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

This study was undertaken to describe pregnancy-associated activated protein C resistance and the presence of the factor V Leiden mutation in a sample population of pregnant Hispanic women.

Twenty healthy Hispanic women with single intrauterine pregnancies were randomly selected. Blood samples were taken before 8 weeks' gestation, every 4 weeks during pregnancy, and at 6 weeks post partum. Samples were collected, separated, and stored at -70 degrees C until assay. Standard and modified partial thromboplastin time-based assays were used to evaluate response to activated protein C. A sensitivity ratio < or =2 indicated resistance to activated protein C. Repeated measures analysis of variance and unpaired t tests were used as appropriate. P <.05 was considered significant.

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 women (50%) acquired activated protein C resistance by 13 weeks' gestation, and this condition persisted through delivery and resolved post partum. Another two had preexisting activated protein C resistance. Results of the standard assay were significantly different for women with preexisting and pregnancy-associated activated protein C resistance (1.55 vs 2.18; P =.01). The modified assay distinguished between women with preexisting and pregnancy-associated activated protein C resistance at 8 weeks' gestation, 24 weeks' gestation, and post partum. The pregnancies of the women with preexisting activated protein C resistance were complicated by oligohydramnios at 34 weeks' gestation and required delivery at 36 weeks' gestation. One infant was small for gestational age. Allele-specific polymerase chain reaction analysis demonstrated that both patients with preexisting activated protein C resistance carried one copy of the factor V Leiden mutation.

The incidences of pregnancy-associated and factor V Leiden mutation-associated activated protein C resistances in our cohort of gravid Hispanic women was higher than previously reported. Factor V Leiden-associated activated protein C resistance in two patients was associated with adverse perinatal outcome.