Maternal plasma levels of complement Factor H in miscarriage and in normal pregnancy: A cohort study

The incidence of clinically recognizable miscarriage in general population is up to 15%. It has been shown that complement Factor H (CFH) mRNA levels were increased in endometrium of women during early pregnancy, compared to non-pregnant women. We hypothesized that patients with miscarriage could have lower protein levels of CFH. The objectives of this prospective cohort is to measure plasma levels of Factor H in pregnancies up to 20 weeks, and to investigated whether there is an association between CFH and miscarriage. Plasma levels of CFH were measured in a cohort of pregnant women, ranging from 3 to 19.6 weeks who attended a gynecologic emergency unit in Brazil. Subjects had a blood sample obtained at the first consultation and were followed up to 24 weeks. After reaching outcome, subjects were divided into 4 groups: (1) miscarriage at entry the study, (2) normal pregnancy, (3) those that evolved to miscarriage, and (4) a control group of 6 non-pregnant, fertile proven women. Kruskal-Wallis test was used for statistical analysis. From 193 eligible women, 4 were excluded due technical problems and 33 were lost to follow-up. Median levels (range) of CFH were 989.2 μg/mL (372-1644) n=64; 1042 μg/mL (600.7-1915) n=74; 1089 μg/mL (813.7-1250) n=12; 1004 μg/mL (901.7-1335) n=6 in groups 1-3 and control, respectively; p=0.46-Kruskal-Wallis; post-hoc power (1-β)=31.6%. Therefore, median plasma levels of CFH are not different between women with miscarriage or normal pregnancy up to 19.6 weeks.