Optimal Pregnancy Spacing According to Research
The optimal interpregnancy interval after a livebirth is 18-23 months, with women advised to wait at least 18 months and ideally 24 months before conceiving again to minimize risks of preterm birth, low birthweight, and perinatal mortality. 1, 2, 3
General Population Recommendations
After Livebirth
Interpregnancy intervals shorter than 6 months carry the highest risk, with a 2.72-fold increased hazard of perinatal death compared to the optimal 18-23 month interval 2
The risk follows a J-shaped curve: both very short intervals (<6 months) and very long intervals (≥60 months) increase adverse outcomes including preterm birth, small for gestational age infants, low birthweight, fetal death, and birth defects 3
Short intervals (<18 months) specifically increase risk of:
Long intervals (≥60 months) are associated with:
Regional Variation in Risk
- The association between short interpregnancy intervals and perinatal mortality varies by geographic context, with the highest risk observed in sub-Saharan Africa (HR 2.95) and lowest in North Africa, West Asia, and Europe (HR 1.98) 2
Special Populations
After Pregnancy Loss (Miscarriage or Abortion)
Women do not need to delay conception after pregnancy loss - intervals of less than 3,6, or 12 months following miscarriage or abortion do not increase risk of perinatal death in the subsequent pregnancy 2
- Multiple studies show similar pregnancy outcomes with interpregnancy intervals of <6-14,15-26, and 27-50 months following spontaneous miscarriage 5
- It is reasonable to attempt conception soon after an uncomplicated miscarriage in otherwise healthy women based on their desire 5
- This contradicts the WHO recommendation of waiting 6 months after pregnancy loss, which is not supported by current evidence 2
After Stillbirth
Women who have experienced stillbirth can conceive within 12 months without increased risk - conception within 12 months of stillbirth is not associated with increased odds of subsequent stillbirth, preterm birth, or small-for-gestational-age birth 6
- In a cohort of 14,452 births following stillbirth, 63% of women conceived within 12 months 6
- Compared to 24-59 month intervals, intervals <6 months showed no increased risk (adjusted OR 1.09 for stillbirth, 0.91 for preterm birth) 6
- This finding applies regardless of the gestational age at which the previous stillbirth occurred 6
After Preterm Birth
For women with a previous preterm birth, an interpregnancy interval of 9 months appears optimal and is not associated with increased risk of recurrent preterm birth according to dose-response analyses 3
After Bariatric Surgery
- Women should postpone pregnancy until stable weight is achieved 1
- Wait 1 year after sleeve gastrectomy or Roux-en-Y gastric bypass 1
- Wait 2 years after adjustable gastric banding 1
Clinical Implementation
Contraceptive Counseling
- Contraceptive counseling should be patient-centered and provided in a shared decision-making framework 1
- Discussion about immediate postpartum contraception should occur during the prenatal period to ensure optimal spacing 1
- Long-acting reversible contraception (LARC) should be offered to facilitate optimal birth spacing 1
High-Risk Considerations
- Women older than 35 years with short interpregnancy intervals face increased morbidity and mortality risks and require particular attention to spacing recommendations 1
Key Clinical Pitfalls
The most common pitfall is applying the outdated WHO recommendation of waiting 6 months after pregnancy loss - current evidence does not support this delay for miscarriage, abortion, or stillbirth 6, 2. Another pitfall is counseling all women uniformly without considering the type of previous pregnancy outcome, as optimal intervals differ substantially between livebirths (18-24 months), pregnancy losses (no mandatory delay), and preterm births (9 months optimal) 6, 2, 3.