1. Folic acid supplementation in early pregnancy and preeclampsia: Preeclampsia is hypertension that develops in pregnancy with proteinuria, affecting at least 5% pregnancies worldwide. In a cohort study, we found that supplementation of folic acid was associated with major reduction in the risk of preeclampsia (Wen et al, AJOG, 2008). This protective effect of folic acid will have huge impact on the prevention of preeclampsia.
2. Selective serotonin reuptake inhibitors (SSRIs) in pregnancy and adverse outcomes: SSRIs are generally considered the first-line drug therapy in most patients with depression. In a large population-based study (Wen et al, AJOG, 2006), we found that SSRIs in pregnancy was associated with increased risks of low birth weight, preterm birth, fetal death, and seizures.
3. Severe maternal morbidity: We developed a set of indicators that included thirteen conditions that may threaten the life of the mother identified from diagnostic codes from the hospital discharge abstract (Wen et al, CMAJ, 2005). We found that these severe maternal conditions occurred in about 1 of 250 deliveries.
4. Vaginal birth after cesarean delivery: In a cohort study, we found the rates of uterine rupture, transfusion, and hysterectomy were significantly higher in the trial-of-labor group while maternal in-hospital death rate was lower in the trial-of-labor group than in the elective cesarean section group. The results of this study provided useful information for physicians and mothers in a very important decision-making for childbirth.
5. Optimal management of twin pregnancy: In a series of studies, we assessed the fetal risks associated with twin delivery, including emergent cesarean delivery in the second twin (Wen et al OB/GY, 2004, Wen et al, AJOG, 2004c,d, Yang et al, AJOG, 2005a,Yang et al, AJP, 2006a), operative vaginal delivery of the first twin on the second twin (Yang et al, AJOG, 2005b, Yang et al, AJP, 2006b), and optimal gestational age (Soucie et al, AJOG, 2006) and interval for the delivery of twins (Edris et al, AJP, 2006).