[Protein S and pregnancy]. / Protein S i trudnoca.

Protein S is a cofactor of protein C which lowers the activated factors VIII and V. Pregnancy reduces the level of protein S to 40-50% of normal levels but it is not clear whether the lowered protein S levels increase the risk of developing thrombo-embolism during pregnancy. This is a report of a 39-year old woman, multipara whose pregnancy terminated as IUGR and who had previously two stillbirths. After the third pregnancy loss of functional protein S level was 20%. Two months after delivery protein S activity was 60%. As it was suspected that low protein S level was a risk factor of complications in pregnancy anticoagulant therapy was used. Thereafter, pregnancy and delivery at 38.5 weeks of gestation were successful and the baby weighted 3400 gr at birth. The aim of this report is to emphasize the important role of follow-up of the level of protein S in pregnancy in order to avoid the risk of thrombo-embolism in pregnancy. Anticoagulant therapy is very successful in such a pregnancy and may ensure safe birth.