Effects of Low-Molecular-Weight and Unfractionated Heparin on Trophoblast Function

Effect of low-molecular-weight heparin calcium combined with magnesium sulfate and labetalol on coagulation, vascular endothelial function and pregnancy outcome in early-onset severe preeclampsia

OBJECTIVE

This paper was aimed at unveiling the effect of low-molecular-weight heparin calcium (LMWH) combined with magnesium sulfate and labetalol on coagulation, vascular endothelial function, and pregnancy outcome in early-onset severe preeclampsia (EOSP).

METHODS

Pregnant women with EOSP were divided into the control group and the study group, each with 62 cases. Patients in the control group were treated with labetalol and magnesium sulfate, and those in the study group were treated with LMWH in combination with the control grou Blood pressure (systolic blood pressure [SBP] and diastolic blood pressure [DBP]), 24-h urine protein, coagulation indices [D-dimer (D-D), plasma fibrinogen (Fg), prothrombin time (PT), activated partial thromboplastin time (APTT), and prothrombin time (TT)], endothelial function [endothelin (ET-1) and nitric oxide (NO)], oxidative stress indices [oxidized low-density lipoproteins (ox-LDL), lipid peroxidation (LPO), superoxide dismutase (SOD), and malondialdehyde (MDA)], pregnancy outcome, and adverse effects occurred in the two groups were compared.

RESULTS

After treatment, lower SBP, DBP, and 24-h urine protein levels; lower Fg and D-D levels; higher PT, APPT, and TT levels; higher NO levels; lower ET-1 levels; lower ox-LDL, MDA, and LPO levels; higher SOD levels; and lower incidence of adverse pregnancy and adverse reactions were noted in the study group in contrast to the control group.

CONCLUSION

EOSP patients given with LMWH combined with magnesium sulfate and labetalol can effectively reduce the patient's blood pressure and urinary protein level; improve coagulation function, oxidative stress, and vascular endothelial function indices; reduce the adverse pregnancy outcomes; and improve the safety of treatment.

Exploring maternal-fetal interface with in vitro placental and trophoblastic models

The placenta, being a temporary organ, plays a crucial role in facilitating the exchange of nutrients and gases between the mother and the fetus during pregnancy. Any abnormalities in the development of this vital organ not only lead to various pregnancy-related disorders that can result in fetal injury or death, but also have long-term effects on maternal health. In vitro models have been employed to study the physiological features and molecular regulatory mechanisms of placental development, aiming to gain a detailed understanding of the pathogenesis of pregnancy-related diseases. Among these models, trophoblast stem cell culture and organoids show great promise. In this review, we provide a comprehensive overview of the current mature trophoblast stem cell models and emerging organoid models, while also discussing other models in a systematic manner. We believe that this knowledge will be valuable in guiding further exploration of the complex maternal-fetal interface.

Low Molecular Weight Heparin-Aspirin-Prednisolone Combination Does Not Increase the Live Birth Rate in Recurrent Implantation Failure: A Retrospective Cohort Study

This study investigates the triple combination of adjuvants (low molecular weight heparin (LMWH)-aspirin-prednisolone) whether it improves the live birth rates of IVF&ICSI patients with previous implantation failure. This retrospective study included 1095 patients with >2 failed either fresh or frozen single embryo transfer cycles between 2014 Jan and 2021 Jan. Patients were divided into two subgroups. Group A consisted of patients with only vaginal progesterone for luteal phase support. Group B consisted of patients with triple (daily subcutaneous LMWH, daily 150 mg aspirin, and daily 16 mg prednisolone) luteal phase supplementation to vaginal progesterone. Demographic parameters, cycle characteristics, embryology, and pregnancy outcomes were compared, and the study's primary outcome was the live birth rate. Demographic parameters were similar between the groups. Positive b-hCG, miscarriage, and live birth rates were similar between groups as Group A vs. Group B, positive b-hCG 30.8% (190/617) vs. 35.4% (169/478), miscarriage rates 4.4% (27/617) vs. 6.7% (32/478), and live birth rates 20.4% (126/617) vs. 23.8% (114/478), respectively. When patients were stratified according to previous failures, live birth rates were still similar. Pregnancy outcomes were significantly improved in only patients with diminished ovarian reserve (Group A vs. Group B, positive b-hCG 24.2% vs. 34.3%, live birth rate 12.1% vs. 21.9%, p < 0.01). Whether the embryo transfer was fresh or frozen-thawed did not affect the results. A combined supplementation of LMWH, aspirin, and prednisolone in the luteal phase does not improve live birth rates of IVF&ICSI patients with previous implantation failure except potentially for patients with diminished ovarian reserve.

Human Maternal-Fetal Interface Cellular Models to Assess Antiviral Drug Toxicity during Pregnancy

Pregnancy is a period of elevated risk for viral disease severity, resulting in serious health consequences for both the mother and the fetus; yet antiviral drugs lack comprehensive safety and efficacy data for use among pregnant women. In fact, pregnant women are systematically excluded from therapeutic clinical trials to prevent potential fetal harm. Current FDA-recommended reproductive toxicity assessments are studied using small animals which often do not accurately predict the human toxicological profiles of drug candidates. Here, we review the potential of human maternal-fetal interface cellular models in reproductive toxicity assessment of antiviral drugs. We specifically focus on the 2- and 3-dimensional maternal placental models of different gestational stages and those of fetal embryogenesis and organ development. Screening of drug candidates in physiologically relevant human maternal-fetal cellular models will be beneficial to prioritize selection of safe antiviral therapeutics for clinical trials in pregnant women.

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.

Circulating maternal placental growth factor responses to low-molecular-weight heparin in pregnant patients at risk of placental dysfunction

BACKGROUND

Patients at high risk of severe preeclampsia and fetal growth restriction have low circulating levels of placental growth factor and features of maternal vascular malperfusion placental pathology at delivery. Multimodal screening and commencement of aspirin prophylaxis at 11 to 13 weeks' gestation markedly reduces the risk of preterm delivery with preeclampsia. However, the additional role of low-molecular-weight heparin and mechanisms of action remain uncertain. Because low-molecular-weight heparin augments the production and release of placental growth factor in vitro by both placental villi and vascular endothelium, it may be effective to suppress the risk of severe preeclampsia in a niche group of high-risk patients with low circulating placental growth factor in the early second trimester.

OBJECTIVE

This study aimed to define a gestational age-specific reference range for placental growth factor and to test the hypothesis that prophylactic low-molecular-weight heparin administered in the early second trimester may restore deficient circulating placental growth factor levels and thereby prolong pregnancy.

STUDY DESIGN

Centile curves for circulating placental growth factor levels from 12 to 36 weeks' gestation were derived using quantile regression of combined data from a published cohort of 4207 unselected nulliparous patients in Cambridge, United Kingdom, at 4 sampling time points (12, 20, 28, and 36 weeks' gestation) and the White majority (n=531) of a healthy nulliparous cohort in Toronto, Canada, at 16 weeks' gestation using the same test platform. Within a specialty high-risk clinic in Toronto, a niche group of 7 patients with a circulating placental growth factor at the <10th centile in the early second trimester received daily prophylactic low-molecular-weight heparin (enoxaparin; 40 mg subcutaneously) and were followed up until delivery (group 1). Their baseline characteristics, delivery details, and placental pathologies were compared with 5 similar patients who did not receive low-molecular-weight heparin during the observation period (group 2) and further with 21 patients who delivered with severe preeclampsia (group 3) in the same institution.

