Background:
Adult obesity is associated with female infertility but few studies have examined the association with childhood obesity and the evidence is inconsistent.
Aims:
To evaluate whether childhood obesity is associated with infertility in women’s later life.
Methods:
The study consisted of 1,754 girls aged 7-15 years who participated in the 1985 Australian Schools Health and Fitness Survey and completed reproductive questionnaires at follow-up in 2004-2006 or 2009-2011 or both. Baseline measures of body composition included height, weight, waist and hip circumferences. Overweight and obesity in childhood were defined according to age and sex-specific international standard definitions for body mass index (BMI). Infertility was defined as having difficulty conceiving (had ever tried for ≥12 months to become pregnant without succeeding) or having ever seen a doctor because of trouble becoming pregnant. Covariates were childhood age, parental education and follow-up length, both childhood and adulthood smoking, socioeconomic status, alcohol intake, adult education level, marital status and adult BMI. Log-binomial regression was used to estimate the association of childhood body composition with infertility.
Results:
In total 8.1% of girls were overweight and 1.0% were obese at baseline. 22.1% of women reported infertility at follow-up. After adjusting for confounders including adult BMI, compared with normal weight girls, those with obesity between ages 7 and 11 were more likely to report infertility (relative risks (RR): 2.92, 95% confidence interval (CI): 1.40-6.07), difficulty conceiving (RR: 3.64, 95% CI: 1.70-7.80) and having ever seen a doctor because of trouble becoming pregnant (RR: 3.81, 95% CI: 1.91-7.57). Being overweight or obese in early adolescence (12-15y) had no association with later infertility.
Conclusions:
Obesity in childhood before age 12 appears to increase the risk of female infertility in later life.