While researching their new book, The Informed Parent: A Science-Based Resource for Your Child's First Four Years, science journalists Tara Haelle and Emily Willingham, Ph.D., sifted through thousands of studies on parenting practices—from birthing and breastfeeding to sleep training and screen time—to find out what moms and dads really need to know. In this adapted excerpt, Haelle and Willingham take a look at the science behind boosting breast milk.
Although about 8 in 10 newborns started to breastfeed in 2011, only half of infants born that year were still breastfeeding at 6 months old, and just over a quarter at 1 year.
For mothers who planned to formula-feed or to stop breastfeeding before a year, that's fine—but a large proportion of those decreases reflects mothers who aren't meeting their own breastfeeding goals. A 2014 study of more than 2,300 women who planned and started to breastfeed found that 12 percent of those women experienced problems related to breast pain, low milk supply, or infant latch. That means 1 in 8 women didn't reach the breastfeeding goal they set for themselves due to these common problems.
In our book, we address some of the most common problems nursing moms face and provide an overview of the related research. In this section, we'll focus on milk production.
Many women worry about low production and want to know ways to boost it. A Cochrane Review didn’t find evidence that drinking extra fluids boosts milk production (though dehydration can hurt it). As for the old wives’ tales about beer drinking, one review found that barley, an ingredient in most beers, can stimulate prolactin, the hormone that stimulates the production of breast milk, but alcohol can inhibit the letdown reflex, so the effects might cancel each other out.
Listening to music while pumping or breastfeeding, relaxation techniques like deep breathing or massages, and having pleasurable food or drink have all been shown to help a little bit with milk supply, most likely because they all reduce stress. Some hormones have been tested for increasing milk supply, such as oxytocin and human growth hormone, but data on effectiveness and safety are thin.
For women who have a diagnosed insufficiency, the prescription drug metoclopramide can increase prolactin levels, resulting in up to 1.5 ounces more milk per feeding, but it should only be used short term, no more than three weeks. It can cause gastrointestinal side effects, anxiety, or sedation in moms, but there’s no evidence of effects in babies.
And then there are the herbal remedies, and lordy, there are a lot!
Unfortunately, there isn’t much reliable research, and plenty of problems exist with what little research there is. Studies are usually small, with 10 to 75 people, and aren’t often well-controlled. The women aren’t necessarily representative of all women, and dosages are all over the map. Because herbs are not regulated in the United States, supplements aren’t standardized, and it’s hard to know how much of an herb is in a capsule and what other ingredients are in there.
We’ll run through the most popular herbs here, but keep in mind that none of them has a strong evidence base, and all the studies discussed are very small. The ones with the “best” evidence are fenugreek, milk thistle, and torbangun.
A trial using tea with fenugreek against a placebo group and a control group led to double the pumped milk from the fenugreek tea group compared to the other two. The best dosage, based on a poorly described anecdotal account of 1,200 women, is three capsules (580 to 610 milligrams) three times a day, and if it’s going to work, the effects should appear within two to three days.
Possible side effects include nausea, diarrhea, flatulence, and smelling like maple syrup (seriously!). Fenugreek can also interfere with some medications and increase the risk of bleeding in women taking blood-thinning medications and may cause congenital anomalies if taken while pregnant. Those allergic to chickpeas, soybeans, or peanuts may have an allergic reaction to fenugreek since it’s in the same family.
Milk Thistle (Silybum marianum/St. Mary’s Milk)
A placebo-controlled trial of 50 Peruvian women found a 64 percent increase in milk production among women taking silymarin (the commercially available form), compared to 22 percent in the placebo group after a month. At two months, the silymarin group experienced an 86 percent increase, compared to 32 percent in the placebo group.
Shatavari (Asparagus racemosus)
One trial found a 33 percent increase in prolactin levels and a 16 percent increase in babies’ weight in women taking this herb, compared to a 10 percent prolactin increase and a 6 percent baby weight increase in the comparison group. Possible side effects are a runny nose or red eyes during preparation, and it may cause congenital anomalies if taken while pregnant.
After a month of use, mothers’ milk volume increased 33 percent compared to a 15 percent drop in two comparison groups, one of which was taking fenugreek. This herb may increase the risk of bleeding in mothers using blood-thinning medications.
Fennel, blessed thistle, chaste tree seed, goat’s rue, raspberry leaf, basil, black seed, anise, caraway seed, alfalfa, and stinging nettle have all been tried or suggested, but no data exist on them. Chaste berry or chaste tree seeds may be unsafe to take while pregnant. Blessed thistle may increase bleeding risk if taken with blood-thinning medication, and fennel may interact with some drugs’ effectiveness.
The bottom line? Experiment, but caveat emptor.