ART – what?

ART stands for Assisted Reproductive Treatment. This is the general term for the different fertility treatments: artificial insemination, IVF, IVF-ICSI, IVM, etc.

If spontaneous natural conception is proving difficult, various ART treatments are available.
  • We already talked about artificial insemination (IUI) under Insemination and stimulation.
  • But sometimes IUI is not appropriate or does not lead to pregnancy. Then IVF (with or without ICSI) may provide a solution. 
    In IVF/ICSI, fertilisation (the fusion of sperm and egg) does not take place in the woman's body, but in a petri dish in the laboratory ('in vitro' means 'in glass'). The embryos form in this dish, hence the name 'test tube baby'.
  • An extra treatment that becomes possible after IVF/ICSI is FRET, an embryo transfer with thawed embryos.
  • And then there is in-vitro maturation (IVM), a patient-friendly treatment yielding increasingly better results.
    IVM allows in vitro-development of embryos after collecting immature eggs and maturing those in the lab (so also in vitro).

Transfer of thawed embryos

Natural cycle
Artificial cycle
Blood tests after transfer
Often more embryos develop in an IVF/ICSI cycle than are necessary for transfer. Any good quality supernumerary embryos are frozen.
If you are not pregnant at the first attempt, or if you want a second child later, the frozen embryos can be thawed and used in a subsequent transfer. You will not need ovarian stimulation, or any other treatment, for this.

An ART treatment with frozen/thawed embryos is called FRET (Frozen Embryo Transfer).

Want to know more?

Is freezing embryos for later use a good idea?

FRET has a number of advantages.
  • Treatment is less severe:
    • there is no hormonal ovarian stimulation, and 
    • no egg retrieval.
  • The chance of embryo implantation is usually the same as with a fresh attempt.
  • For Belgian patients who are entitled to a refund of their treatment by the health insurance, these are extra attempts. The refund applies to (maximum) six attempts with fresh material.

Synchronised to the natural cycle     

Day 1 of your cycle

Day 1 of your cycle is the day you get up with bright red menstrual blood loss.
If your period starts during the day or the blood only turns bright red over the course of the day, the next day applies as day 1.

If possible the frozen and thawed embryos will be transfer within your natural menstruation cycle. Like any other ART treatment at the CRG you need to follow the DPM's instructions.
  • A couple of days before natural ovulation, we start taking blood tests.
  • Sometimes the ovaries are lightly stimulated, to give extra support to the natural cycle.
  • If the blood results indicate that ovulation is close, an ultrasound scan determines the stage of development of the endometrium.
  • As soon as it is believed to be thick enough, the thawing and transfer of the embryos is planned:

    How many embryos?

    According to Belgian law, a maximum of two embryos can be transferred in case of FRET, regardless of your age.

    • The timing of the embryo transfer - click here for the progress - depends on the ovulation.
      The DPM will instruct you.
    • To encourage implantation of the embryo, you may be required to insert vaginal progesterone pessaries three times a day from the moment of ovulation 

    Based on an artificial cycle       

    Sometimes we need to replace the natural cycle (completely) by an artificial one:
    • if there is no natural cycle, for example because the ovaries have been removed, your uterus will be prepared for the transfer of an embryo with oestrogen.
      • These oestrogens are tablets which you take orally.
      • You must start taking them at least two weeks before the embryo transfer;
    • if you still have a natural cycle but it is not right, the natural cycle is suppressed with GnRH-analogues.
      • After three weeks you need to combine the GnRH-analogues with oestrogens.
      • The embryo can be transferred two weeks later at the earliest.
    A couple of days before the embryo transfer you also need to insert progesterone into your vagina.

    Because ovulation does not need to be taken into account, an artificial cycle is very effective and accurate. And the transfer can be planned well in advance.

    Blood tests after transfer      

    • If the embryo transfer with thawed embryos is synchronised with your natural cycle, the same blood tests as with fresh embryos are performed, more specifically on day 12 after transfer.
    • If the transfer did not result in pregnancy, an additional blood test will be performed on day three of the menstruation. The exact time and date of the start of menstruation must be given on the blood test request form.
      Please don't forget this last blood analysis despite you disappointment!
    • A possible pregnancy is followed up in the same way as with a transfer with fresh embryos.