Early Prophylactic Enoxaparin for the Prevention of Preeclampsia and Intrauterine Growth Restriction: A Randomized Trial

Effect of low-molecular-weight heparin on placenta-mediated fetal growth restriction in a tertiary referral hospital: A 7-year retrospective cohort study

OBJECTIVE

To investigate the effect of low-molecular-weight heparin (LMWH) on placenta-mediated fetal growth restriction (FGR).

METHODS

A cohort of 570 pregnant women diagnosed with placenta-mediated FGR were enrolled from January 1, 2015 through to December 31, 2021. A birth database, including demographic data, antenatal complications, and detailed delivery and newborn data, was created to collect variables from the Hospital Information System (HIS) Database. The unique personal registration number, assigned to each patient on first registration with HIS in the West China Second University Hospital, was used to link these patients. LMWH use was defined as at least 1-week prescription from diagnosis of placenta-mediated FGR. Pregnant women received LMWH (Enoxaparin 4000 IU/day) by self-administered subcutaneous injection only when they agreed and signed informed consent. Primary outcome was intrauterine fetal death after 20 weeks of pregnancy. Secondary outcomes included preterm birth (PB), Apgar score less than 7 at 1 min, admission to neonatal intensive care unit (NICU), and birth weight. Logistic regression analysis was conducted to compute adjusted odds ratio (aOR) with 95% confidence intervals (CI) for outcomes.

RESULTS

After controlling for confounders, LMWH use was associated with a decreased risk of intrauterine fetal death (aOR 2.49, 95% CI 1.35-4.57, P = 0.003), PB before 37 weeks of pregnancy (aOR 3.35, 95% CI 2.14-5.23, P < 0.001), PB before 34 weeks of pregnancy (aOR 2.25, 95% CI 1.36-3.74, P = 0.002), Apgar score less than 7 at 1 min (aOR 2.25, 95% CI 1.36-3.74, P = 0.002), NICU admission (aOR 2.29, 95% CI 1.48-3.55, P < 0.001). Using LMWH increased the mean birth weight in PB before 32 weeks of pregnancy (mean ± standard deviation [SD] 1126.4 ± 520.0 g, P = 0.020), PB before 37 weeks of pregnancy (mean ± SD 1563.9 ± 502.7 g, P = 0.019), early-onset FGR (mean ± SD 2125.2 ± 665.7 g, P < 0.001), late-onset FGR (mean ± SD 2343.4 ± 507.9, P < 0.001), and non-severe FGR (mean ± SD 2231.1 ± 607.2 g, P < 0.001).

CONCLUSION

Use of LMWH can significantly improve the fetal and neonatal outcomes among pregnant women with placenta-mediated FGR, particularly reducing the risk of intrauterine fetal death.

Low-molecular-weight heparin for the prevention of preeclampsia in high-risk pregnancies without thrombophilia: a systematic review and meta-analysis

OBJECTIVES

To systematically evaluate the efficacy of low molecular weight heparin (LMWH) to prevent preeclampsia in high risk pregnant women without thrombophilia.

SEARCH STRATEGY

PubMed, Embase and the Cochrane library were searched for articles published before 1st August 2022 using the combination keywords "preeclampsia", "Low Molecular Weight Heparin", "LMWH", "Heparin, Low Molecular Weight", "Dalteparin", "Nadroparin", and "Tinzaparin".

SELECTION CRITERIA

Randomized controlled trials evaluating the use of LMWH in pregnant women at high risk of preeclampsia without thrombophilia.

DATA COLLECTION AND ANALYSIS

Ten studies were included in the meta-analysis (1758 patients in total). Outcomes were expressed as relative risk (RR) with 95% confidence intervals (CI).

RESULTS

LMWH reduced the incidence of PE (RR = 0.67; 95% CI = 0.50-0.90; P = 0.009) in high risk pregnant women without thrombophilia. Subgroup analysis found that the prophylactic effect of LMWH was only significant in studies using low-dose aspirin (LDA) as the primary intervention. The combination of LMWH and LDA was also effective for the prevention of preterm birth and fetal growth restriction, but had no effect on the incidence of placenta abruption.

CONCLUSION

For women at high risk of developing preeclampsia without thrombophilia, the combination of LMWH and low-dose aspirin is effective for the prevention of preeclampsia, preterm birth and fetal growth restriction and is superior to LDA alone.

Analysis of a maternal health medicines pipeline database 2000-2021: New candidates for the prevention and treatment of fetal growth restriction

OBJECTIVE

The Accelerating Innovation for Mothers project established a new database of candidate medicines under development between 2000 and 2021 for five pregnancy-related conditions, including fetal growth restriction. The objective was to assess medicines for fetal growth restriction and their potential for clinical use globally.

