall superior to 3D biometry for predicting macrosomia (area under the receiver operating characteristic curve, 0.88 versus 0.75; P = .03). Specificity was significantly higher for 2D biometry (85% versus 66%; P < .01), whereas the difference in sensitivity was not statistically significant (59% versus 71%; P = .22).

CONCLUSIONS

In this study, the Hadlock 2D formula was superior to the 3D method for predicting birth weight and macrosomia in diabetic women when used approximately 2 weeks before delivery, based on the gestation-adjusted projection method.

Group Prenatal Care Compared With Traditional Prenatal Care: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the effect of group prenatal care on perinatal outcomes compared with traditional prenatal care.

DATA SOURCES

We searched MEDLINE through PubMed, EMBASE, Scopus, Cumulative Index of Nursing and Allied Health literature, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov.

METHODS OF STUDY SELECTION

We searched electronic databases for randomized controlled trials and observational studies comparing group care with traditional prenatal care. The primary outcome was preterm birth. Secondary outcomes were low birth weight, neonatal intensive care unit admission, and breastfeeding initiation. Heterogeneity was assessed using the Q test and I statistic. Pooled relative risks (RRs) and weighted mean differences were calculated using random-effects models.

TABULATIONS, INTEGRATION, AND RESULTS

Four randomized controlled trials and 10 observational studies met inclusion criteria. The rate of preterm birth was not significantly different with group care compared with traditional care (11 studies: pooled rates 7.9% compared with 9.3%, pooled RR 0.87, 95% confidence interval [CI] 0.70-1.09). Group care was associated with a decreased rate of low birth weight overall (nine studies: pooled rate 7.5% group care compared with 9.5% traditional care; pooled RR 0.81, 95% CI 0.69-0.96), but not among randomized controlled trials (four studies: 7.9% group care compared with 8.7% traditional care, pooled RR 0.92, 95% CI 0.73-1.16). There were no significant differences in neonatal intensive care unit admission or breastfeeding initiation.

CONCLUSION

Available data suggest that women who participate in group care have similar rates of preterm birth, neonatal intensive care unit admission, and breastfeeding.

Fetal Sex Differences in Intrapartum Electronic Fetal Monitoring

Objective The article aimed to estimate differences in electronic fetal monitoring (EFM) patterns in term gestations attributable to fetal sex. Study Design We conducted a prospective cohort study of consecutive, singleton, nonanomalous, term gestations that labored during admission. EFM characteristics in the 30 minutes prior to delivery were evaluated. Logistic regression models estimated adjusted risks for EFM features by sex. To further estimate the impact of sex, we limited the analysis to gestations without composite morbidity (morbidity defined as arterial cord pH <7.20, 5-minute Apgar <7, or neonatal intensive care unit admission). Results Of 2,639 deliveries, 1,400 (53%) were male. Male fetuses had a higher number of decelerations (median [interquartile range]: 8 [5, 11] vs. 7 [4, 10], p < 0.003) and increased total deceleration area (adjusted odds ratio [aOR]: 1.11, 95% confidence interval [CI] :1.04, 1.18). Male fetuses were at increased risk for prolonged decelerations (aOR: 1.21, 95% CI: 1.03, 1.42) and repetitive variable decelerations (aOR: 1.24, 95% CI: 1.05, 1.47). Among neonates without composite morbidity (n = 2,446, 92.7%), male sex conferred an increased risk of late decelerations (aOR: 1.21, 95% CI: 1.02, 1.43) and increased total deceleration area (aOR: 1.12, 95% CI: 1.05, 1.20). Conclusion There are significant sex differences in EFM patterns at term among pregnancies without evidence of acidemia. This suggests that interpretation of EFM patterns may need to take into account factors such as fetal sex.

Maternal and Perinatal Outcomes in Women with Insulin Resistance

Objective This study aims to estimate the risks of adverse maternal and perinatal outcomes in women with insulin resistance below the threshold of gestational diabetes mellitus (GDM). Methods This was a retrospective cohort study of 5,983 women with singleton pregnancies undergoing universal GDM screening between 24 and 28 weeks gestation. Subjects were divided into those with a normal 1-hour glucose challenge test (GCT), those with an elevated GCT with all normal values on a 3-hour glucose tolerance test (GTT), and those with an elevated GCT with one abnormal value on GTT. Outcomes included macrosomia, pregnancy-induced hypertension (PIH), cesarean section and operative delivery, shoulder dystocia, indicated-preterm birth, and other neonatal outcomes. Logistic regression was performed to compare outcomes among groups. Results The risk of macrosomia was increased for those with an elevated GCT and all normal values on GTT (adjusted odds ratio [aOR], 1.71; 95% confidence interval [CI]: 1.12, 1.97), and for those with an elevated GCT and one abnormal value (aOR, 2.69; 95% CI: 1.49, 4.83). Risks of PIH, cesarean section, and indicated-preterm birth were also increased in those with an elevated 1-hour GCT and no GDM. Conclusion There are increased risks of macrosomia, PIH, indicated-preterm birth, and cesarean section among those with insulin resistance even in the absence of GDM.

