Postnatal depression and reproductive success in modern, low-fertility contexts

Abstract

Postnatal depression reduces completed fertility; women who experience it early in their childbearing careers are less likely to have a third birth. Postnatal depression at the first birth leads to lowered fertility levels, indicating a causal role in population ageing and highlighting a new incentive to invest in prevention.

Testing the psychological pain hypothesis for postnatal depression

“…Myers et al [1], in their interesting retrospective study of the association of postnatal depression (PND) with reproductive success (RS), conclude that their results ‘for the most part’, were ‘not supportive of the adaptive explanations’ proposed by us [2, 3] and others. Myers et al did not test our adaptationist hypothesis for PND, however, but instead tested something else.…”

Reply to Hagen and Thornhill

“…We thank Hagen and Thornhill for their thoughtful comments on our paper [1]. We appreciate, based on the explanation provided in their commentary, that model we tested differed somewhat from their psychic pain hypothesis (PPH).…”

“…( a ) Methods . Women were first selected on the basis of their having a maternal circumstances score ≥ 2 at parity 1, indicating two or more poor category ratings ( n = 154) (for more details see [1]). A binary logistic regression model was then run with parity progression from parity 2 acting as the dependent variable, and whether maternal circumstances stayed the same/deteriorated or improved between parities 1 and 2 acting as a categorical predictor, while controlling for the demographic factors age at second birth and year of mother’s birth .…”

“…Next, from this sample, women were further selected on the basis of their having a positive score when their maternal circumstances score at parity 2 was subtracted from their score at parity 1, indicating their circumstances improved ( n = 83). A binary logistic regression model was then run with parity progression from parity 2 acting as the dependent variable, and PND incidence (EPDS) at parity 1 (for more details see [1]) acting as the predictor, while also controlling for the demographic factors age at second birth and year of mother’s birth .…”

“…We acknowledged in our original paper [1] that, as Hagen and Thornhill suggest, existing offspring may benefit in terms of investment from their mothers ceasing to reproduce. However, we feel given the detrimental impacts of depression on maternal health and infant development, our results are better interpreted as further evidence of the extremely costly nature of depression which indicates PND would be poorly designed as a signalling mechanism to inform mothers of their already impoverished state.…”