Objective: To study whether fertility treatment, subfertility, or pregnancy planning are related to long-term intellectual development.
Design: Cohort study.
Setting: Not applicable.
Patient(s): A total of 5,032 singletons born from 1990 to 1992 in the Aarhus Birth Cohort were followed up to a mean age of 19 years. These children were born as a result of fertility treatment (n = 210), had subfertile parents who took more than 12 months before conceiving naturally (n = 334), had fertile parents who conceived naturally within 12 months (n = 2,661), or had parents who reported the pregnancy as unplanned (n = 1,827).
Intervention(s): The children were followed up using questionnaires and information from Danish national registers.
Main Outcome Measure(s): Parent reported school difficulties at ages 9–11 years, register-based school grades at ages 16, 17, and 19 years, and conscription intelligence test scores at age 19 years.
Result(s): We found no evidence of school difficulties in childhood, impaired school performance in adolescence, or lower intelligence in young adulthood in multivariate analyses adjusted for parental age, educational level, maternal parity, before pregnancy body mass index (BMI), smoking and alcohol intake in pregnancy, cohabitation status, child gender, and age.
Conclusion(s): In the longest follow-up of cognitive development of children conceived after fertility treatment or by subfertile parents conducted so far, this study did not show any association between pregnancy planning, subfertility, or fertility treatment and cognitive ability or academic performance.