Margaret Harper

Pregnancy outcomes with weight gain above or below the 2009 institute of medicine guidelines

OBJECTIVE: To evaluate pregnancy outcomes according to 2009 Institute of Medicine (IOM) gestational weight gain guidelines. METHODS: This study is a secondary analysis of a preeclampsia prevention trial among nulliparas carrying singletons. Odds ratios and 95% confidence intervals (adjusted for maternal age, race, smoking, and treatment group) were calculated based on total weight gain below or above the IOM guidelines stratified by prepregnancy body mass index (BMI). The referent group was weight gain within the guidelines. RESULTS: Of 8,293 pregnancies, 9.5% had weight gain below, 17.5% within, and 73% above IOM guidelines. With excess weight gain, all BMI categories had an increased risk of hypertensive disorders; normal weight and overweight women also had increased risk of cesarean delivery and neonatal birth weight at or above the 90th centile but a decreased risk of weight below the 10th centile. There were no consistent associations with insufficient weight gain and adverse outcomes. CONCLUSION: Excess weight gain was prevalent and associated with an increased risk of hypertensive disorders, cesarean delivery, and large-for-gestational-age neonates.

The relationship between maternal glycemia and perinatal outcome.

OBJECTIVE: To examine the relationship between varying degrees of maternal hyperglycemia and pregnancy outcomes. METHODS: This was a secondary analysis of a treatment trial for mild gestational diabetes including four cohorts: 1) 473 women with untreated mild gestational diabetes; 2) 256 women with a positive 50-g screen and one abnormal oral glucose tolerance test (OGTT) value; 3) 675 women with a positive screen and no abnormal OGTT values; and 4) 437 women with a normal 50-g screen. Groups were compared by test of trend for a composite perinatal outcome (neonatal hypoglycemia, hyperbilirubinemia, elevated cord C-peptide level, and perinatal trauma or death), frequency of large for gestational age neonates, shoulder dystocia, and pregnancy-related hypertension. Three-hour OGTT levels (fasting, 1-, 2-, and 3-hour) levels were divided into categories and analyzed for their relationship to perinatal and maternal outcomes. RESULTS: There were significant trends by glycemic status among the four cohorts for the composite and all other outcomes (P<.001). Analysis for trend according to OGTT categories showed an increasing relationship between fasting and all postload levels and the various outcomes (P<.05). Fasting glucose 90 mg/dL or greater and 1 hour 165 mg/dL or greater were associated with an increased risk for the composite outcome (odds ratios and 95% confidence intervals of 2.0 [1.03–4.15] and 1.46 [1.02–2.11] to 1.52 [1.08–2.15] for the fasting and 1 hour, respectively). A 1 hour glucose 150 mg/dL or greater was associated with an increased risk for large for gestational age (odds ratios, 1.8 [1.02–3.18] to 2.35 [1.35–4.14]); however, 2- and 3-hour glucose levels did not increase the risk for the composite or large for gestational age until well beyond current gestational diabetes diagnostic thresholds. CONCLUSION: A monotonic relationship exists between increasing maternal glycemia and perinatal morbidity. Current OGTT criteria require reevaluation in determining thresholds for the diagnosis and treatment of gestational diabetes. LEVEL OF EVIDENCE: II

Complications of anesthesia for cesarean delivery

Objective: To quantify anesthesia-related complications associated with cesarean delivery in a well-described, prospectively ascertained cohort from multiple university-based hospitals in the United States and to evaluate whether certain factors would identify women at increased risk for a failed regional anesthetic. Methods: A prospective observational study was conducted of women (n = 37,142) with singleton gestations undergoing cesarean delivery in the centers forming the National Institute of Child Health and Human Development Maternal–Fetal Medicine Units Network. Detailed information was collected regarding choice of anesthesia and procedure-related complications, including failed regional anesthetic and maternal death. Potential risk factors for a failed regional anesthetic were analyzed. Results: Of the women studied, 34,615 (93%) received a regional anesthetic. Few (3.0%) regional procedures failed, and related maternal morbidity was rare. Increased maternal size, higher preoperative risk, rapid decision-to-incision interval, and placement later in labor were all significantly related to an increased risk of a failed regional procedure. Of the general anesthetics, 38% were administered when the decision-to-incision interval was less than 15 minutes. Women deemed at the greatest preoperative risk (American Society of Anesthesiologists score ≥ 4) were approximately 7-fold more likely to receive a general anesthetic (odds ratio 6.9, 95% confidence interval 5.83–8.07). There was one maternal death, due to a failed intubation, in which the anesthetic procedure was directly implicated. Conclusion: Regional techniques have become the preferred method of anesthesia for cesarean delivery. Procedure-related complications are rare and attest to the safety of modern obstetric anesthesia for cesarean delivery in the United States. Level of Evidence: II-2

