Comparing letrozole alone versus letrozole with levothyroxine for women with PCOS and subclinical hypothyroidism

Letrozole Alone vs. Letrozole Plus Levothyroxine for Ovulation Induction in Infertile Women With Both (Polycystic Ovary Syndrome) PCOS and Sub-clinical Hypothyroidism.

Not applicable Interventional Al-Azhar University · NCT06041204

This study is testing if adding levothyroxine to letrozole helps women with PCOS and low thyroid function get pregnant more effectively than letrozole alone.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment200 (estimated)
Ages20 Years to 40 Years
SexFemale
SponsorAl-Azhar University Academic / other
Locations1 site (Cairo)
Trial IDNCT06041204 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to evaluate the effectiveness of letrozole alone compared to a combination of letrozole and levothyroxine for inducing ovulation in infertile women diagnosed with both polycystic ovary syndrome (PCOS) and subclinical hypothyroidism. Participants will be randomly assigned to receive either letrozole only or letrozole plus levothyroxine for a maximum of six months or until pregnancy is achieved. The study seeks to determine if the addition of levothyroxine improves ovulation rates and leads to higher pregnancy and live birth rates.

Who should consider this trial

Good fit: Ideal candidates for this study are women aged 20-40 with a BMI between 18-35 who have been diagnosed with PCOS and subclinical hypothyroidism and have been infertile for at least one year.

Not a fit: Patients with known thyroid disease, those on thyroid medications, or those with other significant causes of infertility may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a more effective treatment option for women with PCOS and subclinical hypothyroidism who are struggling with infertility.

How similar studies have performed: While there have been studies on the individual treatments, this specific combination approach is novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

Age between 20-40 years

BMI between 18-35 kg/m2

Meet diagnostic criteria for PCOS based on the Rotterdam consensus criteria and ESHRE/ASRM modifications (2018):

Oligo- and/or anovulation Clinical and/or biochemical signs of hyperandrogenism Polycystic ovaries on ultrasound

Subclinical hypothyroidism defined as TSH level between 5-10 mIU/L with normal free T4

Infertility duration ≥ 1 year

Intact ovaries and uterus, confirmed by physical exam and imaging

Normal semen analysis in male partner

No tubal or peritoneal factor contributing to infertility

Effective contraception if not attempting conception

Willing and able to provide informed consent

Exclusion Criteria:

Known thyroid disease or on thyroid medications

Abnormal thyroid function tests other than subclinical hypothyroidism

Hyperprolactinemia

Presence of other causes of infertility such as:

Moderate to severe male factor infertility Bilateral tubal occlusion or peritoneal factors Stage III-IV endometriosis Ovarian failure or insufficiency (high FSH or low AMH)

Previous diagnosis of any type of congenital adrenal hyperplasia

Uncontrolled diabetes (HbA1C \>8%)

History of deep vein thrombosis or thromboembolic events

Any contraindication to letrozole or levothyroxine

Previous use of letrozole or levothyroxine in past 6 months

Current or suspected pregnancy

Breastfeeding

Inability to comply with treatment and follow-up procedures

Where this trial is running

Cairo

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions PCOS of Bilateral OvariesSubclinical HypothyroidismFemale InfertilityLetrozoleLevothyroxinePCOSSubclinical hypothyroidism
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.