TUESDAY, Oct. 24, 2017 (HealthDay News) -- While obesity in pregnancy has long been linked to a higher risk for complications during childbirth, there's now another reason to avoid it: a late start to breast milk production.
That's the finding from a new study of more than 200 women with newborns who planned to breast-feed. The researchers found that delays in "lactogenesis" -- the production of breast milk within three days of delivery -- "occurred more frequently among women who were obese at the time of delivery."
The study highlights an issue many new moms have to deal with, said one pediatrician who reviewed the new study.
"Breast-feeding is hard for all mothers," said Dr. Sophia Jan, who directs pediatrics at Cohen Children's Medical Center in New Hyde Park, N.Y. "This study found that breast-feeding is even harder for mothers who were obese prior to pregnancy."
There are potential consequences for babies, too, she said.
"Newborns of mothers whose breast milk comes in late may lose more weight during those initial days and weeks after birth compared to newborns of mothers whose milk comes in within three days postpartum," Jan noted.
These babies also often end up on formula, which cannot match breast milk's nutritional goodness.
The new study was led by Diane Spatz, a professor of nutrition at the University of Pennsylvania School of Nursing. She and her colleagues tracked the onset of breast milk production in 216 women who gave birth to single babies.
The study found that breast milk production was delayed to beyond three days post-delivery in about 46 percent of non-obese women.
However, that rose to almost 58 percent for new moms who were statistically obese.
Statistical obesity begins with a body mass index (BMI) of 30 or above -- BMI being a measurement of height versus weight. For example, a 5-foot-5-inch woman weighing 180 pounds has a BMI of 30.
"Because nearly 1 in 4 women in the United States begins pregnancy with a body mass index [BMI] equal to or greater than 30, the study underscores the need for targeted interventions and support to help these women achieve their personal breast-feeding goals," Spatz said in a university news release.
Dr. Jennifer Wu, an ob-gyn with Lenox Hill Hospital in New York City, agreed.
The new findings should at least let obese women understand that their milk may "come in later," she said, and "encourage them to continue to try breast-feeding for longer."
According to Wu, "hospitals need to partner with milk banks to help meet the needs of these newborns. Patients should be reminded that there are merits to even small amounts of breast milk for their babies."
For her part, Jan said the study raises the question as to why weight gain can slow breast milk production. More studies that try to answer that question would help identify targets for interventions, she said.
The study will be published Nov. 1 in the Journal of Human Lactation.
Find out more about breast-feeding guidelines from the American Academy of Pediatrics.