Cynthia Ferre

Perinatal outcome among singleton infants conceived through assisted reproductive technology in the United States

OBJECTIVE: To examine perinatal outcome among singleton infants conceived with assisted reproductive technology (ART) in the United States. METHODS: Subjects were 62,551 infants born after ART treatments performed in 1996–2000. Secular trends in low birth weight (LBW), very low birth weight (VLBW), preterm delivery, preterm LBW, and term LBW were examined. Detailed analyses were performed for 6,377 infants conceived in 2000. Observed numbers were compared with expected using a reference population from the 2000 U.S. natality file. Adjusted risk ratios were calculated. RESULTS: The proportion of ART singletons born LBW, VLBW, and term LBW decreased from 1996 to 2000. The proportion delivered preterm and preterm LBW remained stable. After adjustment for maternal age, parity, and race/ethnicity, singleton infants born after ART in 2000 had elevated risks for all outcomes in comparison with the general population of U.S. singletons: LBW standardized risk ratio 1.62 (95% confidence interval 1.49, 1.75), VLBW 1.79 (1.45, 2.12), preterm delivery 1.41 (1.32, 1.51), preterm LBW 1.74 (1.57, 1.90), and term LBW 1.39 (1.19, 1.59). Risk ratios for each outcome remained elevated after restriction to pregnancies with only 1 fetal heart or any of 7 other categories: parental infertility diagnosis of male factor, infertility diagnosis of tubal factor, conception using in vitro fertilization without intracytoplasmic sperm injection or assisted hatching, conception with intracytoplasmic sperm injection, conception in a treatment with extra embryos available, embryo culture for 3 days, and embryo culture for 5 days. CONCLUSION: Singletons born after ART remain at increased risk for adverse perinatal outcomes; however, risk for term LBW declined from 1996 to 2000, whereas preterm LBW was stable. LEVEL OF EVIDENCE: III

Combined effects of prepregnancy body mass index and weight gain during pregnancy on the risk of preterm delivery

Background: The association between excessive gestational weight gain and preterm delivery is unclear, as is the association between low gestational weight gain and preterm delivery among overweight and obese women. Methods: Using data from the Pregnancy Risk Assessment Monitoring System in 21 states, we estimated the risk of very (20–31 weeks) and moderately (32–36 weeks) preterm delivery associated with a combination of prepregnancy body mass index (BMI) and gestational weight gain among 113,019 women who delivered a singleton infant during 1996–2001. We categorized average weight gain (kilograms per week) as very low (<0.12), low (0.12–0.22), moderate (0.23–0.68), high (0.69–0.79), or very high (>0.79). We categorized prepregnancy BMI (kg/m2) as underweight (<19.8), normal (19.8–26.0), overweight (26.1–28.9), obese (29.0–34.9), or very obese (≥35.0). We examined associations for all women and for all women with no complications adjusting for covariates. Results: There was a strong association between very low weight gain and very preterm delivery that varied by prepregnancy BMI, with the strongest association among underweight women (adjusted odds ratio = 9.8; 95% confidence interval = 7.0–13.8) and the weakest among very obese women (2.3; 1.8–3.1). Very low weight gain was not associated with moderately preterm delivery for overweight or obese women. Women with very high weight gain had approximately twice the odds of very preterm delivery, regardless of prepregnancy BMI. Conclusions: This study supports concerns about very low weight gain during pregnancy, even among overweight and obese women, and also suggests that high weight gain, regardless of prepregnancy BMI, deserves further investigation.

Perinatal outcomes of twin births conceived using assisted reproduction technology: a population-based study†

BACKGROUND Approximately 18% of multiple births in the USA result from assisted reproduction technology (ART). Although many studies comparing ART and naturally conceived twins report no difference in risks for perinatal outcomes, others report slight to moderate positive or protective associations. METHODS We selected twin deliveries with and without indication of ART from Massachusetts live birth-infant death records from 1997 to 2000 linked to the US ART surveillance system. The sample was restricted to deliveries by mothers with increased socioeconomic status, private health insurance and intermediate/plus prenatal care use. Our final sample included 1446 and 2729 ART and non-ART twin deliveries, respectively. Odds ratios (OR) for associations between ART and perinatal outcomes were adjusted for maternal demographic factors, smoking, prenatal care and hospital care level. RESULTS ART twin deliveries were less likely than non-ART to be very preterm (adjusted OR 0.75; 95% confidence interval 0.58-0.97) or include a very low birthweight (<1500 g) infant (0.75; 0.58-0.95) or infant death (0.55; 0.35-0.88). In stratified analyses, these findings were observed among primiparous deliveries, but there were no risk differences among multiparous ART and non-ART twin deliveries. CONCLUSIONS ART treatment was not a risk factor for adverse perinatal outcome, and risks for several outcomes were somewhat lower among ART twin deliveries. Nonetheless, ART is strongly associated with twinning and twins remain a high-risk group, relative to singletons. Promoting singleton gestation in assisted conception is an important strategy for reducing adverse outcomes.

