Intrapartum-related perinatal mortality risks have fallen, but not among women who attempt to undergo home birth, according to an analysis of birth data in England and Wales between 1994 and 2003.
The analysis, which the researchers stressed had “substantial limitations and should be treated with caution,” indicated that although the intrapartum-related perinatal mortality (IPPM) rate overall was generally low among the women who “booked” or intended to have a home birth, IPPM rates were significantly higher in subsets of women who attempted to give birth at home.
The findings were reported in the April 2 issue of BJOG: An International Journal of Obstetrics and Gynaecology.
The rate of IPPM (defined as deaths from intrapartum “asphyxia,” “anoxia,” or “trauma,” and including stillbirths and deaths that occurred in the first week) was highest among the women who planned to have a home birth but had to transfer their care to a hospital during pregnancy or labor, wrote Dr. Rintaro Mori and associates at the National Collaborating Centre for Women's and Children's Health, London.
Overall, 4,991 intrapartum perinatal deaths occurred among 6,314,315 births. The IPPM rate was 0.79 per 1,000 births, compared with 0.96 per 1,000 actual home births (intended and unintended home births combined) and 1.28 per 1,000 intended home births (those who completed a home birth or had planned to deliver at home but had to transfer).
They also looked at the IPPM rate in three subgroups. The rate was 0.48 per 1,000 births among those who intended to have home birth and completed it at home, compared with 6.05 per 1,000 births among those who planned to have a home birth but transferred their care to a hospital and 1.24 per 1,000 births among those who did not intend to have a home birth (BJOG 2008;115:554–8).
“Although the women who had intended to give birth at home and did so had a generally good outcome, those requiring transfer of care appeared to do significantly worse,” with IPPM rates “well in excess of the overall rate,” the authors observed, noting that they could not determine whether the women had been transferred during pregnancy or at the onset of labor.
The investigators speculated that the improvement in overall IPPM rates might have been due to improvements in clinical care.
The authors listed limitations of the study, including selection bias and potential confounding factors, such as the likelihood that women with risk factors would be advised to plan a hospital birth.
Ideally, they wrote, it would be best to compare the IPPM rates for women who planned a home birth to women at the same risk level who planned to deliver in the hospital, but these data are not available.
The results “certainly indicate the need for further prospective research to evaluate the relative safety of home birth,” they wrote, adding that it was “vital” to collect data prospectively to accurately determine intended and unintended home birth rates, and when and why transfer to a hospital takes place.
Dr. Mori, the lead author of the study, is now at the Osaka (Japan) Medical Center and Research Institute for Maternal and Child Health.