Being born preterm or with low weight implies a risk of infertility and premature loss of ovarian function; a national register study.

Being born with non-optimal birth characteristics has several long-term consequences on health in general but also for the individual's reproductive pattern. In premature ovarian insufficiency (POI) the follicles are depleted or dysfunctional. This results in menopause before the age of 40, and for most of the affected women, it causes infertility. The objective of this study was to evaluate the potential effects of being born with non-optimal birth characteristics on the risk of developing POI. This population-based cohort register study included all women born in Sweden between 1973 and 1993 who were followed until the end of 2012 (age at the end of follow-up ranged between 39 and 59). Women diagnosed with POI were compared with women without this diagnosis with respect to being born small for gestational age, preterm, or with low birth weight. Data on birth characteristics and diagnosis of POI were collected from national registers. A total of 1,033,878 women were included. Being born small for gestational age was associated with a slightly increased odds ratio of POI with 10%. Preterm birth and low birth weight were associated with somewhat increased ORs of POI after exclusion of those born small for gestational age. Similarly, being born preterm or with a low birth weight was also found to be associated with POI to the same extent. Being born with non-optimal birth characteristics may increase the risk of premature ovarian insufficiency.