Risk of invasive pneumococcal disease during pregnancy and postpartum and association with adverse maternal and foetal outcomes: a prospective cohort study, England, 2014-19

Abstract

BackgroundPneumococcal infections are associated with significant morbidity and mortality, especially at the extremes of age and in those with underlying conditions. Little is known about the risks, presentations or outcomes of invasive pneumococcal disease (IPD) during pregnancy or the postpartum period. MethodsThe UK Health Security Agency conducts enhanced national surveillance of IPD in England. We used national surveillance data to calculate IPD risk and outcomes in pregnant, postpartum and non-pregnant women of childbearing age with IPD over a five-year period in England. FindingsThere were 1,701 IPD cases in women aged 15-44 years between 1 July 2014 and 30 June 2019, including 123 (7.2%) pregnant, 38 (2.1%) postpartum and 1,540 (90.7%) non-pregnant women. IPD incidence in pregnant women (0.048/1,000 woman-years) was not significantly different compared to non-pregnant women (0.041/1,000 woman-years; Incidence Rate Ratio [IRR]: 1.17; 95%CI 0.96-1.40; p=0.11). When stratified by trimester, however, women in their third trimester had a 2.27-fold (95%CI 1.79-2.85, p<0.001) increased risk of IPD, compared to non-pregnant women (IRR 2.27, 95%CI 1.78-2.85, p<0.001), while those in the first (IRR 0.49, 95%CI 0.28-0.80) and second trimester (IRR 0.71, 95%CI 0.47-1.04) had a lower risk, albeit only statistically significant for the first trimester. Postpartum women (0.144 per 1,000 woman-years), on the other hand, had a 3.49-fold (95%CI 2.46-4.81, p<0.001) higher IPD risk than non-pregnant women.Most pregnant women developed IPD during their third trimester (80/123, 65.0%), with all but one pregnancy resulting in a live birth. IPD in the second trimester was associated with live birth in 77.8% cases (21/27), while 22.2% experienced a miscarriage (5/27, 18.5%) or stillbirth (1/27, 3.7%). IPD in the first trimester was associated with live birth in 41.7% cases (5/12), miscarriages in 41.7% (5/12), and termination in 16.7% (2/12) cases. Only three neonates (3/142) had confirmed IPD. There were no deaths in pregnant women with IPD compared to 5.5% (85/1,540) in non-pregnant women. InterpretationWhile pregnant women overall did not appear to have an increased risk of IPD compared to non-pregnant women, those infected in third trimester appeared to have more than three times the incidence. Most pregnant and postpartum women had a live birth and subsequent neonatal infection was rare, occurring in 2% live births.