Ovulation stimulation and monitoring


Oocytes grow within tiny liquid-filled sacs or cysts called follicles which are formed in the ovaries.

During this stimulation treatment, the number and size of the developing follicles are measured daily by ultrasound (transvaginal ultrasound). The oocytes themselves cannot be seen as these are microscopic in size.

The follicles produce a hormone called estradiol, the levels of which increase as the follicles grow.

Blood samples are taken periodically to measure estradiol production. Same day results are important in order to evaluate the response to the stimulation.

The necessary dose will depend on both the ultrasound and the hormone analyses and may change from one day to another based on these results. Estradiol levels increase gradually every day until the oocytes are harvested. There is no set estradiol value as there are considerable variations between each woman.

The development of the follicle is assessed by daily ultrasound and hormone controls to determine the most appropriate moment in which to harvest the oocytes.

In some cases, depending on the treatment indicated, serial urinanalysis may also be conducted. These are used to determine the levels of LH hormone, which is responsible for ovulation. If increased LH levels are detected, which means that spontaneous ovulation has commenced, a decision is taken on whether to cancel the cycle or to modify the schedule.

Cancelling an IVF cycle

About 12% of IVF cycles are cancelled for different reasons associated with a poor response to the stimulation.

The following are the most common:

  • Low number of follicles developing (low response).
  • Low or irregular hormone levels which indicate that the oocytes attained would not be of good quality.
  • Early ovulation which prevents the appropriate time of oocyte harvesting to be determined.

In most cases, a new IVF cycle can be attempted following a rest period of a few months by administering a new treatment or altering previous treatment.

Couples with greater social, family and emotional stability have been shown to have a greater likelihood of conception and satisfaction with treatment.

Our Reproductive Medicine Service is therefore developing a Psychosomatic Medicine programme to help couples deal with issues relating to infertility and treatment.


Go to top