Labor outcomes with increasing number of prior vaginal births after cesarean delivery

OBJECTIVE: To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs. METHODS: From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery. RESULTS: Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter. CONCLUSION: Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy. LEVEL OF EVIDENCE: II

Neonatal outcomes in twin pregnancies delivered moderately preterm, late preterm, and term

We compared neonatal outcomes in twin pregnancies following moderately preterm birth (MPTB), late preterm birth (LPTB), and term birth. A secondary analysis of a multicenter, randomized controlled trial of multiple gestations was conducted. MPTB was defined as delivery between 32 (0)/(7) and 33 (6)/(7) weeks and LPTB between 34 (0)/(7) and 36 (6)/(7) weeks. Primary outcome was a neonatal outcome composite consisting of one or more of the following: neonatal death, respiratory distress syndrome, early onset culture-proven sepsis, stage 2 or 3 necrotizing enterocolitis, bronchopulmonary dysplasia, grade 3 or 4 intraventricular hemorrhage, periventricular leukomalacia, pneumonia, or severe retinopathy of prematurity. Among 552 twin pregnancies, the MPTB rate was 14.5%, LPTB 49.8%, and term birth rate 35.7%. The rate of the primary outcome was different between groups: 30.0% for MPTB, 12.8% for LPTB, 0.5% for term birth ( P < 0.001). Compared with term neonates, the primary neonatal outcome composite was increased following MPTB (relative risk [RR] 58.5; 95% confidence interval [CI] 11.3 to 1693.0) and LPTB (RR 24.9; 95% CI 4.8 to 732.2). Twin pregnancies born moderately and late preterm encounter higher rates of neonatal morbidities compared with twins born at term.

Failed Labor Induction Toward an Objective Diagnosis

OBJECTIVE: To evaluate maternal and perinatal outcomes in women undergoing labor induction with an unfavorable cervix according to duration of oxytocin administration in the latent phase of labor after ruptured membranes. METHODS: This was a secondary analysis of a randomized multicenter trial in which all cervical examinations from admission were recorded. Inclusion criteria: nulliparas at or beyond 36 weeks of gestation undergoing induction with a cervix of 2 cm or less dilated and less than completely effaced. The latent phase of labor was defined as ending at a cervical dilation of 4 cm and effacement of at least 90%, or at a cervical dilation of 5 cm regardless of effacement. RESULTS: A total of 1,347 women were analyzed. The overall vaginal delivery rate was 63.2%. Most women had exited the latent phase after 6 hours of oxytocin and membrane rupture (n=939; 69.7%); only 5% remained in the latent phase after 12 hours. The longer the latent phase, the lower the vaginal delivery rate. Even so, 39.4% of the 71 women who remained in the latent phase after 12 hours of oxytocin and membrane rupture were delivered vaginally. Chorioamnionitis, endometritis, or both, and uterine atony were the only maternal adverse outcomes related to latent-phase duration: adjusted odds ratios (95% confidence intervals) of 1.12 (1.07, 1.17) and 1.13 (1.06, 1.19), respectively, for each additional hour. Neonatal outcomes were not related to latent-phase duration. CONCLUSION: Almost 40% of the women who remained in the latent phase after 12 hours of oxytocin and membrane rupture were delivered vaginally. Therefore, it is reasonable to avoid deeming labor induction a failure in the latent phase until oxytocin has been administered for at least 12 hours after membrane rupture. LEVEL OF EVIDENCE: III

