First trimester prediction and prevention of preterm preeclampsia and fetal growth restriction

Background Preterm preeclampsia and fetal growth restriction are significant contributors to morbidity and mortality for pregnant women and their infants. Interventions that alter the course of these two obstetric complications once they are established, are currently limited. Identifying pregnancies at increased risk of developing preterm preeclampsia and growth restriction by screening in the first trimester of pregnancy may allow interventions that prevent or alter the course of disease and improve outcomes. Methods This thesis contains a series of analyses of screening and intervention undertaking in the first trimester of pregnancy. It includes data from over 11,000 pregnancies. Analyses included: 1) Examination of the performance of an algorithm for prediction of preterm preeclampsia 2) Examination of the performance of an algorithm for prediction of small for gestational age neonates. 3) A cohort analysis of the effect of aspirin prescribed to women who screened high risk for preterm preeclampsia in the first trimester of pregnancy reporting on the prevalence of preterm preeclampsia. 4) A cohort analysis of the effect of aspirin prescribed to women who screened high risk for preterm preeclampsia in the first trimester of pregnancy reporting on the prevalence of small for gestational neonates 5) A cost effectiveness analysis comparing first trimester screening for preeclampsia to usual care. Results The key findings of this thesis are: 1) First trimester screening for preterm preeclampsia identified 90% of pregnancies that developed preeclampsia requiring delivery prior to 34 weeks for a 10% screen positive rate. These results indicate good performance of this screening algorithm in our population. 2) First trimester screening for small for gestation age (SGA) neonates did not perform well in our population. Only 15% of preterm and 23% of term small for gestational age neonates were predicted for a screen positive rate of 10%. 3) Prescription of aspirin to women who screened high risk for preterm preeclampsia in the first trimester of pregnancy reduced the rate of preterm preeclampsia by 90% from 0.4% in the observational group to 0.04% in the intervention group p