RESULTS

A gestational age-specific reference range for placental growth factor levels at weekly intervals between 12 and 36 weeks was established for White women with singleton pregnancies. Within group 1, 5 of 7 patients demonstrated a sustained increase in circulating placental growth factor levels, whereas placental growth factor levels did not increase in group 2 or group 3 patients who did not receive low-molecular-weight heparin. Group 1 patients receiving low-molecular-weight heparin therapy exhibited a later gestation at delivery, relative to groups 2 and 3 (36 weeks [33-37] vs 23 weeks [22-26] and 28 weeks [27-31], respectively), and consequently had higher birthweights (1.93 kg [1.1-2.7] vs 0.32 kg [0.19-0.39] and 0.73 kg [0.52-1.03], respectively). The incidence of stillbirth was lowest in group 1 (14% [1 of 7]), relative to groups 2 and 3 (80% [4 of 5] and 29% [6 of 21], respectively). Maternal vascular malperfusion was the most common placental pathology found in association with abnormal uterine artery Doppler.

CONCLUSION

In patients at high risk of a serious adverse pregnancy outcome owing to placental disease, the addition of low-molecular-weight heparin to aspirin prophylaxis in the early second trimester may restore deficient circulating placental growth factor to mediate an improved perinatal outcome. These data support the implementation of a multicenter pilot randomized control trial where patients are recruited primarily based on the assessment of placental function in the early second trimester.

Therapeutic role of enoxaparin in intra-uterine growth restriction: A randomized clinical trial

OBJECTIVE

Intrauterine growth restriction is a leading cause of perinatal mortality and morbidity. Using enoxaparin may enhance the placental circulation and improve the intrauterine growth. This study was conducted to assess the efficacy and safety of enoxaparin in treatment of intra-uterine growth restriction.

STUDY DESIGN

125 women with intrauterine growth restriction were randomized to control group and intervention group (receiving routine high risk pregnancy prenatal care plus daily subcutaneous injection of 40 mg enoxaparin). Prolongation of pregnancy, fetal birth weight, fetal outcome and enoxaparin side effects were compared in 2 groups.

RESULTS

Baseline characteristics were similar in 2 groups. Mean gestational age at delivery was 36.73(±2.71) in enoxaparin group and 36.85(±2.17) in control group which showed no statistically significant difference. Mean fetal birth weight had also no statistically significant difference in enoxaparin and control group (2370.16 ± 580.72 g versus 2456.07 ± 543.06 g). Rate of betamethasone administration, intubation, NICU admission, sepsis, necrotizing enterocolitis, intra-ventricular hemorrhage, hypoglycemia and low apgar score were similar in two groups. No major adverse effect was seen.

CONCLUSION

Enoxaparin did not prolong the pregnancy and fetal birth weight and did not improve the fetal outcome even in patients with impaired baseline Doppler findings.

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

BACKGROUND

Preeclampsia (PE) and intrauterine growth restriction (IUGR) are major causes of maternal and perinatal morbidity and mortality. Previous studies have shown that intervention with low-dose aspirin resulted in a reduction in the occurrence of preterm PE. However, no data are currently available on the effect of low-molecular-weight heparin (LMWH) for the prevention of pregnancy complications in women enrolled at first trimester screening.

OBJECTIVE

We aimed to assess the effectiveness of LMWH in the prevention of PE, IUGR, fetal death, and abruptio placentae in women classified as high risk based on their medical history and in women selected by first trimester screening of PE. Study -Design: This was a multicenter, randomized, open-label, parallel controlled trial in women without thrombophilia between 6.0 and 15.6 weeks of gestation. Inclusion criteria were severe PE or IUGR before 34 weeks of gestation and/or abruptio placentae or unexplained intrauterine death in a previous pregnancy; uterine artery mean pulsatility index Doppler >95th percentile and/or positive first trimester screening for PE. Pregnant women were randomly assigned to receive no intervention or LMWH until the 36th week of gestation. The primary composite outcome consisted of 1 or more of the following: development of PE, IUGR, abruptio placentae, and intrauterine fetal death.

RESULTS

A total of 278 pregnant women were randomly allocated to receive LMWH (n = 134) or no intervention (n = 144). Overall, 115 (41%) women experienced placental insufficiency complications, with no significant differences between the 2 arms: 50/144 (34.7%) in the LMWH arm and 43/134 (32%) in the control arm (p = 0.64, OR: 1.13, 95% CI: 0.68-1.85).

CONCLUSION

LMWH did not reduce the incidence of placenta-mediated complications either in women with previous adverse obstetric history without thrombophilia or in women selected by first trimester screening for PE. Based on these results, we cannot recommend the use of LMWH alone in women at risk of placental complications.

Syndecan-4 regulates extravillous trophoblast migration by coordinating protein kinase C activation

Extravillous trophoblast (EVT) invasion is an essential component of human placentation. Poor EVT invasion is associated with obstetrical complications including preeclampsia. Integration of cues from the extracellular environment is required for directional EVT invasion, but how EVTs coordinate responses to these cues is not well understood. Syndecan-4 (SDC4) is a transmembrane heparan sulfate proteoglycan that binds to, and modulates the activity of, many extracellular proteins implicated in placental development. Therefore, we determined the functional importance of SDC4 for EVT invasion. We found that SDC4 is expressed by a first trimester EVT line (HTR8), and in EVTs in placenta throughout pregnancy, with higher expression during early pregnancy than at term. Higher expression was also observed in placentas from preeclampsia compared to normotensive pregnancies. SDC4-deficient HTR8 EVTs exhibited reduced migration and Matrigel-based invasion, both under basal conditions and following exposure to basic fibroblast growth factor and heparin-binding epidermal growth factor. SDC4-deficient HTR8 EVTs also showed reduced protein kinase C-alpha (PKCα) and AKT phosphorylation. SDC4 directly bound to activated PKCα in EVTs, and inhibition of PKCα decreased EVT invasion and migration. Our findings reveal an essential role of SDC4 as a regulator of EVT motility, in part through coordination of PKCα activation.

Minimally invasive spinal anesthesia for cesarean section in maternal anticoagulation therapy: a randomized controlled trial

BACKGROUND

Anticoagulant therapy during pregnancy is widely used due to the increasing awareness of maternal hypercoagulability. Few studies have reported the use of minimally invasive spinal anesthesia in these parturients. The objective of this study was to evaluate the safety and feasibility of minimally invasive spinal anesthesia in parturients with anticoagulation therapy undergoing cesarean section.

METHODS

This was a randomized, controlled study conducted in 239 parturients using anticoagulants and undergoing selective cesarean section. 37 parturients withdrew, and finally parturients received spinal anesthesia using 27gauge pen type fine spinal needles (experimental group, n = 110) and 22gauge traditional spinal needles (control group, n = 92). The primary efficacy outcomes included low back pain (LBP) and postdural puncture headache (PDPH) after delivery. Secondary efficacy outcomes included visual analogue scale during subarachnoid puncture (VASdural), difference between visual analogue scale (VAS) during peripheral venipuncture and VASdural (∆VAS), VAS of back puncture point 24, 48 and 72 h after operation (VASdural-24 h, VASdural-48 h and VASdural-72 h, respectively), maternal satisfaction and hospitalization stay.

