Ovarian stimulation

There are several methods or regimes of medication in current practice, some quite simple and others more complex. The simplest option is to monitor the natural cycle and collect the egg as close to ovulation as possible. The next step up is to mildly stimulate the ovary to produce a few eggs only - this is called minimal stimulation and is further expanded upon below. Finally there are a number of regimes where control is taken of the hormonal communication pathways between the pituitary gland and the ovary and the ovary stimulated to produce a larger number of eggs - these are called the; pill boost cycle, down regulation cycle and the GNRH Antagonist cycles all of which are further described below.

The pill boost cycle

The oral contraceptive pill is commenced when advised by the clinician. Each couple receive written instructions of their cycle plan. Synarel - A nasal spray is commenced which causes an initial surge of hormones from the Pituitary gland in the brain (which helps with the stimulation of the ovaries to produce more eggs). This then suppresses the pituitary to prevent a premature Luteinising Hormone (LH) surge which could ripen the eggs prior to egg retrieval. This enables us to control the development of eggs through use of daily injections of Follicle Stimulating Hormone (FSH). These medications are called Gonal F or Puregon, they are given as a subcutaneous injection which will be administered by yourself, partner or friend following instruction by the nurse coordinator. Both of these medications are continued until the eggs are ready for collection, determined by scanning and blood tests. When the eggs appear ready for oocyte retrieval a hormone HCG (Human Chorionic Gonadotrophin) is given by injection which initiates ovulation 36 hours later. You will then attend the Day Surgery for your oocyte retrieval (egg pick-up). See OPU and ET for diagrams.

Down regulation cycle

In this regime the nasal spray – Synarel is commenced 2 weeks prior to the FSH injections. When the eggs appear ready for oocyte retrieval a hormone HCG (Human Chorionic Gonadotrophin) is given by injection which initiates ovulation 36 hours later. You will then attend the Day Surgery for your oocyte retrieval (egg pick-up). See OPU and ET for diagrams.

GnRh Antagonist

Cetrotide or Orgalutran can be used as an alternative to Synarel or Lucrin. In this cycle ovulatory response is initiated with FSH injections (Gonal F or Puregon) with early monitoring by ultrasound commencing on around day 6 of stimulation. A second injection (the antagonist), Cetrotide or Orgalutran will be introduced daily to prevent a premature LH surge once the leading follicle reaches 14mm or greater. When the eggs appear ready for oocyte retrieval a hormone HCG (Human Chorionic Gonadotrophin) is given by injection which initiates ovulation 36 hours later. You will then attend the Day Surgery for your oocyte retrieval (egg pick-up). See OPU and ET for diagrams.

One advantage of antagonist cycles is to decrease the risk of Hyperstimulation Syndrome, occasionally it can also be introduced when patients have had a poor response to other types of stimulation, although there is as yet not significant evidence from clinical studies to demonstrate greater effectiveness of these cycles.

Minimal stimulation or natural cycle

In this program follicular development is stimulated with the use of Clomiphene Citrate, a medication usually taken between day 2 & 6 of a cycle. Ovarian response is assessed with ultrasound examination on day 12 or 13 of the cycle with subsequent oocyte maturation induced with HCG. In up to 30% of Clomiphene cycles adequate ovarian response will not be achieved or ovulation may occur prior to planned egg pickup. This is because the natural feedback loop to the pituitary is intact and LH can be released prematurely. Minimal stimulation cycles have a lower success rate than the above 2 FSH cycles but have the advantage of a reduced cost and lesser drug treatment.