Posted By Henci Goer on 07/11/2008 1:16 AM
Maria: I haven't forgotten you. If the number of posts to the Forum slows down enough for me to catch my breath, I'll get to reviewing the Swedish study.
-- Henci
Just got back from the DONA conference, and while I was there, I had the chance to review the Swedish home birth study.
Lindgren HE, et al. Outcome of planned home births compared to hospital births in Sweden between 1992 and 2004. A population-based register study. Acta Obstet Gynecol Scand 2008;13:1-9.
Objective. The aim of this population-based study was to measure the risk of adverse outcome for mother and child in planned home births in a Swedish population irrespective of where the birth actually occurred, at home or in hospital after transfer. Design. A population-based study using data from the Swedish Medical Birth Register. Setting. Sweden 1992-2004. Participants. A total of 897 planned home births were compared with a randomly selected group of 11,341 planned hospital births. Main outcome measures. Prevalence of mortality and morbidity among mothers and children, emergency conditions, instrumental and operative delivery and perineal lacerations were compared. Results. During this period in Sweden the neonatal mortality rate was 2.2 per thousand in the home birth group and 0.7 in the hospital group (RR 3.6, 95% CI 0.2-14.7). No cases of emergency complications were found in the home birth group. The risk of having a sphincter rupture was lower in the planned home birth group (RR 0.2, 95% CI 0.0-0.7). The risk of having a cesarean section (RR 0.4, 95% CI 0.2-0.7) or instrumental delivery (RR 0.3, 95% CI 0.2-0.5) was significantly lower in the planned home birth group. Conclusion. In Sweden, between 1992 and 2004, the intrapartum and neonatal mortality in planned home births was 2.2 per thousand. The proportion is higher compared to hospital births but no statistically significant difference was found. Women in the home birth group more often experienced a spontaneous birth without medical intervention and were less likely to sustain pelvic floor injuries.
To begin with, the fact that the confidence interval (CI) includes "1" means that the difference is not statistically significant, meaning that it could have occurred by chance. However, failure to find a statistically significant difference may be because the study lacked sufficient power to detect a difference, that is, the population of home births was small and there were few deaths (2 deaths among the 897 home births; 7 deaths among 11,341 hospital births). In a larger study, the difference might have achieved statistical significance. Study authors note that 47,361 home births would have been needed to have a reasonable chance of detecting a difference. But let's look closer at the deaths themselves. One death in the home birth population resulted from congenital anomalies. Birth site would have made no difference. If we remove that death from consideration, the death rate in the home birth population falls to 1/897 = 1.1 per 1000. The other death occurred in a water birth, and three experts reviewing the case concluded that the water birth was the main reason for the death. No further details are given, so it is not clear whether this was, in fact, the case, but even if it was, poor care is the likely culprit, for example, not lifting the baby to the surface immediately.
It is also worthwhile to point out that two of the five hospital deaths that did not involve congenital anomalies might have been related to hospital management and might have been avoided had the women been at home. They occurred in women who had epidurals and, as is required more often when a woman has an epidural, vacuum deliveries. One death is specified as relating to hemorrhage resulting from the delivery, and the other related to shoulder dystocia (the head is born, but the shoulders hang up) in a 4000 g (8 lb 13 oz) baby. These tragedies might have been averted had the women been able to push effectively in upright positions. In the latter case, if the baby had still had shoulder dystocia, having a midwife who knew the Gaskin maneuver might have made a difference too. Finally, note the statistically significant differences in anal sphincter tears (0.3% vs. 2.7%), vacuum deliveries (2% vs. 10%), and cesarean surgeries (2% vs. 7%). This was despite that fact that the home birth population contained 8 sets of twins, 11 preterm births, and 79 postterm (more than 42 w) births while the hospital comparison population was composed of term, singleton births.
-- Henci
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