RESULTS

No parturient had PDPH and was suspected with spinal or intracranial haematoma in two groups. There was no significant difference in VASlbp-24 h, VASlbp-48 h and VASlbp-72 h (P = 0.056; P = 0.813; P = 0.189, respectively) between two groups. In experimental group, VASdural (P = 0.017), ∆VAS (P = 0.001) and VASdural-24 h (P < 0.0001) were lower, whereas maternal satisfaction was higher (P = 0.046). There was no significant difference in VASdural-48 h, VASdural-72 h, urination function, strength recovery and hospitalization stay (P = 0.069; P = 0.667; P = 0.105; P = 0.133; P = 0.754, respectively) between the two groups.

CONCLUSIONS

Minimally invasive spinal anesthesia provided lower VASdural, VASdrual-24 h and a higher maternal satisfaction. Hence, it is considered as a safe, reliable and reasonable option for cesarean section parturients during maternal anticoagulation therapy with normal platelet count and coagulation time.

TRIAL REGISTRATION

This study was registered at www.ClinicalTrials.gov at November 11th, 2016 ( NCT02987192 ).

Low-Dose Aspirin May Prevent Trophoblast Dysfunction in Women With Chlamydia Pneumoniae Infection

OBJECTIVE

Previously, we demonstrated that live Chlamydia pneumoniae (Cp) impaired extravillous trophoblast (EVT) viability and invasion and that Cp DNA was detected in placentas from cases with preeclampsia. We sought to elucidate whether (1) inactive forms of Cp also affect EVT function; (2) potential therapeutic interventions protect against the effects of Cp; and (3) anti-Cp antibodies are associated with preeclampsia.

METHODS

Human first-trimester EVTs were infected with ultraviolet light-inactivated Cp. Subgroups of EVTs were pretreated with low-dose acetyl-salicylic acid (ASA), dexamethasone, heparin, and indomethacin. We conducted functional assays after infection with inactivated Cp and measured interleukin 8 (IL8), C-reactive protein (CRP), heat shock protein 60 (HSP60), and tumor necrosis factor-α (TNFα) in culture media. We measured anti-Cp IgG serum levels from women who developed preeclampsia (N = 105) and controls (N = 121).

RESULTS

Inactivated Cp reduced EVT invasion when compared to noninfected cells (P < .00001) without adversely affecting cell viability. Increased levels of IL8, CRP, HSP60, and TNFα were detected in EVTs infected with inactivated Cp compared to noninfected cells (P < .0001). Only pretreatment with low-dose ASA prevented reduced EVT invasion and decreased release of inflammatory mediators (P < .01). Elevated anti-Cp IgG antibodies were more prevalent in serum from cases with preeclampsia compared to controls (67/105 vs 53/121; adjusted P = .013); elevated IgG correlated significantly with elevated serum CRP and elevated soluble fms-like tyrosine kinase-1-placental growth factor ratio.

CONCLUSION

Inactivated Cp induces decreased EVT invasion and a proinflammatory response; these effects were abrogated by pretreatment with low-dose ASA. Our results suggest an association between Cp infection, trophoblast dysfunction, and preeclampsia.

The role of aspirin, heparin, and other interventions in the prevention and treatment of fetal growth restriction

Fetal growth restriction and related placental pathologies such as preeclampsia, stillbirth, and placental abruption are believed to arise in early pregnancy when inadequate remodeling of the maternal spiral arteries leads to persistent high-resistance and low-flow uteroplacental circulation. The consequent placental ischaemia, reperfusion injury, and oxidative stress are associated with an imbalance in angiogenic/antiangiogenic factors. Many interventions have centered on the prevention and/or treatment of preeclampsia with results pertaining to fetal growth restriction and small-for-gestational-age pregnancy often included as secondary outcomes because of the common pathophysiology. This renders the study findings less reliable for determining clinical significance. For the prevention of fetal growth restriction, a recent large-study level meta-analysis and individual patient data meta-analysis confirm that aspirin modestly reduces small-for-gestational-age pregnancy in women at high risk (relative risk, 0.90, 95% confidence interval, 0.81-1.00) and that a dose of ≥100 mg should be recommended and to start at or before 16 weeks of gestation. These findings support national clinical practice guidelines. In vitro and in vivo studies suggest that low-molecular-weight heparin may prevent fetal growth restriction; however, evidence from randomized control trials is inconsistent. A meta-analysis of multicenter trial data does not demonstrate any positive preventative effect of low-molecular-weight heparin on a primary composite outcome of placenta-mediated complications including fetal growth restriction (18% vs 18%; absolute risk difference, 0.6%; 95% confidence interval, 10.4-9.2); use of low-molecular-weight heparin for the prevention of fetal growth restriction should remain in the research setting. There are even fewer treatment options once fetal growth restriction is diagnosed. At present the only management option if the risk of hypoxia, acidosis, and intrauterine death is high is iatrogenic preterm birth, with the use of peripartum maternal administration of magnesium sulphate for neuroprotection and corticosteroids for fetal lung maturity, to prevent adverse neonatal outcomes. The pipeline of potential therapies use different strategies, many aiming to increase fetal growth by improving poor placentation and uterine blood flow. Phosphodiesterase type 5 inhibitors that potentiate nitric oxide availability such as sildenafil citrate have been extensively researched both in preclinical and clinical studies; results from the Sildenafil Therapy In Dismal Prognosis Early-Onset Intrauterine Growth Restriction consortium of randomized control clinical trials are keenly awaited. Targeting the uteroplacental circulation with novel therapeutics is another approach, the most advanced being maternal vascular endothelial growth factor gene therapy, which is being translated into the clinic via the doEs Vascular endothelial growth factor gene therapy safEly impRove outcome in seveRe Early-onset fetal growth reSTriction consortium. Other targeting approaches include nanoparticles and microRNAs to deliver drugs locally to the uterine arterial endothelium or trophoblast. In vitro and in vivo studies and animal models have demonstrated effects of nitric oxide donors, dietary nitrate, hydrogen sulphide donors, statins, and proton pump inhibitors on maternal blood pressure, uteroplacental resistance indices, and angiogenic/antiangiogenic factors. Data from human pregnancies and, in particular, pregnancies with fetal growth restriction remain very limited. Early research into melatonin, creatine, and N-acetyl cysteine supplementation in pregnancy suggests they may have potential as neuro- and cardioprotective agents in fetal growth restriction.

Aspirin vs Heparin for the Prevention of Preeclampsia

Preeclampsia is a hypertensive disorder of pregnancy that remains a significant cause of maternal morbidity and mortality worldwide. Preeclampsia can be resolved by delivery, and most of the proposed preventive treatment approaches are based on processes involved in placental development in early pregnancy. Yet, none of these has been established in clinical practice. Low-dose aspirin is the most promising candidate, nevertheless; while some individual randomized controlled trials showed minimal or no statistically significant benefit, recent metanalyses showed that early initiation before 16 weeks of gestation is associated with prevention of early-onset preeclampsia and reduction in prevalence of perinatal death or morbidity of pregnant women. Heparin could be an alternative antithrombotic and anti-inflammatory median to prevent preeclampsia either alone or in combination with aspirin; however, results are conflicting concerning efficacy.

Enoxaparin for the prevention of preeclampsia and intrauterine growth restriction in women with a history: a randomized trial

BACKGROUND

Preeclampsia and small-for-gestational-age pregnancy are major causes of maternal and perinatal morbidity and mortality. Women with a previous pregnancy affected by these conditions are at an increased risk of recurrence in a future pregnancy. Past trials evaluating the effect of low-molecular-weight heparin for the prevention of recurrence of preeclampsia and small-for-gestational-age pregnancy have shown conflicting results with high levels of heterogeneity displayed when trials were compared.

