Missouri women who used hormonal birth control were 1.4 times more likely to develop gestational diabetes, compared with those who used no birth control, according to a first-in-kind study published online July 17 in Preventing Chronic Disease.
"Although researchers have not established a causal relationship between hormonal contraception use and [gestational diabetes], results of our study suggest there may be an underlying correlating mechanism," wrote Brittney Kramer and her associates at the Missouri Department of Health and Senior Services.
The investigators conducted a logistic regression analysis of 2007-2008 data on 2,741 mothers from the Missouri component of the Pregnancy Risk Assessment Monitoring System, or PRAMS (Prev. Chronic Dis. July 17 [doi: 10.5888/pcd11.140059]).
In all, 8.3% of mothers reported having had gestational diabetes during their most recent pregnancy, and 17.9% reported having used hormonal birth control before pregnancy, the investigators said. The significant association between hormonal birth control and gestational diabetes (adjusted odds ratio, 1.43; 95% confidence interval, 1.32-1.55; P less than .001) existed even after adjusting maternal age, race, education, income, marital status, Medicaid status at delivery, and prenatal care, the researchers added.
Hormonal contraception can potentially alter the hypothalamic-pituitary axis and cortisol and carbohydrate metabolism, the investigators noted. In particular, long-term, high-dose estrogen treatment has been shown to increase unbound cortisol, leading to glucose intolerance, insulin resistance, and increased risk of diabetes, they said (Clin. Sci. (Lond.) 1999;96:513-23).
The PRAMS survey is self-reported by mothers 2-6 months after children are born, and therefore may be subject to recall bias, the researchers noted. Furthermore, the weighting method used for adjustment might not have fully controlled for nonresponse bias, they said.
PRAMS is a national surveillance program sponsored by the Centers for Disease Control and Prevention. The authors disclosed no conflicts of interest.