Risk of Tuberculosis in Pregnancy: A National, Primary Care Based Cohort and Self-Controlled Case Series Study

Objective: Tuberculosis (TB) disease adversely affects mother and child, and strategies to control TB inthis group are important. The aim of this study was to analyse the epidemiology of TB in pregnancy, and establish whether pregnancy is an independent risk factor for TB. Methods: The UK-wide cohort study was based on the General Practitioner Research Database (GPRD),enrolling all women with pregnancies between 1996 and 2008. Incidence rates (IR) andratios (IRR) of TB events during pregnancy, 6 months post-partum, and outside pregnancy were calculated and compared using Poisson regression. A nested self-controlled case series (SCCS) compared the risk of TB in these periods, adjusting for individual and time-bound confounders. Results: The crude TB rate for the combined pregnancy and post-partum period was 15.4 per100,000 person years (py), significantly higher than outside of pregnancy (9.1 per 100,000py, p=0.02). Adjusting for age, region and socio-economic status the post-partum TB risk was significantly higher than outside pregnancy (IRR 1.95, CI 1.24-3.07), whereas there was nosignificant increase during pregnancy (IRR 1.29, CI 0.82-2.03). These observations wereconfirmed in the SCCS (IRR 1.62, CI 1.01-2.58 and 1.03, CI 0.64-1.65 respectively). Conclusions: The incidence of TB diagnosis is significantly increased post-partum. Although we did notfind an increase during pregnancy, the post-partum incidence may reflect an increase during pregnancy given diagnostic, immunological and administrative delays. Clinicians’ awareness should be improved and the effectiveness of public health policy measures such as targeted screening of pregnant and post-partum women in high-risk groups should be evaluated. Mesh Terms: Pregnancy, Tuberculosis, Risk Factors, incidence studie