Relation between reported maternal caffeine consumption during pregnancy and neonatal state and heart rate

Baseline heart rate in infants with prenatal alcohol exposure: A systematic review and independent analysis

BACKGROUND

Infants with fetal alcohol syndrome exhibit a range of developmental anomalies, many related to the heart (e.g., decreased heart rate variability). However, the baseline heart rate in this population remains unclear. We hypothesized that the age at which heart rate was measured or the age during exposure to alcohol affects the baseline heart rate.

METHODS

First, we conducted a systemic review to determine the published heart rate of infants with prenatal alcohol exposure (PAE). Exclusion criteria included potentially confounding factors, including the commonly associated phenotypes of small for gestational age and premature birth. Risk of bias was evaluated based on case study limitations, and data were compared with established heart rate norms. Then, we evaluated the precise age at heart rate measurement using existing datasets from the Collaborative Initiative on Fetal Alcohol Spectrum Disorders and the Maternal Lifestyle Study.

RESULTS

Based on the weighted means of six studies, the baseline heart rate was 4.6 bpm higher in infants with PAE (n = 253) than in control infants (n = 152). Using the individual patient data, baseline heart rates were similar between age-matched infants with PAE and control infants who were born full-term and showed no signs of growth restriction (ANOVA, p > .05; n = 49-124 infants per age and exposure).

CONCLUSIONS

A systematic literature review suggested that heart rate is elevated in infants with PAE, but these findings are limited by the number of studies and how few studies included control infants. The analysis of individual patient data indicates that infants with PAE have normal baseline heart rates. This knowledge may help clinicians detect changes in cardiac function in infants with PAE. (Registered via PROSPERO, #CRD42020191212.).

The impact of caffeine on connexin expression in the embryonic chick cardiomyocyte micromass culture system

Cardiomyocytes are electrically coupled by gap junctions, defined as clusters of low-resistance multisubunit transmembrane channels composed of connexins (Cxs). The expression of Cx40, Cx43 and Cx45, which are present in cardiomyocytes, is known to be developmentally regulated. This study investigates the premise that alterations in gap junction proteins are one of the mechanisms by which teratogens may act. Specifically, those molecules known to be teratogenic in humans could cause their effects via disruption of cell-to-cell communication pathways, resulting in an inability to co-ordinate tissue development. Caffeine significantly inhibited contractile activity at concentrations above and including 1500 μm (P < 0.05), while not affecting cell viability and total protein, in the embryonic chick cardiomyocyte micromass culture system. The effects of caffeine on key cardiac gap junction protein (Cx40, Cx43 and Cx45) expression were analysed using immunocytochemistry and in-cell Western blotting. The results indicated that caffeine altered the expression pattern of Cx40, Cx43 and Cx45 at non-cytotoxic concentrations (≥2000 μm), i.e., at concentrations that did not affect total cell protein and cell viability. In addition the effects of caffeine on cardiomyocyte formation and function (contractile activity score) were correlated with modulation of Cxs (Cx40, Cx43 and Cx45) expression, at above and including 2000 μm caffeine concentrations (P < 0.05). These experiments provide evidence that embryonic chick cardiomyocyte micromass culture may be a useful in vitro method for mechanistic studies of perturbation of embryonic heart development. Copyright © 2015 John Wiley & Sons, Ltd.

Foetal response to maternal coffee intake: role of habitual versus non-habitual caffeine consumption

Little is known about the effect on the human foetus of long-term and acute exposure to caffeine. We studied the organisation of foetal sleep-wake states in 13 healthy near-term foetuses over a wide range of maternal plasma caffeine concentrations (0-13 μg/mL) reflecting normal lifestyle conditions (day 0) and again following intake of two cups of regular coffee (~300 mg of caffeine) intermitted by 50 h of abstinence (day 2; acute effects). On either day, 2 h simultaneous recordings were made of foetal heart rate, general-, eye-, and breathing-movements. The recordings were analysed for the presence of each of four foetal behavioural states: quiet- and active-sleep, quiet- and active-wakefulness. There was a linear relationship between maternal caffeine content and the incidence of foetal general movements during active sleep on day 0 (R = 0.74; P < 0.02). After coffee loading on day 2, foetuses of non- or low-caffeine consumers showed increases in active wakefulness (P < 0.001), general movements (P < 0.05) and heart rate variation (P < 0.01) but lower basal heart rate (P < 0.01) compared with their day 0 values. The changes in foetal heart rate (variation) and behaviour occurred between 90 and 180 min post-consumption. In contrast, foetuses of habitual caffeine consumers remained unaffected suggestive of foetal tolerance to caffeine. The results indicate differential performance between foetuses regularly exposed to caffeine and those caffeine-naive, both under normal maternal lifestyle conditions and in response to maternal coffee ingestion.

The Effects of Alcohol in Breast Milk on Infant Behavioral State and Mother-Infant Feeding Interactions

The short-term impact of infant exposure to alcohol in breast milk on mother-infant interactions and infant arousal was examined. Fourteen mother-infant dyads were tested on 2 occasions that consisted of an alcohol administration and a nonalcohol condition. Mother-infant interactions during feeding were videotaped and coded for dyadic reciprocity, maternal noncontingency, and dyadic conflict. Infants were observed for 1 hr after receiving either plain breast milk or breast milk containing alcohol. Behavioral state, startles, and tremors were recorded every 30 sec. Mother-infant interactions were characterized by higher noncontingency and dyadic conflict in the alcohol condition. After drinking breast milk containing alcohol, infants changed behavioral state more often, startled more, and spent less time in quiet sleep and more time in quiet alert and crying states. These findings suggest that exposure to breast milk containing alcohol may not have a sedating effect, as commonly believed.