Efficacy and safety for preventing of venous thromboembolic complications in high-risk pregnant women: results of the «BEREG» pregnant women registry

Introduction. Recently, along with increasing women age who become pregnant and number of patients with extragenital pathology, a greater role has been referred to preconception preparation and implementation of preventive measures aimed at minimizing development of severe and often fatal conditions, particularly venous thromboembolic events (VTE), which are one of the lead cause of maternal and perinatal mortality in developed countries.

Aim: to analyze the effectiveness and safety of thromboprophylaxis in pregnant women with high VTE risk in real-world clinical practice.

Materials and Methods. The analysis was based on data obtained in the observational (cohort) study "Assessment of the clinical condition of pregnant women during gestation and childbirth in the early postpartum period and 12 months after childbirth, as well as analysis of perinatal outcomes, the condition of the fetus, newborn, and the quality of treatment for these patients" – the "BEREG" register. Inclusion criteria: pregnancy diagnosis at the first visit, the patient's written informed consent and their permanent residence in Tula or the Tula Region. Non-inclusion criteria: the patient's refusal to sign informed consent and their residence in other regions. All patient data were retrieved from outpatient and inpatient records and included complaints, medical history, information about previous and current illnesses, VTE risk factors, anthropometric data such as height, body weight, and body mass index at the time of pregnancy, as well as the type and dose of antithrombotic medication. Special attention was paid to the obstetric history, including the course of previous and current pregnancies, perinatal outcomes and delivery methods. VTE and thromboprophylaxis tactics were assessed using the "Antenatal and Postnatal Assessment of Risk Factors and Pregnancy Management" scale. The newborn's condition was evaluated by assessing birth height, weight and the Apgar score at 1 and 5 minutes of life.

Results. A total of 3214 pregnant women aged from 15 to 46 years were included in the registry, of which 330 (10.3 %) women who received antithrombotic therapy with anticoagulants and/or antiplatelet agents, including 217 (65.8 %) pregnant women receiving combination therapy calcium nadroparin (Fraxiparin) 0.3 ml (2850 IU anti-Xa) subcutaneously per day combined with acetylsalicylic acid (ASA) 150 mg/day per os (group 1) and 113 woman (34.2 %) – monotherapy with ASA 150 mg/day once per os (group 2). The groups were comparable in major clinical and laboratory characteristics. Patient management analysis showed that no cases of VTE, maternal mortality, allergic side effects, thrombocytopenia or heparin-induced thrombosis were observed in either group. However, only in the group of patients receiving ASA monotherapy there were recorded complications such as bleeding during childbirth (n = 1) and fetal death (n = 3), however, not allowing to establish a clear link with the medicine intake due to the small number of observations. It is noteworthy that doctors were not sufficiently informed about the need to use VTE risk assessment scales to optimize the management strategy, as evidenced by the lack of instructions on their use in medical records.

Conclusion. The registry showed the effectiveness and safety of thromboprophylaxis based on the 0,3 ml Fraxiparin in high-risk pregnant women in real-world clinical practice, which is confirmed by the lack of VTE, bleeding, maternal death, allergic side effects, thrombocytopenia and heparin-induced thrombosis. Of note, due to insufficient doctors' alertness about a need to apply VTE risk assessment scale for objectifying treatment strategy, the prophylactic options were chosen arbitrarily: combined therapy with low molecular weight heparin and ASA, or ASA monotherapy.

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