OBJECTIVE

We sought to assess the effectiveness of enoxaparin in addition to high-risk care for the prevention of preeclampsia and small-for-gestational-age pregnancy in women with a history of these conditions.

STUDY DESIGN

This was an open-label randomized controlled trial in 5 tertiary care centers in 3 countries. Women with a viable singleton pregnancy were invited to participate between >6⁺⁰ and <16⁺⁰ weeks if deemed to be at high risk of preeclampsia and/or small for gestational age based on their obstetric history. Eligible participants were randomly assigned in a 1-to-1 ratio to standard high-risk care or standard high-risk care plus enoxaparin 40 mg (4000 IU) by subcutaneous injection daily from recruitment until 36⁺⁰ weeks or delivery, whichever occurred sooner. Standard high-risk care was defined as care coordinated by a high-risk antenatal clinic service, aspirin 100 mg daily until 36⁺⁰ weeks, and-for women with prior preeclampsia-calcium 1000-1500 mg daily until 36⁺⁰ weeks. In a subgroup of participants serum samples were taken at recruitment and at 20 and 30 weeks' gestation and later analyzed for soluble fms-like tyrosine kinase-1, soluble endoglin, endothelin-1, placental growth factor, and soluble vascular cell adhesion molecule 1. The primary outcome was a composite of preeclampsia and/or small-for-gestational-age <5th customized birthweight percentile. All data were analyzed on an intention-to-treat basis. The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12609000699268).

RESULTS

Between July 26, 2010, and Oct. 28, 2015, a total of 156 participants were enrolled and included in the analysis. In all, 149 participants were included in the outcome analysis (72 receiving standard high-risk care plus enoxaparin and 77 receiving standard high-risk care only). Seven women who miscarried <16 weeks' gestation were excluded. The majority of participants (151/156, 97%) received aspirin. The addition of enoxaparin had no effect on the rate of preeclampsia and/or small-for-gestational-age <5th customized birthweight percentile: enoxaparin 18/72 (25%) vs no enoxaparin 17/77 (22.1%) (odds ratio, 1.19; 95% confidence interval, 0.53-2.64). There was also no difference in any of the secondary outcome measures. Levels of soluble fms-like tyrosine kinase-1 and soluble endoglin increased among those who developed preeclampsia, but there was no difference in levels of these antiangiogenic factors (nor any of the other serum analytes measured) among those treated with enoxaparin compared to those receiving standard high-risk care only.

CONCLUSION

The use of enoxaparin in addition to standard high-risk care does not reduce the risk of recurrence of preeclampsia and small-for-gestational-age infants in a subsequent pregnancy.

Modulation of antiphospholipid antibodies-induced trophoblast damage by different drugs used to prevent pregnancy morbidity associated with antiphospholipid syndrome

PROBLEM

Women with antiphospholipid antibodies (aPLs) present a risk of pregnancy morbidity (PM), vascular thrombosis (VT), or both (PM/VT). aPLs affect trophoblast function, and the aim of this study was to determine the modulation of this aPL-induced damage by different drugs.

METHOD OF STUDY

IgG was obtained from women with PM and PM/VT positive to aPLs. Binding of IgG to trophoblastic cells, proliferation, mitochondrial membrane integrity, and trophoblast invasion were assessed. The effect of enoxaparin, aspirin, and aspirin-triggered lipoxin (ATL) were evaluated as well as signal transducer and activator of transcription 3 (STAT3) phosphorylation.

RESULTS

IgG from women with aPLs strongly binds to trophoblastic cells. Integrity of mitochondrial membrane was reduced, and proliferation was increased by IgG-PM/VT. Both IgG-PM and IgG-PM/VT decreased trophoblast invasion, which was restored by enoxaparin, aspirin, and ATL. IgG-PM triggered reduction in STAT3 phosphorylation.

CONCLUSION

Some drugs used to prevent aPL-induced PM modulated the alteration of trophoblast function.

Enoxaparin for the prevention of preeclampsia and intrauterine growth restriction in women with a prior history - an open-label randomised trial (the EPPI trial): study protocol

BACKGROUND

Preeclampsia and intrauterine fetal growth restriction (IUGR) are two of the most common causes of maternal and perinatal morbidity and mortality. Current methods of predicting those at most risk of these conditions remain relatively poor, and in clinical practice past obstetric history remains the most commonly used tool. Aspirin and, in women at risk of preeclampsia only, calcium have been demonstrated to have a modest effect on risk reduction. Several observational studies and randomised trials suggest that low molecular weight heparin (LMWH) therapy may confer some benefit.

METHODS/DESIGN

This is a multicentre open label randomised controlled trial to determine the effect of the LMWH, enoxaparin, on the prevention of recurrence of preeclampsia and/or IUGR in women at high risk due to their past obstetric history in addition to standard high risk care for all participants.

INCLUSION CRITERIA

A singleton pregnancy >6+0 and <16+0 weeks gestation with most recent prior pregnancy with duration >12 weeks having; (1) preeclampsia delivered <36+0 weeks, (2) Small for gestational age (SGA) infant <10th customised birthweight centile delivered <36+0 weeks or, (3) SGA infant ≤3rd customised birthweight centile delivered at any gestation. Randomisation is stratified for maternal thrombophilia status and women are randomly assigned to 'standard high risk care' or 'standard high risk care' plus enoxaparin 40 mg from recruitment until 36+0 weeks or delivery, whichever occurs sooner. Standard high risk care includes the use of aspirin 100 mg daily and calcium 1000-1500 mg daily (unless only had previous SGA with no preeclampsia). The primary outcome is preeclampsia and/or SGA <5th customised birthweight centile. Analysis will be by intention to treat.

DISCUSSION

The EPPI trial has more focussed and clinically relevant inclusion criteria than other randomised trials with a more restricted composite primary outcome. The inclusion of standard use of aspirin (and calcium) for all participants will help to ensure that any differences observed in outcome are likely to be related to enoxaparin use. These data will make a significant contribution to future meta-analyses and systematic reviews on the use of LMWH for the prevention of placental mediated conditions.

TRIAL REGISTRATION

ACTRN12609000699268 Australian New Zealand Clinical Trials Registry. Date registered 13/Aug/2009 (prospective registration).

Randomized controlled study of pre-conception thromboprophylaxis among patients with recurrent spontaneous abortion related to antiphospholipid syndrome

OBJECTIVES

To investigate the effects of pre-conception thromboprophylaxis among patients with recurrent spontaneous abortion and antiphospholipid syndrome.

METHODS

A randomized placebo-controlled trial enrolled patients with a history of recurrent spontaneous abortions and antiphospholipid syndrome who attended an Egyptian center between January 2011 and June 2013. Using a computer-generated sequence, patients were randomly allocated to receive 41 mg enoxaparin subcutaneously plus 81 mg aspirin daily pre-conception, or to receive placebo pre-conception. All patients received enoxaparin and aspirin following identification of fetal heart pulsation. The primary outcomes were live-birth rate and clinical-pregnancy rate at 0-6 months, and at 6-12 months. Intention-to-treat analyses were performed. Clinicians, investigators, and data analysts were masked to the treatment assignments.

