Homebirth Under Fire: What the Headlines Don't Say

By Jill MacCorkle
Issue 117, March/April 2003

Media reports of the latest study on homebirth were short and to the point: Infants born at home had twice the risk of death, and both mothers and infants had higher risks of other complications. The study, "Outcomes of Planned Home Births in Washington State: 1989-1996," appeared in the August 2002 issue of Obstetrics and Gynecology, the official journal of the American College of Obstetricians and Gynecologists (ACOG).1 On the day of publication, ACOG, which represents the interests of 40,000 obstetricians and gynecologists in the US, issued a press release titled "Homebirths Double Risk of Newborn Death."2 The lead author of the study, Jenny W. Y. Pang, said in media reports, "It's still a small risk, but women should know there is an added risk with homebirth."3
In contrast to the headlines, the study itself states, "The results... suggest that planned homebirths are associated with an increased risk of adverse neonatal and maternal outcomes, particularly among nulliparous women. Nonetheless, more light needs to be shed on this controversial topic before practitioners and expectant parents can be fairly counseled about the safety of planned homebirths."4 This presents a tale quite different from the one spun for the media.

Knowing that most consumers and reporters will not read the actual study, ACOG can be reasonably confident that, if its statements simplify or overstate the conclusions, few will realize it. But midwives and homebirth experts were immediately skeptical, because the study appears to contradict a large body of research on homebirth that demonstrates that planned, attended homebirth for low-risk women is as safe as, or safer than, hospital birth. The list of studies that confirm that idea is impressive in its length, depth, and breadth. What, then, to make of the Washington State data?

Findings of the Study The stated objective of the Washington study was to evaluate the risk of neonatal (i.e., less than 28 days of age) death for planned home deliveries with professional providers compared with that of intended hospital deliveries. In addition, the authors analyzed a short list of other complications. They used linked data from Washington State birth and death certificates as their data source. Unfortunately for the accuracy of their research, "Washington State birth certificates do not identify which homebirths are planned."5 The researchers acknowledged the importance of determining that the homebirth group contains only planned births; unplanned births and unattended births are associated with much higher risks for mothers and babies.6

The homebirth group, after correcting for gestational age of 34 weeks or more and for certain pregnancy complications, included 6,133 singleton births, 279 of which were classified as planned homebirths that were transferred to the hospital during labor. The hospital birth cohort included 10,593 singleton births. These formed the main groups of the study. In further analysis, the authors compared only those births of at least 37 weeks and babies with birthweights of more than 2,500 grams (5 lbs. 8 oz.).

Demographic data for the two groups showed that the homebirth mothers were more likely to be white, married, older, nonsmokers, and parous (having had a previous birth). Curiously, the researchers failed to match the two groups for risk factors, instead matching for birth year only. Since the stated objective was to isolate the effect of birth environment on birth outcomes, the researchers should have made the two groups as alike as possible. They did not do so. Although they later adjust for factors such as age and parity, they report the results of these adjustments inconsistently in their data.

There were 20 neonatal deaths noted in the homebirth group, for a rate of 3.3 per thousand, compared to 18 deaths (1.7 per thousand) in the hospital group. The homebirth group also had higher risks of very low (0-3) five-minute APGAR scores and slightly higher rates of assisted ventilation of more than 30 minutes. The risk of assisted ventilation was statistically significant only for babies born to first-time mothers. The researchers also report that mothers in the homebirth group had slightly higher rates of prolonged labor and postpartum bleeding; again, this was statistically significant only for women having a first birth.

The five authors of this study are all physicians. One works in pediatric hematology and oncology, one is an obstetrician-gynecologist, and three are epidemiologists (one of these is also a professor of orthodontics). None of the five has direct experience with homebirth, and no midwives were included in the research group. The assumptions they made, as well as the outcomes and analysis they omitted from the study, illustrate their lack of experience in homebirth and their firm roots in the medical model of childbirth. This was confirmed for me when I spoke at length with Jenny Pang.