From the Guidelines
Anticoagulants do not directly pose a significant risk of infertility, but their use in certain conditions, such as antiphospholipid antibody-positive patients, requires careful management to prevent thrombotic complications during assisted reproductive technology (ART) procedures. The use of anticoagulants, such as heparin or low molecular weight heparin, is recommended in patients with antiphospholipid syndrome (APS) or those at risk of thrombosis during ART procedures, as the risk of thrombosis outweighs the risk of bleeding or other complications 1.
Key Considerations
- Patients with antiphospholipid antibody-positive status are at increased risk for thrombosis, and anticoagulation therapy is conditionally recommended during ART procedures 1.
- The choice of anticoagulant and dosing regimen should be individualized, with prophylactic dosing of enoxaparin (40 mg daily) being a common approach, started at the beginning of ovarian stimulation and withheld 24-36 hours prior to oocyte retrieval 1.
- Patients with obstetric APS will continue anticoagulation therapy throughout pregnancy, while those with thrombotic APS may require therapeutic-dose low molecular weight heparin during ART procedures 1.
Management Strategies
- Ovarian stimulation protocols that yield lower peak serum estrogen levels, such as those incorporating aromatase inhibitors, may be beneficial for patients at risk of thrombosis or ovarian hyperstimulation syndrome 1.
- Aspirin is not commonly used prior to oocyte retrieval due to concerns about bleeding risk, but may be started after retrieval if indicated 1.
- Patients receiving regular anticoagulation therapy with vitamin K antagonists for thrombotic APS should transition to therapeutic-dose low molecular weight heparin for ART procedures 1.
From the Research
Risk of Infertility Associated with Anticoagulants
The use of anticoagulants, also known as blood thinners, has been a topic of interest in relation to infertility. Several studies have investigated the safety and efficacy of anticoagulants in pregnant women and those undergoing in vitro fertilization (IVF) treatments.
Safety of Anticoagulants in Pregnancy
- Enoxaparin, a low-molecular-weight heparin, is considered safe for use in pregnancy and does not cross the placenta 2.
- A systematic review and meta-analysis found that enoxaparin was associated with significantly lower complications than aspirin in pregnant women 3.
- Another study found that low-molecular-weight heparin (LMWH) is both safe and effective in preventing major thromboembolic complications in pregnant women with rheumatic heart disease and prosthetic valve replacement 4.
Risk of Infertility with Anticoagulant Use
- There is no direct evidence to suggest that anticoagulants cause infertility. However, abnormal uterine bleeding, which can affect up to 70% of young women on anticoagulation, may impact fertility 5.
- A study on the safety of IVF under anticoagulant therapy found no bleeding or thromboembolic complications in patients at risk for thrombosis 6.
Management of Anticoagulation in Women of Reproductive Age
- Clinicians should counsel patients on issues related to menstruation, hemorrhagic ovarian cysts, and unintended pregnancy when prescribing anticoagulants 5.
- The subdermal implant may be considered a first-line option for women requiring anticoagulation, given its superior contraceptive effectiveness and ability to reduce the risk of hemorrhagic ovarian cysts 5.