RESULTS

The study enrolled 180 patients(90 in each group). No significant difference was observed between the intervention and control groups in the live-birth rate (67[74%] vs 59[66%]; P=0.25). At 0-6 months, the clinical-pregnancy rate was higher in the intervention group (50[56%]vs 30[33%], P=0.02). No significant difference between the intervention and control groups was observed in the clinical-pregnancy rate at 6-12 months (32[36%] vs 35[39%], P=0.52).

CONCLUSION

Among patients with recurrent spontaneous abortion and antiphospholipid syndrome, pre-conception enoxaparin increased the clinical-pregnancy rate at 0-6 months, but did not affect the clinical-pregnancy rate at 6-12 months or the live-birth rate. ClinicalTrials.gov: NCT01661439.

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.

Aspirin and heparin in pregnancy

INTRODUCTION

A pro-coagulant state during pregnancy can be involved in the occurrence of gestational vascular complications (GVCs) and venous thromboembolism (VTE).

AREAS COVERED

Antithrombotic drugs are used to prevent GVCs and VTE. Aspirin is not efficacious to prevent recurrences in women with previous early loss, while it can prevent pre-eclampsia in some groups of women. Heparins are not effective in the prevention of early recurrent loss and there is uncertainty about their efficacy in women carrying inherited thrombophilias. They could be efficacious in the prevention of GVCs in carriers of inherited thrombophilias, as GVCs have heterogeneous causes, and future studies have to focus on more homogeneous groups of patients. Not enough data are available regarding prophylaxis with heparins to prevent pregnancy-related VTE, but an accurate risk stratification of women during pregnancy and puerperium is crucial for administering prophylaxis in moderate-/high-risk women. Aspirin does not improve live births after assisted reproductive technologies, while heparins increase the number of clinical pregnancies and live births.

EXPERT OPINION

Aspirin is efficacious in the prevention of GVCs in women at risk for pre-eclampsia and in those with antiphospholipid antibodies syndrome. Heparins could give benefit to women at risk for GVCs and/or pregnancy-related VTE.

Antiphospholipid antibodies and the placenta: a systematic review of their in vitro effects and modulation by treatment

BACKGROUND

Antiphospholipid antibodies (aPL) are a family of auto-antibodies that are associated with an increased risk of recurrent miscarriage, intrauterine growth restriction and preterm birth. The placenta is a major target of aPL and it is likely that these antibodies promote pregnancy morbidity by affecting trophoblast function. Numerous studies have investigated the effect of aPL on trophoblast function in vitro. However, different trophoblast models and a variety of culture conditions have been employed, resulting in a myriad of different reported findings. This review systematically summarized those published studies that have investigated the effect of aPL on trophoblast function in vitro. In addition, the reported effects of pharmacological treatment on trophoblast function in the presence of aPL were also systematically reviewed.

METHODS

PubMed, Scopus, Embase and Web of Science databases were searched using the keywords 'placenta OR trophoblast' AND 'antiphospholipid antibody OR antiphospholipid syndrome' up to 25 April 2014. Studies were excluded based on the absence of appropriate controls. The effects of aPL on trophoblast proliferation, death, syncytialization, invasion, hormone production, cytokine production, coagulation and complement activation were recorded. The effects of different treatments on the function of trophoblasts in the presence of aPL were also recorded.

RESULTS

A total of 1071 records were retrieved from the four databases. After removing duplicates, the titles and abstracts of 529 articles were reviewed. Of those, 48 articles were read and relevant experimental results were extracted from 47 articles.

CONCLUSIONS

This systematic review provides an overview of all the studies performed to date on the effects of aPL on trophoblast function in vitro. There is considerable support for aPL decreasing trophoblast viability, syncytialization and invasion in vitro. Some work has also suggested that aPL may affect the production of hormones and signalling molecules by trophoblasts, and may stimulate coagulation and complement activation in vitro. Current reports of the in vitro effects of therapeutic treatments on trophoblast function in the presence of aPL are inconclusive. This systematic review has highlighted many gaps in our knowledge of how aPL work and may direct future research in this area.

Hypoxia and the anticoagulants dalteparin and acetylsalicylic acid affect human placental amino acid transport

Background

Anticoagulants, e.g. low-molecular weight heparins (LMWHs) and acetylsalicylic acid (ASA) are prescribed to women at risk for pregnancy complications that are associated with impaired placentation and placental hypoxia. Beyond their role as anticoagulants these compounds exhibit direct effects on trophoblast but their impact on placental function is unknown. The amino acid transport systems A and L, which preferably transfer essential amino acids, are well-described models to study placental nutrient transport. We aimed to examine the effect of hypoxia, LMWHs and ASA on the activity of the placental amino acid transport systems A and L and associated signalling mechanisms.

Methods

The uptake of C¹⁴-MeAIB (system A) or H³-leucin (system L) was investigated after incubation of primary villous fragments isolated from term placentas. Villous tissue was incubated at 2% O₂ (hypoxia), 8% O₂ and standard culture conditions (21% O₂) or at 2% O₂ and 21% O₂ with dalteparin or ASA. Activation of the JAK/STAT or mTOR signalling pathways was determined by Western analysis of total and phosphorylated STAT3 or Raptor.

Results

Hypoxia decreased system A mediated MeAIB uptake and increased system L mediated leucine uptake compared to standard culture conditions (21% O₂). This was accompanied by an impairment of STAT3 and a stimulation of Raptor signalling. System L activity increased at 8% O₂. Dalteparin treatment reduced system A and system L activity under normoxic conditions and ASA (1 mM) decreased system A and L transporter activity under normoxic and hypoxic conditions.

Conclusions

Our data underline the dependency of placental function on oxygen supply. LMWHs and ASA are not able to reverse the effects of hypoxia on placental amino acid transport. These findings and the uncovering of the signalling mechanisms in more detail will help to understand the impact of LMWHs and ASA on placental function and fetal growth.

Overview of low molecular weight heparin for preventative treatment of adverse obstetric outcomes related to abnormal placentation

Different proportions of cases of preterm and severe preeclampsia, placental abruption, fetal growth restriction, and fetal death share a common causal pathway of abnormal placental implantation. Documentation of an association between the risk of such adverse pregnancy outcomes (APOs) and inherited thrombophilias prompted initial studies to evaluate the benefit of anticoagulants for the prevention of recurrences both in patients with and without inherited thrombophilias. Prenatal administration of low molecular weight heparin (LMWH) has been evaluated in case control, cohort and randomized clinical trials. The evidence suggests a benefit of LMWH in the reduction of recurrences of APOs, with a number needed to treat of 6 (95% confidence interval: 4-10) to prevent one case of recurrent APOs. Such benefit is independent of the presence of inherited thrombophilias or the administration of low dose aspirin. Further studies are needed to establish the optimal duration for the prophylaxis, to better delineate the mechanism of action of LMWH and to explore the role, if any, of maternal serum markers and uterine artery Doppler findings in the modulation of the LMWH prophylaxis.

Heparin for assisted reproduction

BACKGROUND

Heparin as an adjunct in assisted reproduction (peri-implantation heparin) is given at or after egg collection or at embryo transfer during assisted reproduction. Heparin has been advocated to improve embryo implantation and clinical outcomes.  It has been proposed that heparin enhances the intra-uterine environment by improving decidualisation with an associated activation of growth factors and a cytokine expression profile in the endometrium that is favourable to pregnancy.

OBJECTIVES

To investigate whether the administration of heparin around the time of implantation (peri-implantation heparin) improves clinical outcomes in subfertile women undergoing assisted reproduction.

