Myths vs Facts: Breastfeeding During Pregnancy and Tandem Nursing

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By Hilary Flower, author of
Adventures in Tandem Nursing: Breastfeeding During Pregnancy and Beyond, published by La Leche League International in July 2003

You have probably heard most of these common statements circulating about breastfeeding during pregnancy and tandem nursing. I set out to test their veracity, and was surprised by what I found! Test the currency of your own knowledge: which statements are myth, fact, or simply unknown?

1. “At 24 weeks gestation, the uterus changes in such a way that breastfeeding goes from being safe to risky.” …MYTH or FACT?

Myth. Oxytocin is a hormone released during breastfeeding that causes uterine contractions, usually too mild to notice. This fact has raised concern that breastfeeding could contribute to preterm labor in an otherwise healthy pregnancy. The uterus starts out pregnancy fairly insensitive to oxytocin, and somehow the rumor got started that it increases in sensitivity in mid-pregnancy. Research does not support this. Instead, the first marked increase occurs after the 37th week—with little or nothing happening before that time.

2. “When you are breastfeeding during pregnancy, your body gives first to the fetus, then to the nursling, and then what’s left over goes to your own daily needs and reserves.” …MYTH or FACT?

Myth. If your body fat is already perilously low, you will want to note that malnourished women yield some body fat to contribute to fetal weight gain. But we have no research to tell us whether the fetus or nursling gets priority in times of shortage. More importantly, we have no reason to believe that anyone needs to come up short unless the mother is malnourished. Follow your appetite, eat enough calories of a basic mixed diet, and gain weight within the same parameters as if you weren’t breastfeeding, and your body will do the rest.

3. “The newborn always needs to nurse first.” …MYTH or FACT?

Myth. Your newborn may need “first dibs” on colostrum since it is in limited supply in the first day or two. The sensation of your milk “coming in” indicates that your supply has exceeded your children’s demand; you can now count on plenty for both nurslings. Indeed, if you experience engorgement or an overly strong milk flow, your newborn may have an easier time if you nurse your toddler first!

4. “Most mothers experience a significant drop in milk supply during pregnancy.” …MYTH or FACT?

Fact. 70% of mothers notice a significant drop in supply during pregnancy. Still, a minority of mothers continue to produce an abundance of milk throughout pregnancy.

5. “Tandem nursing mothers can make a double supply of milk—just like mothers nursing twins.” …MYTH or FACT?

Fact. In one study a tandem nursing mother made a double supply of milk for the entire seven months that she tandem nursed (and her newborn was well above average in growth!). The only supply concern generally reported by tandem nursing mothers is oversupply.

6. “A majority of children self-wean during their mothers’ pregnancies.” …MYTH or FACT?

Myth. It is true that a majority of children do wean during their mothers’ pregnancies; the question is: who’s idea is it? In one study of La Leche League mothers breastfeeding during pregnancy, 26% of children self-weaned, 28% of the mothers led weaning, and the other 46% went on to tandem nurse.

7. “If you enjoy nursing your child before pregnancy, there’s no reason to believe that pregnancy would change that.” …MYTH or FACT?

Myth. It’s important to note that pregnancy does tend to change “breastfeeding as usual” for many mothers. Some mothers find that nursing during pregnancy causes pain, agitation, or nausea, and such problems can affect their feelings about continuing. (Similarly some toddlers don’t like the changes in flavor and supply of milk.)

8. “Tandem nursing will ensure a smooth sibling adjustment for your older child.” …MYTH or FACT?

Myth. Your older child may experience a range of emotions, from fear of displacement–to anger at you–to delight in the new baby. And remember that sibling relationships tend to have their own rhythms of bonding and fighting, and both can happen at your breast! Realistic expectations, lots of mama love, open communication and a sense of humor will help you move through any challenges that arise.

9. “Breastfeeding reduces morning sickness.” …MYTH or FACT?

Unknown! This appears to be true for many mothers (myself included) but only a scientific study could tell us whether statistics will bear this out or not. On the other hand, some unlucky moms do experience isolated bouts of nausea specifically during breastfeeding sessions.

10. “Tandem nursing mothers are martyrs.” …MYTH or FACT?

Myth. It is true that nursing two children is a big commitment. On the other hand, weaning a reluctant child is no easy task either, particularly if you are pregnant or caring for a new baby. Each mother must choose the option she is most prepared to follow through on.

BONUS QUESTION: “Tandem nursing is rare.” …MYTH or FACT?

Myth. Many mothers are careful about whom they tell, but this invisibility masks a common practice. In one study of 179 mothers who had breastfed at least one child for at least six months, 61% had breastfed during pregnancy, and 35% had tandem nursed.

How did you do?

For more information, see Nursing During Pregnancy and Tandem Nursing: The Official FAQ or read a chapter from Adventures in Tandem Nursing.


  1. Flower, 2003, pp. 223-230; Kimura T, et al. Expression of oxytocin receptor in human pregnant myometrium. Endocrinology 1996; 137:780-85.
  2. Flower, 2003, pp. 248-49; Hamosh M, Dewey KG, Garza C, et al: Nutrition During Lactation. Institute of Medicine, Washington, DC, National Academy Press, 1991.
  3. Flower, 2003, pp. 76-78.
  4. Moscone [sic] SR, Moore MJ. Breastfeeding during pregnancy. J Hum Lact. 1993 Jun;9(2):83-88.
  5. Flower, 2003, pp. 233-234; Prosser CG, Saint L, Hartmann PE. Mammary gland function during gradual weaning and early gestation in women. Aust J Exp Biol Med Sci. 1984 Apr;62 (Pt 2):215-28.
  6. Flower, 2003, pp. 166; Moscone [sic] IBID.
  7. Flower, 2003, pp. 39-66.; Moscone [sic] IBID;
  8. Flower, 2003, pp. 192-199.
  9. Flower, 2003, 263-64.
  10. Flower, 2003, pp. 8-10.
  11. Flower, 2003, p.16; Kendall-Tackett, K. Unpublished Data.

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