DESIGN

Landscape analysis.

SETTING

Global (focus on low- and middle-income countries, LMICs).

SAMPLE

Drugs, dietary supplements and biologics under investigation for prevention or treatment of fetal growth restriction.

METHODS

A research pipeline database of medicines was created through searching AdisInsight, PubMed and various grant and clinical trial databases. Analysis of clinical and preclinical candidates were descriptive.

MAIN OUTCOMES MEASURES

Fetal growth restriction candidates in clinical development were identified and ranked as high, medium or low potential based on prespecified criteria, including efficacy, safety and accessibility.

RESULTS

Of the 444 unique candidates in the database across all five pregnancy-related conditions, 63 were for fetal growth restriction. Of these, 31 were in clinical development (phases I, II or III) and 32 were in preclinical development. Three candidates, aspirin, l-arginine and vitamin D, were ranked as having high potential as preventive agents. There were no high-potential candidates for treating fetal growth restriction, although five candidates were ranked as having medium potential: allylestrenol, dalteparin, omega-3 fatty acids, tadalafil, and United Nations International Multiple Micronutrient Antenatal Preparation (UNIMMAP).

CONCLUSIONS

l-Arginine, aspirin and vitamin D are promising, high-potential preventative agents for fetal growth restriction. Based on the medicines pipeline, new pharmacological agents for fetal growth restriction are unlikely to emerge in the near future.

Clinical risk factors for vasculo-placental disorders: results from a prospective case-control study nested in HEMOTHEPP French cohort study

OBJECTIVE

Determine clinical risk factors for vasculo-placental disorders in singleton pregnancies.

DESIGN

Prospective case-control study nested in HEMOTHEPP French cohort.

SETTING

Women delivered between June, 2015 and January, 2019 in any maternity ward of Finistère.

POPULATION

Cases were women with vasculo-placental disorders (pre-eclampsia, intrauterine growth restriction (IUGR), placental abruption or stillbirth). Controls were women matched for age at delivery and parity.

METHODS

Clinical data were collected by obstetricians or midwives during antenatal care visits and delivery, and recorded by trained research assistants.

MAIN OUTCOME MEASURES

Occurrence of a vasculo-placental disorder.

RESULTS

505 women with vasculo-placental disorder (299 pre-eclampsia, 253 IUGR, 44 placental abruptions, 11 stillbirths) and 1515 matched controls were selected out of 20,075 participants. In multivariable analysis, four clinical parameters were associated with pre-eclampsia: obesity (Odd ratio (OR) = 3.11, 95%CI 2.11-4.58), French overseas origin (OR = 4.41, 95%CI 1.87-10.42), previous vasculo-placental disorder (OR = 5.14, 95%CI 2.72-9.70), aspirin during pregnancy (OR = 10.10, 95%CI 1.99-51.08). Three clinical parameters were associated with IUGR: auto-immune/inflammatory disorder (OR = 3.75, 95%CI 1.83-7.68), previous vasculo-placental disorder (OR = 3.63, 95%CI 2.06-6.41), smoking during pregnancy (OR = 2.66, 95%CI 1.91- 3.71). A previous venous thromboembolism (VTE) was associated with IUGR in univariable but not in multivariable analysis (OR = 3.72, 95%CI 0.82-17.00, p = 0.09).

CONCLUSIONS

Clinical risk factors differ between IUGR and pre-eclampsia, the later, but not the former, being associated with cardiovascular risk factors.

Non-Criteria Obstetric Antiphospholipid Syndrome: How Different Is from Sidney Criteria? A Single-Center Study

This study aims to compare the demographic characteristics, clinical features, serology, and fetal-maternal outcomes between women with obstetric antiphospholipid syndrome (APS) and those with non-criteria (NC)-APS and seronegative (SN)-APS. Two-hundred and sixty-three women with APS obstetric morbidity ever pregnant were included. Of those, 66 met the APS classification criteria, 140 were NC-APS, and 57 were SN-APS. Patients with other autoimmune diseases were excluded. Adverse pregnancy outcomes (APO) included early pregnancy loss, fetal death, preeclampsia, abruptio placentae, and preterm birth. The mean age of the study group was 33.6 ± 5.3 years, and patients were followed up for 129.5 ± 81.9 months. In the NC-APS group, 31 (22.1%) did not fulfill clinical and serological criteria (Subgroup A), 49 (35%) did meet clinical but not serologic criteria (Subgroup B), and 60 (42.9%) fulfilled the serologic criteria but not the clinical ones (Subgroup C). The cardiovascular risk burden was higher in the APS group, due to a higher proportion of smoking. Patients with criteria APS received more intensive treatment than patients in the other study groups. The addition of standard of care (SoC) treatment significantly improved live birth and decreased APO in all groups. Significant clinical differences were observed between the study groups. However, when treated with SoC, fetal-maternal outcomes were similar, with a significant improvement in live births and a decrease in APO. Risk stratification in patients with obstetric morbidity associated with APS can help individualize their treatment.

