Although sleep disruption in adults has been linked to caffeine intake, this study found no significant effect of mothers’ caffeine intake (either prenatally or postpartum) of 300mg per day (about 6- 6oz cups of coffee) on infant night waking. (Santos 2012)
If you are a regular reader of our blog, you know that babies may wake for many reasons during the night, especially in the first 3 months postpartum. In previous posts, we have listed caffeine as a reason for night waking in infants. Let’s take a look at the specifics of this study. Have these researchers determined that the caffeine intake of breastfeeding mothers does not affect night waking in their infants?
The Study: Caffeine Intake of Postpartum Women
As part of this study, researchers analyzed maternal caffeine consumption and the sleep patterns of 885 mother-infant pairs during their first 3 months of life. The average caffeine intake of the mothers at 3 months postpartum was 144 mg per day (about 18 ounces of coffee). The amount of caffeine intake was collected via maternal report, but mothers were asked to measure caffeine intake using a very detailed method. Heavy caffeine use, defined as ≥300 mg per day, was seen in about 14.3% of of the mothers. (Santos 2012)
How Infant Sleep was Studied
When the babies were 3 months old, mothers were asked to report their babies’ sleep habits for about the last 2 weeks. Specifically, mothers were asked to describe 1) the number of hours of sleep during both the day and night; 2) bed sharing practice; 3) the number of night wakings and who woke up with the baby during the night; 4) the cause for nighttime wakings, if known; and 5) quality of child’s sleep patterns. Night waking was defined in this study as anytime a baby awakened and woke up the parent. Frequent waking was defined as 3 or more times per night.
Effects of Caffeine on Infants
In mothers, caffeine is quickly absorbed by the stomach and intestines, then it is distributed through breast milk to the baby. For a breastfeeding mother, about 0.6%-1.5% of the mothers’ dose is available to the baby. (Hale 2010) Though a small amount of caffeine is transferred to the baby through breast milk, the caffeine can accumulate because it is not easily broken down and eliminated from the body. For adults, caffeine stays in the body for about 4.9 hours; for newborns, it stays up to 97.5 hours. Thus newborns are especially sensitive to caffeint. This decreases with a baby’s age. By 6 months of age caffeine stays in the baby’s system only 2.6 hours. (Hale 2010)
In this study, the highest prevalence of frequent night waking (3 or more times per night) was seen in breastfed infants whose mothers drank more than 300 mg of caffeine per day during the entire pregnancy and 3 month postpartum study periods. Even though this association was shown, it was not statistically significant. Also, the sample size of this specific group was only 40, and according to the authors, it’s possible that infants of the heavy caffeine drinking mothers developed a tolerance to the caffeine and possibly explaining why the caffeine did not affect the infants’ sleep.
There are many reasons infants wake in the first 3 months postpartum. Some breastfed babies may be more sensitive to the caffeine intake of their mothers than others. For this study, in a small sample, there was an association, though insignificant, between breastfeeding mothers’ caffeine intake during pregnancy and 3 month postpartum with increased night waking in their infants. Other conclusions have been stated in other references. In their book, Breastfeeding: A guide for the medical professional, Lawrence and Lawrence reported that 6-8 cups of caffeinated beverages per day has been associated with shorter infant sleep duration. More research is needed to come to consensus as to the effects of caffeine on infant sleep.
*The recommendations for caffeine intake for nursing mothers is limited to about 2 servings of caffeinated beverages per day (Mannel, et al. eds, 2008).
Santos IS, Matijasevich A, Domingues MR. Maternal Caffeine Consumption and Infant Nighttime Waking: Prospective Cohort Study. Pediatrics; 2012. [Epub ahead of print]
Lawrence, R. A., and Lawrence, R. M. (2010). Breastfeeding: A guide for the medical professional. Elsevier Mosby, Maryland Heights, Missouri.
Core curriculum for lactation consultant practice. International Lactation Consultant Association; edited by Rebecca Mannel, Patricia J Martens, and Marsha Walker, 2nd edition, 2008.