Nonreassuring Fetal Status in the Second Stage of Labor: Fetal Monitoring Features and Association with Neonatal Outcomes

Objective To examine features of electronic fetal monitoring that prompt a diagnosis of nonreassuring fetal status (NRFS) and their association with acidemia. Study Design We identified all operative (cesarean or operative vaginal) deliveries from a retrospective cohort study of term singletons delivered in the second stage. The primary exposure was indication for delivery, NRFS versus other. We compared fetal monitoring features in the 30 minutes prior to delivery. In those delivered for NRFS, we assessed features associated with acidemia (pH < 7.2). Logistic regression adjusted for confounders. Results Of 5,388 patients, 770 (14%) were delivered operatively. NRFS (77%) was associated with acidemia (adjusted odds ratio 3.7, 95% confidence interval 2.1-6.5). Total deceleration area, repetitive late decelerations, and marked variability were associated with NRFS. However, only number of prolonged decelerations and total deceleration area were associated with acidemia in the NRFS group. Conclusion The majority of deliveries for NRFS and the features that prompt that diagnosis are not associated with acidemia.

Can Transabdominal Cervical Length Measurement Exclude Short Cervix?

OBJECTIVE

This study aims to determine if transabdominal (TA) cervical length may be used to rule out a short cervix on transvaginal (TV) ultrasound.

STUDY DESIGN

We conducted a prospective cohort study of women undergoing routine anatomic survey at 17 to 23 weeks gestation. TA and TV cervical length measurements were obtained in each patient. A short cervix was defined as TV cervical length < 30 mm. Predictive characteristics were calculated for different cutoff values of TA cervical length.

RESULTS

There were 404 patients enrolled, a TA cervical length could not be obtained in 83 women (20.6%) and 318 women had both TA and TV measurements. Of those, 14 (4.4%) had a TV cervical length < 30 mm. TA cervical length measurement ≥ 35 mm excluded the possibility of TV cervical length < 30 mm (negative predictive value, 99.5%; 95% confidence interval [CI], 97.4; 100%). In our cohort, 67.6% (95% CI, 62.2; 72.7%) of TV ultrasounds could have been avoided using a TA cervical length cutoff of ≥ 5 mm.

CONCLUSION

ATA cervical length of at least 35 mm excludes a short cervix of < 30 mm. While TA cervical length screening may not be feasible in 1 in 5 women, it may be used to decrease the burden of universal TV cervical length screening.

Universal cervical length screening: implementation and outcomes

BACKGROUND

Transvaginal measurement of cervical length (CL) has been advocated as a screening tool to prevent preterm birth, but controversy remains regarding the overall utility of universal screening.

OBJECTIVE

We aimed to evaluate the acceptability of a universal CL screening program. Additionally we evaluated risk factors associated with declining screening and subsequent delivery outcomes of women who accepted or declined screening.

STUDY DESIGN

This was a retrospective cohort study of transvaginal CL screening at a single institution from July 1, 2011, through December 31, 2014. Institutional protocol recommended transvaginal CL measurement at the time of anatomic survey between 17-23 weeks in all women with singleton, viable pregnancies, without current or planned cerclage, with patients able to opt out. Patients with CL ≤20 mm were considered to have clinically significant cervical shortening and were offered treatment. We assessed acceptance rate, risk factors for declining CL screening, and the trend of acceptance of CL screening over time. We also calculated the prevalence of CL ≤25, ≤20, and ≤15 mm, and estimated the association between CL screening and spontaneous preterm birth.

RESULTS

Of 12,740 women undergoing anatomic survey during the study period, 10,871 (85.3%; 95% confidence interval [CI], 84.7-85.9%) underwent CL screening. Of those, 215 (2.0%) had a CL ≤25 mm and 131 (1.2%) had a CL ≤20 mm. After the first 6 months of implementation, there was no change in rates of acceptance of CL screening over time (P for trend = .15). Women were more likely to decline CL screening if they were African American (adjusted odds ratio [aOR], 2.17; 95% CI, 1.93-2.44), obese (aOR, 1.18; 95% CI, 1.06-1.31), multiparous (aOR, 1.45; 95% CI, 1.29-1.64), age <35 years (aOR, 1.24; 95% CI, 1.08-1.43), or smokers (aOR, 1.42; 95% CI, 1.20-1.68). Rates of spontaneous preterm birth <28 weeks were higher in those who declined CL screening (aOR, 2.01; 95% CI, 1.33-3.02).

CONCLUSION

Universal CL screening was implemented successfully with 85% of women screened. Overall incidence of short cervix was low and women with significant risk factors for preterm birth were more likely to decline screening. Patients who declined CL screening were more likely to be African American, obese, multiparous, age <35 years, and smokers. Rates of early, but not late, spontaneous preterm birth were significantly higher among women who did not undergo CL screening.

