Waiting 2 to 2.5 years between pregnancies is linked to a much lower risk of delivering a baby extremely early (before 32 weeks) compared to getting pregnant again within six months.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
A systematic review of RCTs could determine whether extending IPI to 24–29 months causally reduces the incidence of extremely preterm birth (<32 weeks).
A systematic review of randomized trials assigning women to conceive at 24–29 months versus <6 months postpartum, with extremely preterm birth (<32 weeks) as the primary outcome, controlling for maternal age, prior preterm birth, and access to prenatal care.
An RCT could determine whether delaying conception to 24–29 months directly reduces the incidence of extremely preterm birth.
A multicenter RCT of 4,000 women with a prior preterm birth, randomized to conceive at 24–29 months versus <6 months postpartum, with extremely preterm birth (<32 weeks) as the primary outcome and adjustment for prior preterm history, maternal age, and BMI.
A prospective cohort could confirm whether 24–29 month IPIs independently reduce extremely preterm birth risk after adjusting for maternal health and prior outcomes.
A prospective cohort of 12,000 women with a prior preterm birth, tracking IPI and monitoring for subsequent extremely preterm birth (<32 weeks), with monthly assessments of health, nutrition, and prenatal care utilization.
A case-control study could compare IPI distributions between women who delivered extremely preterm infants and those who delivered at term.
A matched case-control study of 1,200 extremely preterm births (<32 weeks) and 2,400 term births, matched for maternal age, prior preterm birth, and race, with IPI verified via birth registry data.
A cross-sectional survey could estimate the proportion of extremely preterm births occurring after different IPI ranges.
A national cross-sectional survey of 50,000 women with two or more births, asking about timing of prior births and outcomes, with extremely preterm birth confirmed by hospital records.