Comparison of therapeutic interventions for recurrent pregnancy loss in association with antiphospholipid syndrome: A systematic review and network meta‐analysis

Low-molecular-weight heparin and preeclampsia - does the sword cut both ways? Three case reports and review of literature

BACKGROUND

Low-molecular-weight heparins (LMWH) are the most commonly used anticoagulants during pregnancy. It is considered to be the drug of choice due to its safety in not crossing placenta. Considering the beneficial effect in the improvement of microcirculation, prophylactic application of LMWH in patients with preeclampsia became a trend. However, the bleeding risk related with LMWH in preeclampsia patients has seldomly been evaluated. This current study aimed to identify the potential risks regarding LMWH application in patients with preeclampsia.

CASE SUMMARY

Herein we present a case series of three pregnant women diagnosed with preeclampsia on LMWH therapy during pregnancy. All the cases experienced catastrophic hemorrhagic events. After reviewing the twenty-one meta-analyses, the bleeding risk related with LMWH seems ignorable. Only one study analyzed the bleeding risk of LMWH and found a significantly higher risk of developing PPH in women receiving LMWH. Other studies reported minor bleeding risks, none of these were serious enough to stop LMWH treatment. Possibilities of bleeding either from uterus or from intrabdominal organs in preeclampsia patients on LMWH therapy should not be ignored. Intensive management of blood pressure even after delivery and homeostasis suture in surgery are crucial.

CONCLUSION

Consideration should be given to the balance between benefits and risks of LMWH in patients with preeclampsia.

Recurrent MiscarriageGreen-top Guideline No. 17

In this guideline, recurrent miscarriage has been defined as three or more first trimester miscarriages. However, clinicians are encouraged to use their clinical discretion to recommend extensive evaluation after two first trimester miscarriages, if there is a suspicion that the miscarriages are of pathological and not of sporadic nature. Women with recurrent miscarriage should be offered testing for acquired thrombophilia, particularly for lupus anticoagulant and anticardiolipin antibodies, prior to pregnancy. [Grade C] Women with second trimester miscarriage may be offered testing for Factor V Leiden, prothrombin gene mutation and protein S deficiency, ideally within a research context. [Grade C] Inherited thrombophilias have a weak association with recurrent miscarriage. Routine testing for protein C, antithrombin deficiency and methylenetetrahydrofolate reductase mutation is not recommended. [Grade C] Cytogenetic analysis should be offered on pregnancy tissue of the third and subsequent miscarriage(s) and in any second trimester miscarriage. [Grade D] Parental peripheral blood karyotyping should be offered for couples in whom testing of pregnancy tissue reports an unbalanced structural chromosomal abnormality [Grade D] or there is unsuccessful or no pregnancy tissue available for testing. [GPP] Women with recurrent miscarriage should be offered assessment for congenital uterine anomalies, ideally with 3D ultrasound. [Grade B] Women with recurrent miscarriage should be offered thyroid function tests and assessment for thyroid peroxidase (TPO) antibodies. [Grade C] Women with recurrent miscarriage should not be routinely offered immunological screening (such as HLA, cytokine and natural killer cell tests), infection screening or sperm DNA testing outside a research context. [Grade C] Women with recurrent miscarriage should be advised to maintain a BMI between 19 and 25 kg/m2 , smoking cessation, limit alcohol consumption and limit caffeine to less than 200 mg/day. [Grade D] For women diagnosed with antiphospholipid syndrome, aspirin and heparin should be offered from a positive test until at least 34 weeks of gestation, following discussion of potential benefits versus risks. [Grade B] Aspirin and/or heparin should not be given to women with unexplained recurrent miscarriage. [Grade B] There are currently insufficient data to support the routine use of PGT-A for couples with unexplained recurrent miscarriage, while the treatment may carry a significant cost and potential risk. [Grade C] Resection of a uterine septum should be considered for women with recurrent first or second trimester miscarriage, ideally within an appropriate audit or research context. [Grade C] Thyroxine supplementation is not routinely recommended for euthyroid women with TPO who have a history of miscarriage. [Grade A] Progestogen supplementation should be considered in women with recurrent miscarriage who present with bleeding in early pregnancy (for example 400 mg micronised vaginal progesterone twice daily at the time of bleeding until 16 weeks of gestation). [Grade B] Women with unexplained recurrent miscarriage should be offered supportive care, ideally in the setting of a dedicated recurrent miscarriage clinic. [Grade C].