SEARCH METHODS

A comprehensive and exhaustive search strategy was developed in consultation with the Trials Search Co-ordinator of the Cochrane Menstrual Disorders and Subfertility Group (MDSG). The strategy was used in an attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press, and in progress). Relevant trials were identified from both electronic databases and other resources (last search 6 May 2013).

SELECTION CRITERIA

All randomised controlled trials (RCTs) were included where peri-implantation heparin was given during assisted reproduction. Peri-implantation low molecular weight heparin (LMWH) during IVF/ICSI was given at or after egg collection or at embryo transfer in the included studies. Live birth rate was the primary outcome.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and quality of trials and extracted relevant data. The quality of the evidence was evaluated using GRADE methods.

MAIN RESULTS

Three RCTs (involving 386 women) were included in the review.Peri-implantation LMWH administration during assisted reproduction was associated with a significant improvement in live birth rate compared with placebo or no LMWH (odds ratio (OR) 1.77, 95% confidence interval (CI) 1.07 to 2.90, three studies, 386 women, I(2) = 51%, very low quality evidence with high heterogeneity). There was also a significant improvement in the clinical pregnancy rate with use of LMWH (OR 1.61, 95% CI 1.03 to 2.53, three studies, 386 women, I(2) = 29%, very low quality evidence with low heterogeneity).However these findings should be interpreted with extreme caution as they were dependent upon the choice of statistical method: they were no longer statistically significant when a random-effects model was used.Adverse events were poorly reported in all included studies, with no comparative data available. However, LMWH did cause adverse effects including bruising, ecchymosis, bleeding, thrombocytopenia and allergic reactions. It appeared that these adverse effects were increased if heparin therapy was used over a longer duration.

AUTHORS' CONCLUSIONS

The results of this Cochrane review of three randomised controlled trials with a total of 386 women suggested that peri-implantation LMWH in assisted reproduction treatment (ART) cycles may improve the live birth rate in women undergoing assisted reproduction. However, these results were dependent on small low quality studies with substantial heterogeneity, and were sensitive to the choice of statistical model. There were side effects reported with use of heparin, including bruising and bleeding, and no reliable data on long-term effects. The results do not justify this use of heparin outside well-conducted research trials.These findings need to be further investigated with well-designed, adequately powered, double-blind, randomised, placebo-controlled, multicentre trials. Further investigations could also focus on the effects of the local (uterine) and not systemic application of heparin during ART.

Antithrombotic therapy for pregnancy loss

BACKGROUND Although an association between thrombophilia and pregnancy loss has been observed in many studies, little is known about the pathophysiological mechanisms behind this association. Considering the association between thrombophilia and pregnancy loss, the efficacy of antithrombotic therapy for women with pregnancy loss (with or without thrombophilia) has been studied for the past 30 years. METHODS We performed a comprehensive review of the literature on the strength of the association between thrombophilia and pregnancy loss, the pathophysiological mechanisms and the efficacy of antithrombotic therapy to increase the chance of live birth. RESULTS The association between pregnancy loss and thrombophilia varies according to the type of thrombophilia (e.g. antiphospholipid syndrome versus forms of inherited thrombophilia) and according to the type of pregnancy loss (single versus recurrent pregnancy loss and early versus late pregnancy loss). Thrombophilia may induce thrombosis in decidual vessels or impair placentation through hypercoagulability and inflammation, but these hypotheses need further verification. For women with antiphospholipid syndrome, evidence from small-sized trials suggests a beneficial effect of antithrombotic therapy but additional randomized controlled trials are essential to confirm this. Whether antithrombotic therapy increases the chance of live birth in women with inherited thrombophilia is unknown. Recent randomized controlled trials have consistently shown that antithrombotic therapy does not increase the chance of live birth in women with unexplained recurrent miscarriage. CONCLUSIONS There are large gaps in knowledge and a lack of evidence for treatment of women with pregnancy loss with thrombophilia. To provide a solid base for clinical practice, further studies on the role of coagulation in reproduction, as well as international collaborations in randomized controlled trials of antithrombotic therapy in women with pregnancy loss, and antiphospholipid syndrome or inherited thrombophilia are urgently needed.

Impact of inherited thrombophilias on first and second trimester maternal serum markers for aneuploidy

OBJECTIVE

To evaluate first and second-trimester maternal serum markers in pregnancies complicated with inherited thrombophilias.

METHODS

A case-control study was conducted in 50 pregnancies complicated with hereditary thrombophilia and 100 control pregnancies.

RESULTS

Each woman with inherited thrombophilia received low molecular weight heparin (LMWH) throughout her pregnancy. Gravidity, parity, number of first-trimester and second-trimester abortions, and rate of adverse pregnancy outcomes (APO) were significantly higher in the thrombophilia group compared to the control group (P < 0.001 for all). Among the thrombophilia group median values of pregnancy associated placental protein-A (PAPP-A) (0.6 vs. 0.9; P < 0.001) and free β-human chorionic gonadotropin (β-hCG) (0.9 vs. 1.1; P = 0.001) in the first trimester; median values of α-fetoprotein (AFP) (0.7 vs. 1.1; P = 0.027), unconjugated estriol 3 (uE3) (0.9 vs. 1.1; P < 0.001), and hCG (0.7 vs. 1.2; P < 0.001) in the second trimester were significantly lower with respect to control pregnancies. Multivariate analysis revealed that low uE3 and hCG levels were independently associated with APO.

CONCLUSION

Pregnant women with hereditary thrombophilias, all of whom were treated with LMWH, had decreased levels of all first and second trimester serum markers. In addition, levels of hCG and uE3 in the second trimester could independently predict placenta-related disorders and adverse outcomes in these patients.

Multiple pregnancy failures: an immunological paradigm

Recurrent spontaneous abortion (RSA), three or more pregnancy losses prior to 20 weeks, occurs in about 1% of all pregnancies, 50% of RSA cases remain unexplained and unresolved. Recently, immune pathways have been implicated in the pathophysiology of RSA. Immune tolerance of the fetal-placental unit and placental angiogenesis are mandatory for a successful pregnancy outcome. Unscheduled dysregulation of the placental vasculature is thought to be the pathophysiologic mechanisms underlying an array of pregnancy complications like infertility, miscarriage, pre-eclampsia, and fetal growth restriction and death. Investigations on mechanisms and management of RSA are mired by substandard design and lack of optimal randomized clinical trials and have resulted in disagreement on guidelines for evaluation and treatments for patients with multiple pregnancy losses of unknown etiology. The present review focuses on evidence-based research discussion with immunologic causes, and immune-regulatory therapies recommended for helping patients with a history of RSA. We highlight data that might support revalidation of low molecular weight heparin as a protective therapy in RSA. Newly launched growth factors, GM-CSF, and potentially novel agents to suppress inflammatory rejection, including regulatory T cells, human chorionic gonadotropin, and M-CSF/IL-10, may work in concert with tender-loving-care therapy and give hope to couples with multiple pregnancy losses.

Effects of low molecular weight heparin and heparin-binding epidermal growth factor on human trophoblast in first trimester

OBJECTIVE

To evaluate the effects of low molecular weight heparin (LMWH) and heparin-binding epidermal growth factor (HB-EGF) on the biological function of human trophoblast in first trimester.

DESIGN

Control experiment.

SETTING

Two academic-based reproductive centers.

PATIENT(S)

The first trimester human placentas (gestational age, 5-10 weeks) from patients who underwent electively induced abortions.

