Subcutaneous heparin during the first trimester of pregnancy in women withprosthetic heart valves

Background: Oral anticoagulation therapy in pregnant women with prosthetic heart valves is associated with a greater risk of abortion, fetal malformat ions and thromboembolic complications. Aim: To assess the use of subcutaneo us heparin in women with pregnancies of less than 12 weeks as an alternativ e to oral anticoagulation therapy. Material and methods: Pregnant women wer e admitted to the hospital and coumarinics were replaced with not fractiona ted subcutaneous heparin in a dose of 10,000 IU every 12 hours, aiming at p rolonging partial thromboplastin time, 2 or 2(1/2) times. During the hospit alization period, women were taught about the heparin injection technique. Coumarinics were restarted after week 13 of pregnancy until 10 days prior t o the delivery date in which women were again admitted to the hospital and intravenous heparin was used until the delivery. Results: Between 1991 and 1997, this protocol was used during ten pregnancies in seven women aged 19 to 36 years old. Five had a Starr-Edwards prosthests, one had a mitral Bjor k-Shilley prosthesis and one, a double prosthesis (mitral Starr-Machi and a ortic St Jude). Subcutaneous heparin was started in the fifth week of pregn ancy in 1 case, in the sixth week in seven and in the seventh week in two. There was no maternal mortality and one transient ischemic attack without s equelae. One non complaint patient had a Bjork Shilley prosthetic valve dys function that required a valve replacement at the twelfth week of pregnancy and she had a spontaneous abortion at week 15. Other patient had a pneumon ia at week 37 and gave birth to a stillbirth. There were no fetal malformat ions. Conclusions: This therapeutic protocol can be used among Chilean pati ents, but must be restricted to complaint women and a strict surveillance m ust be maintained.