You may have read about a new Dutch study of homebirth that shows that homebirth increases the risk of neonatal death.
You may have also read the spin, that the risk of homebirth is confined to poor women. This piece in The Washington Post is typical:
The infant mortality rate is also higher in the Netherlands than in European countries with similar medical resources. But as more Dutch mothers have switched in recent years to delivering their babies in hospitals, rather than their homes, doctors have noticed a drop in newborn deaths.
So far, so good.
Researchers wanted to understand why, between 1980 and 2009, the country’s infant mortality rate fell from 4.25 deaths per 1,000 births to 2.42 deaths per thousand births. Over the same period, the share of deliveries in maternity wards swelled from about 61 percent to 73 percent. On the surface, it appeared the home method may simply be riskier for babies.
But the story isn’t that simple. What happened to the women during their home births depended a lot on their income, and relatedly, their access to routine medical care before and after pregnancy, according to a study published this month in the American Economic Journal: Applied Economics…
… [A] poorer woman who preferred a home birth was more likely to encounter tragedy. The 28-day infant mortality rate for them more than doubled, from about 2 deaths per 1,000 births to 5 deaths per 1,000 births.
[pullquote align=”right” color=”#66a018″]The rise in hospital births explains roughly 46–49% of the reduction in infant mortality in the Netherlands between 1980-2009.[/pullquote]
One possible interpretation of the findings of the study is that the danger of homebirth is restricted to poor women, but there is another, far more likely interpretation of the data: homebirth is safe ONLY when nothing goes wrong. Any unforeseen complications double the risk that the baby will die.
The paper Saving Lives at Birth: The Impact of Home Births on Infant Outcomes by Daysal, et al. was written by economists. The math in the paper is probably perfect; however, some of the medical assumptions are problematic.
The basic statistics are incontrovertible: homebirth increases the risk of neonatal death and the recent increase in hospital birth in The Netherlands has been associated with a fall in mortality rates.
According to Daysal, et al.:
Historical data show that 7-day (28-day) mortality declined from 4.25 (5.35) deaths per 1,000 births in 1980–1985 to 2.42 (3.18) deaths in 2005-2009, while the share of hospital births increased from 61.25 percent to 72.06 percent. In addition, using a decomposition … we find that most of the mortality decline between 2000–2008 comes from newborns over 2,500 grams, who are more likely to be low-risk and thus eligible for home births.
This is a critical point. Not only has the neonatal death rate decline in proportion to an increase in hospital birth, but that decline occurred in babies of normal size, suggesting that these were term babies.
Indeed:
Back-of-the-envelope calculations suggest that the rise in hospital births explains roughly 46– 49 percent of the reduction in infant mortality in the Netherlands between 1980 and 2009.
In this paper, the authors looked at all births in The Netherlands from 2000 to 2008. The key finding:
We find that giving birth in a hospital leads to substantial reductions in newborn mortality. We provide suggestive evidence that proximity to medical technologies may be an important channel contributing to these health gains.
That seems pretty definitive, so why is the mainstream media hedging about maternal income?
The study found that the increase in deaths was confined to postal codes with low median incomes. In other words, most of the deaths occurred in poor areas. But that DOESN’T mean that the proximate cause of those deaths is poverty.
In the first place, the authors looked only at addresses, not at actual maternal income. Second, maternal income is likely a proxy for the incidence of complications. It is well known that lower socio-economic status in pregnancy is associated with greater risk of complications. Therefore, a more realistic conclusion is not that homebirth is dangerous for poor women only, but rather that homebirth is dangerous if anything goes wrong. Homebirth is safe only if nothing goes wrong. Once a complication develops, the risk of neonatal death rises dramatically if the baby is anywhere but a hospital.
In fact:
The lack of an impact on the 5-minute Apgar score suggests that the general health of low-risk babies born in a hospital is similar to those born at home shortly after birth. Hence, any mortality reductions from a hospital birth are likely due to the medical care provided after delivery. A hospital birth may reduce infant mortality through various channels, such as the availability of better facilities and equipment, potentially better hygiene or the proximity to other medical services.
As I’ve written many times before, hospitals are like seatbelts; most of the time you don’t need them but wearing them all the time dramatically lowers the risk of death.
The take home message from this paper is NOT that homebirth is safe for wealthy women. The take home message is that homebirth is safe ONLY when nothing goes wrong.
Homebirth is gambling with your baby’s life. You’re gambling that there won’t be any unexpected complications. But if there are complications, your baby is more likely to pay for your gamble with his or her life.
