First-trimester pregnancy-associated plasma protein A and subsequent abnormalities of fetal growth.

ABSTRACT

OBJECTIVE: The purpose of this study was to describe the relationship between first-trimester pregnancy-associated plasma protein A (PAPP-A) and birthweight along its continuum and at its extremes. STUDY DESIGN: This was a retrospective cohort of 1371 women who underwent first-trimester screening for fetal aneuploidy and who delivered at our hospital. RESULTS: First-trimester PAPP-A has a positive relationship with birthweight. As PAPP-A decreases, the risk of small-for-gestational-age (SGA) infants increases. PAPP-A of <10%, <5%, and <1% were associated with an increasing adjusted odds ratio for SGA infants (2.0 [95% CI, 1.2-3.5; P = .012]; 2.4 [95% CI, 1.2-4.7; P = .015]; 9.3 [95% CI, 3.4-25.5; P = .001], respectively). PAPP-A levels of >90% were associated with an adjusted odds ratio for birthweight of >4500 g of 2.9 (95% CI, 1.02-8.17; P = 0.046). CONCLUSION: First-trimester PAPP-A is a marker of placental function that correlates with birthweight along its continuum and at its extremes. The strong association between low PAPP-A and SGA warrants further investigation of its usefulness as a screening tool.