Periconceptional Hormonal Contraception Use and Autism Spectrum Disorder in the Study to Explore Early Development

Prior studies report associations between periconceptional exposure to natural and synthetic oestrogen and progesterone and autism spectrum disorder (ASD). Hormonal contraception contains synthetic forms of one or both hormones. Although hormonal contraception is highly effective when consistently used, unintended pregnancy can occur with irregular use. Given the popularity of hormonal contraception, foetal exposure in utero is possible, yet the potential consequences are unknown.

We investigated the association between periconceptional hormonal contraception use and the development of ASD in offspring.

We analysed data from the Study to Explore Early Development (SEED), a population-based case-control study conducted in select US states, from 2007 to 2020. Children with and without ASD were identified from clinical/education sources and vital records, respectively, and enrolled at ages 2.5-5 years. We confirmed the ASD case status by in-person developmental assessment. We assessed hormonal contraception via a structured interview. We assessed the associations between ASD and hormonal contraception exposure separately for contraception discontinued in the 3 months prior to pregnancy and contraception continued during pregnancy using logistic models to estimate odds ratios (OR) adjusted for biological mother age, education, parity, pre-pregnancy body mass index (BMI), and presence of gynaecologic conditions and 95% confidence intervals (CI).

Of 5210 participants, 9.9% reported discontinuing hormonal contraception use before pregnancy and 2.3% reported continuing use during pregnancy. A suggestive association was found between ASD and hormonal contraception use during pregnancy (aOR 1.38,95% CI 0.93, 2.05). There was no association with use prior to pregnancy (aOR 1.02, 95% CI 0.84, 1.25).

Discontinuation of hormonal contraception prior to conception was not associated with ASD. The prevalence of hormonal contraception use during pregnancy was low. Results were imprecise and may be impacted by recall bias and unmeasured confounding by indication and health behaviours related to planning pregnancy.