The Role of Acetylsalicylic Acid in the Prevention of Pre-Eclampsia, Fetal Growth Restriction, and Preterm Birth

BACKGROUND

Recent studies suggest that low-dose acetylsalicylic acid (ASA) can lower pregnancy-associated morbidity.

METHODS

This review is based on pertinent publications that were retrieved by a selective search in PubMed, with special attention to systematic reviews, metaanalyses, and randomized controlled trials.

RESULTS

Current meta-analyses document a reduction of the risk of the occurrence of pre-eclampsia (RR 0.85, NNT 50), as well as beneficial effects on the rates of preterm birth (RR 0.80, NNT 37), fetal growth restriction (RR 0.82, NNT 77), and perinatal death (RR 0.79, NNT 167). Moreover, there is evidence that ASA raises the rate of live births after a prior spontaneous abortion, while also lowering the rate of spontaneous preterm births (RR 0.89, NNT 67). The prerequisites for therapeutic success are an adequate ASA dose, early initiation of ASA, and the identification of women at risk of pregnancy-associated morbidity. Side effects of treatment with ASA in this patient group are rare and mainly involve bleeding in connection with the pregnancy (RR 0.87, NNH 200).

CONCLUSION

ASA use during pregnancy has benefits beyond reducing the risk of pre-eclampsia. The indications for taking ASA during pregnancy may be extended at some point in the future; at present, in view of the available evidence, it is still restricted to high-risk pregnancies.

Omega-3 fatty acid supplements and recurrent miscarriage: A perspective on potential mechanisms and clinical evidence

Recurrent miscarriage (RM) affects approximately 1%-5% of couples worldwide. Due to its complicated etiologies, the treatments for RM also vary greatly, including surgery for anatomic factors such as septate uterus and uterine adhesions, thyroid modulation drugs for hyperthyroidism and hypothyroidism, and aspirin and low molecular weight heparin for antiphospholipid syndrome. However, these treatment modalities are still insufficient to solve RM. Omega-3 fatty acids are reported to modulate the dysregulation of immune cells, oxidative stress, endocrine disorders, inflammation, etc., which are closely associated with the pathogenesis of RM. However, there is a lack of a systematic description of the involvement of omega-3 fatty acids in treating RM, and the underlying mechanisms are also not clear. In this review, we sought to determine the potential mechanisms that are highly associated with the pathogenesis of RM and the regulation of omega-3 fatty acids on these mechanisms. In addition, we also highlighted the direct and indirect clinical evidence of omega-3 fatty acid supplements to treat RM, which might encourage the application of omega-3 fatty acids to treat RM, thus improving pregnancy outcomes.

Successful Pregnancy and Delivery at Term Following Intravenous Immunoglobulin Therapy with Heparin for Unexplained Recurrent Pregnancy Loss Suspected of Immunological Abnormalities: A Case Report and Brief Literature Review

About 60% of cases of recurrent pregnancy loss have unexplained etiology. Immunotherapy for unexplained recurrent pregnancy loss is still unestablished. A 36-year-old woman, not obese, had a stillbirth at 22 gestational weeks and a spontaneous abortion at 8 weeks. She had been examined for recurrent pregnancy loss at previous clinics with no significant findings. When she visited our clinic, a hematologic test showed a Th1/Th2 ratio imbalance. Ultrasonography, hysteroscopy, and semen analysis showed no abnormalities. She successfully conceived by embryo transfer in hormone replacement therapy cycle. However, she had a miscarriage at 19 weeks. The baby had no deformities, but a chromosomal test was not performed, according to the parents' will. The placenta pathologically suggested hemoperfusion problems. Her and her husband's chromosomal tests showed normal karyotypes. Other examinations revealed a repeated Th1/Th2 ratio imbalance and a high resistance index of uterine radial artery blood flow. She was administered low-dose aspirin, intravenous immunoglobulin, and unfractionated heparin after the second embryo was transferred. Her baby was healthily born by cesarean section at 40 weeks. Intravenous immunoglobulin therapy can be a choice for recurrent miscarriage without risk factors because it has clinically beneficial influences on the patient's immunological aberration.

