Miscarriage/Preterm Labor Risks
This is a common worry, but it does not appear to have a strong foundation. A recent review of research on the pregnant uterus reveals that there is actually no theoretical basis for the common concern that breastfeeding can lead to miscarriage or preterm labor in healthy pregnancies. Instead the uterus has many safeguards preventing a strong reaction to the oxytocin that breastfeeding releases.
Interestingly, experts on miscarriage and preterm labor are not among those who see a potential link between breastfeeding and these pregnancy complications. Miscarriage expert Lesley Regan, PhD, MD, quoted in Adventures in Tandem Nursing, saw no reason that breastfeeding should impact pregnancy, even if the mother has a history of miscarriage or is experiencing a threatened miscarriage.