Very low birth weight associated with bilateral, unilateral cataracts

Ophthalmology. 2010;117(8):1500-1505.

Issue: October 10, 2010

Bilateral and unilateral cataracts are both associated with very low birth weight, a study found. In addition, bilateral cataracts are more closely associated with low birth weight, and unilateral cataracts are correlated with first pregnancies.

The study included 152 infants with infantile cataracts and 4,205 controls enrolled in the National Birth Defects Prevention Study. The infants were born from 2000 to 2004.

In the multivariate analysis, very low birth weight was defined as less than 1,500 g. Low birth weight was defined as 1,500 g to 2,499 g.

The authors interviewed the mothers of 43 infants with bilateral cataracts and 109 infants with unilateral cataracts.

Reported respiratory illness during pregnancy showed an inverse relationship to unilateral cataracts, but that result was not statistically significant.

Women who reported having urinary tract infections and using aspirin during pregnancy had a greater likelihood of having an infant with bilateral cataracts, but these associations were not statistically significant.

Data showed an elevated risk of unilateral cataract associated with prenatal substance abuse, but the association was not statistically significant.

"We found that women who had infants with unilateral cataracts were more likely to report using alcohol and illicit substances during pregnancy, although these findings were not statistically significant," the authors said. "It is possible that these associations might be more pronounced in those who smoked during pregnancy. ... We were unable to further explore these potential interactions within the sample size of our study; however, future studies looking at the interaction between alcohol, substance abuse and smoking are merited."

Overall, approximately half (44% in this database) of infants with bilateral cataracts have a first-degree relative with a history of infantile cataracts. When there is no family history of cataracts, 72% of the children with cataracts have them unilaterally and most are isolated, without other birth defects.

Babies born at less than 1,500 grams are at increased risk for either bilateral or unilateral cataracts. Even those babies with only mild low birth weight (1,500-2,499 grams) have an increased risk for bilateral (but not unilateral) cataracts. No evidence was found for an association between cataracts and maternal gestational diabetes or maternal smoking. Isolated cataracts were more likely unilateral and those cataracts associated with other birth defects were more likely bilateral.

Since cataracts need to be found early to achieve the best outcomes, infants with low birth weight and those with first-degree relatives who have cataracts need timely screening. The case-control method is an appropriate way to study this problem. The data base utilized is a large multisite effort but specific ophthalmic information on the extent of the cataract was often not available. Possible associations of cataracts with maternal substance abuse and urinary tract infections remain unproven.

– M. Edward Wilson, MD
OSN Pediatrics/Strabismus Board Member