Aim:  To compare maternal and neonatal outcomes of Tibetan and Han Chinese women delivering vaginally at high altitude (3650 meters) in Lhasa, Tibet Autonomous Region, People's Republic of China.
Method:  Comparative analysis of data from a prospective observational study of Tibetan (n = 938) and Han Chinese (n = 146) women delivering at three hospitals between January 2004 and May 2005.
Results:  Han Chinese women had higher rates of pre-eclampsia/gestational hypertension than Tibetan women, (10.3% vs 5.9%, P = 0.04). There was no difference in rates of postpartum hemorrhage between Tibetan and Han women (12.8% vs 17.1%, P = 0.15). Han newborns weighed significantly less than Tibetan newborns (P < 0.01), and were twice as likely to be small for gestational age, (24.5% vs 11.6%, P < 0.01). Tibetan newborns were less likely to have poor neonatal outcomes than Han newborns (P < 0.01).
Conclusion:  In high altitude deliveries in Tibet, adverse outcomes were significantly more common among Han Chinese.