Low-molecular-weight heparin for prevention of preeclampsia and other placenta-mediated complications: a systematic review and meta-analysis

BACKGROUND

Evidence on the impact of low-molecular-weight heparin, alone or in combination with low-dose aspirin, for the prevention for preeclampsia in high-risk patients is conflicting.

OBJECTIVE

We conducted a meta-analysis of studies published to assess the effectiveness of low-molecular-weight heparin for the prevention of preeclampsia and other placenta-related complications in high-risk women.

DATA SOURCES

A systematic search was performed to identify relevant studies, using the databases PubMed and Cochrane Central Register of Controlled Trials, without publication time restrictions.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials comparing treatment with low-molecular-weight heparin or unfractionated heparin (with or without low-dose aspirin), in high-risk women, defined as either history of preeclampsia, intrauterine growth restriction, fetal demise, or miscarriage or being at high risk after first-trimester screening of preeclampsia.

STUDY APPRAISAL AND SYNTHESIS METHODS

The systematic review was conducted according to the Cochrane Handbook guidelines. The primary outcome was the development of preeclampsia. We performed prespecified subgroup analyses according to combination with low-dose aspirin, low-molecular-weight heparin type, gestational age when treatment was started, and study population (patients with thrombophilia, at high risk of preeclampsia or miscarriage). Secondary outcomes included small for gestational age, perinatal death, miscarriage, and placental abruption. Pooled odds ratios with 95% confidence intervals were calculated using a random-effects model. Quality of evidence was assessed using the grading of recommendations assessment, development, and evaluation methodology.

RESULTS

A total of 15 studies (2795 participants) were included. In high-risk women, treatment with low-molecular-weight heparin was associated with a reduction in the development of preeclampsia (odds ratio, 0.62; 95% confidence interval, 0.43-0.90; P=.010); small for gestational age (odds ratio, 0.61; 95% confidence interval, 0.44-0.85; P=.003), and perinatal death (odds ratio, 0.49; 95% confidence interval, 0.25-0.94; P=.030). This reduction was stronger if low-molecular-weight heparin was started before 16 weeks' gestation (13 studies, 2474 participants) for preeclampsia (odds ratio, 0.55; 95% confidence interval, 0.39-0.76; P=.0004). When only studies including low-dose aspirin as an intervention were analyzed (6 randomized controlled trials, 920 participants), a significant reduction was observed in those with combined treatment (low-molecular-weight heparin plus low-dose aspirin) compared with low-dose aspirin alone (odds ratio, 0.62; 95% confidence interval, 0.41-0.95; P=.030). Overall, adverse events were neither serious nor significantly different. Quality of evidence ranged from very low to moderate, mostly because of the lack of blinding, imprecision, and inconsistency.

CONCLUSION

Low-molecular-weight heparin use was associated with a significant reduction in the risk of preeclampsia and other placenta-mediated complications in high-risk women and when treatment was started before 16 weeks' gestation. Combined treatment with low-dose aspirin was associated with a significant reduction in the risk of preeclampsia compared with low-dose aspirin alone. However, there exists important clinical and statistical heterogeneity, and therefore, these results merit confirmation in large well-designed clinical trials.

Arterial Stiffness as a Cardiovascular Risk Factor for the Development of Preeclampsia and Pharmacopreventive Options

Arterial stiffness (AS) describes the rigidity of the arterial walls. Epidemiological studies have shown that increased AS is an independent predictive marker of cardiovascular (CV) morbidity and mortality in both pregnant and non-pregnant women. Preeclampsia (PE), a form of pregnancy-induced hypertension, affects approximately 5% of pregnancies worldwide. Preeclamptic women have a higher risk of CV disease (CVD), mainly because PE damages the heart's ability to relax between contractions. Different pharmacological approaches for the prevention of PE have been tested in clinical trials (e.g. aspirin, enoxaparin, metformin, pravastatin, and sildenafil citrate). In current clinical practice, only low-dose aspirin is used for PE pharmacoprevention. However, low-dose aspirin does not prevent term PE, which is the most common form of PE. Compromised vascular integrity precedes the onset of PE and therefore, AS assessment may constitute a promising predictive marker of PE. Several non-invasive techniques have been developed to assess AS. Compared with normotensive pregnancies, both carotid-femoral pulse wave velocity (cfPWV) and augmentation index (AIx) are increased in PE. In view of simplicity, reliability, and reproducibility, there is an interest in oscillometric AS measurements in pregnancies complicated by PE.

