Maternal Prepregnancy Underweight and Risk of Early and Late Stillbirth in Black and White Gravidas

• Published in: Journal of the National Medical Association Vol. 101; no. 6; pp. 582 - 587
• Main Authors: Salihu, Hamisu M., Mbah, Alfred K., Alio, Amina P., Lynch, O’Neil, Wathington, Deanna, Kornosky, Jennifer L.
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 01.06.2009; National Medical Association; Elsevier Limited
• Subjects: African Americans - statistics & numerical data; Age Factors; Biological and medical sciences; Body Mass Index; Confidence Intervals; European Continental Ancestry Group - statistics & numerical data; Female; General aspects; Gestational Age; health disparities; Humans; Logistic Models; Maternal Welfare; Medical sciences; Miscellaneous; Missouri - epidemiology; obstetrics/gynecology; Odds Ratio; Pregnancy; Pregnancy Complications - epidemiology; Pregnancy Complications - ethnology; Pregnancy Outcome - epidemiology; Premature Birth; Public health. Hygiene; Public health. Hygiene-occupational medicine; race/ethnicity; Risk Factors; Stillbirth - epidemiology; Stillbirth - ethnology; Thinness - complications; Thinness - epidemiology; Time Factors; United States - epidemiology; United States; Missouri; obstetrics/gynecology; health disparities; body mass index; race/ethnicity; Ethnic origin; Late; Stillborn; Gynecology; Body weight; Negroid; Risk; Corporal biometry; Leanness; Obstetrics; Ethnic group; Death in utero; Pregnancy; Body mass index; Mother; Risk factor; Race; Early; Caucasoid; Public health; Inequality
• ISSN: 0027-9684; 1943-4693
• DOI: 10.1016/S0027-9684(15)30944-5

The association between underweight and stillbirth remains poorly defined, especially across racial/ethnic sub-populations. We investigate the association of pre-pregnancy underweight on the risk for early and late stillbirth among black and white mothers. We conducted analysis on the Missouri maternally linked data files covering the period 1989-1997 inclusive. Using body mass index (BMI), we categorized mothers as underweight (BMI >18.5) and normal weight (BMI = 18.5-24.9). By applying logistic regression modeling with adjustment for intracluster correlation, we estimated the risk for total, early (≤28 weeks of gestation), and late stillbirth (>28 weeks of gestation) among black and white mothers. A total of 1808 cases of stillbirth were registered. The rate of stillbirth among white mothers was 3.7 per 1000, while the rate among blacks was 7.1 per 1000. Underweight black mothers had comparable risk for total (OR, 0.9; 95% CI, 0.7-1.2), early (OR, 1.1; 95% CI, 0.8-1.5), and late stillbirth (OR, 0.8; 95% CI, 0.5-1.2) as compared to their normal-weight counterparts. By contrast, underweight white gravidas had a 30% reduced likelihood (OR, 0.7; 95% CI, 0.6-0.9) for late stillbirth as compared to normal-weight white mothers. However, the risks for total and early stillbirth among underweight white mothers were similar to those of normal-weight white mothers. Low prepregnancy BMI has similar effects on fetal survival in both blacks and whites except for late stillbirth. The underweight white survival advantage over blacks in late pregnancy could probably be due to greater access for identified white at-risk groups to effective obstetrical interventions as previously reported.