Facilitating safety evaluation in maternal immunization trials: a retrospective cohort study to assess pregnancy outcomes and events of interest in low-risk pregnancies in England

• DOI: 10.1186/s12884-022-04769-x
• Publication Date: 2022-06-01T09:02:46Z
• Authors: Megan Riley; Dimitra Lambrelli; Sophie Graham; Ouzama Henry; Andrea Sutherland; Alexander Schmidt; Nicola Sawalhi-Le...; Robert Donaldson; Sonia K. Stoszek
• Keywords: Pregnancy outcomes; Research; Vaccination; Background rate; Infant, Newborn; Pregnancy Outcome; Infant; Maternal vaccination; Gynecology and obstetrics; Miscarriage; 3. Good health; Abortion, Spontaneous; Low-risk pregnancy; Maternal immunization trial; 03 medical and health sciences; 0302 clinical medicine; England; Pregnancy; RG1-991; Humans; Female; Uterine Hemorrhage; Retrospective Studies

Abstract Background Maternal characteristics like medical history and health-related risk factors can influence the incidence of pregnancy outcomes pregnancy-related events interest (EIs). Data on these endpoints in low-risk pregnant women are needed for appropriate external safety comparisons maternal immunization trials. To address this need, study estimated proportions EIs different cohorts (including pregnancies) England, contained Clinical Practice Research Datalink (CPRD) Pregnancy Register linked to Hospital Episode Statistics (HES) between 2005 2017. Methods The 7 15 were calculated for: (1) all pregnancies (AP) represented CPRD HES (AP cohort; N = 298 155), (2) with a gestational age (GA) ≥ 24 weeks (AP24+ 208 328), (3) (LR 137 932) GA no diagnosis predefined high-risk conditions until GA. Results Miscarriage was most common adverse outcome AP cohort (1 379.5 per 10 000 but could not be assessed other because only included weeks, miscarriages reclassified as stillbirths. Preterm delivery (< 37 GA) AP24+ LR (742.9 680.0 pregnancies, respectively). Focusing fetal/perinatal distress or asphyxia 824.3 1 833.0 pregnancies), vaginal/intrauterine hemorrhage (799.2 729.0 labor protraction/arrest disorders (752.4 774.5 pregnancies). Conclusions This generated from cohorts, including pregnancies. reported largely consistent estimates. These results may facilitate interpretation data trials monitoring vaccines. They also any intervention studied populations women.