The increasing number of preterm births in the US during the early 1990s and 2000s appear linked to the increasing number of medically induced labours, according to a new study.
The number of preterm births across the US rose by 30% between 1992 and 2004, and that increase may be attributable to the number of medically induced labours, which nearly doubled during the same period, researchers found.
The study's senior researcher said he doesn't think doctors are inducing labour for non-medical reasons; they may just be erring on the side of caution by delivering the babies early for good medical reasons.
The problem, said Dr Michael Kramer, is that the decision to do early labour induction is "socially contagious."
"I think the threshold has been going down for induction over the years, and I don't think we've shown that's been a benefit," said Dr Kramer, of the McGill University Faculty of Medicine in Montreal. Dr Kramer and a colleague, X Zhang, used data from the US National Center for Health Statistics to compare the labour induction and preterm birth rates in each state for non-Hispanic white women between 1992 to 1994 and 2002 to 2004.
Curb the rise
Overall, preterm births increased from 6.4% in 1992 to 8.5% in 2004. During that time, labour inductions rose from 13.7% to 26%.
The researchers, who published their study online in BJOG: An International Journal of Obstetrics & Gynaecology, also examined whether caesarean sections were linked to the rise in preterm births.
While there was a rise in C-sections throughout the US during the study period, the researchers say that is not a major factor contributing to preterm births because most C-sections are done during naturally-occurring labours - not during early inductions of labour.
Dr Kramer said he believes doctors can curb the rise in preterm births without conferring additional risk on the babies. That goal is already being realised in Ohio.
Through an elective education program known as the Ohio Perinatal Quality Collaborative, more women appear to be delivering their babies near full term (39 to 41 weeks) instead of "near term" (36 to 38 weeks) since the initiative started in 2008.
"It's tremendously successful and thousands of women in Ohio have moved to late-term delivery from pre-term delivery," said Dr Michele Walsh, a member of OPQC and chief of neonatology at UH Rainbow Babies & Children's Hospital in Cleveland.
(Reuters Health, September 2012)
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