Aug 03 2010
More and more American women (1 in 200) are opting for home birth, and midwife-assisted home birth is common in other developed countries. How safe is it compared to birth in a hospital? A new study sheds some light on the subject. It was recently published in the American Journal of Obstetrics and Gynecology: Maternal and newborn outcomes in planned home birth vs planned hospital births: a metaanalysis, by Wax et al.
All the existing studies have flaws. It would be ideal to do a study where women were randomly assigned to home or hospital birth; that isn’t possible, so we have to fall back on studies that are possible. Just comparing home births to hospital births isn’t good enough, because high-risk births occur primarily in hospitals, and between 9% and 37% of planned home births end up with transfer to the hospital during labor and are converted into hospital births. Cohort studies comparing planned home with planned hospital births provide the best sources of data by intended delivery location. There have been several such studies, but the numbers were small and the results were inconclusive. This new study is a meta-analysis that combines the data into one large set for better understanding.
Wax et al. combed the published literature and found studies covering 342,056 planned home and 207,551 planned hospital deliveries. Studies were included in their analysis if they were performed in developed Western countries, published in English-language peer-reviewed literature, if maternal and newborn outcomes were analyzed by planned delivery location, and if data were presentable in a 2X2 table. They looked at several measures of maternal intervention (epidurals, C-sections, etc.), maternal outcomes (mortality, hemorrhage, infection, etc.), and neonatal outcomes (Apgar scores, perinatal deaths, etc.). Here’s what they found:
RESULTS: Planned home births were associated with fewer maternal interventions including epidural analgesia, electronic fetal heart rate monitoring, episiotomy, and operative delivery. These women were less likely to experience lacerations, hemorrhage, and infections. Neonatal outcomes of planned home births revealed less frequent prematurity, low birthweight, and assisted newborn ventilation. Although planned home and hospital births exhibited similar perinatal mortality rates, planned home births were associated with significantly elevated neonatal mortality rates.
CONCLUSION: Less medical intervention during planned home birth is associated with a tripling of the neonatal mortality rate.
It’s important to understand the difference between perinatal and neonatal mortality. The write-up of the study is confusing because a typo erroneously defines perinatal mortality as deaths up to 28 days after birth. Perinatal mortality includes stillbirths and deaths in the first 7 days of life; neonatal mortality includes all deaths in the first 28 days of life.
Neonatal death was twice as likely overall with home birth (Odds Ratio 1.98, 95% confidence interval 1.19–3.28) and three times as likely for non-anomalous births (OR 2.87, CI 1.32–6.25). Non-anomalous means without congenital defects. These findings are robust, consistent across all studies, and even more impressive in that women planning home deliveries had equal or lower obstetric risk. The relative risk is striking, but the absolute risk is small due to the small number of home births. They estimate the population-based attributable risk of overall neonatal death to be 0.3%.
One of the stated goals of women planning home births is to avoid unnecessary interventions. They did indeed have fewer interventions. But planned home births were characterized by a greater proportion of deaths attributed to respiratory distress and failed resuscitation. Intrapartum asphyxia is a major cause of death in hospital births, and it is decreased by interventions. This raises the question of whether the decreased obstetric intervention in the home birth group may have caused more neonatal deaths due to asphyxia.
Women intending home deliveries had better outcomes: fewer infections, 3rd-degree lacerations, perineal and vaginal lacerations, hemorrhages, and retained placentas; and there was no significant difference in the rate of umbilical cord prolapse. There were too few maternal deaths to analyze.
Babies of mothers planning home births were less likely to be born preterm or be of low birthweight, but were more likely to have an extended gestation of 42 weeks. Perinatal mortality was similar, but neonatal mortality was significantly greater. This is puzzling and it would have been helpful to know more about the cause of death and the course of illness. How could intrapartum events cause equal mortality up to one week and greater mortality only between 7 and 28 days? The incidence of infection in the babies was not reported. Fear of hospital-acquired infections is one stated reason for choosing home delivery: is it a valid reason? One could argue that the best solution is to reduce the rate of hospital-acquired infection, not to avoid the hospital. Mothers had fewer infections, but is it possible that more babies got infections during home births, infections that contributed to death between 7 and 28 days? What other factors might account for delayed deaths? And why should the death rate of normal babies exceed that of babies with congenital defects?
The authors commented that
the lower obstetric risk characterizing women self-selecting planned home birth likely underestimates the risk and overestimates the benefit of this delivery choice.
They reported that a study published after their analysis found similar perinatal mortality rates in planned home and hospital deliveries, but after adjustment for the later gestational ages at delivery and greater birthweights among home births, the perinatal mortality was actually greater for planned home deliveries, especially for women who required transfer to the hospital. Up to 37% of women planning a home birth with their first pregnancy end up being transferred to the hospital because of emergencies that arise during the labor process.
They commented that the studies analyzed were of low-risk women considering home birth with highly trained, regulated midwives who are fully integrated into existing health care systems. As such, they might not be generalizable to all women opting for home birth in the United States.
Midwives’ groups are already attacking this new study as flawed and politically motivated, but of course they themselves are politically motivated to show the safety of home birth, and their own studies are flawed. Passions run high on both sides of the debate. This study is far from perfect, and it’s certainly not the final answer, but it’s the best we’ve got to go on at the moment.
I think the real message from this study is that we need to develop a better understanding of which interventions are really necessary to save babies’ lives and how to improve the outcome of all deliveries, whether at home or in a hospital.
A non-trivial percentage of planned home births end up with transport to a hospital. Home birth advocates recognize that these emergencies occur. It seems intuitively obvious that increasing the time delay for emergency interventions ought to increase adverse outcomes, that distance from a hospital is a crucial factor, and that the optimum scenario is immediate availability of emergency response, i.e. labor in a hospital rather than at home.
I submit that delayed treatment of unexpected emergencies constitutes a small but undeniable risk for planned home births. It has not been established that the benefits of home birth (lower maternal infection rate, etc.) can outweigh that risk. And it has not been established that those benefits couldn’t be obtained just as well by improving hospital practices. What do women really want? If they just want to be at home, they may be willing to accept a small increase in risk. If they want fewer interventions, that doesn’t require that they give birth at home.
I admit to prejudice. I support the right of informed patients to choose home birth with a qualified midwife and reasonable precautions, but I personally want no part of it. Having delivered a lot of babies myself and having seen normal low-risk deliveries turn to disaster in a heartbeat, I would never have considered having my own babies at home, and I would personally be very frightened to attend a home birth, especially if there was a 37% chance of it ending with a nerve-wracking rush to the hospital. I would rather see babies born within easy reach of a C-section and other lifesaving interventions. I think this could be accomplished by integrating the “kinder, gentler,” less interventionist midwife approach into a home-like hospital birthing facility in close coordination and communication with obstetricians and pediatricians. This approach would increase patient satisfaction without sacrificing safety, and it is already being tried in many hospitals.
This study leaves a lot of questions unanswered, but it does give us better information to help patients make an informed decision.
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