BACKGROUND: The choice to give birth at home with a regulated midwife in attendance became available to expectant women in British Columbia in 1998. The purpose of this study was to evaluate the safety of home birth by comparing perinatal outcomes for planned home births attended by regulated midwives with those for planned hospital births. METHODS: We compared the outcomes of 862 planned home births attended by midwives with those of planned hospital births attended by either midwives (n = 571) or physicians (n = 743). Comparison subjects who were similar in their obstetric risk status were selected from hospitals in which the midwives who were conducting the home births had hospital privileges. Our study population included all home births that occurred between Jan. 1, 1998, and Dec. 31, 1999. RESULTS: Women who gave birth at home attended by a midwife had fewer procedures during labour compared with women who gave birth in hospital attended by a physician. After adjustment for maternal age, lone parent status, income quintile, use of any versus no substances and parity, women in the home birth group were less likely to have epidural analgesia (odds ratio 0.20, 95% confidence interval [CI] 0.14-0.27), be induced, have their labours augmented with oxytocin or prostaglandins, or have an episiotomy. Comparison of home births with hospital births attended by a midwife showed very similar and equally significant differences. The adjusted odds ratio for cesarean section in the home birth group compared with physician-attended hospital births was 0.3 (95% CI 0.22-0.43). Rates of perinatal mortality, 5-minute Apgar scores, meconium aspiration syndrome or need for transfer to a different hospital for specialized newborn care were very similar for the home birth group and for births in hospital attended by a physician. The adjusted odds ratio for Apgar scores lower than 7 at 5 minutes in the home birth group compared with physician-attended hospital births was 0.84 (95% CI 0.32-2.19). INTERPRETATION: There was no increased maternal or neonatal risk associated with planned home birth under the care of a regulated midwife. The rates of some adverse outcomes were too low for us to draw statistical comparisons, and ongoing evaluation of home birth is warranted.