Thrombophilia and placenta-mediated pregnancy complications: from the bench to bedside to policy

Aspirin, low molecular weight heparin, or both in preventing pregnancy complications in women with recurrent pregnancy loss and factor V Leiden mutation

Objective: The aim of this study was to compare the effects of low molecular weight heparin (LMWH), LMWH plus low dose aspirin, or low dose aspirin only on pregnancy outcomes in recurrent pregnancy loss (RPL) patients with factor V Leiden mutation (FVLM).Materials and methods: A total of 2764 RPL patients were evaluated in for the etiology of RPL. Mutations in factor V Leiden homozygous and heterozygous were determined. Subsequently, 196 of these patients were diagnosed with FVLM and included in the study; of these 174 completed the study. At the sixth week of gestation of subsequent pregnancy participants were randomly distributed into three groups. Group A (n = 61) was composed of patients with an oral dose of 100 mg aspirin daily, Group B (n = 59) consisted of patients using 40 mg enoxaparin and 100 mg orally aspirin daily, and Group C (n = 54) included patients using 40 mg enoxaparin daily during pregnancy.Results: Among the 174 patients who completed the study, the live birth and miscarriage rates were similar for the three groups (p = .843 and p = .694, respectively). There was no significant difference among the groups in rates of eclampsia, placental abruption, intrauterine fetal growth restriction and gestational diabetes mellitus. The number of preeclamptic patients was significantly higher in Group A than Groups B and C. The levels of preterm birth was significantly higher in Group A than Groups B and C.Conclusion: Using low dose aspirin, LMWH plus aspirin, or LMWH alone yielded comparable live birth rates in RPL patients with FVLM. However, LMWH decreased the risk of preeclampsia in this group of patients. LMWH might therefore have a preventive role regarding preeclampsia.

Prophylactic Low Molecular Weight Heparin Improving Perinatal Outcome in Non-thrombophilic Placental-Mediated Complications

OBJECTIVE

To study the role of low molecular weight heparin (LMWH) in perinatal outcome.

METHODS

A randomized, case control study was conducted at Safdarjang hospital, New Delhi. Patients were recruited from Sept. 2011 to May 2013 and were followed up till delivery. Thirty cases and controls were enrolled which comprised non-thrombophilic patients with previous history of preeclampsia, fetal growth restriction, abruption, and stillbirth (>20 weeks). Study group received daily single dose of LMWH depending upon the weight, subcutaneously; it was started before 15 weeks of gestation and continued up to 36 weeks. Nursery/NICU admission, APGAR score at 0 and 5 min, birth weight, gestational age at delivery, mode of delivery were observed among the interventional and control groups.

RESULT

There was substantial reduction (80 %) in nursery/NICU admission. The mean gestational age and birth weight of the cases were observed to be higher as compared to those of control (38.05 ± 2.02 vs. 37.58 ± 2.06 weeks and 2770 ± 400 vs. 2530 ± 0.533 g).

CONCLUSION

Prophylactic LMWH before 15 weeks of gestation improved the perinatal outcome in non-thrombophilic pregnant women.

Low-molecular-weight heparin for prevention of placenta-mediated pregnancy complications: protocol for a systematic review and individual patient data meta-analysis (AFFIRM)

BACKGROUND

Placenta-mediated pregnancy complications include pre-eclampsia, late pregnancy loss, placental abruption, and the small-for-gestational age newborn. They are leading causes of maternal, fetal, and neonatal morbidity and mortality in developed nations. Women who have experienced these complications are at an elevated risk of recurrence in subsequent pregnancies. However, despite decades of research no effective strategies to prevent recurrence have been identified, until recently. We completed a pooled summary-based meta-analysis that strongly suggests that low-molecular-weight heparin reduces the risk of recurrent placenta-mediated complications. The proposed individual patient data meta-analysis builds on this successful collaboration. The project is called AFFIRM, An individual patient data meta-analysis oF low-molecular-weight heparin For prevention of placenta-medIated pRegnancy coMplications.

METHODS/DESIGN

We conducted a systematic review to identify randomized controlled trials with a low-molecular-weight heparin intervention for the prevention of recurrent placenta-mediated pregnancy complications. Investigators and statisticians representing eight trials met to discuss the outcomes and analysis plan for an individual patient data meta-analysis. An additional trial has since been added for a total of nine eligible trials. The primary analyses from the original trials will be replicated for quality assurance prior to recoding the data from each trial and combining it into a common dataset for analysis. Using the anonymized combined data we will conduct logistic regression and subgroup analyses aimed at identifying which women with previous pregnancy complications benefit most from treatment with low-molecular-weight heparin during pregnancy.

