Maternal ADHD Diagnoses Before and After Childbirth: A Danish Population-Based Cohort Study

The rates of women of reproductive age diagnosed with ADHD have increased significantly. However, little is known about how pregnancy, childbirth, and the postpartum period influence ADHD related problems, help-seeking behaviors or the timing of ADHD diagnosis. This study aimed to investigate incident ADHD diagnoses among women from 5 years before to 5 years after childbirth.

The population-based cohort study utilized Danish nationwide registers to identify mothers of all childbirths between 2010 and 2018. ADHD diagnoses, defined as ICD-10 codes (F90 or F98.8) or redemption of ADHD medication prescriptions, were recorded during 1994 to 2023. Women who received an ADHD diagnosis prior to the five-year pre-birth period were excluded. We estimated calendar-year adjusted incidence of first-time maternal ADHD diagnoses using Poisson regression, and compared incidence across pre-pregnancy, pregnancy, postpartum up to 2 years, and 2 to 5 years postpartum, reporting adjusted incidence rate ratios (IRRs). Analyses included psychiatric comorbidities and non-ADHD psychotropic medication use prior to an ADHD diagnosis, for women diagnosed with ADHD postpartum.

The study included 363,904 mothers with a total of 524,936 childbirths. ADHD incidence rates decreased significantly during pregnancy (IRR = 0.28, 95% CI [0.22, 0.37]), remained lower than the pre-pregnancy period 2 years postpartum (IRR 0.82, 95% CI [0.74, 0.92]), and increased significantly above pre-pregnancy levels 2 to 5 years postpartum (IRR = 1.24, 95% CI [1.13, 1.35]). Among mothers diagnosed with ADHD postpartum, 53.9% had an in- or outpatient contact to psychiatric services or redeemed non-ADHD psychotropic medication prescriptions, in the period from childbirth until ADHD diagnosis.

Incident ADHD diagnoses among women giving birth increased postpartum above pre-pregnancy levels, with peak rates observed between 2 and 5 years after childbirth. These findings highlight the postpartum period as a potential critical window of ADHD symptom worsening, underscoring the need for targeted mental health screenings and support for women during the years after childbirth.