Maternal Postnatal Depression and Completion of Infant Immunizations: A UK Cohort Study of 196,329 Mother-Infant Pairs, 2006-2015.

Objective: To examine the relationship between maternal postnatal depression and completion of infant vaccinations. Methods: We conducted a cohort study using data from The Health Improvement Network (THIN), a large UK primary care electronic health record database. We identified 196,329 mother-infant pairs in which the infant was born between 2006 and 2015. Postnatal depression was identified through antidepressant prescriptions or diagnoses or symptoms of depression in first year after childbirth. Primary outcome was completion of three 5-in-1 vaccination doses in infants before 1 year of age; this vaccine protects against diphtheria, tetanus, whooping cough, polio, and Haemophilus influenzae type b. We used Poisson regression models to compare likelihood of infant 5-in-1 vaccine uptake among children of women with a record of postnatal depression to likelihood among those without. Results: Of the 196,329 women, 20,802 (10.6%) had a record of postnatal depression and/or antidepressant prescription. There was no difference in infants' 5-in-1 vaccination completion between those of mothers with a record and those of mothers' without (adjusted incidence rate ratio [IRR]  = 1.01; 95% CI, 0.99-1.02). Those from more socially deprived areas were less likely to complete infant vaccinations compared to those from the least deprived areas (IRR = 0.92; 95% CI, 0.90-0.93). Likelihood of completing infant vaccination decreased over time, comparing 2014-2015 to 2006-2007 (IRR = 0.90; 95% CI, 0.89-0.92). Conclusions: Among mothers who engage with primary care, maternal postnatal depression is not associated with lower rates of infant vaccination, though more research is needed to conclude if either more severe depression or unrecognized depression is associated with lower completion rates.