Tuesday, September 9, 2008

Natural birth is less safe for babies

Recent research in the U.S. has shown that babies are more likely to die if the duration of pregnancy is left in the hands of Mother Nature. This was a relatively large study, and it is not the first time that overdue births have been linked with adverse outcomes for the infant. In fact, this is one if the reasons that many hospitals choose to induce labor or schedule a cesarean delivery - to increase the chances of an infant's survival. I think that critics of cesarean delivery would do well to remember that there are grave risks involved with planned vaginal delivery too.

The research

Data from 1,815,811 liveborn infants in California from 1999 to 2003 was retrieved; multiple births, congenital anomalies and infants with a gestational age of less than 38 weeks (exactly) or greater than 42 weeks and 6 days, weeks were excluded. The results found that compared to infants born at 38, 39, or 40 weeks, those born between 41 weeks (exactly) and 42 weeks and 6 days had a greater odds of neonatal mortality.

When subdivided by gestational week, infants delivered between 41 weeks (exactly) and 41 weeks and 6 days showed elevated mortality relative to earlier term births. Additional analyses supported this increased neonatal mortality across all normal birthweight categories.

The researchers conclude that “Infants born beyond 41w0d of gestation experience greater neonatal mortality relative to term infants born between 38w0d and 40w6d.”

Increased neonatal mortality among normal-weight births beyond 41 weeks of gestation in California. Tim A. Bruckner PhDa, Yvonne W. Cheng MD, MPHa, b and Aaron B. Caughey MD, PhDb.

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