Friday, July 13, 2012

Homebirth with a CNM vs. a non-nurse midwife

In a recent post (Homebirth kills babies) I analyzed the data in the Linked Birth Infant Death database and demonstrated that homebirth with a direct entry midwife has almost triple the neonatal death rate of hospital birth for comparable risk women. Similar results were presented at the Pedatric Academic Societies May 2009 meeting.

According to the Medscape article:

Dr. Michael H. Malloy, at the University of Texas Medical Branch in Galveston, compared a range of adverse outcomes among infants by delivery attendant type and site of delivery occurring in the U.S. over a recent 5-year period...

The present analysis was limited to term (37-to-42 weeks), singleton, vaginal deliveries.

"I decided to restrict the analysis to this low-risk population because they would be the best candidates for home delivery," Dr. Malloy said.

During the study period, there were 10,330,214 (88.5%) hospital physician-attended births available for analysis; 1,237,129 (10.6%) hospital-CNMW births ... 13,529 (0.1%) home-CNMW births; 42,375 (0.4%) home-other nurse midwife ...

The number of neonatal deaths for each of the categories was respectively 6,992; 614... 14; 75
The neonatal death rates in each group were 0.68/1000 hospital MD births; 0.5/1000 hospital CNM births, 1/1000 home CNM births and 1.7/1000 homebirth direct entry midwives. These are almost exactly the same as the death rates that I calculated from the same database for the 2 year period 2003-2004.

In both cases, homebirth with a direct entry midwife has triple the rate of neonatal death as low risk hospital birth. In both cases, homebirth with a direct entry midwife (such as a CPM) is the most dangerous form of planned birth in the US.

As Dr. Malloy explains:
"However, while there were only 14 neonatal deaths occurring in association with a home-CNMW assisted delivery, the risk of death was more than two-fold higher for CNMW-home deliveries and four-fold higher for deliveries by other midwives versus CNMW-hospital deliveries.

The prevalence Apgar scores of less than 4 was eight times higher for CNMW-home deliveries than for CNMW-hospital deliveries. What's more, the risk of neonatal mortality and low Apgar scores was still increased for CNMW-home deliveries versus CNMW-hospital deliveries after adjusting for multiple potential confounders (including maternal age, race, education, parity, presence of one or more medical or labor complications, presence of an anomaly in infant, gestational age, and infant sex).

"The increased risk of low Apgar scores among infants delivered at home suggests that the causal pathway to the increased risk of neonatal mortality may be through the occurrence of asphyxiating conditions at birth that are not easily handled by the home environment," Dr. Malloy noted.

Overall, the results demonstrate that the safest setting for a delivery is an in-hospital delivery attended by a CNMW, and women who decide to deliver in the home "need to recognize the greater risk associated with that choice," he said.

Finally, as for why in-hospital CNMW deliveries had a lower risk of mortality in his study than in-hospital physician deliveries, Dr. Malloy said he assumes it's because physicians are delivering a higher risk population, which he could not completely control for in his logistic regression analysis.
Dr. Malloy would be expected to be very sympathetic to homebirth. He has published several papers on C-sections and neonatal mortality in association with Drs. MacDorman and Declerq alleging (and then forced to back track) on claims that C-sections increase the risk of neonatal death.

Dr. Malloy's data confirms what anyone can see for themselves. The existing US statistics on homebirth shows that homebirth with a direct entry midwife has triple the rate of neonatal mortality of low risk hospital birth. It is the most dangerous form of planned birth in the US.

If women want to have a homebirth, they can, but as Dr. Malloy states, they "need to recognize the greater risk associated with that choice."

This piece first appeared on The Skeptical OB in August 2009.

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