Longitudinal evaluation of activated protein C resistance among normal pregnancies of Hispanic women

OBJECTIVE: This study was undertaken to describe pregnancy-associated activ ated protein C resistance and the presence of the factor V Leiden mutation in a sample population of pregnant Hispanic women. STUDY DESIGN: Twenty healthy Hispanic women with single intrauterine pregna ncies were randomly selected. Blood samples were taken before 8 weeks' gest ation, every 4 weeks during pregnancy, and at 6 weeks post partum. Samples were collected, separated, and stored at -70 degrees C until assay. Standar d and modified partial thromboplastin time-based assays were used to evalua te response to activated protein C. A sensitivity ratio less than or equal to 2 indicated resistance to activated protein C. Repeated measures analysi s of variance and unpaired t tests were used as appropriate. P < .05 was co nsidered significant. RESULTS: Mean (+/-SEM) maternal age was 29 +/- 5 years, and most women were multiparous. Mean gestational age at delivery was 38 weeks' gestation, and the mean birth weight was 3000 g. According to the standard assay, 10 wome n (50%) acquired activated protein C resistance by 13 weeks' gestation, and this condition persisted through delivery and resolved post partum. Anothe r two had preexisting activated protein C resistance. Results of the standa rd assay were significantly different for women with preexisting and pregna ncy-associated activated protein C resistance (1.55 vs 2.18; P = .01). The modified assay distinguished between women with preexisting and pregnancy-a ssociated activated protein C resistance at 8 weeks' gestation, 24 weeks' g estation, and post partum. The pregnancies of the women with preexisting ac tivated protein C resistance were complicated by oligohydramnios at 34 week s' gestation and required delivery at 36 weeks' gestation. One infant was s mall for gestational age. Allele-specific polymerase chain reaction analysi s demonstrated that both patients with preexisting activated protein C resi stance carried one copy of the factor V Leiden mutation. CONCLUSION: The incidences of pregnancy-associated and factor V Leiden muta tion-associated activated protein C resistances in our cohort of gravid His panic women was higher than previously reported. factor V Leiden-associated activated protein C resistance in two patients was associated with adverse perinatal outcome.