INTERVENTION(S)

Cultured trophoblast treated with LMWH or LMWH and HB-EGF.

MAIN OUTCOME MEASURE(S)

The biological function (proliferation, invasion, and differentiation) of trophoblast and the interaction between LMWH and HB-EGF on trophoblast in vitro.

RESULT(S)

1) At a dose of 0.25 IU/mL-2.5 IU/mL LMWH promoted trophoblast proliferation, enhanced their invasion, and increased hCG secretion. The LMWH had little effect or the opposite effect at other concentrations. These differences were statistically significant. 2) Combined use of LMWH and HB-EGF significantly promoted proliferation and invasion, but there was no difference in hCG secretion compared with solo LMWH or solo HB-EGF.

CONCLUSION(S)

The LMWH exerts a cytoprotective effect by regulating trophoblast proliferation, invasion, and differentiation. The HB-EGF is an important factor in the effects of LMWH on trophoblast function.

The possible options for the prevention of preeclampsia

This review summarizes the possible options for the prevention of preeclampsia based on important factors of patomechanism. The effects of antioxidants have been described in numerous clinical researches based on the oxidative hypothesis. Another important factor is the change of nitric oxide activity. Nitric oxide donors are able to compensate the symptoms of preeclampsia. The inverse relationship between the calcium intake and gestational hypertension has been known for a long time. The calcium supplementation seems to be a good opportunity to prevent preeclampsia. With low molecular weight heparins we can intervene in the patomechanisms of preeclampsia by antithrombocyte effects, vasoactive properties and impact on throphoblast cell morphology and differentiation. Thrombocyte aggregation inhibitors were examined in number of studies because they reduced thromboxane mediated vasoconstriction and inhibited placental thrombosis. Several studies verify whether prophylaxis with low molecular weight heparins and low dose aspirin could improve pregnancy outcome in preeclampsia. Orv. Hetil., 2012, 153, 144–151.

Placental and trophoblastic in vitro models to study preventive and therapeutic agents for preeclampsia

In the field of preeclampsia, enormous efforts are ongoing to identify biomarkers predicting the syndrome already in the first trimester of pregnancy. At the same time, there is the need for in vitro models to test such biomarkers prior to their use in clinical trials. In addition, in vitro models may accelerate the development and evaluation of the benefit of any putative therapeutics. Therefore, in vitro systems have been established to evaluate the release of biomarkers and measure the effect of putative therapeutics using placental villous explants as well as the choriocarcinoma cell line BeWo. For explants, a cryogenic method to freeze, transport and thaw villous explants was developed to use such tissues for a multi-site tissue culture evaluation. Here we focus on three out of many in vitro models that have been established for human placental trophoblast. (1) Choriocarcinoma cell lines such as BeWo, Jeg-3 and Jar cells (2) isolated primary trophoblast cells, and (2) villous explants from normal placentas delivered at term. Cell lines were used to assess the effect of differentiation and fusion on the expression and release of a preeclampsia marker (placental protein 13; PP13) and beta-hCG. Moreover, cell lines were used to study the effect of putative preeclampsia therapeutics such as vitamins C and E, heparin and aspirin on marker release and viability. Cryopreservation of villous explants enabled shipment to a remote laboratory and testing of parameters in different countries using explants from one and the same placenta. Recently published data make it tempting to speculate that the choriocarcinoma cell line BeWo as well as fresh and cryogenically stored placental villous explants may well serve as in vitro models to study preventive and therapeutic agents in the field of preeclampsia.

The effects of antenatal anticoagulants (low-molecular-weight heparin and aspirin) on neonatal pulmonary vasculature in rabbits

Low-molecular-weight heparin and aspirin are the most prescribed medical agents as anticoagulants in pregnancy. Our objective was to investigate the effects of antenatal use of low-molecular-weight heparin and aspirin on pulmonary vascular development in neonatal rabbits. Seven pregnant rabbits (42 newborn rabbits) were divided into 5 groups as follows: control group (group 1, n = 14), heparin treated (group 2, n = 8), heparin and aspirin treated (group 3, n = 7), only aspirin treated (group 4, n = 6), and high-dose heparin treated (group 5, n = 12). Pulmonary histologic evaluations were carried out for all groups. Angiogenesis was also tested by CD34 immunostained microvessel count (mvc). Pathologic examination of pulmonary vasculature revealed that pulmonary vascular thickening occurred at the level of alveoli in heparin-, heparin- and aspirin-, and high-dose-heparin-treated groups (groups 2, 3, and 5). The percentage of wall thickness was different in groups 2 (26%), 3 (28.2%), and 5 (30.8%) compared with group 1 (21.4%). Statistical differences were observed between group 1 vs 2, 3, and 5. Microvessel count was also different between groups 2 (mvc = 90.5), 3 (mvc = 90.2), and 5 (mvc = 96.3) vs group 1 (mvc = 86.7). The microvessel count was statistically different between groups that received low-dose heparin vs high-dose heparin. Antenatal administration of low-molecular-weight heparin showed an effect on pulmonary vascular development. This effect may be explained by the influence of heparin on angiogenesis through placental growth factors. Further experiments are needed to understand the pathophysiology of these findings, and clinical studies are needed to correlate of these results.

Luteal phase empirical low molecular weight heparin administration in patients with failed ICSI embryo transfer cycles: a randomized open-labeled pilot trial

BACKGROUND

The pathology underlying recurrent implantation failures (RIF) is not clear and treatment options proposed are generally not evidence based. Although the effect of heparin on trophoblast biology has not been studied extensively, given the available data suggesting a possible beneficial effect of heparin on embryo implantation, we decided to undertake this pilot study.

METHODS

One hundred and fifty women with > or =2 failed assisted reproduction treatment cycles were included in this randomized open-label pilot trial. Participants underwent controlled ovarian stimulation with the long protocol and were randomly allocated to receive 1 mg/kg/day low molecular weight heparin (LMWH) or no treatment in addition to routine luteal phase support (LPS) on the day after oocyte retrieval. LPS and LMWH was continued up to the 12th gestational week in pregnant participants.

RESULTS

There were 26 (34.7%) live births in the LMWH group, and 20 (26.7%) in the control group (absolute difference 8.0%, 95% CI -4.2 to 24.9%, P = 0.29). There were 34 (45.3%) and 29 (38.7%) clinical pregnancies in the LMWH and control groups, respectively (absolute difference 6.6%, 95% CI -9.0 to 21.8%, P = 0.41). Implantation rates were 24.5 and 19.8% in the LMWH and control groups, respectively (absolute difference 4.7%, 95% CI -4.7 to 14.1%, P = 0.33).

CONCLUSION

Despite lack of statistical significance, observed relative increase by 30% in live birth rates with LMWH may be regarded as a clinically significant trend necessitating further research on the use of empirical LMWH in women with RIF and possibly in all women undergoing assisted reproduction treatment. Failure to demonstrate statistical significance of the observed treatment difference may be due to limited sample size of this pilot study.

Dalteparin for the prevention of recurrence of placental-mediated complications of pregnancy in women without thrombophilia: a pilot randomized controlled trial

BACKGROUND

The role of anticoagulants for the prevention of placental-mediated pregnancy complications is uncertain.

OBJECTIVES

Our aim was to investigate the effectiveness of dalteparin, a low-molecular-weight heparin, in preventing the recurrence of these complications in women without thrombophilia.

