Caffeine intake and fetal health

Caffeine and fetal growth

Studies of caffeine and fetal growth restriction are equivocal. Some studies showed no effects on growth, whilst others demonstrated a risk of growth retardation with increased exposure to caffeine, although with the inability to determine the role of confounding factors^1,20,21.

The 2010 Committee Opinion of the American College of Obstetricians and Gynecologists (reaffirmed in 2023) stated that the relationship between caffeine and growth restriction remains undetermined²⁵.

A 2015 meta-analysis reviewing the associations between caffeine consumption and risk of low birth weight concluded that for every additional 100mg of caffeine per day the risk of low birth weight increased by 3%²⁶. However, a 2015 Cochrane review of the effect of restricting caffeine intake by mothers concluded that there is insufficient data to confirm or refute the effectiveness of caffeine avoidance on birthweight or other pregnancy outcomes¹⁸.

A 2023 dose-response meta-analysis suggested a significant positive association between maternal caffeine intake and risk of low birth weight. It also suggested that each additional 100mg per day of caffeine intake was associated with an increased risk of low birth weight²⁷.  

Caffeine and congenital malformations

Brent et al. concluded in their risk analyses that it is very unlikely that regular or even high exposures to dietary caffeine increase the risk of birth defects for pregnant mothers exposed to caffeine²¹. With a few exceptions, studies have not reported an increased risk of malformations with greater caffeine consumption.

One paper reported weak positive associations between maternal caffeine consumption and spina bifida (neural tube defect), but without a dose-effect relationship and with a negative association for tea. However, the authors suggested control for confounding by smoking and alcohol may be insufficient¹¹. A further case-control study, with 776 cases and 8,756 controls, concluded that cigarette smoking, alcohol intake and caffeine intake were not likely to be associated with increased risk of spina bifida¹². Additionally, a further study suggested that gene variants like slow/fast caffeine metabolisers may run different risks¹³.

A 2015 meta-analysis considering maternal coffee consumption and the incidence of neural tubedefects (NTD), suggested that maternal coffee consumption during pregnancy was not significantly associated with the occurrence of total NTD or the spina bifida subtype of NTD¹⁴.

A 2011 study did not suggest an association between maternal caffeine intake and birth defects²⁸. A further study suggested that coffee and tea consumption was not associated with any limb deficiency subtype²⁹.

Caffeine and fetal death

Four studies detailed in a review of data gathered between 2000 and 2009 evaluated the relationship between caffeine and fetal death¹. Three of the studies were conducted by the same research group, in which two reported a moderately positive association and the third found no relationship. The fourth study also noted a positive association. None sufficiently address the concerns regarding confounding by pregnancy symptoms. As with studies of miscarriage, the interpretation of the work on caffeine and fetal death needs to consider that these studies may also share common sources of bias which may explain the observed relationship with caffeine use¹.

A 2022 meta-analysis suggested that caffeine intake during pregnancy was associated with a higher relative risk of pregnancy loss in cohort and case-control studies in a non-linear association²². The dose-response analysis suggested that an increase of one cup of coffee per day during pregnancy was associated with 3% increased risk of pregnancy loss²². Likewise, increased intake of 100mg of caffeine per day during pregnancy increased the risk of pregnancy loss by 14% and 26% based on cohort and case-control studies respectively²². The authors suggested that more research was required to understand the mechanisms that may be involved.

Maternal coffee consumption and childhood leukemia

There are limited studies in this area, and while some research suggests an association between consumption of coffee during pregnancy and subsequent increased risk of childhood leukemia, more research is needed to better understand this. Pregnant and breastfeeding women are advised by EFSA to drink no more than 200mg of caffeine per day from all sources, which is equivalent to 2-3 cups of coffee⁴.

In 2016 IARC reviewed data on childhood leukemia in relation to coffee consumption and concluded that a lack of consistency amongst studies led to inconclusive and inadequate evidence of any association between coffee consumption and childhood leukemia³⁰.

• Authors of a 2015 meta-analysis comprising a total of 3,649 cases and 5,705 controls concluded that their findings “confirm the detrimental association between maternal coffee consumption and childhood leukemia risk, and provide indications for a similar role for maternal cola consumption”³¹

• A further study published in 2015 examining parental smoking, maternal alcohol, coffee and tea consumption during pregnancy, and childhood acute leukemia concluded that childhood acute leukemia was not associated with coffee consumption during pregnancy, but an association was seen between coffee consumption and acute lymphoblastic leukemia³²

• A 2018 review of data on maternal coffee intake in 2,552 cases and 4,876 controls suggested that coffee intake over 2 cups per day during pregnancy may increase risk of childhood acute lymphoblastic leukemia, although the authors acknowledged that there were limitations in the research. They supported current advice to limit caffeine intake during pregnancy³³