The effects of pregnancy and childbirth on a woman’s body don’t go away over time: New research from Pennsylvania State University (Penn State) has found a link between the frequency of a woman’s birth and the way she’s aged, and body functions .
The researchers found that effects on aging were only observed after menopause. “Our results suggest that pregnancy and childbirth may contribute to the alteration and dysregulation of various physiological systems that can affect postmenopausal aging,” said Talia Shirazi, a PhD student in biological anthropology at Penn State. Ms. Shirazi made her comments in a Penn State press release. Pre-menopausal women are likely to be protected from premature biological aging because they are still producing ovarian hormones.
Energy in energy out
When women are pregnant, their bodies are biologically stressed as the growth and accommodation of the fetus consume enormous amounts of energy. Breastfeeding is also physiologically demanding. A woman’s metabolism, blood pressure and immune system, and other body functions all take a toll in carrying, giving birth, and feeding a baby. The researchers found that women who gave birth were more likely to die of kidney disease, high blood pressure and diabetes, to name a few, compared to women who did not give birth.
Ms. Shirazi, one of the study’s authors, discussed the path to biological aging for these women in a tweet. Biological aging is the comparison of people of similar chronological ages who are different and of different ages.
Because physiological resources are limited, we make trade-offs between growth, maintenance, and reproduction. In women, reproduction, especially pregnancy, is FREE. More energy for reproduction = less for growth / maintenance. (2 / n)
– Talia Shirazi (@talia_shirazi) November 25, 2020
The sweet spot
To test biological age, researchers looked at metabolic health, kidney and liver health, immune function, inflammation, and red blood cell health.
The study included just over 2,000 women. The researchers found that women with few or many children aged biologically faster. Women with 3-4 children in the slowest age. However, this relationship only applied to postmenopausal women.
Women who age faster showed signs in all areas. Researchers have attributed this to the far-reaching effects of pregnancy.
Ms. Shirazi stated in another tweet that her results were somewhat surprising and that other studies looking at cell age showed differences even in pre-menopausal women.
She had two explanations. First, the hormones that women produce when they are fertile protect them from some of the effects of aging. The other that “Cellular actions may be more sensitive and capture changes before they cause system-level dysfunction,” she wrote in a tweet.
Not just babies
Pregnancy isn’t the only thing that can cause someone to age faster. Things like race, weight and BMI, socioeconomic status, or smoking can all contribute to advanced biological aging. The Penn State researchers tried to take these into account when looking at the data.
There’s more to it than that
However, the data is not everything. The researchers found that women who have no children or just one child may be sick or have less social support. Illness or a lack of social support could also contribute to biological aging. In their work, they called for more research on the social factors of biological aging.
In addition, they did not have access to data on miscarriages, stillbirths, or abortions. Up to a fifth, if not more, of pregnancies end in miscarriage. This could be a significant source of missing data.
This study was also a cross-sectional study, meaning it was a single snapshot. What actually happened to the women in the study in old age is unknown, as is any major health complaints they may have had.
Until the science behind it is better understood, it is difficult to say for sure why the number of children someone has affects biological aging. More research can be expected on how pregnancy affects certain areas such as metabolism or liver function to better understand how wearing, childbirth, and breastfeeding accelerate aging in women.