Maternal 25-Hydroxyvitamin D and Preterm Birth in Twin Gestations

OBJECTIVE: To assess whether there was an independent association between maternal 25-hydroxyvitamin D concentrations at 24–28 weeks of gestation and preterm birth in a multicenter U.S. cohort of twin pregnancies. METHODS: Serum samples from women who participated in a clinical trial of 17 &agr;-hydroxyprogesterone caproate for the prevention of preterm birth in twin gestations (2004–2006) were assayed for 25-hydroxyvitamin D concentrations using liquid chromatography tandem mass spectrometry (n=211). Gestational age was determined early in pregnancy using a rigorous algorithm. Preterm birth was defined as delivery of the first twin or death of either twin at less than 35 weeks of gestation. RESULTS: The mean serum 25-hydroxyvitamin D concentration was 82.7 nmol/L (standard deviation 31.5); 40.3% of women had concentrations less than 75 nmol/L. Preterm birth at less than 35 weeks of gestation occurred in 49.4% of women with 25-hydroxyvitamin D concentrations less than 75 nmol/L compared with 26.2% among those with concentrations of 75 nmol/L or more (P<.001). After adjustment for maternal race and ethnicity, study site, parity, prepregnancy body mass index, season, marital status, education, gestational age at blood sampling, smoking status, and 17 &agr;-hydroxyprogesterone caproate treatment, maternal 25-hydroxyvitamin D concentration of 75 nmol/L or more was associated with a 60% reduction in the odds of preterm birth compared with concentrations less than 75 nmol/L (adjusted odds ratio [OR] 0.4, 95% confidence interval [CI] 0.2–0.8). A similar protective association was observed when studying preterm birth at less than 32 weeks of gestation (OR 0.2, 95% CI 0.1–0.6) and after confounder adjustment. CONCLUSIONS: Late second-trimester maternal 25-hydroxyvitamin D concentrations less than 75 nmol/L are associated with an increase in the risk of preterm birth in this cohort of twin pregnancies. LEVEL OF EVIDENCE: II

Relationship between 1-hour glucose challenge test results and perinatal outcomes

OBJECTIVE: To estimate the relationship between 1-hour 50 g glucose challenge test values and perinatal outcomes. METHODS: This was a secondary analysis of data from a multicenter treatment trial of mild gestational diabetes mellitus. Women with glucose challenge test values of 135–199 mg/dL completed a 3-hour oral glucose tolerance test. Mild gestational diabetes mellitus was defined as fasting glucose less than 95 mg/dL and two or more abnormal oral glucose tolerance test values: 1-hour 180 mg/dL or more; 2-hour 155 mg/dL or more; and 3-hour 140 mg/dL or more. Our study included untreated women with glucose challenge test values of 135–139 mg/dL and 140–199 mg/dL and a comparison group with values less than 120 mg/dL. Primary outcomes included a perinatal composite (stillbirth, neonatal death, hypoglycemia, hyperbilirubinemia, neonatal hyperinsulinemia, and birth trauma), large for gestational age (LGA, birth weight above the 90th percentile based on sex-specific and race-specific norms), and macrosomia (greater than 4,000 g). RESULTS: There were 436 women with glucose challenge test values less than 120 mg/dL and 1,403 with values of 135 mg/dL or more (135–139, n=135; 140–199, n=1,268). The composite perinatal outcome occurred in 25.6% of those with glucose challenge test values less than 120 mg/dL compared with 21.1% for values of 135–139 mg/dL and 35.3% for values of 140–199 mg/dL. Rates of LGA by group were 6.6%, 6.8%, and 12.4%, respectively. Rates of macrosomia by group were 7.8%, 6.1%, and 12.1%, respectively. Compared with glucose challenge test values less than 120 mg/dL, the adjusted odds ratios (ORs) (95% confidence intervals [CIs]) for values of 140–199 mg/dL were 1.48 (1.14–1.93) for the composite outcome, 1.97 (1.29–3.11) for LGA, and 1.61 (1.07–2.49) for macrosomia. For glucose challenge test values of 135–139 mg/dL, adjusted ORs and 95% CIs were 0.75 (0.45–1.21), 1.04 (0.44–2.24), and 0.75 (0.30–1.66), respectively. The subcategories with glucose challenge test values of 140–144 mg/dL and 145–149 mg/dL also were associated with an increase in selected outcomes when compared with those with values less than 120 mg/dL. CONCLUSIONS: Glucose challenge test values of 135–139 mg/dL were not associated with adverse outcomes compared with values less than 120 mg/dL; however, glucose challenge test values of 140 mg/dL or more were associated with an increase in odds of the composite perinatal outcome, LGA, and macrosomia. LEVEL OF EVIDENCE: II

