Pregnancy, delivery and perinatal outcome in female survivors of polio

Abstract

Objective To investigate possible effects on pregnancy, delivery and perinatal outcome in female survivors of polio. Methods In a cohort design, data from the national population based Medical Birth Registry of Norway (MBRN) were used to compare all 2495 births recorded 1967–1998 by female survivors of polio with all 1.9 mill non-polio deliveries. The results were adjusted for time period, maternal age, and birth order by unconditional logistic regression, with effects presented as adjusted Odds Ratios (OR) with a corresponding 95% Confidence Interval (CI) and p values. Results Female polio survivors had a higher occurrence of pre-eclampsia (3.4% vs. 2.8%, p = 0.003, OR = 1.4, CI = 1.1–1.7), gestational proteinuria (1.3% vs. 0.5%, p < 0.001, OR = 2.0, CI = 1.4–2.8), renal disease prior to pregnancy (1.4% vs. 0.9%, p = 0.001, OR = 1.8, CI = 1.2–2.5), vaginal bleeding (3.8% vs. 2.0%, p < 0.001, OR = 1.7, CI = 1.4–2.1), and urinary tract infection during pregnancy (3.5% vs. 2.4%, p < 0.001, OR = 1.7, CI = 1.4–2.1). Deliveries complicated by obstruction of the birth process were more common in the polio group (6.1% vs. 2.0%, p < 0.001, OR = 4.8, CI = 4.0–5.6), and cesarean section was performed at a higher rate throughout the time period (13.2% vs. 8.3%, p < 0.001, OR = 2.7, CI = 2.4–3.1). Infants of polio mothers had a lower mean birth weight (3383 g vs. 3483 g, p < 0.001), and more often had a birth weight below 2500 g (6.9% vs. 5.2%, p = 0.001, OR = 1.3, CI = 1.1–1.5). There was no difference regarding pregnancy length. The risk of perinatal death was increased (2.1% vs. 1.1%, p = 0.05, OR = 1.3, CI = 1.0–1.7). Conclusion Pregnancy in female survivors of polio is associated with an increased risk for complications during pregnancy and delivery, as well as an adverse perinatal outcome. Awareness towards risk factors should improve pre-natal care and possibly prevent complications.