Birthing trauma linked to diminished IQ.

Baby boomers who lose the academic race with their siblings may want to look back to the womb for answers. A controversial new report suggests long, unproductive labor may marginally reduce a child's intellectual prowess.

Although many researchers have attempted to link intelligence to the birthing process, a new study suggests infants delivered after more than 12 hours of unproductive labor suffer impaired intellectual development, perhaps as a result of subtle brain damage.

Many first-time mothers labor for more than 12 hours. How long a physician allows a woman to labor should rest on whether the mother's contractions continue to move the baby into and through the birth canal, concludes Frederick J. Roemer who headed the new study. An obstetrician in East Cleveland, Ohio, Roemer likened a baby during labor to a nail entering a wall. Just as the nail's head can deform under a hammer's powerful blows if some obstruction prevents the metal fastener from progressing smoothly into the wall, so the baby's soft, vulnerable head may sustain injury if labor contractions unproductively slam it for hours against a bony impediment, Roemer says.

Roemer began his scientific quest by culling hospital obstetric records on white, middle-class infants born at a local hospital between 1952 and 1954. He focused on 30 infants delivered by cesarean section -- surgical removal -- after more than 12 hours of unproductive labor. These children were compared with a group of 40 younger siblings, each of whom had avoided the trauma of labor when their mother's physician elected to schedule cesarean deliveries.

When each of the children reached about 10 years of age, Roemer sent the parents and teachers a questionnaire to assess the youth's progress. The survey included a request for each child's scores on standardized intelligence tests.

Though Roemer acquired a mountain of data, he didn't seriously begin wading through it until he retired. He and biostatistician Douglas Y. Rowland of Case Western Reserve University in Cleveland have now found that younger siblings clearly outperformed older brothers and sisters on IQ tests.

In the May OBSTETRICS AND GYNECOLOGY, Roemer's team reports that scores for the 40 younger children averaged about 118 -- a statistically significant 11 points higher than the 30 children who had experienced a traumatic birth. Records show that other white, middle-class children in that community scored about 110 on the same IQ tests, he adds.

More importantly, comparisons within families showed that 20 of the 30 birth-trauma children ranked lower on IQ tests than one or more of their younger siblings -- a finding that Roemer's team argues is not likely due to chance.

First-born children usually outperform their younger siblings on IQ tests and other academic measures, Roemer notes, perhaps because of the parental attention lavished on the temporarily "only" child. However, though 29 of 30 birth-trauma subjects were first-borns, they lagged behind their younger siblings on every measure, including graded "performance evaluations" conducted by their school. Roemer says these findings fit with the theory that prolonged and obstructed labor may harm intellectual development later in life.

Obstetrician Ronald A. Chez of the University of South Florida College of Medicine in Tampa described the principal finding as "highly provocative." However, these "worthwhile" data "probably can't be replicated," he writes in an editorial accompanying the report by Roemer's team, because the 1950's practices that led to the alleged brain trauma no longer confront most U.S. newborns. For instance, he argues, today's newborns stand to benefit from drugs that make labor less traumatic.

Roemer's team counters that the report's general message should indeed hold true for babies born in the 1990s -- especially to women who opt for natural childbirth methods. The Cleveland researchers also believe their results argue for a timely decision to perform cesarean deliveries, especially after 12 hours of unproductive labor.