The day when sufficient follicle maturation is observed you will be informed of the exact time for your last injection which will induce final oocyte maturation and ovulation (Pregnyl or Profasi or Ovitrelle) as well as the dose that must be used. This injection is human chorionic gonadotrophin which mimics the LH action and induces final oocyte maturation and ovulation. The injection is administered late in the evening or after midnight. Ovulation is expected about 36 hours later.

This last injection concludes the painful phase of daily injections and marks the end of GnRH analogue and gonadotrophin administration. The following day is a day to rest and prepare for the egg collection. This last injection is very particular in that it must be done at a very specific time, which will be the deciding factor for the time of egg collection. If we attempt to retrieve the eggs before they develop completely, i.e. much earlier than 36 hours after the injection, we shall collect immature eggs. On the contrary, if the injection is done before the programmed time there is a danger that ovulation will occur prior to the egg collection and the eggs will be lost.

If the injection is not done, the egg collection will have to be cancelled or postponed. The eggs will not be mature and it will not be possible to recover them from the ovary. If the injection is not done you must inform our Unit the following morning so your egg collection is re-programmed and the entire cycle is not cancelled.