Pregnancy entails numerous and diverse changes, both physical and even mental, in women's bodies, as multiple scientific studies have shown. It is known that during pregnancy, women's biological age accelerates, but with the postpartum period, this phenomenon partially reverses.
However, a review published in Trends in Endocrinology & Metabolism provides a new insight by suggesting that "very closely spaced pregnancies could prevent the body from fully recovering, favoring the accumulation of changes associated with biological aging, with possible consequences for maternal health in the long term," according to Jesse Poganik, from the Genetics Division within the Department of Medicine at Mass General Brigham, in Boston, Massachusetts, United States, the lead author of the study, along with Stephen Albright.
The researchers suggest that the time elapsed between pregnancies could be a relevant factor in women's aging, although "further studies are still needed to verify this hypothesis."
In this review, they suggest that the recovery time between pregnancies could ultimately affect the mother's long-term health. Repeated pregnancies with short intervals between them could prevent full recovery, allowing some changes to accumulate over successive pregnancies. According to Poganik, this could potentially alter the overall aging trajectory, although he acknowledges that these changes do not necessarily equate to biological damage. "We know that a certain level of parity, or carrying a pregnancy to term, is actually beneficial for a person's life expectancy."
Currently, the World Health Organization (WHO) recommends waiting a minimum of 24 months (two years) after a birth before conceiving another child, as a way to reduce health risks for both the mother and the baby. However, Poganik explains that additional research would be needed to make specific recommendations based on biological aging rather than pregnancy outcomes, including measuring biological age in multiple pregnancies and then following mothers for decades afterward.
Beyond the study of long-term aging, this research also has implications for improving maternal health during and after pregnancy. According to Poganik, one of the short-term goals is to address current clinical challenges, "including the significant crisis of maternal mortality in the United States compared to other industrialized countries." He believes that any information that can be obtained to improve maternal health is a valuable tool for research.
Real implications for women
The new study reconsiders the time after childbirth as a potentially important window for women's long-term health, rather than just a period of recovery from childbirth. The framework, according to the researchers, refers to the physical demands of pregnancy and how to help women fully recover from them. Several factors that seem to support recovery - such as breastfeeding, sleep, and metabolic health - could be influenced by better postpartum care and support. "If our predictions come true, future guidelines on pregnancy spacing could assess the mother's long-term health along with childbirth outcomes. Eventually, they could be personalized through biological age measurements. However, it is important to emphasize that this work does not change current medical advice: since 2005, the WHO has recommended waiting at least two years between pregnancies."
As this is a review study, no new data has been collected but rather the published evidence from multiple fields has been analyzed to demonstrate if the proposed direction is consistent. Studies evaluating biological age using various approaches were reviewed: data from wearable devices, brain imaging, biological age scores derived from routine blood analyses, and epigenetic clocks, which measure biological age through chemical modifications in DNA. "Studying changes during pregnancy is just one way to gain a more fundamental understanding of aging in general."