Prophylactic low-molecular-weight heparin in women with thrombophilia undergoing in vitro fertilization

To verify whether low-molecular-weight heparin (LMWH) could increase pregnancy rates and/or decrease abortion rates in women with thrombophilia undergoing assisted reproduction cycles.

Cross-sectional study with patients undergoing in vitro fertilization (IVF) (N = 104). Women without thrombophilia (control group, n = 20), women with thrombophilia who did not receive LMWH (untreated group, n = 30), and women with thrombophilia, treated with daily enoxaparin from the day of embryo transfer until week 36 of gestation (treated group, n = 54). All women underwent controlled ovarian hyperstimulation. IVF was performed by intracytoplasmic sperm injection, and embryos were transferred on day 3. Pregnancy was detected by β-human chorionic gonadotropin (biochemical pregnancy) and fetal heartbeat at week 5 to 6. Ongoing pregnancy was determined by ultrasound on week 12.

Patients in the untreated thrombophilia group presented with significantly lower ongoing pregnancy rates and live birth rates and significantly higher early pregnancy loss and abortion rates when compared with the control and the treated thrombophilia groups.

In women with diagnosed coagulation disorders, use of LMWH is important to avoid miscarriages.