04/03/2012 06:11 pm ET

Caffeine Pregnancy Effects: Mom's Intake May Not Hurt Baby's Sleep

Pregnant women are typically advised to limit their caffeine intake to no more than 200 milligrams per day and to stick to that rule while breastfeeding. However, there are conflicting reports about how caffeine affects babies in utero as well as through breast milk. A new study out of Brazil that will be published in the journal Pediatrics suggests that both pregnant and nursing moms may be able to indulge in a few small cups of coffee without disturbing the sleep patterns of their infants.

To establish how caffeine consumption by the mother -– both during pregnancy and while breastfeeding -- might affect her baby, researchers tracked 885 infants. Twenty percent of the mothers consumed heavy amounts of caffeine (defined as 300 milligrams or more, equivalent to two to four cups of coffee) while others drank less.

The team, led by Dr. Ina Santos from Federal University of Pelotas, interviewed the moms about their caffeine intake while they were a) still in the hospital, b) after giving birth and c) three months postpartum. At that three-month marker, they asked the mothers to detail the sleeping habits of their babies from the past 15 days. The babies whose mothers consumed greater amounts of caffeine woke up slightly more often than those who consumed less, but not enough that there was a statistical significance.

"Maternal caffeine consumption, even in large amounts during gestation and lactation, had no consequences on sleep of the infant at 3 months of age" the researchers concluded.

Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern in Dallas, pointed out to USA Today that mothers are often told to avoid caffeine because it's a stimulant to the central nervous system; it can increase the baby's heart rate while in the womb, which may cause distress. In this particular study though, Sandon saw that the mothers' caffeine intakes, at around 300 milligrams, weren't all that high.

"At that amount, it could be that coffee drinking is more likely a problem for the mother than for the infant," she said. "The child's sleep patterns might not be disrupted. But it could actually be disrupting the mother's sleep patterns at a time when it's already difficult for the mother to get adequate rest."

Some earlier studies have suggested a connection between large amounts of caffeine and miscarriages, along with lower birth weights.