Follicular puncture

Mature oocyte

Mature oocyte

To allow a follicular puncture to be scheduled, ovulation is induced artificially by administering hCG about 36 hours before the planned puncture. The woman is usually admitted to the centre on the same day, 1-2 hours before oocyte retrieval, and she must bring along her pre-operative and pre-anaesthetic report.

Oocytes are retrieved by ultrasound-guided transvaginal puncture.

  • The follicles are localised by ultrasound guidance, as in previous controls, and then punctured via the vagina.
  • The follicular liquid containing the oocyte is aspirated and immediately identified and evaluated in the IVF laboratory.

The follicular puncture is conducted by one of the doctors in the IVF team. It is carried out in theatre and a full pre-anaesthetic revision is necessary to decide what type of anaesthesia is the most appropriate on a case by case basis (generally sedation). The follicular liquid obtained during follicular puncture is immediately sent to the in vitro fertilisation laboratory.

An embryologist will observe and evaluate each of the oocytes and follicular cells and classify these according to their maturation. These are then distributed in the appropriate culture dishes and stored at 37º under adequate humidity and gas conditions until insemination.

The number of oocytes obtained per cycle varies greatly for each womanIf some of the oocytes retrieved are not mature enough, the culture time is longer and insemination conducted 6 hours after retrieval or the next day, as considered appropriate. Some oocytes may be very immature or degenerate, unfit for insemination criteria and these are disregarded.

The number of oocytes obtained per cycle varies greatly for each woman. On average, 8-10 mature oocytes are obtained per cycle. It is important to remember that the number of oocytes obtained may differ from the number of follicles observed during the daily ultrasound checks.

On the day after the follicular puncture, information will be provided about the number of embryos obtained (fertilisation rate) and the day and time of the embryo transfer shall be scheduled.

Unable to obtain oocytes

The possibility of not been able to retrieve oocytes is rare, but it may happen that the follicles are inaccessible or that the quality or maturity of the oocytes is inadequate. When this occurs, the case is reviewed and future plans established to avoid a repetition of this situation. A few treatment-free months are advisable before embarking on a new stimulation cycle.


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