Jesse Poganik, PhD, of the Division of Genetics within the Department of Medicine at Mass General Brigham, is the senior author of a paper published in Trends in Endocrinology & Metabolism, " The Postpartum Recovery Window as a Determinant of Maternal Aging ." Stephen Albright, formerly of Mass General Brigham, is the lead author.
Q: What challenges or unmet needs make this study important?
In many studies, it appears that women who have more children have a higher risk of heart disease and a shorter lifespan, but this effect is inconsistent across populations and no good explanation for it exists. Against this backdrop, new tools to assess biological age — the age reflected by one's biological state, rather than simply the number of years they have been alive — have revealed that pregnancy temporarily elevates biological age, while postpartum recovery can return it closer to baseline. However, we still do not know how to connect these short-term changes to long-term health outcomes, which is the gap this paper aimed to fill.
Q: What central question(s) were you investigating?
Why is having more children detrimental to the long-term health of some women, but not others? We propose that the timing between pregnancies may be the key factor.
Since pregnancy elevates biological age and the postpartum period represents a window during which biological age recovers, then the length of that window may be critically important. If the window is cut short by another pregnancy, the costs may compound across pregnancies. We call this the "recovery period hypothesis."
Q: What methods or approach did you use?
This paper is a review, so rather than collecting new data, we surveyed published evidence from multiple fields and asked whether it pointed in a consistent direction. We reviewed studies that assessed biological age using a variety of approaches: data from wearable devices, brain imaging, biological age scores derived from routine blood tests and epigenetic clocks, which measure biological age through chemical modifications on DNA.
We then connected this body of literature to population studies on birth spacing, number of children and long-term maternal health outcomes. From this synthesis, we built a framework and laid out specific, testable predictions that could confirm or rule it out.
Q: What did you find?
Our main findings were threefold. First, the evidence that biological age temporarily increases during pregnancy and partially recovers afterward is remarkably consistent: it appears in studies from Europe, the United States and the Philippines, and recurs across measurement types ranging from brain structure to chemical modifications on DNA.
Second, recovery can take anywhere from a few months to a year or more and appears to be influenced by factors like pre-pregnancy weight, breastfeeding and possibly sleep.
And lastly, early evidence suggests that becoming pregnant again during the postpartum window can interrupt recovery. Based on this, we propose that the interval between pregnancies may be a missing piece in explaining the link between number of children and later-life health. This remains a hypothesis, and testing it directly will require studies that follow women for decades beyond their childbearing years.
Q: What are the real-world implications, particularly for patients?
This paper reframes the time after delivery as a potentially important window for a woman's long-term health, rather than just a period of healing from birth. Our framework concerns the physical demands of pregnancy and how to help women recover from them fully. Several factors that appear to support recovery — such as breastfeeding, sleep and metabolic health — could be influenced by better postpartum care and support.
If our predictions hold up, future guidance on pregnancy spacing could weigh the mother's long-term health alongside birth outcomes, and might eventually be personalized using biological age measurements. However, it's important to emphasize that this work does not change current medical advice: since 2005, the World Health Organization has recommended waiting at least two years in between pregnancies.
Q: Tell us about any follow-up studies you have planned to validate or build on these findings.
Our next goal is to directly test our recovery period hypothesis. This would involve a longitudinal study following women before, during and after pregnancy, measuring biological age repeatedly and recording the timing between pregnancies precisely.
We are already studying how biological age changes throughout pregnancy and the postpartum period using the latest technology, which lets us calculate the biological ages of individual organs and cell types rather than a single whole-body number. That resolution matters because different organ systems may recover on different timelines, and some changes during pregnancy may be healthy adaptations rather than signs of aging.
We also plan to analyze existing datasets linking reproductive histories to long-term health and investigate whether pregnancy spacing explains differences in outcomes across populations.
Paper cited: Albright, SM., Poganik, JR. "The Postpartum Recovery Window as a Determinant of Maternal Aging." Trends in Endocrinology & Metabolism. DOI: 10.1016/j.tem.2026.09.002
Funding: This paper was supported by the Hevolution Foundation and the Brigham and Women's Connors Center WHISPR (Women's Health Interdisciplinary Stress Program of Research) Award through a generous donation from the Gretchen S. Fish Fund for Women's Health and Stress Research.
