Study Suggests 18 to 23 Months Between Pregnancies
A Harvard Medical School study points to that window as offering the best maternal health outcomes.
Updated on Nov. 5, 2026 in Women’s Health
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Researchers at Harvard Medical School identified an 18 to 23 month gap between pregnancies as potentially offering the best health outcomes for mothers. Obstetrician Dr Chelsea Watt said the recommendation is broadly consistent with Australian guidelines.
Why it matters
The findings add to ongoing discussion about how spacing pregnancies may affect a mother's recovery and long-term health. Quick succession of pregnancies may not give the body enough time to recover, while the study's authors note that pregnancy temporarily raises biological age.
The study identified an 18 to 23 month gap between pregnancies as the recommended interval for maternal health outcomes. Researchers have not yet established that shorter intervals cause permanent or accelerated biological ageing.
The players
Harvard Medical School
A medical school affiliated with Harvard University in Boston, Massachusetts, which conducted the study.
Dr Chelsea Watt
An obstetrician and gynaecologist and founder of Redefine Women's Health who commented on the recommendation.
The details
The study considered maternal health and the relationship between pregnancy and ageing, examining how pregnancy affects biological ageing. Biological age transiently rises during pregnancy, peaking around the third trimester or at delivery, and some level of parity is associated with benefits to lifespan.
Timeline
Biological age transiently peaks in the third trimester or at delivery.
Fertility declines more notably after age 35.
Health Landscape
Dr Chelsea Watt said the 18 to 23 month recommendation is broadly consistent with Australian guidelines on pregnancy spacing. The finding therefore aligns with existing clinical guidance rather than departing from it.
Readers planning pregnancies may consider how the spacing between births relates to recovery and maternal health. Discussing timing with a healthcare provider can help individuals weigh these findings against personal circumstances.
The takeaway
Spacing pregnancies roughly 18 to 23 months apart is the interval this study associates with the best maternal health outcomes. Individuals considering timing should consult a healthcare provider about their own circumstances.
Further reading
Explore more in Women's Health for related coverage on pregnancy and maternal wellbeing.
Source note: This article includes information reported by Body and Soul.
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