Table 2.

Selected studies examining the impact of anticoagulation on pregnancy outcomes in women with inherited thrombophilia

Author, year, sample sizeInclusion criteriaInherited thrombophilia Sample SizeInterventionLive birth outcome*Overall findings for impact of anticoagulation on live birth
All inherited thrombophilias N (%)Sample size of FVL or PGM homozygosity (N)
Randomized controlled trials 
Quenby, 2023
N  =  326 
Women with FVL, PGM, AT, PC or PS, and RPL 326 (100%) N  =  5 FVL HOM
N  =  5 in Group 1
N  =  0 in Group 2
N  =  2 PGM HOM
N  =  0 in Group 1, N  =  2 in Group 2 
Group 1: LMWH
Group 2: no treatment 
72% Group 1
71% Group 2 
No difference on live birth outcomes 
Karadag, 2020
N  =  174 
Women with FVL and RPL 174 (100%) 62  =  FVL HOM
N  =  23 in Group 1,
N  =  21 in Group 2,
N  =  18 in Group 3 
Group 1: Aspirin
Group 2: LMWH + ASA
Group 3: LMWH 
86.9% Group 1
86.4% Group 2
83.3% Group 3 
No difference on live birth outcomes 
Schleussner, 2015
N  =  449 
Women with a history of at least 2 consecutive early miscarriages or 1 late miscarriage
Patients were then screened for FVL, PGM, AT, PS, PC 
63 (14%) FVL HOM and PGM HOM patients were excluded Group 1: LMWH
Group 2: No treatment 
86% Group 1
86.7% Group 2 
No difference on live birth outcomes 
Rodger, 2014
N  =  289 
Women with FVL, PGM, AT, PS, PC or APS and previous pregnancy complications or venous thromboembolism risk factors
62/164 in intervention group and 67/143 in control group had history of pregnancy loss 
283 (97%) N  =  4 FVL HOM
Did not specify which group 
Group 1: LMWH
Group 2: No treatment 
Pregnancy Loss
Group 1: 8.2%
Group 2: 7% 
No difference on pregnancy loss outcomes 
Martinelli, 2012
N  =  135 
Women with FVL, PGM, AT, PS, PC and history of pregnancy complications (25/67 in intervention and 24/68 in control group had a history of intrauterine fetal death) 131 (97%) Did not specify Group 1: LMWH
Group 2: No treatment 
Intrauterine fetal death
Group 1: 3.2%
Group 2: 1.5% 
No difference in intrauterine fetal death 
Visser, 2011
N  =  207 
Women with RPL, with or without FVL, PGM, PS, PC 26 (12.5%) Specifically excluded high risk thrombophilia of FVL HOM or PGM HOM Group 1: LMWH + placebo
Group 2: LMWH + ASA
Group 3: ASA 
Group 1: 71%
Group 2: 65%
Group 3: 61%
Outcomes in IT:
Group 1: 13/17 Group 2: 9/15
Group 3: 12/19 
No difference on pregnancy loss outcomes 
Clark, 2010
N  =  294 
Women with at least 2 consecutive early pregnancy losses, once enrolled each was screened for IT 10 (3%) None Group 1: LMWH + ASA
Group 2: No treatment 
Pregnancy loss
Group 1: 22%
Group 2: 20% 
No difference on pregnancy loss outcomes 
Kaandorp, 2010
N  =  364 
Women with FVL, PGM, AT, PS, PC and a history of unexplained recurrent miscarriages 47 (12%) Did not specify Group 1: LMWH + ASA
Group 2:ASA
Group 3: Placebo 
Group 1: 69.1%
Group 2: 61.6%
Group 3: 67% 
No difference in live birth rate 
Laskin, 2009
N  =  88 
Women with FVL, PGM, PS, PC, MTHFR mutation, positive antinuclear antibody, or positive antiphospholipid antibody and a history of recurrent pregnancy loss 19 (21.5%) None Group 1: LMWH + ASA
Group 2: ASA 
Group 1: 77.8%
Group 2: 79.1% 
No difference on pregnancy loss outcomes 
Gris, 2004
N  =  160 
Women with FVL, PGM, PS, and 1 unexplained pregnancy loss 160 (100%) None Group 1: LMWH
Group 2: ASA 
Group 1: 86%
Group 2: 29% 
The only RCT that showed a benefit to LMWH 
Observational Studies 
Dugalic, 2019
Prospective
N  =  358 
