Crude and adjusted odds ratios for adverse maternal and perinatal outcomes in twins versus singleton pregnancies.

1Severe adverse maternal outcome index: maternal death, admission to ICU, blood transfusion or hysterectomy.*Odds ratio adjusted for maternal age, maternal education, marital status, parity, antenatal visits, malaria, prelabour premature rupture of membranes, chronic hypertension, pregnancy-induced hypertension, pre-eclampsia, eclampsia, vaginal bleeding in 2nd half of pregnancy, mode of delivery and facility (as random effect).†odds ratio adjusted for maternal age, maternal education, marital status, parity, antenatal visits, mode of delivery, chronic hypertension, malaria, prelabour premature rupture of membranes, pregnancy-induced hypertension, pre-eclampsia, eclampsia, vaginal bleeding in 2nd half of pregnancy, severe anaemia, infant sex, birth order, fetal presentation, facility (as a random effect) and clustering effect of twin neonates.