Maternal genetic liability for neuroticism and breastfeeding intention, initiation and maintenance

Relationships between maternal mental health and breastfeeding outcomes are complex, with evidence of bi-directional effects complicated by culturally specific residual confounding and selection bias.

This study aimed to examine, for the first time, associations between maternal genetic liability for neuroticism and breastfeeding intention, initiation and maintenance.

We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC) prospective birth cohort. Maternal genotype data were used to create polygenic scores (PGS) for neuroticism. Mothers self-reported breastfeeding intentions at 32 weeks gestation, breastfeeding initiation within the first week after birth and maintenance of breastfeeding to 6 months after birth. We examined associations between maternal genetic liability for neuroticism and breastfeeding outcomes by using unadjusted logistic regression models (n = 4611). We also examined associations between paternal genetic liability for neuroticism and breastfeeding outcomes as a negative control (n = 1446).

There was evidence that genetic liability for neuroticism was associated with lower odds for breastfeeding maintenance (odds ratio 0.86, 95% CI 0.83-0.94, p < 0.001), with no evidence for associations with intention or initiation. That is, mothers with higher genetic liability for neuroticism were less likely to maintain breastfeeding to 6 months postpartum. There were no associations between paternal PGS for neuroticism and breastfeeding outcomes.

The specificity of links between neuroticism and maintenance of breastfeeding could direct targeting of efforts to support women with emotional difficulties in maintaining breastfeeding. This is important because currently, most efforts to support breastfeeding women focus on intention and initiation.