Oil of Oregano in Pregnancy: Not Recommended
Oil of oregano should be avoided during pregnancy due to lack of safety data and potential reproductive toxicity associated with essential oils. The most recent guideline evidence explicitly advises against using essential oils, including oregano, for treatment during pregnancy given the absence of FDA-approved standardization and availability of safer alternatives 1.
Why Oregano Oil Should Be Avoided
Guideline-Based Recommendations
Essential oils including oregano are not recommended for use in pregnancy based on 2022 CDC guidelines, which note that these products lack regulation, standardization, and are equal or inferior to FDA-approved alternatives 1.
The guidelines specifically list oregano among essential oils (tea tree, laurel, anise, basil, bergamot, lavender, mint, oregano, grapefruit, rosemary, winter savory, and ginger) that should not be used due to lack of regulation and proven efficacy 1.
Safety Concerns
Essential oils and their constituents can cause maternal reproductive toxicity, including abortion, hormone modulation, maternal toxicity, teratogenicity, and embryo-fetotoxicity 2.
First trimester exposure carries the highest risk for fetal malformations when exposed to potentially teratogenic substances 3.
Multiple herbal medicines and essential oils have been documented to cross the placenta, potentially reaching the fetus and inducing uterine contractions or hormonal imbalances that could result in abortion 4.
Evidence Quality Issues
There is insufficient scientific evidence regarding the efficacy and safety of most herbal supplements during pregnancy, with the notable exception of ginger for nausea 5.
A systematic review found that out of 33 identified herbal medicines used in Asian countries during pregnancy, eight were classified as potentially harmful and seven had no available safety information 6.
15.2% of pregnant women self-prescribe aromatherapy oils, yet there is no reported evidence of efficacy or comprehensive risk assessment for pregnancy-related use 7.
Safer Alternatives
For Upper Respiratory Symptoms
Saline nasal irrigation is the recommended first-line therapy for rhinosinusitis in pregnancy, providing symptom relief without drug exposure 3.
When bacterial infection is confirmed, pregnancy-compatible antibiotics (penicillins or cephalosporins) should be prescribed instead of herbal or essential oil products 3.
Critical Caveat
Lack of regulation is a major concern: Essential oil products are not standardized, making it impossible to predict allergy risk, toxicity, or actual constituent content 1.
Women using any herbal or essential oil products should disclose this to their healthcare providers, as severe adverse events have been reported with various herbal supplements during pregnancy 5.