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Women's Health: Delaying caesarean delivery cuts infant breathing problems

Planned C-sections are best done at a full 39 weeks of pregnancy or later, Canadian researcher says

Women planning to give birth by caesarean section should schedule the operation for no earlier than 39 weeks of pregnancy: The timing may be critical in reducing the risk that the newborn will suffer breathing problems, according to a Canadian study.

Dr. Lexy Regush of the University of Saskatchewan’s department of obstetrics, gynecology and reproductive sciences reviewed the medical charts of 985 infants born by scheduled C-section at Royal University Hospital in Saskatoon between April 2001 and May 2005.

She was looking for occurrences of two breathing-related complications: transient tachypnea of the newborn, a form of rapid breathing that usually clears up soon after birth, and respiratory distress syndrome, a potentially fatal condition in which the newborn’s lungs don’t inflate properly.

Babies delivered by caesarean section at less than 39 weeks were more likely to develop both of these conditions. Transient tachypnea occurred at a rate of eight per cent in these infants, compared with only three per cent among babies delivered after more than 39 weeks. Similarly, three per cent of babies delivered at less than 39 weeks developed respiratory distress syndrome, but this condition did not affect any babies delivered by C-section after more than 39 weeks.

The downside of waiting until 39 weeks for a planned C-section is that there is a 12 to 14 per cent chance of going into labour before the operation.

Regush says it’s important to have the date of conception re-checked when planning a C-section. In the study, conception dates were estimated using the date of the last menstrual period as well as ultrasound data.

The conception dates that had been recorded in women’s medical charts were off by two days on average, and as many as 35 days. And it was more common to have overestimated the duration of pregnancy than to have underestimated it. This meant that a planned C-section could inadvertently have been scheduled too early, thus putting the baby at unnecessarily higher risk for breathing problems.

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