Women with (FVL, PGM, AT, PC, PS; also included PA1, and MTHFR) with previous pregnancy outcomes including miscarriage and intrauterine fetal demise 195 (54%) Did not specify Group 1: LMWH
Group 2: Control 
Group 1: 100%
Group 2: 91.5% 
Live birth rate was higher when LMWH was implemented 
Calvijo, 2019
Retrospective
N  =  88 
Women with IT (FVL, PGM, AT, PC, PS)
Early pregnancy loss <10 weeks (26/88)
Late pregnancy loss >10 weeks (11/88) 
88 (100%) None Group 1: before IT diagnosis, and no LMWH
Group 2: following IT, treated with LMWH 
OR for miscarriage (M) or fetal loss (FL) following LMWH use:
M: 0.41 (0.20-0.82) P  =  0.012
FL: 0.08 (00.5-1.39) P  =  0.085 
Miscarriage rate was lower when LMWH was implemented 
Aracic, 2016
Prospective
N  =  50 
Women with IT and history of adverse pregnancy outcomes (conventional IT: FVL, PGM, AT, PC, PS) and others included (MTHFR, PAI-1 polymorphism, ACE polymorphism)
80/128 prior pregnancies resulted in first or second term pregnancy loss 
50 (100%) None Group 1: LMWH
Group 2  =  no treatment 
Group 1: 96%
Group 2: 37.5% 
Live birth rate was higher when LMWH was implemented 
Aynioglu, 2016
Retrospective
N  =  153 
Women with history of prior pregnancy loss and IT (FVL, PGM, AT, PS, PC and included MTHFR) 153 (100%) N  =  1 FVL HOM Group 1
N  =  1 PGM HOM Group 2 
Group 1: LMWH + ASA
Group 2: untreated 
Proportion of the 85 live births in the cohort attributed to each group:
Group 1: 80%
Group 2: 20% 
Live birth rate was higher in intervention group 
Sokol, 2016
Retrospective
N  =  70 
Women with IT (FVL, PGM, AT, PS, PC, and MTHFR) with mean number of prior pregnancy loss >1 70 (100%) N  =  1 FVL HOM
N  =  1 PGM HOM 
Group 1: LMWH
Group 2: control 
Miscarriage rate
Group 1: 1.7%
Group 2: 30% 
Miscarriage rate was lower when LMWH was implemented 
Tormene, 2012
Bidirectional
N  =  416 
Women with FVL or PGM
Mean number of prior pregnancy loss
Group 1: 1.15
Group 2: 1.58
Group 3: 1.52
Group 4: 0.53 
416 (100%) Group 1:
N  =  1 PGM HOM
N  =  8 FVL HOM
N  =  14 compound heterozygotes
Group 2: none
Group 3: none
Group 4:
N  =  2 PGM HOM, N  =  14 FVL HOM,
N  =  23 compound heterozygotes 
Group 1: LMWH
Group 2: LMWH + ASA
Group 3: ASA
Group 4: none 
LMWH protective effect on miscarriages (OR 0.52; 95% CI, 0.29-0.94) Miscarriage rate was lower when LMWH was implemented 
Kupferminc, 2011
Retrospective
N  =  116 
Women with IT (FVL, PGM, PS, PC) and history of adverse pregnancy outcomes
17/87 in Group 1 had pregnancy loss
6/29 in Group 2 had pregnancy loss 
116 (100%) Did not specify Group 1: LMWH
Group 2: no treatment 
Pregnancy loss >20 weeks
Group 1: 0
Group 2: 7% 
LMWH did not change pregnancy loss >20 weeks 
Grandone, 2008
Retrospective
N  =  32 
Women with pregnancy loss and AT, PS or PS 32 (100%) Did not specify Group 1: LMWH in 8 pregnancies
Group 2: no treatment in 95 pregnancies 
Group 1: 88.9%
Group 2: 28.4% 
Live birth rate was higher with LMWH 
Carp, 2003
Prospective
N  =  85 
Women with IT (FVL, PGM, AT, PS, PC, and MTHFR) and pregnancy loss 85 (100%) Did not specify Group 1: LMWH
Group 2: no treatment 
Group 1: 70.2%
Group 2: 43.8% 
Live birth rate was higher with LMWH 
Brenner, 2000
Prospective
N  =  50 
Women with IT (FVL, PGM, PS, PC, MTHFR), also included APS and recurrent pregnancy loss 50 (100%) Did not specify Group 1: LMWH
Group 2: no treatment 
Group 1:75%
Group 2: 20% 
Live birth rate was higher with LMWH 
Author, year, sample sizeInclusion criteriaInherited thrombophilia Sample SizeInterventionLive birth outcome*Overall findings for impact of anticoagulation on live birth
