Abstract Number: PB2520
Meeting: ISTH 2020 Congress
Background: Pregnancy is associated with an increased risk of venous thromboembolism (VTE) and inherited thrombophilia also increases the risk of obstetrical complications (OC), but data on the efficacy of low- molecular-weight heparin (LMWH) for their prevention are poor.
Aims: To evaluate the risk of pregnancy-related recurrent VTE and OC with or without LMWH.
Methods: Single-center retrospective cohort study of fertile women (age 18-40 years) referred to our Center from 2000 to 2018 for a thrombophilia screening with at least a previous VTE and at least one pregnancy following VTE ended within September 2018. Women with antiphospholipid antibodies were excluded. Data on pregnancy-related VTE, pregnancy outcomes, and the use of LMWH were collected.
Results: 208 women were included and the first pregnancy following VTE was considered. No thrombotic or bleeding events were observed in 140 pregnancies with LMWH, while 10 out of 68 (15%) pregnancies without LMWH were complicated (7 deep vein thrombosis, 2 pulmonary embolism and one cerebral vein thrombosis). Nine women (90%) with recurrent VTE had had a previous hormone-related event. The incidence of miscarriages was lower in pregnancies with LMWH than in those without, whereas late OC and terminations were similar among the two groups (Table 1). The incidence of late OC was higher in women with thrombophilia who received LMWH (18%) than in those who did not (7%) (Table 2). The incidence of terminations was doubled in women with thrombophilia (12%) than in those without (6%).
Conclusions: LMWH prophylaxis during pregnancy resulted effective and safe for the prevention of recurrent VTE and miscarriage, but not of late OC, particularly in women with thrombophilia. A previous hormone-related VTE was a prevalent condition for pregnancy-related recurrent VTE. Women with thrombophilia decide for terminations twice more than those without.
| Pregnancy LMWH + N= 140 | Pregnancy LMWH- N= 68 | RR (95%CI) | |
| Full term | 93 (72%) | 30 (49%) | 1.5 (1.1-1.9) |
| Miscarriage | 15 (12%) | 19 (31%) | 0.4 (0.2-0.7) |
| Late obstetrical complication | 22 (17%)* | 12 (20%) | 0.9 (0.5-1.6) |
| Termination | 10 (7%) | 7 (10%) | 0.7(0.3-1.7) |
| *9 small for gestational age, 7 preeclampsia, 1 eclampsia,4 placental abruption and 1 stillbirth. 8 small for gestational age, 1 preeclampsia, 1 eclampsia, 1 placental abruption and 1 stillbirth | |||
[Table 1. Pregnancy outcomes with or without low molecular weight heparin antithrombotic prophylaxis.]
| Thrombophilia + N=85 | Thrombophilia – N=123 | |||||
| LMWH + N=67 | LMWH – N=18* | RR (95%CI) | LMWH+ N=73 | LMWH – N=50 | RR (95%CI) | |
| VTE | – | 3 (21%) | – | – | 7 (15%) | – |
| Pregnancy outcome | ||||||
| Full term | 43 (71%) | 6 (43%) | 1.6 (0.9-3.1) | 50 (73%) | 24 (42%) | 1.4 (1.0-1.9) |
| Miscarriage | 7 (12%) | 7 (50%) | 0.2 (0.1-0.5) | 8 (12%) | 12 (21%) | 0.5 (0.2-1.0) |
| Late obstetrical complication | 11 (18%) | 1 (7%) | 2.5(0.4-18.0) | 11 (16%) | 11 (23%) | 0.7 (0.3-1.4) |
| Termination | 6 (9%) | 4 (22%) | 0.4 (0.1-1.3) | 4 (5%) | 3 (6%) | 0.9 (0.2-3.9) |
| *7 women had multiple thrombophilia defects | ||||||
[Table 2. Risk of pregnancy-related VTE and obstetrical complications in women with or without thrombophilia.]
To cite this abstract in AMA style:
Abbattista M, Martinelli I, Gianniello F, Artoni A, Bucciarelli P, Capecchi M, Peyvandi F. Efficacy and Safety of Low-Molecular-Weight Heparin for the Prevention of Pregnancy-Related Recurrent Venous Thromboembolism and Obstetrical Complications [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/efficacy-and-safety-of-low-molecular-weight-heparin-for-the-prevention-of-pregnancy-related-recurrent-venous-thromboembolism-and-obstetrical-complications/. Accessed March 3, 2021.« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/efficacy-and-safety-of-low-molecular-weight-heparin-for-the-prevention-of-pregnancy-related-recurrent-venous-thromboembolism-and-obstetrical-complications/