Maternal serum protein S forms in pregnancies complicated by intrauterine growth restriction

OBJECTIVES: The clinical relevance of protein S deficiency in pregnant women remains controversial. Major debate exists regarding which parameter (total protein S antigen, free protein S antigen or functional protein S) should be evaluated in order to define protein S deficiency. The present study aimed to identify which of these parameters correlate with intrauterine growth restriction (IUGR). STUDY DESIGN: A retrospective case-control study of women with IUGR (n=27) and healthy controls (n=123) in the third trimester of pregnancy. RESULTS: The maternal serum of women in the IUGR group had significantly lower levels of functional and free protein S compared with the control group: 54.07 ± 24.72% vs 65.20 ± 17.95% (p<0.005) and 42.88 ± 11.01% vs 56.64 ± 13.30% (p<0.0001), respectively. No significant correlation was found between total protein S and IUGR. CONCLUSIONS: Levels of functional and free protein S are correlated with IUGR.