Low cholesterol may raise preterm birth risk

NEW YORK (Reuters Health) - White women with low levels of total cholesterol during pregnancy are at heightened risk for preterm delivery, new research shows.

"We were surprised by the significant, four-fold increase of premature birth among white mothers and equally surprised that this finding was not confirmed among African American mothers," study chief Dr. Maximilian Muenke from the National Institutes of Health in Bethesda, Maryland, told Reuters Health.

The findings add to previous research showing that high levels of total cholesterol also raise the risk of preterm birth, Muenke and colleagues note in the October issue of the journal Pediatrics.

"We can confirm studies that show that high maternal cholesterol is associated with prematurity," said Muenke. "Our findings that mothers with low cholesterol have babies born prematurely are novel."

The study team compared birth outcomes for 118 pregnant women with low total cholesterol levels (159 mg/dL or less) and for 940 pregnant women with higher levels.

Preterm delivery occurred in 12.7 percent of women with low cholesterol levels compared with just 5.0 percent of women with "mid-range" cholesterol levels, the report indicates.

Among the white women in the study, the corresponding rates of preterm delivery were 4.9 percent versus 20.6 percent; for black women the figures were 5.2 percent versus 3.6 percent.

On average, even term infants born to mothers with low cholesterol weighed 150 grams less than those born to mothers with normal cholesterol levels.

As mentioned, high cholesterol levels were associated with high preterm birth rates: 11.8 percent among white mothers and 13.2 percent among black mothers.

"If we or others can confirm our current findings, it may be recommended that women of childbearing age should know their cholesterol levels. At this point cholesterol is not screened for routinely in women before they become pregnant."

SOURCE: Pediatrics, October 2007.