Serious health problems related to late preterm births

More than half a million babies are born preterm in the United States each year, and preterm births are on the rise.

Late preterm births, or births that occur between 34 and 36 weeks (approximately 4 to 6 weeks before the mother's due date), account for more than 70% of preterm births. Despite the large number of affected babies, many people are unaware of the serious health problems related to late preterm births. A new study and an accompanying editorial soon to be published in The Journal of Pediatrics investigate the serious neurological problems associated with late preterm births.

Dr. Joann Petrini of the March of Dimes and colleagues from institutions throughout the United States studied more than 140,000 babies born between 2000 and 2004, ranging from preterm (30-37 weeks) to full term (37-41 weeks). The researchers evaluated the babies' neurological development and found that late preterm babies were more than three times as likely to be diagnosed with cerebral palsy as full term babies. They also found that late preterm babies were at an increased risk for developmental delay or mental retardation.

Editorialist Dr. Michael Kramer of McGill University points out that the "rates of preterm births are increasing, especially in the United States, and the associated risks are a serious public health concern." He sees the increasing number of twins and induced labors as contributing factors in the rise of preterm births. "The rise in twins may be due to the use of fertility treatments like hormones and in-vitro fertilization," Dr. Kramer explains. However, he notes that the increased risks may not always come from early delivery itself, but from other underlying problems, such as gestational diabetes, that may lead to early delivery.

According to Dr. Petrini, "The negative outcomes of many babies born late preterm can no longer be described as temporary or benign." She suggests that late preterm babies may benefit from neuron-developmental assessments and stresses that elective delivery through cesarean section or induction should not be performed before 39 weeks unless medically necessary. Additionally, Dr. Kramer urges mothers and families to be aware of the risks when considering infertility treatments and induction of labor.