- The objective was to evaluate the contribution of hydramnios and small for gestational age (SGA) as a combined pathology to maternal and neonatal morbidity and mortality. The study population consisted of 192 SGA neonates with hydramnios, 5,515 SGA neonates with a normal amount of amniotic fluids, 3,714 appropriate for gestational age (AGA) neonates with polyhydramnios and 83,763 AGA neonates with a normal amount of amniotic fluid. A cross-sectional population based study was designed between the four study groups. Multiple logistic regression analysis was used to assess the contribution of these abnormalities and different risk factors to maternal and perinatal complications. The combination of hydramnios/SGA was found to be an independent risk factor for perinatal mortality (OR 20.55; CI 12.6-33.4). Congenital anomalies, prolapse of cord, hydramnios, SGA and grand multiparity were also independent risk factors for perinatal mortality. Independent risk factors for neonatal complications were prolapse of umbilical cord (OR 4.13; 95% CI 1.48-11.5), hydramnios/SGA (OR 2.72; 95% CI 1.81-4.07), chronic hypertension (OR 2.45; 95% CI 1.02-5.9), congenital malformations (OR 1.93; 95% CI 1.14-3.24) and SGA (OR 1.47; 95% CI 1.07-2). Significant independent risk factors for medical interventions during labor were fetal distress (OR 198.46; 95% CI 47.27-825.27), GDM Class B-R (OR 21.22; 95% CI 2.34-192.25), GDM class A (OR 4.64; 95% CI 2.62-8.21), severe pregnancy-induced hypertension (PIH; OR 7.74; 95% CI 2.35-25.42), hydramnios (OR 1.95; 95% CI 1.3-2.91), hydramnios/SGA (OR 1.84; 95% CI 1.12-3.02) and malpresentation (OR 1.56; 95% CI 1.32-1.84). The combination of hydramnios and SGA is an independent risk factor for perinatal mortality and maternal complications. We suggest that the growth restriction of these fetuses is responsible for the neonatal complications, while the hydramnios contributes mainly to maternal complications.