Angiogenic markers could predict adverse pregnancy outcomes

Adverse pregnancy outcomes (APOs) have been a devastating actuality in clinic. However, the pre-onset risk factors, that correlated with pregnancy failure, including antiphospholipid antibodies (APLs) and angiogenic factors, remain unclear. A retrospective study was performed in this research, and data from 145 pregnant women were collected during their pregnancy. Patients were finally divided into non-APO group (n = 89) and APO group (n = 56) according to their pregnancy outcomes. The associations among their characteristics, laboratory tests, therapies, and outcomes were analyzed. Univariate analysis demonstrated that patients with APOs showed significant prevalence of lupus anticoagulant (LAC) positive (P < 0.001), antiphospholipid syndrome (P = 0.030), and heparin prior to pregnancy (P = 0.041). LAC positive was correlated with shorter gestational age (P = 0.043) and gestational weeks of pre-term delivery (P = 0.011). Increased ratio of soluble vascular endothelial growth factor receptor-1/placental growth factor in pregnancies with APLs was correlated with the APOs and worse neonatal outcomes, including gestational age (P = 0.028), fetal death (P = 0.011), gestational weeks of pre-term delivery (P = 0.002), and birth weight percentile (P = 0.016). Angiogenic markers in pregnancies with APLs were correlated with the incidence of APOs.

Comparison of treatments for the prevention of fetal growth restriction in obstetric antiphospholipid syndrome: a systematic review and network meta-analysis

Women with criteria and non-criteria obstetric antiphospholipid syndrome (APS) carry an increased risk of pregnancy complications, including fetal growth restriction (FGR). The management of obstetric APS traditionally involves clinicians, obstetricians and gynaecologists; however, the most appropriate prophylactic treatment strategy for FGR prevention in APS is still debated. We performed a systematic review and network meta-analysis (NetMA) to summarize current evidence on pharmacological treatments for the prevention of FGR in APS. We searched PubMed and Embase from inception until July 2020, for randomized controlled trials and prospective studies on pregnant women with criteria or non-criteria obstetric APS. NetMA using a frequentist framework were conducted for the primary outcome (FGR) and for secondary outcomes (fetal or neonatal death and preterm birth). Adverse events were narratively summarised. Out of 1124 citations, we included eight studies on 395 pregnant patients with obstetric APS treated with low-dose aspirin (LDA) + unfractionated heparin (UFH) (n = 132 patients), LDA (n = 115), LDA + low molecular weight heparin (n = 100), LDA + corticosteroids (n = 29), LDA + UFH + intravenous immunoglobulin (n = 7), or untreated (n = 12). No difference among treatments emerged in terms of FGR prevention, but estimates were largely imprecise, and most studies were at high/unclear risk of bias. An increased risk of fetal or neonatal death was found for LDA monotherapy as compared to LDA + heparin, and for no treatment as compared to LDA + corticosteroids. The risk of preterm birth was higher for LDA + UFH + IVIg as compared to LDA or LDA + heparin, and for LDA + corticosteroids as compared to LDA or LDA + LMWH. No treatment was associated with an increased risk of bleeding, thrombocytopenia or osteopenia.

Risk factors for pregnancy morbidity in women with antiphospholipid syndrome

Antiphospholipid syndrome (APS) increases the risk of obstetric complications, but risk factors for pregnancy morbidity in women with APS remain incompletely characterized. This retrospective study included pregnant women with APS and a control group without APS admitted to Peking University People's Hospital between January 2013 and September 2019. Clinical data were extracted from medical records. Univariate and multivariate logistic regression analyses were used to identify factors associated with adverse pregnancy outcomes (fetal loss, premature birth, fetal growth restriction [FGR], preeclampsia and neonatal death). We included 64 pregnancies in 59 patients with APS (age, 32.3 ± 4.3 years) and 256 pregnancies in 256 women without APS (age, 30.4 ± 3.3 years). Compared with the control group, the APS group had higher incidence rates of preeclampsia (10.9 % vs. 2.3 %, P = 0.002), premature rupture of membranes (17.2 % vs. 3.9 %, P < 0.001), postpartum hemorrhage (23.4 % vs. 4.3 %, P < 0.001), fetal loss (4.7 % vs. 0.8 %, P = 0.024) and premature delivery at ≤34 weeks (7.8 % vs. 2.3 %, P = 0.047). The incidence rates of hypertension during pregnancy, HELLP syndrome, gestational diabetes, oligohydramnios and FGR were similar in both groups. Multivariate logistic regression revealed that three or more prior spontaneous miscarriages (odds ratio [OR], 6.162; 95 % confidence interval [CI], 1.271-29.882; P = 0.024) and double-positivity for antiphospholipid antibodies (OR, 4.024; 95 %CI, 1.025-15.794; P = 0.046) were independently associated with adverse pregnancy outcomes. APS increases the risks of adverse maternal and fetal outcomes during pregnancy. Three or more spontaneous miscarriages and double-positivity for antiphospholipid antibodies are risk factors for adverse pregnancy outcomes in women with APS.