DISCUSSION

The goal of the proposed individual patient data meta-analysis is a thorough estimation of treatment effects in patients with prior individual placenta-mediated pregnancy complications and exploration of which complications are specifically prevented by low-molecular-weight heparin.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (International Prospective Registry of Systematic Reviews) 23 December 2013, CRD42013006249.

Low dose aspirin and low-molecular-weight heparin in the treatment of pregnant Libyan women with recurrent miscarriage

Background

Recurrent miscarriage is a major women’s health problem. Aspirin and heparin have been shown to have potentially beneficial effects on trophoblast implantation. However, few published data on this issue are available from developing countries.

Methods

An open clinical trial was conducted at the Department of Obstetrics and Gynecology at Misurata Teaching Hospital in Libya from January 2009 to December 2010 to investigate the effects of treatment with low dose aspirin (LDA) versus treatment with low-molecular-weight-heparin (LMWH) in combination with LDA on patients with a history of recurrent miscarriages. A total of 150 women were enrolled in the study. Women were eligible for the study if they had a history of three or more consecutive miscarriages. Participants were randomly assigned to receive either LDA (75 mg daily) alone or a combination of LDA and LMWH (75 women per treatment group). The primary outcomes were the rate of miscarriages and live births for each group.

Results

Compared with the group who received LDA alone, the combination group had a significantly lower number of miscarriages (22/75 [29%] vs. 43/75 [47%], P < 0.001) and had a significantly higher number of live births (53/75 [71%] vs. 32/75 [42%], P < 0.001). Two preterm infants in the LDA group and three in the combination group were admitted to the neonatal intensive care unit. There were no significant differences in the mean (SD) birth weights of neonates born in either group (2955.4 ± 560 vs. 3050 ± 540 g for the LDA and combination groups, respectively, P = 0.444). There were no congenital abnormalities detected in either group.

Conclusion

The combination of LDA and LMWH is better than LDA alone for the maintenance of pregnancy in patients with recurrent first trimester miscarriage.

Trial registration

NCT01917799

Heparin in pregnant women with previous placenta-mediated pregnancy complications: a prospective, randomized, multicenter, controlled clinical trial

To assess whether antithrombotic prophylaxis with low-molecular-weight heparin effectively prevents recurrence of late pregnancy complications, 135 women with previous history of preeclampsia, hemolytic anemia, elevated liver enzymes and low platelet count syndrome, intrauterine fetal death, fetal growth restriction, or placental abruption who had been referred within the 12th gestational week were randomized to medical surveillance alone (n = 68) or combined to open-label nadroparin (3800 IU daily subcutaneous injections) treatment (n = 67) in the setting of a randomized, parallel-group, superiority trial, run in Italy from April 2007 to April 2010. Primary outcome was a composite end point of late-pregnancy complications. Analysis was by intention to treat. The study was stopped for futility at the time of the first planned interim analysis. Among the 128 women eventually available for final analyses, 13 of the 63 (21%) randomized to nadroparin compared with 12 of the 65 (18%) on medical surveillance alone progressed to the primary end point. The absolute event risk difference between treatment arms (2.2; -1.6 to 16.0) was not statistically significant (P = .76). Thus, nadroparin did not prevent late-pregnancy complications in women at risk of recurrence. This finding challenges the role of antithrombotic prophylaxis with low-molecular-weight heparin in the prevention of recurrent late pregnancy complications The trial was registered at http://ricerca-clinica.agenziafarmaco.it as EudraCT 2006-004205-26.

Low molecular weight heparin versus no treatment in women with previous severe pregnancy complications and placental findings without thrombophilia

Low molecular weight heparin (LMWH) treatment has been recommended for pregnant women with previous adverse pregnancy and who were diagnosed as having a thrombophilia. We now examined the effect of LMWH on pregnant women without thrombophilias who had severe pregnancy complications and placental vasculopathy in an earlier pregnancy. Seventy-two women with a history of severe preeclampsia, fetal growth restriction (FGR) less than fifth percentile, severe placental abruption and/or stillbirth after 20 weeks, whose thrombophilia workup was negative, were enrolled. Placental vasculopathy was defined as villous infarcts, fibrinoid necrosis of decidual vessels, fetal vessel thrombosis, evidence of placental abruption and perivillous fibrin deposition. The study group consisted of 32 pregnant women who were treated with LMWH and 40 pregnant women who were not treated with LMWH (control group) in their ensuing pregnancy in our institution between 2003 and 2007. The incidences of severe preeclampsia, FGR, placental abruption and stillbirth in the previous pregnancies were similar for both groups. The incidences of severe preeclampsia and placental abruption in the study group in the index pregnancy were significantly lower than the control group (3.13 versus 20%, P = 0.03; and 0 versus 15%, P = 0.03, respectively). The respective incidence of FGR was 6.25 versus 22.5%, and of overall adverse outcome was 9.4 versus 60% (P = 0.001). Treatment with LMWH may reduce the rate of the recurrence of severe pregnancy complications and significant placental vasculopathy in women without thrombophilias.

