What foods and medications should be avoided during in vitro fertilization (IVF) stimulation?

Foods and Medications to Avoid During IVF Stimulation

During IVF ovarian stimulation, avoid vitamin K antagonists (warfarin), cyclophosphamide, aspirin prior to oocyte retrieval, and highly processed foods high in trans fats, added sugars, and sodium, while adopting a Mediterranean-style diet rich in whole plant foods. 1

Medications to Avoid or Modify

Anticoagulants Requiring Transition

• Vitamin K antagonists (warfarin) must be discontinued and transitioned to therapeutic-dose low molecular weight heparin (LMWH) for patients with thrombotic antiphospholipid syndrome undergoing ovarian stimulation, as warfarin is contraindicated during fertility treatment 1
• The transition typically involves enoxaparin 1 mg/kg subcutaneously every 12 hours, withheld for oocyte retrieval and resumed subsequently 1

Chemotherapy Agents

• Cyclophosphamide (CYC) must be discontinued during ovarian stimulation as it directly impacts maturing follicles, while other necessary immunosuppressive and biologic therapies can be continued in patients with stable disease 1
• Alkylating agents and radiation can induce high risk of mutations in spermatozoa and oocytes, making it essential to complete fertility preservation before starting cancer-directed therapy 1

Aspirin Timing

• Aspirin should not be used prior to oocyte retrieval due to concern that its prolonged antiplatelet action may increase bleeding risk at the time of retrieval 1
• Aspirin may be started after oocyte retrieval if clinically indicated for patients with antiphospholipid antibodies 1

Foods and Dietary Patterns to Avoid

Highly Processed Foods

• Avoid processed foods containing trans fatty acids, as well as foods high in added sugars, saturated fat, and sodium including processed meats, as these negatively affect gut microbiome composition and promote metabolic abnormalities 1
• Limit processed meats to no more than 150 grams weekly, as multiple international dietary guidelines consistently recommend restricting these foods 1
• Synthetic emulsifiers like carboxymethylcellulose and polysorbate-80 found in processed foods impair gut barrier function and promote low-grade inflammation 1

Specific Foods to Limit

• Limit high-fructose corn syrup and acellular nutrients found in ultra-processed foods, as these promote bacterial overgrowth in the small intestine and unfavorable microbial profiles that negatively influence immune and endocrine functions 1
• Restrict foods high in refined grains, as these lack the dietary fibers and phytochemicals that support healthy gut microbiota 1

Recommended Dietary Approach

Mediterranean Diet Pattern

• Adopt a Mediterranean-style diet emphasizing whole plant foods, vegetables, fruits, whole grains, legumes, nuts, fish, and lean poultry as this provides phytochemicals and dietary fibers that promote health through gut microbiota biotransformation 1, 2
• Consume 5-6 servings of vegetables and 2 servings of fruits daily, with emphasis on dark green, red, and orange types 1
• Include at least half of grain intake as whole grains rather than refined grains 1

Protein Sources

• Favor fish twice weekly, consume legumes at least twice weekly, and limit red meat to 500 grams weekly while choosing lean or low-fat options when consuming meat and poultry 1
• Include a small handful of nuts daily as part of the dietary pattern 1

Critical Considerations for Specific Patient Populations

Patients with Antiphospholipid Antibodies

• Women with positive antiphospholipid antibodies, obstetric antiphospholipid syndrome, or treated thrombotic antiphospholipid syndrome require prophylactic anticoagulation with heparin or LMWH during ovarian stimulation due to the potentially life-threatening risk of thrombosis from elevated estrogen levels 1
• Prophylactic dosing of enoxaparin is typically 40 mg daily, started at the beginning of ovarian stimulation, withheld 24-36 hours prior to oocyte retrieval, and resumed following retrieval 1

Patients with Hormone-Sensitive Cancers

• Women with estrogen receptor-positive tumors may benefit from ovarian stimulation protocols incorporating aromatase inhibitors (letrozole) or selective estrogen receptor modulators (tamoxifen) to minimize peak estrogen exposure, though these alternative protocols have comparable oocyte yields to standard protocols 1

Risk of Ovarian Hyperstimulation Syndrome

• Patients at risk for ovarian hyperstimulation syndrome may benefit from ovarian stimulation protocols that yield lower peak serum estrogen levels 1
• Underlying thrombophilia increases the risk of severe ovarian hyperstimulation syndrome, which can include arterial and venous thrombosis 1

Common Pitfalls to Avoid

• Do not continue warfarin during ovarian stimulation—always transition to LMWH in consultation with reproductive endocrinology specialists 1
• Do not assume all immunosuppressive medications must be stopped—only cyclophosphamide directly impacts maturing follicles and must be discontinued 1
• Do not use aspirin immediately before oocyte retrieval due to bleeding risk, even in patients who will require it for thromboprophylaxis 1
• Do not rely solely on supplements to compensate for poor dietary patterns—the foundation should be a whole-food, Mediterranean-style diet 1, 2