Pravastatin is useful for prevention of recurrent severe placenta-mediated complications - a pilot study

BACKGROUND

Preeclampsia with severe features and other severe placenta-mediated complications may be life threatening to mother and fetus, especially when they are recurrent. Recurrence of pregnancy complications is common, however, when combined treatment with low molecular weight heparin and low dose aspirin fails, there are not any proven therapeutic options for prevention of recurrence of obstetrical complications.

OBJECTIVE

We aimed to determine the impact of adding pravastatin to low molecular weight heparin and low dose aspirin for improving pregnancy outcome in women with severe recurrent placenta-mediated complications.

DESIGN

A retrospective study of 32 women with severe recurrent placenta-mediated complications (preeclampsia with severe features, placental abruption, severe intrauterine growth retardation or intra uterine fetal death) in spite of treatment with low molecular weight heparin and low dose aspirin in previous pregnancy. All women were treated in the index pregnancy with 20 mg pravastatin starting at 12 weeks, with low molecular weight heparin and low dose aspirin. Antiphospholipid syndrome was evident for 10 of the 32 women.

RESULTS

In the index pregnancy, only one woman had recurrence of severe placenta-mediated complications. Gestational age at delivery in the index pregnancy compared to previous pregnancy when women were treated with low molecular weight heparin and low dose aspirin was 36.5 ± 1.7 vs. 32 ± 3.6 weeks, and mean birth weight 2691 ± 462 vs. 1436 ± 559 grams, compared to previous pregnancy when women were treated with low molecular weight heparin and low dose aspirin (p < .001 for both). Of the 17 women with previous preeclampsia with severe features, 15 had no recurrence of preeclampsia and 2 women had mild preeclampsia at term. Of the 8 women with previous severe intrauterine growth retardation, all delivered at significant higher gestational age compare to previous pregnancy, [37.0 ± 1 vs. 34 ± 3 weeks, (p < .05)] with higher mean birth-weight [2648 ± 212 vs. 1347 ± 465 grams, (p = .05)]. Of the 3 women with previous placental abruption, one delivered at 32 weeks due to non-reassuring fetal heart monitoring, one woman was delivered at 36 weeks due to mild preeclampsia, and one woman underwent elective induction of labor at 37 weeks with no intrauterine growth retardation. Of the 4 women with previous recurrent intrauterine fetal death, 3 women delivered at 37 weeks after elective induction, and one woman at 30 weeks with a birthweight of 960 grams due to severe intrauterine growth retardation.

CONCLUSIONS

Additive treatment with pravastatin to low molecular weight heparin and low dose aspirin may be a promising option in cases of previous severe recurrent placenta-mediated complications.

False-Positive Maternal Serum Screens in the Second Trimester as Markers of Placentally Mediated Complications Later in Pregnancy: A Systematic Review and Meta-Analysis

BACKGROUND

Multiple-marker, maternal serum screening (MSS) has been the cornerstone of prenatal diagnosis since the 1980s. While combinations of these markers are used to predict fetal risk of Down syndrome and other genetic conditions, there is some evidence that individual markers may also predict nongenetic pregnancy complications, particularly those related to placental dysfunction. The objective of this meta-analysis was to investigate the utility of false-positive, second-trimester MSS for Down syndrome as a marker of placentally mediated complications amongst singleton pregnancies globally.

METHODS

Electronic searches of PubMed, Medline, Embase, CINAHL, Web of Science, Scopus, and grey literature to 2019 were performed to identify observational studies comparing risk of pregnancy complications amongst pregnancies with false-positive MSS versus controls. A random-effects model of pooled odds ratios by outcome of interest (stillbirth, preeclampsia, fetal growth restriction, and preterm birth) and subgrouped by type of MSS test (double-, triple-, and quadruple-marker MSS) was used.

RESULTS

16 studies enrolling 68515 pregnancies were included. There were increased odds of preeclampsia (OR 1.28, 95% CI 1.09-1.51) and stillbirth (OR 2.46, 95% CI 1.94-3.12) amongst pregnancies with false-positive MSS. There was no significant association with preterm birth or growth restriction.

CONCLUSIONS

There is some evidence of an association between false-positive, second-trimester MSS for Down syndrome and increased odds of preeclampsia and stillbirth. Future large-scale prospective studies are still needed to best determine the predictive value of false-positive MSS as a marker of placentally mediated complications later in pregnancy and evaluate potential clinical interventions to reduce these risks.