Intimate partner violence, multiple mental health conditions and risk of small vulnerable newborn births: a maternity population-based data linkage study

<h2>Summary</h2><h3>Background</h3> Small vulnerable newborn birth (SVN) encompasses infants born preterm, small for gestational age, or low birthweight, and accounts for most neonatal deaths worldwide. This maternity population-based administrative data-linkage cohort study aimed to estimate the risk of SVN associated with maternal intimate partner violence (IPV) experience. <h3>Methods</h3> Records were included for women who accessed maternity services in Northern Ireland and had a singleton pregnancy, with liveborn or stillborn infants born 24–42 weeks' gestation, with an estimated pregnancy start date 01 January 2011–31 December 2021. Pregnancy records were linked to community-dispensed prescriptions and hospital diagnoses data. Data were provided by the Honest Broker Service. IPV, maternal characteristics, and SVN were ascertained through maternity records. Mental health conditions were ascertained via medications or ICD-10 hospital diagnosis codes. Generalised estimating equations were utilised to perform modified Poisson regression with a log link, with clustering to account for women with more than one pregnancy during the study period. The risk of SVN given exposure to IPV was estimated, adjusted for number of mental health conditions and additional maternal characteristics. <h3>Findings</h3> From 248,645 eligible pregnancies to 157,507 individual women, IPV was disclosed in 11,388 (4.6%) pregnancies (active: n=3713, 1.5%; historical: n=7675, 3.1%). The group with highest prevalence of IPV was pregnant adolescents (n = 995, 12.2%). Disparate prevalence estimates were also seen between the most (8.5%) and least (1.9%) deprived areas. Risk of SVN was increased for women reporting both active IPV (RR = 1.21, 95% CI: 1.13–1.31) and historical IPV (RR = 1.18 (95% CI: 1.12–1.25) independent of the number of coexisting mental health conditions and other maternal characteristics. <h3>Interpretation</h3> IPV, both active and historical, is associated with an increased risk of birth of babies who are small and vulnerable, and so its detection, even IPV of historical nature, and response should be prioritised through training and creation of referral pathways. <h3>Funding</h3> UKRI's ADRC NI (ES/W010240/1) & Strategic Priority Fund "Tackling multimorbidity at scale" programme (MR/W014432/1).