- In This Feature
- The Acronyms
- Inducing Ovulation
- IVF (In Vitro Fertilization)
- The Fertility Guide: The ART Procedures
- Retrieving the Eggs
- GIFT (Gamete Intrafallopian Transfer)
- ZIFT (Zygote Intrafallopian Transfer)
- ICSI (Intracytoplasmic Sperm Injection)
- Cryopreservation of Eggs
- Decision-Making Guidance for Couples
- Summary and Perspective
The Fertility Guide: The ART Procedures
The ovaries are most easily suppressed by beginning the GnRH agonist in the middle of the luteal phase, usually about day 21. This does imply that, as silly as it may sound, you should not attempt pregnancy in a month in which you anticipate starting a GnRH agonist on day 21. There are a fairly large number of cases in which an agonist has been started and a pregnancy has occurred, and there do not appear to be any adverse effects. However, why chance it? After starting the agonist on day 21, the next period should begin on time. If it doesn't, contact your physician.
Once the period begins, an ultrasound is performed and the hormone estradiol checked to ensure that ovarian suppression has been achieved. The gonadotropins, which must be given by injection, are then begun and continued for a total of eight to 10 days. The dose of the gonadotropins is individualized, but the goal is the development of multiple follicles. When gonadotropins are used for ovulation induction and inseminations, the goal is the development of just a few follicles. When gonadotropins are used for an ART procedure, the goal is the development of multiple follicles (the sacs where eggs develop). For purposes of discussion, let's say that we would like 10 follicles to develop.
The response to the gonadotropins is monitored with a combination of ultrasounds and estradiol levels. While these certainly don't need to be performed every day, the monitoring must be frequent enough that the physician can determine when the follicles are mature. While the eggs themselves can't be seen by ultrasound, the follicles are easily visualized. When a follicle reaches a certain size, the likelihood of there being a mature and healthy egg within that follicle is maximal. Physicians differ, but a follicular diameter of 18 millimeters is commonly used as suggesting maturity. When the follicles reach a mature size, hCG is given, which induces the final maturation and egg release. Approximately 40 hours after hCG, ovulation will occur.
With the use of a GnRH agonist in addition to the gonadotropins, premature ovulation, or ovulation significantly before 40 hours after hCG, is very rare. Therefore, egg retrieval, the process of actually removing the eggs from the ovaries, is scheduled between 34 and 36 hours after hCG, thus ensuring that the eggs will be mature but will not yet have been released from the ovaries.
There is another means of inducing ovulation for ART procedures that has also been successful. This technique has been used for individuals who are defined as low responders—individuals whose ovaries do not respond to the standard ovulation induction technique with production of as many eggs as would have been expected. In this approach, a standard low-dose oral contraceptive (OCP) is begun with the menses the month before the anticipated cycle and taken for 21 days. Beginning on the third day after stopping the OCPs, Lupron (the GnRH agonist) is administered in very small amounts—20 to 40 micrograms twice a da). Stimulation with gonadotropins is then begun on the third day of Lupron administration at a dosage of 225 units twice daily. Monitoring is then performed as with the standard protocol, and stimulation is continued until follicular maturity.