Does Nausea and Vomiting of Pregnancy Play a Role in the Association Found Between Maternal Caffeine Intake and Fetal Growth Restriction?

Abstract

ObjectivesThe aim of this study was to explore the relationships between nausea and vomiting in pregnancy and (a): fetal growth restriction; and (b) maternal caffeine metabolism and fetal growth restriction. MethodsA cohort of 2643 pregnant women, aged 18-45 years, attending two UK maternity units between 8-12 weeks gestation, was recruited. A validated tool assessed caffeine intake at different stages of pregnancy and caffeine metabolism was assessed from a caffeine challenge test. Experience of nausea and vomiting of pregnancy was self-reported for each trimester. Adjustment was made for confounders, including salivary cotinine as a biomarker of current smoking status. ResultsThere were no significant associations between fetal growth restriction and nausea and vomiting in pregnancy, even after adjustment for smoking and alcohol intake. There were no significant differences in the relationship between caffeine intake and fetal growth restriction between those experiencing symptoms of nausea and vomiting and those who did not, for either the first (p=0.50) or second trimester (p=0.61) after adjustment for smoking, alcohol intake and caffeine half-life. There were also no significant differences in the relationship between caffeine half-life and fetal growth restriction between those experiencing symptoms of nausea and vomiting and those who 2 did not, for either the first trimester (p=0.91) or the second trimester (p=0.45) after adjusting for smoking, alcohol intake and caffeine intake. ConclusionThe results from this study show no evidence that the relationship between maternal caffeine intake and fetal growth restriction is modified by nausea and vomiting in pregnancy.

Scientific Opinion on the safety of caffeine

“…When caffeine intake was analysed as a continuous variable, the risk of FGR increased exponentially up to 30 mg per day and linearly thereafter, and no threshold was identified (CARE Study Group, 2008). The association between caffeine intake and FGR did not appear to be mediated by nausea and vomiting during pregnancy (Boylan et al, 2013). Caffeine intake was also associated with an increased risk of late miscarriage or stillbirth (Greenwood et al, 2010).…”

Maternal caffeine intake during pregnancy is associated with risk of low birth weight: a systematic review and dose-response meta-analysis

“…Nonetheless, in a recent large cohort study by Sengpiel et al ., the observation that higher maternal caffeine intake was associated with higher SGA risk was not affected by adjustment for nausea [ 9 ]. Furthermore, in the CARE study nausea and vomiting in pregnancy was not associated with fetal growth restriction and did not modify the association between maternal caffeine intake and fetal growth restriction [ 59 ].…”

Caffeine intake during pregnancy and adverse birth outcomes: a systematic review and dose–response meta-analysis

“…Though caffeine metabolism may be moderated by CYP1A2 activity, smoking status, or nausea [25], numbers of studies reporting stratified analyses were too few to enable investigation of effect modification by these factors. We conducted sensitivity analysis excluding potentially highly influential studies and studies that might be considered materially different.…”