Maternal Chlamydia infection during pregnancy among younger mothers and risk of gastroschisis in singleton offspring

Prevalence of gastroschisis has been increasing in the United States (US) since 1980s. Genital infection with Chlamydia has also been increasing in prevalence, particularly among younger women. The etiology of gastroschisis is unknown. Ongoing research suggests multiple causal factors may be involved, including Chlamydia infection in mothers during pregnancy.

Using birth certificate data from 2014 US vital records, we conducted a population-based case-control study to examine the association between prenatal Chlamydia exposure in young women (16-25 years of age) and gastroschisis in singleton offspring. Cases consisted of live births with gastroschisis, and controls had no major birth defects reported in their birth certificate. Logistic regression analysis was used to estimate crude and adjusted odds ratios (cOR and aOR) and 95% confidence intervals (CI).

There were 809 cases (95.6% were isolated cases) and 1,260,293 controls. Chlamydia during pregnancy was reported in 4.5% of case and 3.6% control mothers (p = .21). Case mothers were significantly more likely to be younger (16-20 years of age) at the time of delivery compared to control mothers (p < .0001). We found no significant association between Chlamydia infection during pregnancy and gastroschisis (cOR = 1.24; 95% CI = 0.89-1.73 and aOR = 1.06; 95% CI: 0.66-1.70).

With the caveat of possible misclassification of exposure and outcome variables in birth certificate data, we found no significant association between prenatal exposure to Chlamydia and gastroschisis in the offspring born to younger mothers. Future studies should refine measures by focusing on relevant risk period and biomarkers.