Last month I wrote about menarcheal age in Ethiopian girls, and that food insecurity leads to a delay in the onset of menstruation. This fits with the general response of the reproductive system to energetic stress – low energy leads to suppression of the hypothalamus, which interferes with ovulatation and, in stronger cases, with menstruation itself.
But, it would seem, not all stressors are the same. Over the past decade or so, a series of studies have shown that, unlike food shortages, the stresses of childhood neglect, abuse, and even the absence of a father tend to accelerate rather than delay puberty.
So how do researchers understand the effects of these different types of stress during development? The leading hypothesis is an evolutionary one, based on something called life history theory. The theory is that there is a tradeoff between reproduction and survival. Early energy put into reproduction comes at a cost of long term survival, and delayed reproduction may result in no reproduction at all unless the chances of surviving are good. This can be used to understand different life history strategies such as weeds (early reproduction, short survival) versus trees (later reproduction, longer survival). It can be used to look at different strategies within a species. And it can also be used to look at a contingent strategy within a species, one that is expressed in different ways depending on the circumstances.
In the case of humans and abuse during development, the argument is that abuse, neglect and the absence of a father all indicate more adverse conditions, in which long-term survival is less likely, and accelerated reproduction is favored.
There is good reason to be cautious when assessing evolutionary arguments about humans, especially when sex and reproduction come into the story. However, in this case the data are persuasive. Here are a few links to articles that have addressed the topic:
Childhood abuse and early menarche: findings from the black women’s health study.
Childhood sexual abuse and early menarche: the direction of their relationship and its implications.
A life history assessment of early childhood sexual abuse in women.
Sexual trajectories of abused and neglected youths
Age of menarche: the role of some psychosocial factors.