A Randomized Trial Comparing Skin Antiseptic Agents at Cesarean Delivery

BACKGROUND

Preoperative skin antisepsis has the potential to decrease the risk of surgical-site infection. However, evidence is limited to guide the choice of antiseptic agent at cesarean delivery, which is the most common major surgical procedure among women in the United States.

METHODS

In this single-center, randomized, controlled trial, we evaluated whether the use of chlorhexidine-alcohol for preoperative skin antisepsis was superior to the use of iodine-alcohol for the prevention of surgical-site infection after cesarean delivery. We randomly assigned patients undergoing cesarean delivery to skin preparation with either chlorhexidine-alcohol or iodine-alcohol. The primary outcome was superficial or deep surgical-site infection within 30 days after cesarean delivery, on the basis of definitions from the Centers for Disease Control and Prevention.

RESULTS

From September 2011 through June 2015, a total of 1147 patients were enrolled; 572 patients were assigned to chlorhexidine-alcohol and 575 to iodine-alcohol. In an intention-to-treat analysis, surgical-site infection was diagnosed in 23 patients (4.0%) in the chlorhexidine-alcohol group and in 42 (7.3%) in the iodine-alcohol group (relative risk, 0.55; 95% confidence interval, 0.34 to 0.90; P=0.02). The rate of superficial surgical-site infection was 3.0% in the chlorhexidine-alcohol group and 4.9% in the iodine-alcohol group (P=0.10); the rate of deep infection was 1.0% and 2.4%, respectively (P=0.07). The frequency of adverse skin reactions was similar in the two groups.

CONCLUSIONS

The use of chlorhexidine-alcohol for preoperative skin antisepsis resulted in a significantly lower risk of surgical-site infection after cesarean delivery than did the use of iodine-alcohol. (Funded by the National Institutes of Health and Washington University School of Medicine in St. Louis; ClinicalTrials.gov number, NCT01472549.).

What is prenatal screening and why to do it?

Patients and providers are faced with a wide array of choices to screen for structural abnormalities, aneuploidy, and genetic diseases in the prenatal period. It is important to consider the features of the diseases being screened for, the characteristics of the screening tests used, and the population being screened when evaluating prenatal screening techniques.

Effect of Prenatal Supplementation With Vitamin D on Asthma or Recurrent Wheezing in Offspring by Age 3 Years: The VDAART Randomized Clinical Trial

IMPORTANCE

Asthma and wheezing begin early in life, and prenatal vitamin D deficiency has been variably associated with these disorders in offspring.

OBJECTIVE

To determine whether prenatal vitamin D (cholecalciferol) supplementation can prevent asthma or recurrent wheeze in early childhood.

DESIGN, SETTING, AND PARTICIPANTS

The Vitamin D Antenatal Asthma Reduction Trial was a randomized, double-blind, placebo-controlled trial conducted in 3 centers across the United States. Enrollment began in October 2009 and completed follow-up in January 2015. Eight hundred eighty-one pregnant women between the ages of 18 and 39 years at high risk of having children with asthma were randomized at 10 to 18 weeks' gestation. Five participants were deemed ineligible shortly after randomization and were discontinued.

INTERVENTIONS

Four hundred forty women were randomized to receive daily 4000 IU vitamin D plus a prenatal vitamin containing 400 IU vitamin D, and 436 women were randomized to receive a placebo plus a prenatal vitamin containing 400 IU vitamin D.

MAIN OUTCOMES AND MEASURES

Coprimary outcomes of (1) parental report of physician-diagnosed asthma or recurrent wheezing through 3 years of age and (2) third trimester maternal 25-hydroxyvitamin D levels.

RESULTS

Eight hundred ten infants were born in the study, and 806 were included in the analyses for the 3-year outcomes. Two hundred eighteen children developed asthma or recurrent wheeze: 98 of 405 (24.3%; 95% CI, 18.7%-28.5%) in the 4400-IU group vs 120 of 401 (30.4%, 95% CI, 25.7%-73.1%) in the 400-IU group (hazard ratio, 0.8; 95% CI, 0.6-1.0; P = .051). Of the women in the 4400-IU group whose blood levels were checked, 289 (74.9%) had 25-hydroxyvitamin D levels of 30 ng/mL or higher by the third trimester of pregnancy compared with 133 of 391 (34.0%) in the 400-IU group (difference, 40.9%; 95% CI, 34.2%-47.5%, P < .001).

CONCLUSIONS AND RELEVANCE

In pregnant women at risk of having a child with asthma, supplementation with 4400 IU/d of vitamin D compared with 400 IU/d significantly increased vitamin D levels in the women. The incidence of asthma and recurrent wheezing in their children at age 3 years was lower by 6.1%, but this did not meet statistical significance; however, the study may have been underpowered. Longer follow-up of the children is ongoing to determine whether the difference is clinically important.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00920621.