Maternal depression during pregnancy is associated with increased birth weight in term infants

Abstract

Previous research of maternal depression during pregnancy suggests an association with low birth weight in newborns. Review of these studies reveals predominant comorbidity with premature birth. This current study examines antenatal depression and birth weight in term, medically low-risk pregnancies. Maternal physiological and demographic measures were collected as well. In total, 227 pregnant women were recruited to participate in four experimental protocols at Columbia University Medical Center. Results indicate that depressed pregnant women who carry to term had significantly higher heart rates, lower heart rate variability, and gave birth to heavier babies than those of pregnant women who were not depressed. Low income participants had significantly higher levels of depression, as well as significantly higher heart rates and lower heart rate variability, than those in higher income groups. In full-term infants, maternal prenatal depression appears to promote higher birth weight, with elevated maternal heart rate as a likely mediating mechanism.

Keywords: birth weight; heart rate; heart rate variability; maternal depression; neonatal outcomes; newborn; pregnancy; prenatal depression.

© 2016 Wiley Periodicals, Inc.

Figures

Figure 1

Depression and resting maternal heart rate (p<.001 and heart rate variability not depressed n="128," maternal beat-to-beat are adjusted residuals after regression in which study was entered as the predictor variable. error bars represent sem.>

Figure 2

Maternal heart rate, heart rate variability and depression in the context of maternal prepregnancy BMI. Heart rate variability (RMSSD) is the root mean square of successive differences in R-to-R intervals, i.e., beat-to-beat variability, a time domain index of vagal modulation of heart rate (Berntson, et al., 1997). BMI categories based on cutoffs established by the Center for Disease Control and Prevention (2014) – Underweight N=7 (below 18.5) Normal weight N=87 (18.5 to 24.9) Over weight N=46 (25 to 29.9) Obese N=30 (30 and above). Significant main effect for depression (p=.006) but not BMI. Error bars represent ± 1 SEM.

Figure 3

Income and resting maternal heart rate (p=.007) and heart rate variability (p=.02). As previously stated, maternal heart rate and beat-to-beat variability (RMSSD) are adjusted residuals after regression in which study was entered as the predictor variable. Sample size for each income category is given in Table 1. Error bars represent ± 1 SEM.

Figure 4

Birth weight by maternal heart rate (p=.013) and heart rate variability (p<.001 n="69" for each tertile. birth weight is adjusted residuals after regression in which gestational age and sex were entered as the predictor variables. error bars represent sem.>

Figure 5

Estimated standardized path coefficients for the effect of depression on birth weight. 35% of variance in heart rate is accounted for by the mediating effects of heart rate variability; 5% of the variability in birth weight is accounted for by the mediating effects of heart rate.