Serum FSH Levels During Controlled Ovarian Stimulation
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- This is an observational study: the protocol does not assign a study treatment.
- Who it may be relevant to
- Registry conditions: Female Subjects Undergoing Controlled Ovarian Hyperstimulation. Basic parameters: 18 years — 44 years · Female.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Canada
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
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.
Detailed description
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:
1. Baseline (cycle day 3) 2. Day 7 or 8 of gonadotropin stimulation 3. 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)
Primary outcome measures
- -Trigger day FSH levels [Time frame: 60 months]
- Trigger day E2 levels [Time frame: 60 months]
- Number of patients reaching trigger [Time frame: 60 months]
- Number of oocytes retrieved [Time frame: 60 months]
- Number of transferable embryos [Time frame: 60 months]
Secondary outcome measures (3)
- Biochemical pregnancy rate [Time frame: 60 months]
- Clinical pregnancy rate [Time frame: 60 months]
- Miscarriage rate [Time frame: 60 months]
Eligibility criteria
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.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Cohort
Study locations
Canada · 1 center
- MUHC Reproductive Centre — Montreal
Publications
- Sun PP, Zhang YM, Zhu HY, Sun N, Ma HG. The relationship between serum FSH level and ovarian response during controlled ovarian stimulation. Ginekol Pol. 2023;94(6):470-475. doi: 10.5603/GP.a2022.0010. Epub 2022 Apr 14. PMID 35419793
- de Koning CH, Schoemaker J, Lambalk CB. Estimation of the follicle-stimulating hormone (FSH) threshold for initiating the final stages of follicular development in women with elevated FSH levels in the early follicular phase. Fertil Steril. 2004 Sep;82(3):650-3. doi: 10.1016/j.fertnstert.2004.01.043. PMID 15374709
- Bentov Y, Burstein E, Firestone C, Firestone R, Esfandiari N, Casper RF. Can cycle day 7 FSH concentration during controlled ovarian stimulation be used to guide FSH dosing for in vitro fertilization? Reprod Biol Endocrinol. 2013 Feb 22;11:12. doi: 10.1186/1477-7827-11-12. PMID 23433095
- Abdalla H, Thum MY. An elevated basal FSH reflects a quantitative rather than qualitative decline of the ovarian reserve. Hum Reprod. 2004 Apr;19(4):893-8. doi: 10.1093/humrep/deh141. Epub 2004 Mar 11. PMID 15016786
Identifiers
NCT: NCT07460674 · 2026-11743