Abnormal body weight in adolescence a risk factor for infertility in Asian women

Underweight or obesity during adolescence may contribute to unexplained infertility later in life, as suggested in a large study involving Japanese women.

The prospective cohort study included 15,907 married women aged 30–44 years. These women completed self-reported questionnaires, with survey data cross-sectionally analysed. Those with a history of cancer and those with a partner with infertility or missing data were excluded.

The main outcome measure of infertility was defined as a self-reported history of infertility for at least 2 years. Researchers also documented age and cause of infertility.

Of the women, 2,825 (17.8 percent) reported being infertile. Looking at the baseline BMI (at age 18 years), the percentage of women who self-reported infertility was 12.8 percent in the underweight group (BMI <18.5 kg/m²), 4.5 percent in the overweight group (BMI ≥25 and <30 kg/m²), and 0.4 percent in the obese group (BMI ≥30 kg/m²).

Multiple logistic regression analysis showed that the odds of infertility were 31 percent and 82 percent greater among women who were underweight (adjusted odds ratio [aOR], 1.31, 95 percent confidence interval [CI], 1.16–1.47) or obese (aOR, 1.82, 95 percent CI, 1.04–3.17) during adolescence, respectively, as compared with those who had normal weight during the same period.

Additional analysis indicated that being underweight during adolescence was positively associated with infertility of unknown cause.

The findings highlight the importance of maintaining a healthy weight from a young age, according to the researchers.