By Lyndal Green - Posted on Nov 4, 2011 26 34 There is a very well researched book on this subject called "Adventures in Tandem Nursing: Breastfeeding During Pregnancy and Beyond" by Hilary Flower. Yes nipple stimilation can cause the uterus to contract, but it will not cause a miscarriage or early labour unless there is other risk factors involved. Not all Obstetricians agree, but this is usually because they have not looked at the research. I am a registered midwife in Australia and I have also breastfed through pregnancy and beyond (12mths in fact). Its not for everyone, and it does come with its own challenges. I found it to be a very empowering experience. 12 By Tine Brok - commented on Apr 8, 2013 279 9 Absolutely Lyndal, it's an excellent book, and the research I have seen says the same thing, that in fact the receptors in the uterus for oxytocin do not become active until the baby is ready to be born, in fact their readiness is triggered by the maturation of the baby's lungs. therefore, as you say, without other risk factors there is no safety issue with breastfeeding causing early birth. I am currently 4 months pregnant and breastfeeding my 16 month old son, a huge, extremely clever thriving boy. I breastfed his sister all through his pregnancy too! In fact none of my kids has yet completely weaned lol!