What we have learned about best practices for recruitment and retention in multicenter pregnancy studies.

For 30 years, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network has had significant impact on clinical practice in obstetrics. The MFMU Network has conducted 50 randomized clinical trials and observational studies designed to improve pregnancy outcomes for mothers and children. Each center has a designated clinical research nurse coordinator who coordinates the day-to-day operations of each trial and leads a research team that is responsible for recruitment and retention of participants.

Use and attitudes of obstetricians toward 3 high-risk interventions in MFMU Network hospitals.

Objective: We sought to evaluate the frequency of, and factors associated with, the use of 3 evidence-based interventions: antenatal corticosteroids for fetal lung maturity, progesterone for prevention of recurrent preterm birth, and magnesium sulfate for fetal neuroprotection.

Study Design: A self-administered survey was conducted from January through May 2011 among obstetricians from 21 hospitals that included 30 questions regarding their knowledge, attitudes, and practice of the 3 evidence-based interventions and the 14-item short version of the Team Climate for Innovation survey. Frequency of use of each intervention was ascertained from an obstetrical cohort of women between January 2010 and February 2011.

The effect of plurality and obesity on betamethasone concentrations in women at risk for preterm delivery.

Objective: Antenatal corticosteroids (ACS) decrease respiratory distress syndrome in singleton gestations. Twin data are less clear. Obesity and body mass index (BMI) also affect medication distribution volume.

Repeated courses of antenatal corticosteroids: are there effects on the infant's auditory brainstem responses?

Our objective was to assess the effects of repeated antenatal corticosteroid treatments on the neonatal auditory brainstem response (ABR), a sensitive measure of neonatal brain maturity and auditory function. To achieve this, we performed and blindly evaluated neonatal ABRs on a subset of infants delivering within a multicenter randomized placebo-controlled clinical trial comparing single versus repeated courses of antenatal corticosteroid treatments for women at 23-31 weeks gestation who remained at increased risk for preterm birth. The women were randomly assigned to either the single or the repeated antenatal corticosteroid treatment group.

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.

Follow-up of children exposed in utero to 17 alpha-hydroxyprogesterone caproate compared with placebo.

Objective: To assess whether there are evident adverse effects of 17 alpha-hydroxyprogesterone caproate after in utero exposure.

Methods: This study evaluated surviving children of mothers who participated in a multicenter placebo-controlled trial of weekly intramuscular 17 alpha-hydroxyprogesterone caproate, with a 2:1 allocation to 17 alpha-hydroxyprogesterone caproate and placebo, respectively. The guardian was interviewed about the child's general health.

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.

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.

Single versus weekly courses of antenatal corticosteroids: evaluation of safety and efficacy.

Objective: The purpose of this study was to determine if weekly corticosteroids improve neonatal outcome without undue harm.

Study Design: Women 23 to 32 weeks receiving 1 course of corticosteroids 7 to 10 days prior were randomized to weekly betamethasone or placebo.

Results: The study was terminated by the independent data and safety monitoring committee with 495 of the anticipated 2400 patients enrolled.

Uterine contraction frequency before and after successful tocolytic therapy for preterm uterine contractions.

Objective: To examine the association between prelabor uterine contraction frequency (UCF) and the success of tocolytic therapy for preterm labor (PTL).

Study Design: Eleven centers conducted a prospective, observational study of UCF recorded between 22(0/7) and 36(6/7) weeks' gestational age or until delivery > or = 2 times/d on > or = 2 d/wk in women with singleton pregnancies with and without risk factors for preterm birth. Uterine contraction data obtained from patients diagnosed with PTL allowed comparison of mean UCF both before and after an acute episode of PTL treated with either intravenous, subcutaneous or oral tocolysis.

What we have learned about the predictors of preterm birth.

The Preterm Prediction Study conducted by the Maternal Fetal Medicine Network between 1993 and 1996 studied a large number of risk factors for preterm birth in more than 3,000 women at 10 centers. The goals of the study were to better understand the strength of one risk factor versus another and to explore interactions among the predictors looking for combinations of factors that were more predictive of preterm birth than any single factor used alone. The most potent factors that were associated with spontaneous preterm birth at < 32 weeks were a positive cervical-vaginal fetal fibronectin test (odds ratio, 32.