Maternal Preeclampsia, Risk of Premature Birth, and ROP
JAMA Ophthalmology, September 2017
Studies of the effect of preeclampsia on premature birth and retinopathy of prematurity (ROP) have produced conflicting results. In research aimed at clarifying this relationship and explaining the discrepancies, Shulman et al. found that preeclampsia was associated with elevated risk of ROP in an unrestricted cohort, but it reduced the risk of ROP in a preterm-only cohort.
For this study, the researchers reviewed records of 290,992 live births that occurred during a 10-year period (January 2001–December 2010). They used generalized estimating equations for logistic regression, with covariate adjustment, to determine the relationship between ROP and maternal preeclampsia among 2 cohorts: the entire study population and the preterm subgroup with very low birth weight born before 31 weeks’ gestation (n = 2,015). Infants in the latter group weighed < 1,500 g.
In the full (unrestricted) cohort, preeclampsia was associated with an increased risk of all ROP, severe ROP, infant death, and having a premature/low birth weight baby. In the premature/low birth weight cohort, preeclampsia was inversely associated with all ROP, severe ROP, and infant death.
In conclusion, these findings suggest an overall adverse effect of preeclampsia on ROP and are consistent with evidence of a protective effect of preeclampsia on infants born prematurely. However, it is unclear whether the latter denotes a true direct protective effect, collider bias, and/or another form of uncontrolled confounding.
The original article can be found here.