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The first step in all IVF procedures aims to:

  • Keep the natural gonadotrophins low during the follicular development by down regulation.
  • Stimulate the ovaries to produce multiple follicles so that the increased number of eggs can be collected.
  • And to control the timing of ER to retrieved eggs when mature before they are spontaneously released.
The ovaries are stimulated by the FSH (Follicle Stimulating Hormone) injections administered for 12-16 days. Some resistant cases take longer to respond. The doses may be adjusted depending upon follicle growth. The treatment usually begins by Down regulation done with GnRH agonists. The aims are:
  • To reduce the natural Gonadotrophins levels before extraneous injections.
  • To give some safeguard against the effects of OHSS.
  • To control the undesired spontaneous rupture of follicles.
There are long and short protocols. The timing and dosage of FSH & hCG remains the same in all the regimens of down regulation. In IVF long protocol is preferred. Long protocol begins from day-21 of the preceding cycle (7-10 days prior to the anticipated onset of menstruation).

It is performed either by a Single subcutaneous injection of Depot GnRH agonist with effect lasting for 4-8 weeks or by Short acting GnRH agonists administered daily until the day of hCG injection.

Short Protocol is used in selected cases with irregular infrequent periods. Short acting GnRH agonist is administered daily from day 2 of the cycle until the day of hCG administration.

Monitoring Pituitary Down Regulation . In cycles where FSH and LH levels have been high in the early follicular phase, the GnRH agonists are administered. Effective down regulation is judged by endometrial thickness less than 4mm and number of small follicles (<8 mm) less than 4. Hormone levels (LH < 5 IU/L, E2 < 50 pg/ml and Progesterone < 1 ng/ml) may be estimated to supplement the sonographic findings.

Some women experience minor side effects from these which include headaches and menopause like symptoms such as hot flushes and vaginal dryness. These problems are temporary.

Gonadotrophins Administration Numerous eggs must be grown to insure fertilization and progression to the embryo stage. FSH is administered which directly stimulate the ovaries causing egg recruitment and then also support the eggs growth and development. FSH is available as HMG, FSH and recombinant FSH (rFSH) injections.

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