Management of Antiphospholipid Syndrome

Antiphospholipid syndrome (APS), is an acquired autoimmune disorder characterised by thrombosis, pregnancy morbidity, and the presence of antiphospholipid antibodies (aPL). Although venous thromboembolism is the most common manifestation, thrombotic events in APS may also occur in virtually any vascular bed, with cerebral circulation being the arterial territory most commonly affected. As APS is a heterogeneous condition, its management should be tailored with a patient-centred approach based on individual risk assessment, which includes the aPL profile, concomitant auto-immune diseases, and traditional cardiovascular risk factors. Although literature data are conflicting regarding primary prophylaxis, there is some evidence indicating that antiplatelet agents may reduce the risk of a first thrombotic event in individuals with a high-risk profile. In patients with thrombotic APS, current evidence-based guidelines recommend lifelong vitamin K antagonists (VKAs), preferably warfarin. The optimal intensity of anticoagulation following arterial thrombosis remains controversial. Arterial thrombosis should be treated either with high-intensity warfarin at a target INR > 3.0, or low-dose aspirin (LDA) combined with moderate-intensity warfarin (INR 2.0-3.0). It is recommended to avoid direct oral anticoagulants (DOACs) in patients with high-risk APS, mainly those with triple-positive PL and previous arterial events. They would only be used exceptionally in selected patients with low-risk venous thromboembolism (VTE). In low-risk VTE patients currently treated with a DOAC due to warfarin intolerance or a previous unstable International Normalized Ratio on warfarin, the decision of continuing DOACs would be taken in carefully selected patients. In women with obstetric APS, the combination therapy with LDA plus heparin remains the conventional strategy.

Cytokine imbalance at materno-embryonic interface as a potential immune mechanism for recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a prominent reproductive disease that distresses about 2%-5% of couples. RPL is the loss of two or more successive spontaneous pregnancies prior to the 20th week of embryo development. The commencement of pregnancy necessitates implantation of the embryo into responsive maternal decidua synchronized with the process of placentation, decidual and myometrial trophoblast incursion as well as refashioning of spiral blood arteries of uterus. The collapse of any of the processes fundamental for pregnancy success may result into an array of pregnancy problems including spontaneous pregnancy loss. Endometrium of human female manufactures an extensive range of cytokines during the proliferative and secretory stage of the menstrual cycle. These endometrial cytokines are thought as major players for making the uterus ready for embryo implantation and placental development during pregnancy. Decidual cytokines regulate the invasion of trophoblast and remodeling of spiral arteries as well as take part in immune suppression to accomplish the pregnancy. Deterrence of maternal rejection of embryo needs a regulated milieu, which takes place essentially at the embryo-maternal interface and the tissues of the uterus. The reasons of RPL remain anonymous in a large number of cases that lead to difficulties in management and severe trauma in couples. Cytokine modulatory therapies have been shown promising for preventing RPL. Further study of novel factors is wanted to establish more effective RPL treatment protocols. The present study aims to review the outcome of cytokine breach at materno-embryonic interface and the efficacy of cytokine modulatory therapies in RPL.

Antiphospholipid syndrome

Antiphospholipid syndrome is one of the more common acquired causes of hypercoagulability. Its major presentations are thrombotic (arterial, venous, or microvascular) and pregnancy morbidity (miscarriages, late intrauterine fetal demise, and severe pre-eclampsia). Classification criteria include 3 different antiphospholipid antibodies: lupus anticoagulant, anticardiolipin, and anti-beta 2 glycoprotein I. Management includes both preventive strategies (low-dose aspirin, hydroxychloroquine) and long-term anticoagulation after thrombosis.