Background: Although serum basal follicle stimulating hormone (FSH) is widely used to evaluate the ovarian response, the necessity of levels of serum FSH during the controlled ovarian hyperstimulation (COH) is controversy. When the ovarian response to COH is suboptimal due to the insufficient dose of FSH, which is often adjusted in subsequent treatment accordingly, we could detect serum FSH levels and considering that exogenous FSH is inadequate to optimal FSH threshold. We, therefore, aim to evaluate the association between the ovarian response and the difference value of serum FSH concentration in the first five days of ovarian stimulation.
Methods: In this retrospective single-center study, patients were enrolled for first IVF/ICSI during the period from August 2015 to December 2017. The COH only included gonadotrophin-releasing hormone agonist (GnRH-a) protocols in which endogenous serum FSH values were suppressed, and stimulated with 150IU fixed-dose recombinant FSH (rFSH) during the first five days. Patients met all inclusion criteria were selected: age ≤ 40 years, body mass index (BMI) ≤ 32 kg/m2, regular menstruation cycle of 21-35 days and non-ovarian factor infertility. Groups were divided by the amount of oocytes collection as follows: (A) poor responders (n=27), (B) normal responders (n=638), (C) hyper responders (n=205). A multivariable logistic regression model was performed to evaluate the relationship between the ovarian response and difference value of serum FSH levels during the first five days of ovarian stimulation.
Result(s): The difference value of serum FSH level (ΔFSH) between the sixth day and the first day during ovarian stimulation was measured as the primary outcome. Mean serum ΔFSH levels between groups B and C were 7.45 and 6.87, which had significant differences (p=0.0259). ΔFSH was stratified in quartiles as below: (a) ΔFSH≤5.16, (b) ΔFSH 5.16-7.11, (c) 7.11-9.09, (d) ΔFSH˃9.09. After adjusted by potential confounding factors, there was no relationship exists between ΔFSH levels and ovarian response.
Conclusion(s): There is no relevance between the ovarian response and ΔFSH in the 150 IU fixed dose rFSH treatment protocol during COH. Serum FSH might not be used as an effective predictor for ovarian response and reproduction potential in IVF/ICSI clinical practice.