Outcome of pregnancy in women with hereditary thrombophilia.

OBJECTIVES

The aims of this study are to review the outcome of pregnancy in women with thrombophilia, and investigate the possible beneficial effect of heparin therapy in these women.

METHODS

We reviewed the hospital records of 126 women who were referred to the high-risk obstetrical hematology clinic between June 1996 and December 1999. The placental histology and outcome of 39 pregnancies in 24 women with hereditary thrombophilia were studied, and pregnancies which were treated with heparin were compared with those without treatment.

RESULTS

An adverse pregnancy outcome occurred in 54% of the pregnancies. All seven miscarriages (18%) occurred in pregnancies that were not treated with heparin. However, heparin treatment did not prevent the development of obstetric complications in later pregnancies (odds ratio=0.955, 95% C.I.=0.255-3.577, Fisher's exact test). Excluding miscarriages, 28% of the placentas had thrombotic lesions, and the pregnancies with placental thrombotic lesions were more likely to have complications than those pregnancies without placental abnormalities (P=0.023, C.I.=1.257-5.197, Fisher's exact test).

CONCLUSIONS

Pregnancy complications in cases of hereditary thrombophilia may be related to placental abnormalities. Heparin therapy is likely to be useful in preventing miscarriage in cases of hereditary thrombophilia.