Change in mononuclear leukocyte responsiveness in midpregnancy and subsequent preterm birth

OBJECTIVE: To estimate the associations of change in immune response with preterm delivery, omega-3 supplementation, and fish diet. METHODS: This was an ancillary study to a randomized trial of omega-3 fatty acid supplementation for the prevention of recurrent preterm birth. In vitro maternal peripheral blood mononuclear leukocyte production of the anti-inflammatory cytokine, interleukin-10, and the proinflammatory cytokine, tumor necrosis factor-&agr;, in response to stimulation with lipopolysaccharide, was measured at 16–22 weeks of gestation (baseline) and again at 25–28 weeks of gestation (follow-up) among women with prior spontaneous preterm birth. Changes in concentrations from baseline to follow-up ([INCREMENT]) were compared separately among groups defined by gestational age category at delivery, fish diet history, and omega-3 compared with placebo treatment assignment with Kruskal-Wallis tests. RESULTS: Interleukin-10 [INCREMENT] differed by gestational age category among 292 women with paired assays. Concentrations increased less in women delivering between 35 and 36 6/7 weeks of gestation (48.9 pg/mL) compared with women delivering at term (159.3 pg/mL) and decreased by 65.2 pg/mL in women delivering before 35 weeks of gestation (P=.01). Tumor necrosis factor-&agr; &Dgr; also differed by gestational age category among 319 women, but the pattern was inconsistent. Those delivering between 35 and 36 6/7 weeks of gestation exhibited decreased concentrations of tumor necrosis factor-&agr; at follow-up compared with baseline (−356.0 pg/mL); concentrations increased among women delivering before 35 weeks of gestation and those delivering at term, 132.1 and 86.9 pg/mL (P=.03). Interleukin-10 &Dgr; and tumor necrosis factor-&agr; &Dgr; were unaffected by either omega-3 supplementation or fish diet. CONCLUSION: Recurrent preterm birth was associated with decreased peripheral blood mononuclear leukocyte production of interleukin-10 in response to a stimulus during the second trimester. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00135902. LEVEL OF EVIDENCE: II

Perinatal outcomes in hispanic and non-hispanic white women with mild gestational diabetes

OBJECTIVE: To compare perinatal outcomes between self-identified Hispanic and non-Hispanic white women with mild gestational diabetes mellitus (GDM) or glucose intolerance. METHODS: In a secondary analysis of a mild GDM treatment trial, we compared perinatal outcomes by race and ethnicity for 767 women with glucose intolerance (abnormal 50-g 1-hour screen, normal 100-g 3-hour oral glucose tolerance test), 371 women with mild GDM assigned to usual prenatal care, and 397 women with mild GDM assigned to treatment. Outcomes included: composite adverse perinatal outcome (neonatal death, hypoglycemia, hyperbilirubinemia, hyperinsulinemia, stillbirth, birth trauma), gestational age at delivery, birth weight, and hypertensive disorders of pregnancy. Adjusted regression models included: 100-g 3-hour oral glucose tolerance test results, parity, gestational age, body mass index, maternal age at enrollment, and current tobacco use. RESULTS: The sample of 1,535 women was 68.3% Hispanic and 31.7% non-Hispanic white. Among women with glucose intolerance, Hispanic women had more frequent composite outcome (37% compared with 27%, adjusted odds ratio [OR] 1.62, 95% confidence interval [CI] 1.10–2.37) with more neonatal elevated C-cord peptide (19% compared with 13%, adjusted OR 1.79, 95% CI 1.04–3.08) and neonatal hypoglycemia (21% compared with 13%, adjusted OR 2.04, 95% CI 1.18–3.53). Among women with untreated mild GDM, outcomes were similar by race and ethnicity. Among Hispanic women with treated mild GDM, composite outcome was similar to non-Hispanic white women (35% compared with 25%, adjusted OR 1.62, 95% CI 0.92–2.86), but Hispanic neonates had more frequent hyperinsulinemia (21% compared with 10%, adjusted OR 2.96, 95% CI 1.33–6.60). CONCLUSION: Individual components of some neonatal outcomes were more frequent in Hispanic neonates, but most perinatal outcomes were similar between Hispanic and non-Hispanic ethnic groups. LEVEL OF EVIDENCE: II