BMI Versus Body Fat Percentage - Which is the Better Predictor of Fertility Outcomes in IVF Cycles?

The goal of this prospective observational cohort study is to evaluate whether body composition measured using bioelectrical impedance analysis (BIA) (including measures of body fat% and visceral fat) serve as a better predictor than body mass index (BMI) of outcomes of in vitro fertilization (IVF) cycles. Participants undergoing IVF will have body composition assessed using a BIA scale prior to treatment, including measurement of body fat percentage.

Associations between BMI, BIA-derived body composition measures, and IVF treatment outcomes will be evaluated. Outcomes of interest include ovarian stimulation requirements, number of mature oocytes (eggs) retrieved, number of oocytes fertilized, and number and quality of embryos available for cryopreservation (freezing). Furthermore, ongoing pregnancy and miscarriage rates will be evaluated.

The main question is to determine which of either BIA metrics or BMI are a better predictor of ongoing pregnancy or miscarriage rates. Furthermore, we would like to assess if there is an association between BIA metrics or BMI and the response to ovarian stimulation (egg recruitment), number and maturity rate of oocytes retrieved, number of oocytes fertilized and the number and quality of embryos available for cryopreservation.

Participants will be asked to step on a BIA scale at the start of their cycle before taking medications to stimulate/recruit oocytes. This scale provides additional information on body fat % and visceral fat % in addition to body weight.

The study aims to determine whether measures of adiposity obtained using BIA may provide a more informative assessment of the relationship between body composition and IVF outcomes than BMI alone.