Trend, clinical characteristics, and pregnancy outcomes of pregnancy associated venous thromboembolism: a retrospective analysis of nearly 10 years

Background: Pregnancy-associated venous thromboembolism (PA-VTE) seriously threatens maternal health. We aimed to investigate the clinical characteristics, risk factors, treatments, and pregnancy outcomes to better prevent and treat PA-VTE.

Methods: PA-VTE patients were selected from 171,898 women who were registered in the Department of Obstetrics of Fujian Maternity and Child Health Hospital from January 2014 to August 2023 and delivered to calculate the incidence. Clinical data were collected to retrospectively analyze the clinical characteristics, risk factors, treatments, and pregnancy outcomes of PA-VTE. Descriptive statistical analysis was used.

Results: There were 122 cases of PA-VTE with an incidence of 0.71 per 1000 pregnancies; the incidence showed an upward trend and peaked in 2022 (1.24‰). Pregnant women accounted for 28.69% (35/122), the onset were 5-39⁺⁶ weeks and incidence increased with the increase of trimester, reaching the highest level in puerperium with 87 cases (71.31%). VTE was mainly found in the lower extremities (112/122); a few were found in cranial venous sinus (4/122), pelvic vein (1/122), and pulmonary embolism (PE) in five cases. 78.68% (96/122) had clinical manifestations. By Royal College of Obstetricians and Gynaecologists (RCOG) risk assessment scale, 45.71% (16/35) of antepartum patients had risk score ≥3 with a maximum of 9, distributed in eight cases in the first trimester, four cases in the second trimester, and four cases in the third trimester. Patients with risk score <3 all occurred in the second and third trimester. Primary risk factors included advanced maternal age (AMA), thrombophilia. All patients received anticoagulant therapy, and seven patients were placed inferior vena cava (IVC) filter in antepartum period. Except one case of abortion in PPROM, the rest continued pregnancy to 29⁺¹ to 40 weeks, only one case of postpartum hemorrhage and one case of severe neonatal asphyxia. The onset time in puerperium was three hours to 28 days after delivery; 62.07% (54/87) patients were scored ≥2. The main risk factors included elective cesarean section, AMA, and preterm birth. Anticoagulant therapy was given after diagnosis; two cases were placed with IVC filter, one case was placed with left iliac vein stent and thrombolysis.

Conclusions: The incidence of PA-VTE showed an increasing trend over the past decade, predominantly occurring postpartum. Main risk factors included AMA, thrombophilia, preterm birth, and elective cesarean section. Higher risk scores correlated with earlier onset. Early risk assessment, appropriate prophylaxis, and standardized anticoagulation therapy resulted in favorable maternal and fetal outcomes, with temporary IVC filter placement being beneficial in selected cases.