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NCT Number: NCT07398924

Vaginal Estradiol and Oral Guaifenesin in Clomiphene Ovulation Induction

Clomiphene citrate is commonly used for ovulation induction; however, it may negatively affect endometrial development and cervical mucus quality, which can reduce pregnancy rates. Various adjunctive treatments have been proposed to overcome these antiestrogenic effects.

This randomized clinical trial aimed to compare the effects of vaginal estradiol and oral guaifenesin, alone or in combination, on endometrial thickness, cervical mucus characteristics, and clinical pregnancy rates in women undergoing ovulation induction with clomiphene citrate.

A total of 90 women with infertility undergoing ovulation induction were randomly assigned to one of three treatment groups: clomiphene citrate plus guaifenesin, clomiphene citrate plus vaginal estradiol, or clomiphene citrate combined with both guaife

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Key information

Conditions

Female Infertility Anovulatory Infertility Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Genital Diseases Genital Diseases, Female Infertility Infertility, Female Unexplained Infertility Urogenital Diseases

Age range

18 year–40 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Van Yuzuncu Yil University Dursun Odabasi Medical Center

Van, Di̇yarbakir, 21640, Turkey (Türkiye)

About this study

This study was designed as a single-center, randomized, parallel-group interventional clinical trial conducted at a university-affiliated tertiary care hospital. Women diagnosed with infertility and scheduled for ovulation induction with clomiphene citrate were eligible for inclusion.

Participants were randomly assigned to one of three treatment arms: clomiphene citrate plus oral guaifenesin, clomiphene citrate plus vaginal estradiol, or clomiphene citrate combined with both oral guaifenesin and vaginal estradiol. Clomiphene citrate was administered according to standard ovulation induction protocols. Adjunctive treatments were initiated during the follicular phase.

Baseline demographic and clinical characteristics were recorded. Follicular development and endometrial thickness were assessed by transvaginal ultrasonography. Cervical mucus characteristics, including spinnbarkeit and cervical mucus score, were evaluated during the periovulatory period. Ovulation was triggered when appropriate follicular criteria were met.

The primary outcome of the study was the clinical pregnancy rate. Secondary outcomes included endometrial thickness, cervical mucus quality, ovulation response, cycle cancellation, and miscarriage rate. Statistical analyses were performed to compare outcomes between treatment groups.

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • - Women aged 18 to 40 years
  • Diagnosis of infertility
  • Indication for ovulation induction with clomiphene citrate
  • Regular or irregular menstrual cycles suitable for ovulation induction
  • At least one patent fallopian tube
  • Normal uterine cavity on ultrasonography
  • Male partner with normal or mildly abnormal semen parameters
  • Willingness to participate and provide informed consent

Exclusion criteria

  • - Known hypersensitivity to clomiphene citrate, guaifenesin, or estradiol
  • Severe male factor infertility
  • Presence of uterine anomalies or intrauterine pathology
  • Endocrine disorders affecting ovulation (e.g., uncontrolled thyroid disease, hyperprolactinemia)
  • Polycystic ovary syndrome requiring alternative stimulation protocols
  • History of recurrent pregnancy loss
  • Use of hormonal treatment within the last 3 months

Treatment and study plan

Clomiphene Citrate.

Drug

Clomiphene citrate administered orally for ovulation induction according to standard clinical protocols.

Other names: Clomifene Citrate

Guaifenesin

Drug

Oral guaifenesin administered during the follicular phase to improve cervical mucus characteristics.

Other names: Glyceryl guaiacolate

Estradiol (E2)

Drug

Vaginal estradiol administered during the follicular phase to improve endometrial development.

Other names: Vaginal Estradiol

Primary outcomes

  1. Clinical pregnancy rate

    Time frame: From ovulation trigger administration to confirmation of clinical pregnancy by transvaginal ultrasonography within the same treatment cycle (approximately 4-6 weeks).

    Clinical pregnancy was defined as the presence of an intrauterine gestational sac detected by transvaginal ultrasonography.

Secondary outcomes

  1. Endometrial thickness

    Time frame: On the day of ovulation trigger administration (cycle day-specific).

    Endometrial thickness was measured by transvaginal ultrasonography.

  2. Cervical mucus score

    Time frame: During the peri-ovulatory period, from the day before ovulation trigger to the day after ovulation trigger (approximately 2-3 days).

    Cervical mucus quality was evaluated using cervical mucus scoring.

  3. Spinnbarkeit

    Time frame: During the peri-ovulatory period, from the day before ovulation trigger to the day after ovulation trigger (approximately 2-3 days).

    Spinnbarkeit was assessed as an indicator of cervical mucus stretchability.

  4. Miscarriage rate

    Time frame: Up to 12 weeks of gestation

    Miscarriage was defined as pregnancy loss before 12 weeks of gestation.

  5. Cycle cancellation rate

    Time frame: By the end of the treatment cycle (one cycle, approximately 28 days).

    Cycle cancellation was recorded when ovulation induction could not be completed.

Sponsors and collaborators

Lead sponsor

Yuzuncu Yil University

Other

Registry information

Official study title

Comparison of Vaginal Estradiol and Oral Guaifenesin Interventions in Patients Undergoing Ovulation Induction With Clomiphene Citrate

Acronym: CC-OVI

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
Feb 10, 2026
Registry last updated
Feb 10, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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