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Despite improvements in antenatal and intrapartum care, stillbirth, defined as in utero fetal death at 20 weeks of gestation or greater, remains an important, largely unstudied, and poignant problem in obstetrics. More than 26,000 stillbirths were reported in the United States in 2001. Although several conditions have been linked to stillbirth, it is difficult to define the precise etiology in many cases. This paper reviews known and suspected causes of stillbirth including genetic abnormalities, infection, fetal-maternal hemorrhage, and a variety of medical conditions in the mother. The proportion of stillbirths that have a diagnostic explanation is higher in centers that conduct a defined and systematic evaluation. The evidence for recommended diagnostic tests for stillbirth are discussed. The ongoing work of the National Institute of Child Health and Human Development Stillbirth Collaborative Research Network, a consortium of 5 academic centers in the United States that are studying the scope and causes of stillbirth, is presented.

In this study, conventional events are quite common, even in healthy term infants. Extreme events were common only in preterm infants, and their timing suggests that they are not likely to be immediate precursors to SIDS. The high frequency of obstructed breathing in study participants would likely preclude detection of many events by conventional techniques. These data should be important for designing future monitors and determining if an infant is likely to be at risk for a cardiorespiratory event.

Among a large and geographically diverse cohort of nulliparous women with singleton gestations, non-Hispanic black women are most likely to experience preterm birth, hypertensive disease of pregnancy, and SGA birth. These disparities were not materially altered for preterm birth or SGA birth by adjustment for demographic differences and did not appear to be explained by differences in self-reported psychosocial factors.

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Objective The primary aim of The Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b) is to determine maternal characteristics, including genetic, physiological response to pregnancy, and environmental factors that predict adverse pregnancy outcomes (APOs). Methods Nulliparous women in the first trimester of pregnancy were recruited into an observational cohort study. Participants were seen at three study visits during pregnancy and again at delivery. We collected data from in-clinic interviews, take-home surveys, clinical measurements, ultrasound studies, and chart abstractions. Maternal biospecimens (serum, plasma, urine and cervico-vaginal fluid) at antepartum study visits and delivery specimens (placenta, umbilical cord, cord blood) were collected, processed, and stored. The primary outcome of the study was defined as pregnancy ending prior to 37+0 weeks gestation. Key study hypotheses involve APOs of spontaneous preterm birth, preeclampsia, and fetal growth restriction. Results 10,037 women were recruited to the study. Basic characteristics of the cohort at screening are reported in this Methods paper. Conclusion The nuMoM2b cohort study methods and procedures presented can help investigators when planning future projects.

Background Genetic abnormalities have been associated with 6 to 13% of stillbirths, but the true prevalence may be higher. Unlike karyotype analysis, microarray analysis does not require live cells, and it detects small deletions and duplications called copy-number variants. Methods The Stillbirth Collaborative Research Network conducted a population-based study of stillbirth in five geographic catchment areas. Standardized postmortem examinations and karyotype analyses were performed. A single-nucleotide polymorphism array was used to detect copy-number variants of at least 500 kb in placental or fetal tissue. Variants that were not identified in any of three databases of apparently unaffected persons were then classified into three groups: probably benign, clinical significance unknown, or pathogenic. We compared the results of karyotype and microarray analyses of samples obtained after delivery. Results In our analysis of samples from 532 stillbirths, microarray analysis yielded results more often than did karyotype analysis (87.4% vs. 70.5%, P<0.001) and provided better detection of genetic abnormalities (aneuploidy or pathogenic copy-number variants, 8.3% vs. 5.8%; P = 0.007). Microarray analysis also identified more genetic abnormalities among 443 antepartum stillbirths (8.8% vs. 6.5%, P = 0.02) and 67 stillbirths with congenital anomalies (29.9% vs. 19.4%, P = 0.008). As compared with karyotype analysis, microarray analysis provided a relative increase in the diagnosis of genetic abnormalities of 41.9% in all stillbirths, 34.5% in antepartum stillbirths, and 53.8% in stillbirths with anomalies. Conclusions Microarray analysis is more likely than karyotype analysis to provide a genetic diagnosis, primarily because of its success with nonviable tissue, and is especially valuable in analyses of stillbirths with congenital anomalies or in cases in which karyotype results cannot be obtained. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development.)

Context.-Studies have demonstrated strong associations between the prone sleep position (on the stomach) and sudden infant death syndrome (SIDS). In 1992, the American Academy of Pediatrics recommended that infants be placed to sleep laterally (on their side) or supine (on their back) to reduce SIDS risk, and in 1994, the national public education campaign "Back to Sleep" was launched. Objective.-To determine the typical sleep position of infants younger than 8 months in the United States, the changes that occurred after these recommendations, and the factors associated with the placement of infants prone or supine. Design.-Annual nationally representative telephone surveys. Setting.-The 48 contiguous states of the United States. Participants.-Nighttime caregivers of infants born within the last 7 months between 1992 and 1996. Approximately 1000 interviews were conducted per year. Main Outcome Measures.-The position the infant was usually placed in for sleep, and the position the infant was most commonly found in when checked during the night's sleep. Results.-Ninety-seven percent of respondents in each wave of the survey usually placed their infant to sleep in a specific position. Infants were placed in the prone position by 70% of caregivers in 1992, prior to the campaign, but only 24% in 1996. Supine and lateral placements increased during this time period, from 13% in 1992 to 35% in 1996 and from 15% in 1992 to 39% in 1996, respectively. Significant predictors of prone placement included maternal race reported as black