PATIENTS/METHODS

Between August 1 2000 and June 20 2007, 116 pregnant women with: (i)

RESULTS

Among the 110 women included in the final analysis, dalteparin was associated with a lower rate of the primary outcome [5.5% (n = 3/55) vs. 23.6% (n = 13/55), adjusted odds ratio (OR) 0.15, 95% confidence interval (CI) 0.03-0.70]. Secondary outcomes were not statistically different between the groups. Bleeding problems or thrombocytopenia did not occur.

CONCLUSION

In this pilot study, dalteparin is effective in decreasing the recurrence of placental-mediated complications in women without thrombophilia. Our results require confirmation in further randomized trials.

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Key Words Collapse

MESH Headings

• Adult
• Dalteparin/adverse effects
• Dalteparin/therapeutic use
• Female
• Fetal Death
• Humans
• Infant, Low Birth Weight
• Infant, Newborn
• Pilot Projects
• Placenta/physiopathology
• Pre-Eclampsia/prevention & control
• Pregnancy
• Pregnancy Complications/drug therapy
• Pregnancy Complications/prevention & control
• Pregnancy Outcome
• Secondary Prevention

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Grants Collapse

Affiliation(s)

E Rey Division of Obstetrics Medicine, Department of Obstetrics and Gynaecology, CHU Sainte-Justine, Montreal, QC, Canada.
P Garneau
M David
R Gauthier
L Leduc
N Michon
F Morin
C Demers
S R Kahn
L A Magee
M Rodger

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Phenytoin but not valproate directly affected in vitro trophoblast differentiation

OBJECTIVE

Epilepsy has been associated with poor obstetric outcomes that could be the result of the epilepsy itself or a direct effect of anti-epileptic medication on placentation. The aim of this study was to investigate any direct effect of anti-epileptic drugs on an established, in vitro bioassay of trophoblast differentiation.

STUDY DESIGN

Primary extravillous trophoblast cells were cultured in the presence of phenytoin and sodium valproate at a range of concentrations with appropriate solvent controls. The formation of multinuclear giant cells was used as a marker of trophoblast differentiation.

RESULTS

Phenytoin inhibited giant multinuclear cell formation in a dose-dependent manner; in contrast sodium valproate had no effect (p=0.011).

CONCLUSIONS

This study found that two anti-epileptic medications induced different effects on an in vitro trophoblast bioassay, suggesting that further research should be aimed at elucidating which anti-epileptic medication is most suitable for pregnant women.

Control of human trophoblast function

The trophoblast, i.e. the peripheral part of the human conceptus, exerts a crucial role in implantation and placentation. Both processes properly occur as a consequence of an intimate dialogue between fetal and maternal tissues, fulfilled by membrane ligands and receptors, as well as by hormone and local factor release. During blastocyst implantation, generation of distinct trophoblast cell types begins, namely the villous and the extravillous trophoblast, the former of which is devoted to fetal-maternal exchanges and the latter binds the placental body to the uterine wall. Physiological placentation is characterized by the invasion of the uterine spiral arteries by extravillous trophoblast cells arising from anchoring villi. Due to this invasion, the arterial structure is replaced by amorphous fibrinoid material and endovascular trophoblastic cells. This transformation establishes a low-resistance, high-capacity perfusion system from the radial arteries to the intervillous space, in which the villous tree is embedded. The physiology of pregnancy depends upon the orderly progress of structural and functional changes of villous and extravillous trophoblast, whereas a derangement of such processes can lead to different types of complications of varying degrees of gravity, including possible pregnancy loss and maternal life-threatening diseases. In this review we describe the mechanisms which regulate trophoblast differentiation, proliferation, migration and invasiveness, and the alterations in these mechanisms which lead to pathological conditions. Furthermore, based on the growing evidence that proper inflammatory changes and oxidative balance are needed for successful gestation, we explain the mechanisms by which agents able to influence such processes may be useful in the prevention and treatment of pregnancy disorders.

Investigation of the effects of heparin and low molecular weight heparin on E-cadherin and laminin expression in rat pregnancy by immunohistochemistry

BACKGROUND

Heparin and low molecular weight heparin (LMWH) are used widely to improve the pregnancy outcome in women with thrombophilia, miscarriage, recurrent miscarriage and fetal death. This study was designed to investigate the effects of heparin and LMWHs, enoxaparin and tinzaparin, on E-cadherin and laminin expression in placental and decidual tissues in rat pregnancy.

METHODS

Wistar albino female rats (n = 48) were randomly assigned to four study groups (normal saline, heparin, enoxaparin and tinzaparin) in the preconceptional period. Tissue sections of placenta and decidua were immunohistochemically examined for the expression of E-cadherin and laminin.

RESULTS

E-cadherin placental staining score of heparin group was significantly lower and E-cadherin decidual staining score of heparin and enoxaparin groups were significantly lower than control group. There were no significant differences in placental and decidual laminin staining scores among the study groups.

CONCLUSIONS

Heparin and enoxaparin can reduce E-cadherin expression but not laminin expression in rat pregnancy. They might modulate trophoblast invasion. We suggest that this is the possible underlying mechanism involving in improvement of trophoblast invasion by the use of heparin and LMWH in patients with the history of miscarriage.

Low-molecular-weight heparin improves the performance of uterine artery Doppler velocimetry to predict preeclampsia and small-for-gestational age infant in women with gestational hypertension

This study investigated whether a short course of subcutaneous low-molecular-weight heparin (LMWH) might modify the performance of uterine artery Doppler to predict preeclampsia and small-for-gestational age (SGA) newborns in a high-risk population. A controlled, open-labeled study included 94 women with gestational hypertension and 30 healthy women enrolled at 24 to 26 weeks gestation. Doppler evaluation of uterine arteries resistance index (RI) was performed before and after a two-week course of LMWH (enoxaparin, 4000 IU/d, n = 56 hypertensive patients) or no treatment (n = 38 hypertensive women and 30 healthy controls). There was a significant decrease of uterine artery RI after LMWH (p < 0.001, paired Student's t-test), whereas the untreated hypertensive patients and the healthy control group showed no change between the two Doppler evaluations. The change induced by LMWH was restricted to women with normal outcome, whose RI decreased from (mean +/- standard error) 0.62 +/- 0.01 to 0.56 +/- 0.01 (p < 0.0001). By consequence, the second RI measurement, performed after LMWH administration, had fewer false positive results and higher positive likelihood ratios (LR+) to predict both preeclampsia (LR + 5.91) and SGA (LR + 4.69) compared with the first Doppler examination (LR + 1.97 and 2.22, respectively). Thus, LMWH improved the performance of uterine artery RI to predict preeclampsia and SGA in women with gestational hypertension.

Recurrent miscarriage

Many human conceptions are genetically abnormal and end in miscarriage, which is the commonest complication of pregnancy. Recurrent miscarriage, the loss of three or more consecutive pregnancies, affects 1% of couples trying to conceive. It is associated with psychological morbidity, and has often proven to be frustrating for both patient and clinician. A third of women attending specialist clinics are clinically depressed, and one in five have levels of anxiety that are similar to those in psychiatric outpatient populations. Many conventional beliefs about the cause and treatment of women with recurrent miscarriage have not withstood scrutiny, but progress has been made. Research has emphasised the importance of recurrent miscarriage in the range of reproductive failure linking subfertility and late pregnancy complications and has allowed us to reject practice based on anecdotal evidence in favour of evidence-based management.