Study Suggests 18-23 Months Between Pregnancies
Women planning more than one pregnancy may want to discuss this spacing window with their doctor.
Updated on Nov. 5, 2026 in Women’s Health
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A Harvard Medical School study identified 18 to 23 months as the gap between pregnancies that could offer the best health outcomes for mothers. Obstetrician Dr Chelsea Watt said the recommendation is broadly consistent with Australian guidelines.
Why it matters
The findings point to spacing between pregnancies as a factor in maternal health, relevant to women planning future pregnancies. The researchers suggest that quick succession of pregnancies may not give the body enough time to recover.
The Harvard Medical School study examined maternal health and the effects of pregnancy on biological ageing, identifying an 18 to 23 month interval as the gap that could offer the best outcomes. The study is described as considering the relationship between pregnancy and ageing, though its design and sample size are not specified in the available material.
The players
Harvard Medical School
Harvard Medical School is a major American medical school known for research across clinical and population health fields.
Dr Chelsea Watt
Dr Chelsea Watt is an Australian obstetrician and gynaecologist and founder of Redefine Women's Health.
The details
Biological age transiently rises during pregnancy, peaking around the third trimester or at delivery, and the study examined how the body recovers from longevity-related factors after a pregnancy. When pregnancies follow each other too quickly, the body may not have enough time to recover between them. Some level of parity, meaning carrying a pregnancy to term, is associated with benefits to lifespan, while fertility declines with age, particularly after 35.
Timeline
Biological age transiently peaks in the third trimester or at delivery during pregnancy.
Fertility declines more notably after age 35.
Health Landscape
The recommendation places pregnancy spacing within ongoing research on how childbearing relates to biological ageing and long-term maternal health. Its alignment with Australian guidelines, as noted by Dr Watt, suggests some consistency across national health perspectives on this question.
Women thinking about the timing of future pregnancies may find this study worth raising with their physician or obstetrician. The findings suggest that spacing pregnancies may matter for recovery, so it is a useful topic to discuss in the context of personal health and family planning.
The takeaway
The study identifies an 18 to 23 month interval between pregnancies as a possible window for better maternal outcomes, though the evidence is not yet conclusive on causation. Discussing pregnancy spacing and reproductive planning with a healthcare provider is a practical step for anyone considering future pregnancies.
Further reading
For more on how pregnancy and reproductive timing affect women's health, explore our Women's Health coverage.
Source note: This article includes information reported by Body and Soul.
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