Clinical trial NCT05318547: Assessing Women's Preferences for Postpartum Thromboprophylaxis: the PREFER-PostPartum
Official title: Assessing Women's Preferences for Postpartum Thromboprophylaxis: the PREFER-PostPartum
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Pregnancy
Lead sponsor: Fondation Hôpital Saint-Joseph
Sponsor class: OTHER
First posted: 2022-04-08
Enrollment: 52
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: OTHER

Brief summary: The risk of venous thromboembolism (VTE), which consists of deep vein thrombosis (DVT) and pulmonary embolism (PE), increases during pregnancy and most strikingly in the postpartum period (6 weeks after delivery). Extensive research efforts have led to the identification of many risk factors for VTE events. Examples of such factors include maternal characteristics (personal history of VTE, thrombophilia, obesity, race) and obstetrical characteristics (methods of delivery, pre-term delivery, growth retardation). These allow care providers to risk stratify women at the time of delivery into low, moderate and high-risk women, based on experts' opinion. Further, a risk score, which was recently developed and validated on English and Swedish populations, estimates the risk of postpartum VTE in individuals.

Thromboprophylaxis (TPX) focuses on the use of short-term low-molecular-weight heparin (LMWH). LMWH is believed to reduce the risk of VTE by 50-70%, but the evidence is indirect, with a lack of large-scale randomized trial in the setting of the postpartum period. Further, LMWH is both inconvenient (subcutaneous injections) and possibly associated with haemorrhagic side effects. Alternative drugs do not exist, because direct oral anticoagulants (DOAC) and aspirin are not studied in this setting and because DOAC are contra-indicated in pregnancy and breastfeeding.

Given the unclear balance of benefits and risks, current guidelines vary greatly in the proportion of women with recommended TPX. Gassmann et al. have recently demonstrated, among a cohort of parturients at the Geneva University Hospitals: a recommendation of postpartum TPX in 40.1% of women, with an estimated mean risk of postpartum VTE of 0.12%, according to the 2015 UK guidelines (RCOG), and a recommendation of postpartum TPX in 8.7% of women, with an estimated mean risk of postpartum VTE of 0.20%, according to the 2018 US guidance (ACOG).These low risks of VTE to trigger a recommendation of TPX use contrast with that of experts' opinions, which advocate for a threshold of VTE risk of 1-3% to recommend the use of TPX. Currently, all women delivering by C-section in Geneva receive TPX regardless of their VTE risk.

This dramatic discrepancy of TPX guidance between guidelines, and between guidelines and individual experts, highlights the uncertainty in this setting. Womens' preferences would be critically important here, to guide a rationale and desired use of TPX. Quite surprisingly, such preferences have never been elicited, in spite of the very large number of births every year (5 and 4 million in Europe and the US, respectively).

To inform prescription patterns of postpartum TPX, investigators propose to conduct this prospective study to elicit values and preferences of pregnant and postpartum women.


Eligibility criteria: Inclusion Criteria:

* Women aged ≥18 years
* Ongoing pregnancy or in the early postpartum period (within 7 days of delivery)
* Participants may be with or without prior VTE or major bleeding, and with or without previous/current use of postpartum TPX.
* Fluency in French
* Women are able and willing to give free, informed and written consent

Exclusion Criteria:

* Fetal or neonatal death, in order not to bother women during their mourning.
* Women under tutorship or curatorship
* Women deprived of liberty
* Women under court protection There will be no further exclusion criteria, to maximize the external validity of the study.

Primary outcomes:
measure: Definition of the Threshold of Risk for Postpartum Venous Thromboembolism
timeFrame: Day 1
Secondary outcomes:
measure: Correlation of the time of interview (antenatal vs. postnatal) with the risk threshold
timeFrame: Day 1
measure: Correlation of demographic factors with the risk threshold
timeFrame: Day 1
measure: Correlation of medical factors with the risk threshold
timeFrame: Day 1
measure: Correlation of obstetric factors with the risk threshold
timeFrame: Day 1
Other outcomes:
Locations:
city: Paris
country: France
facility: Groupe Hospitalier Paris Saint-Joseph
Study officials:
affiliation: Fondation Hôpital Saint-Joseph
name: Justine P Hugon Rodin, MD
role: PRINCIPAL_INVESTIGATOR
References:
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citation: Blondon M, Harrington LB, Boehlen F, Robert-Ebadi H, Righini M, Smith NL. Pre-pregnancy BMI, delivery BMI, gestational weight gain and the risk of postpartum venous thrombosis. Thromb Res. 2016 Sep;145:151-6. doi: 10.1016/j.thromres.2016.06.026. Epub 2016 Jun 24.
citation: Sultan AA, West J, Grainge MJ, Riley RD, Tata LJ, Stephansson O, Fleming KM, Nelson-Piercy C, Ludvigsson JF. Development and validation of risk prediction model for venous thromboembolism in postpartum women: multinational cohort study. BMJ. 2016 Dec 5;355:i6253. doi: 10.1136/bmj.i6253.
citation: Mismetti P, Laporte S, Darmon JY, Buchmuller A, Decousus H. Meta-analysis of low molecular weight heparin in the prevention of venous thromboembolism in general surgery. Br J Surg. 2001 Jul;88(7):913-30. doi: 10.1046/j.0007-1323.2001.01800.x.
citation: Alalaf SK, Jawad RK, Muhammad PR, Ali MS, Al Tawil NG. Bemiparin versus enoxaparin as thromboprophylaxis following vaginal and abdominal deliveries: a prospective clinical trial. BMC Pregnancy Childbirth. 2015 Mar 28;15:72. doi: 10.1186/s12884-015-0515-2.
citation: Bates SM, Rajasekhar A, Middeldorp S, McLintock C, Rodger MA, James AH, Vazquez SR, Greer IA, Riva JJ, Bhatt M, Schwab N, Barrett D, LaHaye A, Rochwerg B. American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy. Blood Adv. 2018 Nov 27;2(22):3317-3359. doi: 10.1182/bloodadvances.2018024802.