Depending on the response, the dose is maintained, increased or reduced. The woman revaluated after another 5 days (10 days since start). If required the dose is readjusted. The woman is now monitored after every 2/3 days.
When follicles are > 17 mm, it is an indicator of maturity and approaching ovulation. The multiple follicles developed are of variable diameters. While some grow to > 20 mm, many may be < 15 mm. In such cases the stimulation is to continue until FD of 50 % follicles is > 18 mm. 9 mm thick triple line Endometrium reflects that the uterus is ready for implantation.
A minimum of 3 follicles need to develop to maturity to proceed to egg retrieval. If this is not achieved, cycle is cancelled and we do not proceed to egg retrieval. About 90 % of women under 40 with normal FSH and normal antral follicle counts will develop at least this minimum number.
In women not at risk of OHSS, or poor responders (normally identified before the treatment cycle), the visits can be limited. Only one TVS performed on stimulation day 9 or 10 can be enough. If the patient on that day had three follicles of 18 mm (means of two diameters), fewer than 15 follicles and an endometrial thickness of 7 mm or more, hCG is given. If the follicle did not fulfill these criteria on the day of the scan, a follicular growth of 2 mm/24 hours is predicted and hCG given accordingly. Egg retrieval is scheduled 36 hours after hCG administration.