OC-19 Antithrombothic prophylaxis and ART procedures: an Italian prospective cohort study

Assisted reproductive technologies (ART) have been widely used in couples suffering from infertility. The clinical pregnancy rate is low, varying from 20 to 35% per cycle started. The role of antithrombotic drugs in improving pregnancy rate is controversial, although some Fertility Clinics have adopted different protocols either in thrombophilic and non-thrombophilic women. Between March 1998 and July 2011 we prospectively evaluated a cohort of 1107 women approaching ART (2214 cycles) consecutively referred to our Thrombosis Unit (S. Giovanni R.). All were investigated for inherited and acquired thrombophilias. Median follow-up was 34.53 months (range 2–143 months). At the enrolment, 327 women (29.5%) have experienced 946 ART cycles. One hundred twenty-two (37.3%) women obtained a clinical pregnancy (176 pregnancies), with 21 (16%) live-born children. Overall, 115 (10.4%) women carried al least one thrombophilia (45 the FVL, 57 the PTm, 13 severe thrombophilias). After screening, 595 (53.8%) underwent at least 1 attempt (1268 cycles, 27 lost to follow-up). In 424 (33.4%) cycles an antithrombotic prophylaxis (342 treated with aspirin, 66 with LMWH, 16 with aspirin+LMWH) was used. Pregnancy rate was 21.4% (265/1241 cycles) with 171 (13.8%) live-born children. Clinical pregnancies were not significantly different in treated vs untreated cycles (p: 0.42, OR: 1.1, 95% CI: 0.8–1.5). The rate of live-born was not significantly different in treated vs untreated cycles (p: 0.73, OR: 0.9, 95% CI: 0.6–1.3) prophylaxis. Overall, 7 thrombotic events (3 PE, 3 DVT, 1 arterial thrombosis; 6 of them in untreated women) were observed. Among them, 4 (0.3%, 2 DVT, 2 PE) occurred after screening, only 1 during LMWH prophylaxis. In women undergoing ART procedures, the use of antithrombotic prophylaxis is not associated with an improved pregnancy rate or live-born children. Thrombotic complications are less frequent in women receiving an antithrombotic prophylaxis