All inherited thrombophilias N (%)Sample size of FVL or PGM homozygosity (N)
Randomized controlled trials 
Quenby, 2023
N  =  326 
Women with FVL, PGM, AT, PC or PS, and RPL 326 (100%) N  =  5 FVL HOM
N  =  5 in Group 1
N  =  0 in Group 2
N  =  2 PGM HOM
N  =  0 in Group 1, N  =  2 in Group 2 
Group 1: LMWH
Group 2: no treatment 
72% Group 1
71% Group 2 
No difference on live birth outcomes 
Karadag, 2020
N  =  174 
Women with FVL and RPL 174 (100%) 62  =  FVL HOM
N  =  23 in Group 1,
N  =  21 in Group 2,
N  =  18 in Group 3 
Group 1: Aspirin
Group 2: LMWH + ASA
Group 3: LMWH 
86.9% Group 1
86.4% Group 2
83.3% Group 3 
No difference on live birth outcomes 
Schleussner, 2015
N  =  449 
Women with a history of at least 2 consecutive early miscarriages or 1 late miscarriage
Patients were then screened for FVL, PGM, AT, PS, PC 
63 (14%) FVL HOM and PGM HOM patients were excluded Group 1: LMWH
Group 2: No treatment 
86% Group 1
86.7% Group 2 
No difference on live birth outcomes 
Rodger, 2014
N  =  289 
Women with FVL, PGM, AT, PS, PC or APS and previous pregnancy complications or venous thromboembolism risk factors
62/164 in intervention group and 67/143 in control group had history of pregnancy loss 
283 (97%) N  =  4 FVL HOM
Did not specify which group 
Group 1: LMWH
Group 2: No treatment 
Pregnancy Loss
Group 1: 8.2%
Group 2: 7% 
No difference on pregnancy loss outcomes 
Martinelli, 2012
N  =  135 
Women with FVL, PGM, AT, PS, PC and history of pregnancy complications (25/67 in intervention and 24/68 in control group had a history of intrauterine fetal death) 131 (97%) Did not specify Group 1: LMWH
Group 2: No treatment 
Intrauterine fetal death
Group 1: 3.2%
Group 2: 1.5% 
No difference in intrauterine fetal death 
Visser, 2011
N  =  207 
Women with RPL, with or without FVL, PGM, PS, PC 26 (12.5%) Specifically excluded high risk thrombophilia of FVL HOM or PGM HOM Group 1: LMWH + placebo
Group 2: LMWH + ASA
Group 3: ASA 
Group 1: 71%
Group 2: 65%
Group 3: 61%
Outcomes in IT:
Group 1: 13/17 Group 2: 9/15
Group 3: 12/19 
No difference on pregnancy loss outcomes 
Clark, 2010
N  =  294 
Women with at least 2 consecutive early pregnancy losses, once enrolled each was screened for IT 10 (3%) None Group 1: LMWH + ASA
Group 2: No treatment 
Pregnancy loss
Group 1: 22%
Group 2: 20% 
No difference on pregnancy loss outcomes 
Kaandorp, 2010
N  =  364 
Women with FVL, PGM, AT, PS, PC and a history of unexplained recurrent miscarriages 47 (12%) Did not specify Group 1: LMWH + ASA
Group 2:ASA
Group 3: Placebo 
Group 1: 69.1%
Group 2: 61.6%
Group 3: 67% 
No difference in live birth rate 
Laskin, 2009
N  =  88 
Women with FVL, PGM, PS, PC, MTHFR mutation, positive antinuclear antibody, or positive antiphospholipid antibody and a history of recurrent pregnancy loss 19 (21.5%) None Group 1: LMWH + ASA
Group 2: ASA 
Group 1: 77.8%
Group 2: 79.1% 
No difference on pregnancy loss outcomes 
Gris, 2004
N  =  160 
Women with FVL, PGM, PS, and 1 unexplained pregnancy loss 160 (100%) None Group 1: LMWH
Group 2: ASA 
Group 1: 86%
Group 2: 29% 
The only RCT that showed a benefit to LMWH 
Observational Studies 
Dugalic, 2019
Prospective
N  =  358 
Women with (FVL, PGM, AT, PC, PS; also included PA1, and MTHFR) with previous pregnancy outcomes including miscarriage and intrauterine fetal demise 195 (54%) Did not specify Group 1: LMWH
Group 2: Control 
Group 1: 100%
Group 2: 91.5% 