Commentary: Eliminating Disparities in Perinatal Outcomes—Lessons Learned

The disparity between blacks and whites in perinatal health ranges from a 2.3-fold excess risk among black women for preterm delivery and infant mortality to a 4-fold excess risk among black women for maternal mortality. To stimulate concerted public health action to address such racial and ethnic disparities in health, the national Healthy People objectives call for elimination of all health disparities by the year 2010. Eliminating health disparities requires a greater understanding of the factors that contribute to their development. This commentary summarizes the state of the science of reducing such disparities and proposes a framework for using the results of qualitative studies on the social context of pregnancy to understand, study, and address disparities in infant mortality and preterm delivery. Understanding the social context of African American womens lives can lead to an improved understanding of the etiology of preterm birth, and can help identify promising new interventions to reduce racial and ethnic disparities in preterm delivery.

The joint effect of vaginal Ureaplasma urealyticum and bacterial vaginosis on adverse pregnancy outcomes

Objective. To examine associations of vaginal Ureaplasma urealyticum (UU) and bacterial vaginosis (BV) with preterm delivery (PTD), small for gestational age (SGA), and low birth weight (LBW). Material and methods. A population‐based, prospective cohort study of 2,927 pregnancies. After exclusion of multiples and antibiotic use sample size was 2,662. BV (Amsels criteria) and UU (culture) were assessed in week 17. Gestational age was determined by last menstrual period, confirmed by ultrasound measurement in 97.5%. SGA infants were calculated from intrauterine fetal growth measurements. Results. There was no increased risk for spontaneous PTD among women with BV only (crude odds ratio 1.0, 95% CI 0.4–2.7), among women with UU only (1.3, 0.8–2.0), nor among women with UU + BV (0.9, 0.4–2.3) compared to women without UU and BV. However, there was a threefold increased risk of a LBW birth in women with UU + BV (3.1, 1.8–5.4), a twofold risk of a LBW birth among women with UU only (1.9, 1.3–2.9), but no increased risk among women with BV only (0.8, 0.3–2.2). Similarly, women with UU + BV had over a twofold increased risk of an SGA birth (2.3, 1.3–4.0), women with UU only had a 70% increase (1.7, 1.1–2.5), whereas a nonsignificant increase was found in women with BV only (1.3, 0.6–2.9). Adjustment by established confounders (smoking, previous PTD, previous LBW, and Escherichia coli) did not affect risk estimates. Conclusion. This analysis suggests that UU is independently associated with fetal growth and LBW and that BV with UU may enhance the risk of these outcomes.

Foreword: The Social Context of Pregnancy for African American Women: Implications for the Study and Prevention of Adverse Perinatal Outcomes

This special issue of the Maternal and Child Health Journal largely results from a 1999 conference sponsored by the Centers for Disease Control and Prevention (CDC) titled “The Social Context of Pregnancy Among African American Women: Implications for Preterm Delivery Prevention.” During this conference, results of qualitative and quantitative research were presented to identify potential new explanatory risk factors for adverse pregnancy outcomes and to better understand how known factors interact among women in the real world. Knowledge of the social context of African American women’s lives, in particular, along with improved understanding of the etiology of preterm birth can generate new perspectives for future research and new interventions to reduce racial and ethnic disparities in preterm delivery. While other publications have contributed to our understanding of medical and biologic factors influencing pregnancy outcome, this issue focuses on furthering our understanding of the social factors influencing pregnancy outcome. Preterm delivery (PTD) is the birth of an infant before completing 37 weeks of gestation. Singleton PTDs to non-Hispanic black women in the United States declined between 1990 and 1997 in 24 states, and the national rate for black women fell by 9.8% from 178.5 per 1000 live births in 1990 to 160.9 in 1997 (1). Despite this improvement, racial disparities persist: PTD is still twice as common among black women compared with white women.

Racial Differences in the Patterns of Singleton Preterm Delivery in the 1988 National Maternal and Infant Health Survey

Objectives: To determine if the association between race and preterm delivery would persist when preterm delivery was partitioned into two etiologic pathways. Methods: We evaluated perinatal and obstetrical data from the 1988 National Maternal and Infant Health Survey and classified preterm delivery as spontaneous or medically indicated. Discrete proportional hazard models were fit to assess the risk of preterm delivery for Black women compared with White women adjusting for potential demographic and behavioral confounding variables. Results: Preterm delivery occurred among 17.4% of Black births and 6.7% of White births with a Black versus White unadjusted hazard ratio (HR) of 2.8 (95% CI = 2.4−3.3). The adjusted HR for a medically indicated preterm delivery showed no racial difference in risk (HR = 1.0, 95% CI = 0.4−2.6). However, for spontaneous preterm delivery between 20 and 28 weeks gestation, the Black versus White adjusted hazard ratio (HR) was 4.9 (95% CI = 3.4−7.1). Conclusions: Although we found an increased unadjusted HR for preterm delivery among Black women compared with White women, the nearly fivefold increase in adjusted HR for the extremely preterm births and the absence of a difference for medically indicated preterm delivery was unexpected. Given the differences in the risks of preterm birth between Black and White women, we recommend to continue examining risk factors for preterm delivery after separating spontaneous from medically indicated preterm birth and subdividing preterm delivery by gestational age to shed light on the reasons for the racial disparity.

