Evaluation of a Preventive Therapeutic Strategy for Postpartum Venous Thromboembolism in Women With Genetic Risk Factor (POSTPART AS5-2)

Evaluation of a Preventive Therapeutic Strategy for Postpartum Venous Thromboembolism in Asymptomatic Women With Heterozygous Factor V Leiden ou Factor II Mutation.

Background : pregnancy and postpartum period are times of increased risk for deep vein thrombosis (DVT).

The incidence of venous thromboembolic disease (VTE) during pregnancy is estimated at 1-2 per 1,000, and this risk increases in the postpartum period, rising up to 80-fold. VTE is a multifactorial condition, and several studies have identified risk factors for DVT during this period. These factors may be related to the patient herself-such as age, overweight, smoking, a personal or family history of DVT, and/or thrombophilia. Factors related to the pregnancy itself and peripartum events-such as preeclampsia, multiple pregnancy, the mode of delivery (emergency or elective cesarean section), and postpartum hemorrhage-have also been identified as DVT risk factors.

Resistance to activated protein C caused by the Factor V Leiden mutation affects about 5% of the population and, in its heterozygous form, increases the risk of VTE by 3- to 10-fold depending on the study, raising the absolute risk to approximately 1 in 400. The heterozygous mutation of the prothrombin (Factor II) gene affects about 2% of the population and increases the risk of VTE threefold. However, although the risk is increased, the absolute risk of VTE remains low (0.5 to 1%).

Regarding prevention, recommendations are heterogeneous and often based on a low level of evidence. In certain situations (e.g., history of provoked thrombosis, moderate thrombophilia), prophylaxis is not always recommended, or its duration is not clearly defined, and the benefit-risk balance remains uncertain.

The main objective of this study is to describe the duration of anticoagulation prescribed after delivery according to the characteristics of patients carrying these mutations and their mode of delivery. The secondary composite objective is to compare two treatment durations (less than 2 weeks vs. 6 weeks) to determine whether a shorter treatment is less effective in preventing deep vein thrombosis, and whether a longer treatment is associated with more adverse effects.

The target population therefore consisted of adult women carrying an asymptomatic heterozygous mutation of Factor V or Factor II, who had been followed up or had consulted at the Hospices Civils de Lyon for obstetric or hematologic evaluation related to this mutation.

Investigators extracted health data of the included patients from the Hospices Civils de Lyon medical software. They also contacted patients by phone to complete data collection, particularly to determine whether they had experienced a deep vein thrombosis within 12 weeks after delivery, or any adverse effects related to anticoagulant therapy.

Study Overview

• Status: Completed
• Conditions: Pregnancy; Postpartum; Factor V Leiden Heterozygous Mutation; Factor II Heterozygous Mutation
• Intervention / Treatment: Other: Retrospective collection of health data; Other: Phone call to every participant

• Study Type: Observational
• Enrollment (Actual): 86

Contacts and Locations

Study Locations

• France
  • Bron, France, 69500
    • Service d'hémostase clinique - Hôpital Louis Pradel
  • Lyon, France, 69004
    • Service Gynécologie Obstétrique - Hôpital de la Croix Rousse

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Female patients over than 18 years old, carrying asymptomatic heterozygous Factor V Leiden or Factor II mutation ; who consulted in Hospices Civils de Lyon for this condition, and who delivered between 01/01/2020 and 31/12/2026.

Description

Inclusion Criteria:

• Age > 18
• Heterozygous asymptomatic Factor V Leiden mutation or Factor II mutation, diagnosed before or during pregnancy
• Delivering between 01/01/2020 and 31/12/2025
• Patient with French social security rights

Exclusion Criteria:

• NA

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
2 weeks or less postpartum thromboprophylaxis; Patients receiving 2 weeks (or less) preventive anticoagulation with low molecular weight heparin after giving birth	Other: Retrospective collection of health data; From Hospices Civils de Lyon database, collection in Word Excel document of anonymized health data : Age, contact details, medical history, first degree family medical history, smoking status, previous estroprogestative contraception utilization, number of gestation, number of miscarriages, any medically assisted reproduction, singleton ou multiple pregnancy, obstetrical complication such as preeclampsia or postpartum hemorrhage, due date, delivering mode, any procoagulant treatment administration, anesthesia, thromboprophylaxis treatment duration; Other: Phone call to every participant; Phone call to every participant to assess any thromboembolic event in 12 first postpartum weeks, any treatment side effect, and their personal experience of the treatment
6 weeks postpartum thromboprophylaxis; Patients receiving 6 weeks preventive anticoagulation with low molecular weight heparin after giving birth	Other: Retrospective collection of health data; From Hospices Civils de Lyon database, collection in Word Excel document of anonymized health data : Age, contact details, medical history, first degree family medical history, smoking status, previous estroprogestative contraception utilization, number of gestation, number of miscarriages, any medically assisted reproduction, singleton ou multiple pregnancy, obstetrical complication such as preeclampsia or postpartum hemorrhage, due date, delivering mode, any procoagulant treatment administration, anesthesia, thromboprophylaxis treatment duration; Other: Phone call to every participant; Phone call to every participant to assess any thromboembolic event in 12 first postpartum weeks, any treatment side effect, and their personal experience of the treatment

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Thromboprophylaxis treatment duration	Evaluation of the given thromboprophylaxis treatment duration according to patients' characteristics	At baseline

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon
• Investigators: Principal Investigator: Lucia Rugeri, Service de Gynécologie Obstétrique - Hôpital de la Croix Rousse

Study record dates

Study Major Dates

• Study Start (Actual): February 4, 2026
• Primary Completion (Actual): March 13, 2026
• Study Completion (Actual): March 13, 2026

Study Registration Dates

• First Submitted: January 6, 2026
• First Submitted That Met QC Criteria: January 6, 2026
• First Posted (Actual): January 15, 2026

Study Record Updates

• Last Update Posted (Actual): April 6, 2026
• Last Update Submitted That Met QC Criteria: March 31, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Pregnancy; Postpartum; Thromboprophylaxis; Thrombophilia; Low molecular weight heparin (LMWH); Veinous thromboembolism (VTE); Heterozygous factor V Leiden mutation; Prothrombin gene mutation
• Additional Relevant MeSH Terms: Hematologic Diseases; Hemic and Lymphatic Diseases; Thrombophilia
• Other Study ID Numbers: 69HCL25_1157; 2025-A02800-49 (Other Identifier: ID-RCB)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No