Race and preterm birth rates in North America

Influence of Gestational Weight Gain on the Risk of Preterm Birth for Underweight Women Living in Food Deserts

OBJECTIVE

Preterm birth (PTB) and food insecurity are two of the most significant public health crises in the United States. Effects of being underweight among populations with low food security are not well understood. We assess whether the protective effect of gestational weight gain (GWG) for women with low prepregnancy body mass index (BMI) differs by accessibility to sources of healthy food.

STUDY DESIGN

Population-based retrospective cohort study using Ohio birth records analyzing all live births, 2006 to 2015. Analyses were stratified by maternal BMI (underweight, normal, overweight, and obese), Institute of Medicine (IOM) recommended GWG (under vs. met), and whether the U.S. Department of Agriculture (USDA) classified the residential census tract for each birth as a food desert. Food access data were retrieved from the USDA's 2018 Food Access Research Atlas. Covariates were selected using least absolute shrinkage and selection operator regression. Logistic regression models estimated the risk ratio (RR) of PTB for each group based on under or exceeded recommended GWG (reference = met), adjusting for coexisting risk factors.

RESULTS

Analysis was performed on 1,124,299 births. PTB risk was highest for underweight women below GWG recommendations (no food desert: 21.3%, RR = 2.15, 95% confidence interval [CI]: 1.81-2.57; food desert: 21.0%, RR = 1.46, 95% CI: 0.96-2.21). Underweight women living in food deserts who exceeded GWG recommendations had lower PTB risk than those who met GWG recommendations (13.5 vs. 14.3%, RR = 0.85, 95% CI: 0.51-1.41). Factors other than GWG significantly associated with PTB included in the adjusted analysis include maternal age and race, education, marital status, interpregnancy interval, and presence of prepregnancy diabetes or hypertension.

CONCLUSION

Underweight women who do not meet GWG recommendations are at high risk for PTB. Increasing pregnancy weight gain to a level that exceeds IOM recommendations was not associated with a reduction in PTB risk for underweight women who reside in food deserts compared with women who met GWG recommendations.

KEY POINTS

· Women with low prepregnancy BMI are at high risk of PTB.. · Food insecurity increases the risk of PTB for underweight women.. · Excessive GWG for underweight women in food deserts does not reduce PTB risk..

Maternal plasma cholesterol concentration and preterm birth: a meta-analysis and systematic review of literature

Background: Women that previously had preterm labor are at an increased risk for heart disease. Because spontaneous preterm birth is an adverse pregnancy outcome that affects millions of children worldwide, our objective was to review and analyze studies that have examined associations between maternal total cholesterol (TC), LDL-C, and HDL-C concentrations during pregnancy and the risk of preterm birth to potentially define biomarkers or targets for treatment.Method: A search was performed and 22 articles were found that examined the association of maternal plasma cholesterol concentrations and preterm birth. A meta-analysis was performed on 10 of the articles, those that used maternal lipid concentrations as the outcome and presented results as means plus variables, and a qualitative review was performed on all 22 articles.Results: The meta-analysis showed no relationship between maternal TC, LDL-C, or HDL-C and increased risk of preterm birth, although, a near significant relationship between low maternal HDL-C concentration and preterm birth (p = .055). Importantly, associations increased when cholesterol concentrations were combined with inflammatory markers or metabolic syndrome factors.Conclusions: The relationship between maternal cholesterol levels and preterm birth is heterogeneous. Associations are strengthened when maternal cholesterol concentrations are combined with other factors that may be related to more recently defined lipoprotein functions.