Infant sleep and maternal caffeine consumption
Is there a relationship between maternal caffeine consumption and infant night waking?
One of the first rewards for new mothers is to have their baby sleep through the night, or at least for a significant proportion of it.
Young babies take weeks to months to establish a consolidated nighttime sleep, and when they do the sense of relief that mothers’ experience is obvious. Poor sleep may affect the resilience of the mother, her mood and capacity to manage often challenging times, especially for first time mothers.
A higher prevalence of night waking is associated with being male, more daytime naps, exclusive breastfeeding, bed-sharing, being nursed to sleep, lower socio-economic groups and infant-demanding parenting (i.e. prolonged holding, rapid response to infant frets and cries etc).
Caffeine is a common drink consumed by adults and is recognised to interfere with sleep onset and have an insomnia-like effect in a dose-dependent fashion in some people. Caffeine consumption is associated with frequent nighttime waking. Caffeine crosses the placenta and is present in the breast milk of nursing mothers.
Santos and colleagues from Brazil decided to examine the reasonable supposition that maternal caffeine intake could be associated with disrupted infant sleep in the early months of life using a questionnaire for a subset of 885 mothers (about 25% of total) from a birth cohort.
Self-reported caffeine consumption was described retrospectively for each trimester of pregnancy and the first three months of the infant’s life. Caffeine was consumed in coffee or maté (A tea-like beverage that is popular in Brazil) and caffeine variables in milligrams were generated considering the source, preparation method, frequency and amount consumed per serving to establish the average daily intake.
Infants of mothers consuming more than 300mg/day of caffeine (heavy consumers) were considered exposed to caffeine. Infant sleep patterns were described in terms of number of wakings in the 15 days before interview, when the child was three months of age. Only infants from singleton pregnancies were included.
Frequent night wakers were those who awoke more than one standard deviation above the average (mean ± SD: 1.8 ± 0.9 wakings per night), which was 2.7 times or more per night.
Interestingly, and perhaps reassuringly for many mothers, there was no statistically significant relationship between caffeine consumption and nighttime wakings.
Out of interest, all but one of the 885 mothers reported caffeine intake in pregnancy. As pregnancy progressed, the average caffeine intake fell (178, 175 and 166mg/day in the first, second and third trimester respectively) and was lower when the infant was three months of age (144 mg/day).
Heavy consumption was reported by 20% of mothers overall, falling from 24.1% in the first trimester to 14.3% by three months post-partum.
A limitation of the study is that only 40 women of the 20% of heavy caffeine consumers (approximately 180 women) were breastfeeding at three months.
After birth, heavy consumption of caffeine was associated with higher maternal age and maternal depression. Depressed mothers had twice the rate of heavy caffeine consumption as non-depressed mothers. This in itself is an interesting fact that may be useful in discussing how mothers are managing in the first months after delivery.
Clinical Professor Dominic Fitzgerald MBBS, PhD, FRACP
Paediatric respiratory and sleep physician at The Children’s Hospital at Westmead, NSW.
Santos I.S et al. Maternal caffeine consumption and infant nighttime waking: Prospective cohort study. Pediatrics 2012; 129: 860; originally published online 2 April, 2012; DOI: 10.1542/peds.2011-1773
Tags: , Child health