Low molecular weight heparin treatment during subsequent pregnancies of women with inherited thrombophilia and previous severe pregnancy complications

OBJECTIVES

The aim of this study was to investigate the effect of low molecular weight heparin (LMWH) on incidence of adverse outcome in women with thrombophilias and previous severe pregnancy complications.

MATERIALS AND METHODS

The study included 116 women with history of severe preeclampsia, fetal growth restriction (FGR)  ≤5th percentile, severe placental abruption and stillbirth  >20 weeks carrying factor V Leiden or prothrombin mutations, or protein S or C deficiency. Eighty-seven women referred to us for follow-up were treated with LMWH starting from weeks 5-15 (study group, A). Twenty-nine non-treated women referred only for delivery in our institution constituted the control group (B).

RESULTS

The incidence of severe pregnancy complications in previous pregnancies was similar in both groups. Following treatment with LMWH, the incidence of severe preeclampsia was 4.6% in group A compared to 21% in group B, p = 0.007. The incidence of FGR was 2.3% in group A compared to 21% in group B, p = 0.03. The incidence of stillbirth or placental abruption was 0% in group A compared to 7% in group B, p = 0.06. The total incidence of adverse outcome was 7% in group A compared to 55% in group B, p = 0.0001.

CONCLUSION

LMWH treatment of women with previous severe pregnancy complications and thrombophilias significantly reduces the rate of recurrence.

SPIN (Scottish Pregnancy Intervention) study: a multicenter, randomized controlled trial of low-molecular-weight heparin and low-dose aspirin in women with recurrent miscarriage

To assess whether treatment with enoxaparin and low-dose aspirin, along with intensive pregnancy surveillance, reduces rate of pregnancy loss compared with intensive pregnancy surveillance alone in women with history of 2 or more consecutive previous pregnancy losses, a parallel group, multicenter, randomized controlled trial was performed in the United Kingdom and New Zealand. Participants (n = 294) presenting for initial antenatal care at fewer than 7 weeks' gestation with history of 2 or more consecutive previous pregnancy losses at 24 or fewer weeks' gestation and no evidence of anatomic, endocrine, chromosomal, or immunologic abnormality were randomly assigned to receive either enoxaparin 40 mg subcutaneously and 75 mg of aspirin orally once daily along with intense pregnancy surveillance or intense pregnancy surveillance alone from random assignment until 36 weeks' gestation. The primary outcome measure was pregnancy loss rate. Of the 147 participants receiving pharmacologic intervention, 32 (22%) pregnancy losses occurred, compared with 29 losses (20%) in the 147 subjects receiving intensive surveillance alone, giving an odds ratio of 0.91 (95% confidence interval, 0.52-1.59) of having a successful pregnancy with pharmacologic intervention. Thus, we observed no reduction in pregnancy loss rate with antithrombotic intervention in pregnant women with 2 or more consecutive previous pregnancy losses. The trial was registered at http://www.controlled-trials.com as ISRCTN06774126.

Anticoagulants to prevent placenta-mediated pregnancy complications: a review of current evidence

PURPOSE OF REVIEW

Placenta-mediated pregnancy complications are relatively common and are associated with significant morbidity and mortality. Although anticoagulants are increasingly being used to prevent these complications, the evidence supporting their use is limited. This article will focus on reviewing the current evidence base for the use of anticoagulants to prevent placenta-mediated pregnancy complications in women with or without identifiable thrombophilia.

RECENT FINDINGS

Controversy exists whether inherited or acquired thrombophilias cause placenta-mediated complications. Small randomized studies with methodological limitations suggest that antepartum anticoagulant prophylaxis will reduce pregnancy loss in women with both acquired and inherited thrombophilia and prior pregnancy loss. There are no published randomized controlled trials examining anticoagulant prophylaxis in thrombophilic women with prior preeclampsia, intrauterine growth restriction or placental abruption. More recently, the benefit of antepartum anticoagulant prophylaxis in women without thrombophilia with prior placenta-mediated pregnancy complications has been suggested in a small pilot randomized trial.

SUMMARY

Overall, although antepartum anticoagulant prophylaxis has the potential to reduce placenta-mediated pregnancy complications in women with and without identifiable thrombophilia, the data generated by these trials are methodologically limited and inadequate. Hence, we conclude that further trials are required prior to adopting the use of antepartum anticoagulant prophylaxis to prevent placenta-mediated pregnancy complications in routine clinical practice.