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Study: Developmental Delay for Late Preterm Babies

Developmental Risks Are Possible for Babies Delivered at 34 to 36 Weeks of Pregnancy
WebMD Health News
Reviewed by Laura J. Martin, MD

May 31, 2011 -- Late preterm babies born from 34 to 36 weeks of pregnancy may be at an increased risk for modest developmental and academic problems up to age 7, when compared to babies born at full term, according to a new study.

Most research on the risks associated with preterm birth looks at infants born between 23 and 28 weeks of pregnancy, but significant brain development takes place in the last four to six weeks of gestation. Interrupting these processes, coupled with the often complicated medical problems faced by premature babies, may account for an increased risk of developmental and academic problems.

"Although late preterm infants were previously considered similar to term infants, emerging evidence suggests that significant adverse developmental outcomes among late preterm infants, which further indicates that longer-term outcomes of prematurity, remain a concern even for those infants born at the more optimistic late-preterm stages of pregnancy," conclude study researchers led by Jennifer E. McGowan, of the School of Nursing and Midwifery at Queen's University Belfast in Belfast, U.K.

The study suggests that the closer to term a pregnancy goes, the lower these risks. Late preterm babies fare better than those born earlier, but both groups are at greater risk for developmental problems than term infants.

Researchers analyzed 10 studies looking at early childhood outcomes among babies born at 34 to 36 weeks. Babies born between 34 and 36 weeks gestation were at greater risk for developmental delays, and scored lower on standardized tests of academic achievement, compared to infants born at term. Late preterm infants were also more likely to require early intervention to help them catch up, and were more likely to be underweight and shorter than infants born at term, the study shows.

'Consequences to Early Delivery'

"In the past, only very, very tiny preterm babies were believed to be at risk for problems later in life," says Shoo Lee, MD, the chief of pediatrics at Mount Sinai Hospital in Toronto. "And we are realizing that this is not true and that all preterm babies including those born between weeks 34 to 36 are at risk."

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