Abstract: The study was performed to confirm the progress of pregnancy and labor in relation to maternal age and find the factors related to neonatal asphyxia in primigravidas and primiparas aged 35 or older and determine way of delivery to reduce neonatal asphyxia in older women with such factors. Background: Primigravidas and primiparas aged 35 and older have higher risks compared with younger women. With aging of the mother, maternal mortality rate is higher, incidence of pregnancy complications such as placenta previa, abruption, preterm delivery, low birth weight and hypertension are higher compared with that of younger women. Therefore it is important to manage well such high risk pregnancies. Objects and methods: 272 primigravidas and primiparas over 35 years of age and 491 women less than 35 years were studied. χ2 test, T - test and Odds Ratio - test (OR - test) and 95% - confidence interval (95% CI) were applied for analysis. Results: Incidences of severe pregnancy-induced hypertension, a grade 3 placenta, abnormal Nonstress Test (NST), positive Contraction Stress Test (CST), neonatal asphyxia in primigravidas and primiparas aged 35 or older were significantly higher compared with that of younger women and labor time in women over 35 years of age was significantly longer than younger women. And the factors related to neonatal asphyxia in primigravidas and primiparas aged 35 or older were severe pregnancy-induced hypertension, a grade 3 placenta, abnormal NST and positive CST, and rate of neonatal asphyxia could be reduced by 2.1% by cesarean section in older women with such factors.Abstract: The study was performed to confirm the progress of pregnancy and labor in relation to maternal age and find the factors related to neonatal asphyxia in primigravidas and primiparas aged 35 or older and determine way of delivery to reduce neonatal asphyxia in older women with such factors. Background: Primigravidas and primiparas aged 35 and older h...Show More