Re: Breastfeeding during pregnancy I can't answer the question about research " that nursing through a subsequent pregnancy interfered with uterine lining development." (Please share references if you get any.) Here are some references on breastfeeding during pregnancy, which may be of interest. I have been looking into the question of breastfeeding during pregnancy, as we have WIC clients who are breastfeeding during pregnancy and I was interested in learning more about recommendations to make to them, especially about nutrition needs. I was also asked to speak on this topic at a conference this summer. It was difficult to find references. Some of the following references were shared by Grace Marquis from the University of Alabama. Breastfeeding during pregnancy is more common than many realize. Despite this, we really don't know a lot about the effects of breastfeeding during pregnancy. In addition to references cited below, I talked with several friends/acquaintances/WIC clients who breastfed through a pregnancy and had full-term babies of good birthweight. I was concerned about advice at both ends of the spectrum--some women had been essentially told "no problem" with no investigation of their diet or information on what we don't know. Other women had been told "not a good idea", again, apparently on the opinion of their health care provider. Here is some of what we don't know: *How does pregnancy affect breastmilk composition? *How does lactation affect pregnancy? *How do studies done in marginally nourished populations translate to recommendations for well nourished women? *Effect of oxytocin--can it lead to premature labor in some women? If so, who? *Effects of breastfeeding during pregnancy on mother, fetus, and breastfeeding child, especially if intake of calories or other nutrients inadequate. *What are the nutrient needs to support pregnancy and lactation? Are they additive? Are there factors which spare calories? *Is/are there any reason(s) to recommend not breastfeeding while pregnant? If so, what? There are many good reasons why women wish to continue breastfeeding while pregnant. In my opinion, until more research is available, we need to assess the variables for the pregnant woman and her nursing child, and the fetus. This information should be discussed with the woman, so she can make a decision based on informed choice. We also need to discuss the need for adequate nutrient intake/weight gain, and help her plan for an adequate diet.) (If history of pregnancy loss/prematurity, uterine pain or bleeding, or continued weight loss, prudent to encourage weaning, again, in my opinion--considering needs of fetus.) References: Breastfeeding During Pregnancy in: Mohrbacher, N, Stock, J. The Breastfeeding Answer Book. 1990. La Leche League International, Franklin Park, Illinois. Garza C. Lactation during pregnancy. IN: Gleicher N (ed.). Principles of medical therapy in pregnancy. 1985. New York: Medical Book Company. 263-268. Siega-Riz, M, Adair, L. Biological determinants of pregnancy weight gain in a Filipino population Am J Clin Nutr 1993;57:365-72. Merchant K, Martorell R, Haas J. Maternal and fetal responses to the stresses of lactation concurrent with pregnancy and short recuperative intervals. Am J Clin Nutr 1990;52:280-8. Moscone SR, Moore MJ. Breastfeeding during pregnancy. J Hum Lact 9(2)1993:83-88. Kendall-Tackett, K, Sugarman, M. The social consequences of long term breastfeeding J Hum Lact 11(3) 1995:179-83. Newton N, Theotokatos M. Breastfeeding during pregnancy in 503 women: does a psychobiological weaning mechanism exist in humans? Proceedings of the Fifth International Congress on Psychosomatic Obstetrics and Gynecology. London: Academic Press. 1979. pp 845-49. (These are some of the primary references. There are other articles, many of which are referenced in the sources above.) It's difficult to find this informaton with a literature search. If anyone has additional references (or opinions), please share them with me. Mary Johnson/Minnesot Department of Health/WIC