Prenatal Exposure to Maternal Bereavement and Childbirths in the Offspring: A Population-Based Cohort Study

Abstract

IntroductionThe decline in birth rates is a concern in public health. Fertility is partly determined before birth by the intrauterine environment and prenatal exposure to maternal stress could, through hormonal disturbance, play a role. There has been such evidence from animal studies but not from humans. We aimed to examine the association between prenatal stress due to maternal bereavement following the death of a relative and childbirths in the offspring.Materials and MethodsThis population-based cohort study included all subjects born in Denmark after 1968 and in Sweden after 1973 and follow-up started at the age of 12 years. Subjects were categorized as exposed if their mothers lost a close relative during pregnancy or the year before and unexposed otherwise. The main outcomes were age at first child and age-specific mean numbers of childbirths. Data was analyzed using Cox Proportional Hazards models stratified by gender and adjusted for several covariates. Subanalyses were performed considering the type of relative deceased and timing of bereavement.ResultsA total of 4,121,596 subjects were followed-up until up to 41 years of age. Of these subjects, 93,635 (2.3%) were exposed and 981,989 (23.8%) had at least one child during follow-up time. Compared to unexposed, the hazard ratio (HR) [95% confidence interval] of having at least one child for exposed males and females were 0.98 [0.96–1.01] and 1.01 [0.98–1.03], respectively. We found a slightly reduced probability of having children in females born to mothers who lost a parent with HR = 0.97 [0.94–0.99] and increased probability in females born to mothers who lost another child (HR = 1.09 [1.04–1.14]), the spouse (HR = 1.29 [1.12–1.48]) or a sibling (HR = 1.13 [1.01–1.27]).ConclusionsOur results suggested no overall association between prenatal exposure to maternal stress and having a child in early adulthood but a longer time of follow-up is necessary in order to reach a firmer conclusion.

Reproductive function in the sons of women who experienced stress due to bereavement before and during pregnancy: a nationwide population-based cohort study

“…Although we saw a slightly increased risk of reproductive disorders based on the composite outcome, there was no association when considering the diagnosis of or treatment for infertility. We previously saw that men exposed to the same definition of maternal bereavement used in this study have fewer children and have them a little later than the unexposed men (11,12). If these associations were causal, they could be due to a biological mechanism or result from differences in behavior.…”

“…In animal studies, maternal stress during pregnancy has been shown to affect fertility and reproductive behavior in the offspring (6)(7)(8)(9)(10). In humans, previous studies have suggested that men and women prenatally exposed to maternal bereavement had their first child slightly later and ended up with slightly fewer children (11,12). Additionally, women born to mothers who had experienced bereavement during the first trimester of pregnancy were more likely than unexposed women to be diagnosed with infertility or to receive treatment (13).…”

Correction: Prenatal Exposure to Maternal Bereavement and Childbirths in the Offspring: A Population-Based Cohort Study

“…We recently published a study on the effect of prenatal stress exposure and the offspring probability of having children [ 1 ]. We found no overall effect of prenatal exposure to maternal bereavement on the offspring probability of having a child and the number of childbirths.…”