What are the effects of danazol (Danazol) in early pregnancy?

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From the Guidelines

Danazol is not recommended during early pregnancy due to the risk of abnormalities of sexual differentiation in the fetus. If you're referring to danazol (danazol), it's a synthetic androgen that can cause masculinization of a female fetus and should be avoided during pregnancy, especially in the first trimester. This medication is typically used to treat endometriosis, fibrocystic breast disease, and hereditary angioedema, but it carries a significant risk of birth defects, as noted in the international consensus and practical guidelines on the gynecologic and obstetric management of female patients with hereditary angioedema caused by c1 inhibitor deficiency 1. Some key points to consider when taking danazol include:

  • The mean half-life for danazol was 9.44 ± 2.74 hours, which may require a shorter period for avoiding AAs before attempting conception, although it is recommended to discontinue 2 months before attempting conception 1
  • A negative pregnancy test result should be obtained before commencing AA therapy
  • If a patient becomes pregnant while taking AAs, administration of the drug should be discontinued and the family should be informed of the risk of abnormalities of sexual differentiation in the fetus 1 If you're currently taking danazol and discover you're pregnant, contact your healthcare provider immediately to discuss stopping the medication and alternative treatments. The risks occur because danazol can cross the placental barrier and interfere with normal fetal development, particularly sexual differentiation. If you need treatment for a condition typically managed with danazol during pregnancy, your doctor can recommend safer alternatives based on your specific medical needs. Always consult with your healthcare provider before starting or stopping any medication during pregnancy.

From the FDA Drug Label

Use of danazol in pregnancy is contraindicated. A sensitive test (e.g., beta subunit test if available) capable of determining early pregnancy is recommended immediately prior to start of therapy. If a patient becomes pregnant while taking danazol, administration of the drug should be discontinued and the patient should be apprised of the potential risk to the fetus Exposure to danazol in utero may result in androgenic effects on the female fetus; reports of clitoral hypertrophy, labial fusion, urogenital sinus defect, vaginal atresia, and ambiguous genitalia have been received

Danazol use in early pregnancy is contraindicated due to potential risk to the fetus, including androgenic effects on female fetuses.

  • The drug should be discontinued if pregnancy occurs during therapy.
  • A sensitive test for early pregnancy should be performed before starting danazol therapy 2.

From the Research

Danazol in Early Pregnancy

  • Danazol is a synthetic steroid that has been used to treat endometriosis, but its use in early pregnancy is contraindicated due to potential teratogenic effects 3.
  • A study published in 1992 found that exposure to danazol in utero can cause virilization of female fetuses, resulting in cliteromegaly, fused labia, and urogenital sinus formation 3.
  • The same study found that the risk of virilization is higher with higher doses of danazol, but it can occur even at lower doses, and that discontinuing danazol therapy before the 8th week of pregnancy may reduce the risk of virilization 3.
  • There is limited information on the use of danazol in early pregnancy, and it is not recommended due to the potential risks to the fetus 3.
  • Other studies have focused on the use of danazol for treating endometriosis, but not specifically in early pregnancy 4, 5, 6.
  • A study published in 2018 discussed the current and emerging therapeutics for the management of endometriosis, but did not mention the use of danazol in early pregnancy 4.
  • Another study published in 2000 found that danazol is effective in relieving painful symptoms related to endometriosis, but did not address its use in early pregnancy 5.
  • A study published in 2010 compared the effectiveness of gonadotrophin-releasing hormone analogues (GnRHas) with danazol for pain associated with endometriosis, but did not discuss the use of danazol in early pregnancy 6.
  • A study published in 2012 discussed the use of non-steroidal anti-inflammatory drugs (NSAIDs) in pregnancy, but did not mention danazol specifically 7.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The effects of fetal exposure to danazol.

British journal of obstetrics and gynaecology, 1992

Research

Danazol for pelvic pain associated with endometriosis.

The Cochrane database of systematic reviews, 2000

Research

Gonadotrophin-releasing hormone analogues for pain associated with endometriosis.

The Cochrane database of systematic reviews, 2010

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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