Home testing for timing of natural frozen embryo transfer (nFET) procedures; a solution for reducing clinic visits during Covid-19

This study sought to determine whether timing of nFET using home ovulation tests (OT) is a viable alternative to multiple clinic visits.

Background

• Natural Frozen Embryo Transfer (nFET) is an increasingly popular procedure as it avoids early embryonic exposure to an artificially created hormonal environment which may be detrimental to pregnancy outcomes.1,2
• nFET requires tracking of hormonal and endometrial changes in order to identify the day of ovulation and to appropriately schedule the day of transfer.
• Tracking of cycles is typically done through repeated blood tests and transvaginal ultrasound scans requiring an average of 4.35 clinic visits per cycle.
• These methods are invasive and expensive and multiple clinic visits can be inconvenient and time consuming for the patient.
• During the Covid-19 pandemic, infertile couples have found provision of treatment delayed due to closure of fertility clinics and concern for the potential risks associated with Covid-19 in pregnancy.
• Objective: We sought to determine whether timing of nFET using home ovulation tests (OT) is a viable alternative to multiple clinic visits

Methods   

• This was a prospective study of 46 women aged 24-45 years undergoing standard nFET at IVF Australia, Bondi Junction.   
• Regular clinic visits were completed in parallel with home cycle monitoring of urinary estrogen and luteinising hormone (LH) using the Clearblue™ Advanced Digital Ovulation Test.   
• The OT used displays `High` fertility when it detects a rise in the level of estrogen, and `Peak` fertility when it detects the LH surge.   
• To calculate the predictive ability of the OT, the first reported `High` was used prior to the clinically defined day of ovulation.    or `Peak` day
• A qualitative questionnaire was used to capture women`s treatment experience, opinions and the perceived advantages and disadvantages of each method.   
• The study was conducted between March 2017 and August 2019.   

Results

• The pregnancy rate was 46% for the 37 women who underwent FET confirmed by positive serum hCG.
• Clinic ovulation day was defined for 36 women through repeated blood tests and ultrasound scans, and of these, 35 used OTs.
• The OT indicated `Peak` fertility in 29 women; 6 women stopped testing before likely day of `Peak` fertility as transfer day was already scheduled.
• The mean time to ovulation from `Peak` fertility was 0.8 days (Table 1).
• `High` fertility was detected by 29 volunteers and occurred on average 4.1 days prior to ovulation (Table 1).