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NCT Number: NCT07460674

Serum FSH Levels During Controlled Ovarian Stimulation

Follicle-stimulating hormone (FSH) plays a central role in controlled ovarian stimulation (COS) during in vitro fertilization (IVF) cycles. While baseline FSH is commonly used to assess ovarian reserve, the clinical significance of dynamic FSH changes during stimulation remains unclear. Limited evidence suggests that serum FSH levels during COS may reflect ovarian response and could be associated with follicular development and treatment outcomes, yet FSH is not routinely monitored throughout stimulation protocols.

This prospective single-center cohort study aims to evaluate the dynamics of serum FSH levels during COS and to examine their association with ovarian response and IVF outcomes. Serum FSH, luteinizing hormone (LH) and estradiol (E2) will be measured at predefined time points during stimulation. Associations between FSH levels and oocyte yield, embryo development, and pregnancy outcomes will be analyzed to better understand the clinical relevance of FSH monitoring during IVF treatment.

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Key information

Conditions

Female Subjects Undergoing Controlled Ovarian Hyperstimulation

Age range

18 year–44 year

Sex eligibility

Female

Study type

Observational

Primary location

MUHC Reproductive Centre

Montreal, Quebec, H2L 4S8, Canada

About this study

Background and Rationale

Follicle-stimulating hormone (FSH), secreted by the anterior pituitary gland in response to gonadotropin-releasing hormone (GnRH), plays a critical role in ovarian follicular development and estradiol production. In assisted reproductive technologies (ART), exogenous FSH is administered during controlled ovarian stimulation (COS) to promote multifollicular growth. Although baseline FSH is widely used as a marker of ovarian reserve and predictor of ovarian response, the clinical significance of dynamic FSH changes during stimulation remains insufficiently characterized.

Day 7 of stimulation represents a clinically important time point during which follicular growth and synchronization are assessed. Prior studies have suggested that serum FSH levels during COS may correlate with ovarian response and may reflect an individualized FSH threshold beyond which increasing exogenous dosing may not improve follicular recruitment. However, consensus is lacking regarding the clinical utility of serial FSH monitoring during stimulation, and it is not routinely incorporated into IVF protocols.

Understanding the relationship between FSH dynamics, follicular development, estradiol production, and treatment outcomes may support more individualized stimulation strategies and improve reproductive outcomes.

Study Design

This is a prospective observational cohort study conducted at a single academic fertility center at the McGill University Health Centre (MUHC) Reproductive Centre.

Study Population

Eligible participants include patients undergoing controlled ovarian stimulation for IVF or ICSI at the MUHC Reproductive Centre. All stimulation protocols (GnRH agonist and antagonist) and all gonadotropin formulations (including Gonal-F, Menopur, Rekovelle, and Puregon) are included.

Data Collection

Demographic and clinical data will include age, body mass index (BMI), obstetric history, indication for treatment, and stimulation protocol details.

Serum hormone levels of will be measured at three predefined time points:

  • Baseline (cycle day 3)
  • Day 7 or 8 of gonadotropin stimulation
  • Trigger day (day of trigger shot before oocyte retrieval)

Blood samples will be collected at time points that coincide with routine visits for women undergoing ovarian stimulation, during which blood tests are already performed as part of standard clinical care

The hormones measured include:

Serum Follicle-stimulating hormone (FSH) (mIU/mL) Luteinizing hormone (LH) (mIU/mL) Estradiol (E2) (pmol/L) Anti-Müllerian Hormone (AMH) (ng/mL)

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Patients undergoing controlled ovarian stimulation
  • All stimulation protocols (agonist and antagonist).
  • All gonadotropin formulation (Gonal-F, Menopur, Rekovelle, Puregon).

Exclusion criteria

  • Cancer fertility preservation patients .
  • Patients over age 44.

Treatment and study plan

Primary outcomes

  1. -Trigger day FSH levels

    Time frame: 60 months

    Serum Follicle-stimulating hormone (FSH) (mIU/mL) measured at the day of the trigger shot

  2. Trigger day E2 levels

    Time frame: 60 months

    Serum Estradiol (E2) (pg/mL) levels measured at trigger shot day

  3. Number of patients reaching trigger

    Time frame: 60 months

    The number of patients that received the trigger shot and proceeding to oocyte retrieval / The number pf patients canceled during the ovarian stimulation

  4. Number of oocytes retrieved

    Time frame: 60 months

    The number of oocytes collected in the oocyte retrieval procedure

  5. Number of transferable embryos

    Time frame: 60 months

    Number of embryos were transferred in the fresh cycle plus the number of frozen embryos

Secondary outcomes

  1. Biochemical pregnancy rate

    Time frame: 60 months

    Positive pregnancy test (i.e positive serum HCG level >20 U/L after 11 days of ET of D5 embryo and 13 after D3 embryo transfer) per transfer

  2. Clinical pregnancy rate

    Time frame: 60 months

    Pregnancy diagnosed by ultrasound with at least one embryo and a discernable heartbeat per transfer

  3. Miscarriage rate

    Time frame: 60 months

    Spontaneous loss of clinical pregnancy before 12 weeks per transfer

Sponsors and collaborators

Lead sponsor

McGill University Health Centre/Research Institute of the McGill University Health Centre

Other

Registry information

Important dates

Study start
2026
Primary completion
2030
Study completion
2030
First posted
Mar 10, 2026
Registry last updated
Mar 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.