Therese Nilsson

Professor

Disease exposure in early life affects female reproduction

Author

Ingrid van Dijk
Therese Nilsson
Luciana Quaranta

Summary, in English

Mounting evidence shows that early-life adversity negatively affects health in late life, but much less is known about if and how early-life conditions affect health in mid-life. In particular, knowledge is very limited regarding the connection between early-life adversity and reproductive health. This paper studies the effect of early-life disease exposure on women’s reproductive careers in mid-life. Using the Scanian Economic Demographic Database and data on local infant disease load exposure in the year of birth, we follow women’s reproductive careers over a period of more than 100 years (1896-2000). We comprehensively examine effects on the reproductive career using several outcome measures. The detailed data allow us to study the likelihood of giving birth, birth intervals, offspring sex ratio and separately analyze first-born and later-born children. Using purposively digitized obstetric records, we also examine offspring’s birthweight for a sub-sample of individuals. Results of survival models show that women exposed to a high disease load in infancy have a lower likelihood of having first and a higher order (second and higher) births. Furthermore, exposed women give birth to a lower proportion of boys (i.e. lower offspring sex ratio), in line with the notion that women reproducing in adverse physical or contextual conditions miscarry more often if they are pregnant with boys. At the same time, boys of exposed women who are born in early gestation are heavier than boys born to unaffected mothers, possibly as a result of out-selection in-utero of weaker male fetuses. These findings indicate that early-life exposure to a relatively mild adverse exposure have a continuing impact on reproduction and health across female life course, and even translate to the early-life health of the next generation.

Department/s