Background: Low birth weight remains the primary cause of neonatal morbidity and mortality in the United States. We examined whether maternal happiness about a pregnancy, in addition to her report of the father's happiness, predicts birth weight and risk for low birth weight (<2,500 g).
Methods: In this prospective cohort study, the mother's report of her and her partner's happiness about the pregnancy was measured before 21 weeks' gestation on a scale from 1 to 10 (1 to 3 unhappy, 4 to 7 ambivalent, or 8 to 10 happy). "Mother reports partner happier" occurred when the mother perceived the father's happiness score at least 5 points greater than her own. Information on birth weights and maternal sociodemographic, medical, and psychosocial factors were obtained from surveys and medical records.
Results: Of 162 live births, 9 were low birth weight (5.6%). Compared with women who reported happiness with the pregnancy, risk for low birth weight was greater when the mother reported partner happier about the pregnancy (relative risk 10.0, 95% confidence interval, 3.1-32.4). This predictor of birth weight remained significant in multivariate linear regression analyses (coefficient = -472 g, SE = 171 g, P = .007) after adjustment for other known predictors of birth weight.
Conclusions: Maternal report of greater partner happiness about a pregnancy is associated with birth weight and appears to define low- and high-risk subgroups for low birth weight in a low-income population. Further study in larger samples is needed to confirm our findings and to assess whether maternal report of greater partner happiness is itself a modifiable factor or is a marker for other factors that might be modified with targeted interventions.