Maternal Plasma Afamin Levels in Pregnancies Complicated by Fetal Growth Restriction and Their Association With Doppler Markers of Placental Dysfunction.

AIM: To compare maternal plasma afamin between pregnancies with fetal growth restriction (FGR) defined by fetal biometry and healthy controls, to test whether the cross-sectional association between afamin and gestational age differs in FGR, and to examine associations with Doppler indices.

METHODS

In this prospective study, 84 women assessed at 28-40 weeks (40 FGR, 44 controls) underwent same-day maternal blood sampling and umbilical-, middle-cerebral-, and uterine-artery Doppler. FGR was defined by an estimated fetal weight or abdominal circumference below the 5th percentile. Plasma afamin was measured by enzyme-linked immunosorbent assay. Analyses included a group-by-gestational-age interaction model, multivariable logistic regression, adjusted partial correlations, and receiver operating characteristic analysis.

RESULTS

Afamin was higher in FGR than controls (109.6 ± 5.8 vs. 98.2 ± 9.4 mg/L; p < 0.0001), persisting after adjustment (adjusted difference 11.2 mg/L). In controls, afamin was strongly associated with gestational age (r = 0.95), whereas in FGR it was not (r = -0.03); the group-by-gestational-age interaction was significant (p < 0.0001). Afamin was associated with FGR after adjustment (odds ratio 4.99 per 5 mg/L), an effect concentrated before 34 weeks. Pooled afamin-Doppler (Spearman) correlations did not remain significant after adjustment for group. Afamin did not correlate with body mass index. The area under the curve was 0.837.

CONCLUSIONS

In biometrically defined FGR, plasma afamin was elevated and, unlike in controls, was not associated with gestational age. Afamin was associated with FGR after covariate adjustment, but its strength varied with gestational age; these cross-sectional, exploratory findings require validation before clinical use.