Live birth rate was higher when LMWH was implemented 
Calvijo, 2019
Retrospective
N  =  88 
Women with IT (FVL, PGM, AT, PC, PS)
Early pregnancy loss <10 weeks (26/88)
Late pregnancy loss >10 weeks (11/88) 
88 (100%) None Group 1: before IT diagnosis, and no LMWH
Group 2: following IT, treated with LMWH 
OR for miscarriage (M) or fetal loss (FL) following LMWH use:
M: 0.41 (0.20-0.82) P  =  0.012
FL: 0.08 (00.5-1.39) P  =  0.085 
Miscarriage rate was lower when LMWH was implemented 
Aracic, 2016
Prospective
N  =  50 
Women with IT and history of adverse pregnancy outcomes (conventional IT: FVL, PGM, AT, PC, PS) and others included (MTHFR, PAI-1 polymorphism, ACE polymorphism)
80/128 prior pregnancies resulted in first or second term pregnancy loss 
50 (100%) None Group 1: LMWH
Group 2  =  no treatment 
Group 1: 96%
Group 2: 37.5% 
Live birth rate was higher when LMWH was implemented 
Aynioglu, 2016
Retrospective
N  =  153 
Women with history of prior pregnancy loss and IT (FVL, PGM, AT, PS, PC and included MTHFR) 153 (100%) N  =  1 FVL HOM Group 1
N  =  1 PGM HOM Group 2 
Group 1: LMWH + ASA
Group 2: untreated 
Proportion of the 85 live births in the cohort attributed to each group:
Group 1: 80%
Group 2: 20% 
Live birth rate was higher in intervention group 
Sokol, 2016
Retrospective
N  =  70 
Women with IT (FVL, PGM, AT, PS, PC, and MTHFR) with mean number of prior pregnancy loss >1 70 (100%) N  =  1 FVL HOM
N  =  1 PGM HOM 
Group 1: LMWH
Group 2: control 
Miscarriage rate
Group 1: 1.7%
Group 2: 30% 
Miscarriage rate was lower when LMWH was implemented 
Tormene, 2012
Bidirectional
N  =  416 
Women with FVL or PGM
Mean number of prior pregnancy loss
Group 1: 1.15
Group 2: 1.58
Group 3: 1.52
Group 4: 0.53 
416 (100%) Group 1:
N  =  1 PGM HOM
N  =  8 FVL HOM
N  =  14 compound heterozygotes
Group 2: none
Group 3: none
Group 4:
N  =  2 PGM HOM, N  =  14 FVL HOM,
N  =  23 compound heterozygotes 
Group 1: LMWH
Group 2: LMWH + ASA
Group 3: ASA
Group 4: none 
LMWH protective effect on miscarriages (OR 0.52; 95% CI, 0.29-0.94) Miscarriage rate was lower when LMWH was implemented 
Kupferminc, 2011
Retrospective
N  =  116 
Women with IT (FVL, PGM, PS, PC) and history of adverse pregnancy outcomes
17/87 in Group 1 had pregnancy loss
6/29 in Group 2 had pregnancy loss 
116 (100%) Did not specify Group 1: LMWH
Group 2: no treatment 
Pregnancy loss >20 weeks
Group 1: 0
Group 2: 7% 
LMWH did not change pregnancy loss >20 weeks 
Grandone, 2008
Retrospective
N  =  32 
Women with pregnancy loss and AT, PS or PS 32 (100%) Did not specify Group 1: LMWH in 8 pregnancies
Group 2: no treatment in 95 pregnancies 
Group 1: 88.9%
Group 2: 28.4% 
Live birth rate was higher with LMWH 
Carp, 2003
Prospective
N  =  85 
Women with IT (FVL, PGM, AT, PS, PC, and MTHFR) and pregnancy loss 85 (100%) Did not specify Group 1: LMWH
Group 2: no treatment 
Group 1: 70.2%
Group 2: 43.8% 
Live birth rate was higher with LMWH 
Brenner, 2000
Prospective
N  =  50 
Women with IT (FVL, PGM, PS, PC, MTHFR), also included APS and recurrent pregnancy loss 50 (100%) Did not specify Group 1: LMWH
Group 2: no treatment 
Group 1:75%
Group 2: 20% 
Live birth rate was higher with LMWH 
*

(or similar) for entire population (not just IT group).

ACE, angiotensin converting enzyme polymorphism; APS, antiphospholipid antibody syndrome; ASA, aspirin; AT, antithrombin deficiency; HOM, homozygosity; PC, protein C deficiency; PS, protein S deficiency.

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