Recent Changes in the Trends of Teen Birth Rates, 1981–2006

PURPOSE To explore trends in teen birth rates by selected demographics. METHODS We used birth certificate data and joinpoint regression to examine trends in teen birth rates by age (10-14, 15-17, and 18-19 years) and race during 1981-2006 and by age and Hispanic origin during 1990-2006. Joinpoint analysis describes changing trends over successive segments of time and uses annual percentage change (APC) to express the amount of increase or decrease within each segment. RESULTS For teens younger than 18 years, the decline in birth rates began in 1994 and ended in 2003 (APC: -8.03% per year for ages 10-14 years; APC: -5.63% per year for ages 15-17 years). The downward trend for 18- and 19-year-old teens began earlier (1991) and ended 1 year later (2004) (APC: -2.37% per year). For each study population, the trend was approximately level during the most recent time segment, except for continuing declines for 18- and 19-year-old white and Asian/Pacific Islander teens. The only increasing trend in the most recent time segment was for 18- and 19-year-old Hispanic teens. During these declines, the age distribution of teens who gave birth shifted to slightly older ages, and the percentage whose current birth was at least their second birth decreased. CONCLUSIONS Teen birth rates were generally level during 2003/2004-2006 after the long-term declines. Rates increased among older Hispanic teens. These results indicate a need for renewed attention to effective teen pregnancy prevention programs in specific populations.

Seasonal Variation of 25-Hydroxyvitamin D among non-Hispanic Black and White Pregnant Women from Three US Pregnancy Cohorts

BACKGROUND Vitamin D deficiency during pregnancy has been associated with increased risk of complications and adverse perinatal outcomes. We evaluated seasonal variation of 25-hydroxyvitamin D [25(OH)D] among pregnant women, focusing on patterns and determinants of variation. METHODS Data came from three cohort studies in the US that included 2583 non-Hispanic Black and White women having prenatal 25(OH)D concentrations determined. Fourier time series and generalised linear models were used to estimate the magnitude of 25(OH)D seasonality. We modelled seasonal variability using a stationary cosinor model to estimate the phase shift, peak-trough difference, and annual mean of 25(OH)D. RESULTS We observed a peak for 25(OH)D in summer, a nadir in winter, and a phase of 8 months, which resulted from fluctuations in 25(OH)D3 rather than 25(OH)D2. After adjustment for covariates, the annual mean concentrations and estimated peak-trough difference of 25(OH)D among Black women were 19.8 ng/mL [95% confidence interval (CI) 18.9, 20.5] and 5.8 ng/mL [95% CI 4.7, 6.7], and for non-Hispanic White women were 33.0 ng/mL [95% CI 32.6, 33.4] and 7.4 ng/mL [95% CI 6.0, 8.9]. CONCLUSIONS Non-Hispanic Black women had lower average 25(OH)D concentrations throughout the year and smaller seasonal variation levels than non-Hispanic White women. This studys confirmation of 25(OH)D seasonality over a calendar year has the potential to enhance public health interventions targeted to improve maternal and perinatal outcomes.

Maternal Serum 25‐Hydroxyvitamin D Concentrations during Pregnancy and Infant Birthweight for Gestational Age: a Three‐Cohort Study

BACKGROUND In response to inconsistent findings, we investigated associations between maternal serum 25-hydroxyvitamin D [25(OH)D] concentrations and infant birthweight for gestational age (BW/GA), including potential effect modification by maternal race/ethnicity and infant sex. METHODS Data from 2558 pregnant women were combined in a nested case-control study (preterm and term) sampled from three cohorts: the Omega study, the Pregnancy, Infection and Nutrition study, and the Pregnancy Outcomes and Community Health study. Maternal 25(OH)D concentrations were sampled at 4 to 29 weeks gestation (80% 14-26 weeks). BW/GA was modelled as sex and gestational age-specific birthweight z-scores. General linear regression models (adjusting for age, education, parity, pre-pregnancy body mass index, season at blood draw, and smoking) assessed 25(OH)D concentrations in relation to BW/GA. RESULTS Among non-Hispanic Black women, the positive association between 25(OH)D concentrations and BW/GA was of similar magnitude in pregnancies with female or male infants [beta (β) = 0.015, standard error (SE) = 0.007, P = 0.025; β = 0.018, SE = 0.006, P = 0.003, respectively]. Among non-Hispanic White women, 25(OH)D-BW/GA association was observed only with male infants, and the effect size was lower (β = 0.008, SE = 0.003, P = 0.02). CONCLUSIONS Maternal serum concentrations of 25(OH)D in early and mid-pregnancy were positively associated with BW/GA among non-Hispanic Black male and female infants and non-Hispanic White male infants. Effect modification by race/ethnicity may be due, in part, to overall lower concentrations of 25(OH)D in non-Hispanic Blacks. Reasons for effect modification by infant sex remain unclear.