Ovarian stimulation involves daily injections of FSH (follicle-stimulating hormone), starting at the beginning of a menstrual cycle. The difference between a woman’s natural baseline FSH and the higher FSH levels from the injections stimulates the growth of ovarian follicles.  

The FSH dosage varies depending on:  

- The goal of stimulation (1-2 mature follicles for timed intercourse or IUI, more than 2 follicles for IVF)  

- The patient’s age  

- Body weight  

- Ovarian reserve markers  

Since premature ovulation must be prevented, ovarian stimulation is always combined with ovulation suppression. There are two main types of suppression protocols:  

- Agonist Protocol (GnRH analogs like Decapeptyl, Synarel, Zoladex)  

  - Ovulation suppression begins before ovarian stimulation (either on day 2-3 or day 18-20 of the cycle).  

  - Injections continue throughout the stimulation period and can be given daily or as a single long-acting dose.  

  - Some forms can also be administered intranasally.  

- Antagonist Protocol (GnRH antagonists like Orgalutran, Cetrotide, Fyremadel)  

  - Ovulation suppression starts a few days after the beginning of ovarian stimulation.  

In both cases, the goal is to prevent premature ovulation and allow the follicles to fully mature before egg retrieval or fertilization.  

 Is One Ovulation Suppression Protocol Better Than the Other?  

For women with normal ovarian reserve, both protocols have similar success rates. However:  

- Agonist protocols tend to require longer treatment durations and higher FSH doses.  

- They can over-suppress ovulation, which may be problematic for women with low ovarian reserve.  

- If not started at the right time, GnRH agonists can cause ovarian cysts.  

For women with high ovarian reserve or risk of over-response, two stimulation strategies may be used:  

- Step-up protocol: Starts with a low FSH dose, which is gradually increased.  

- Step-down protocol: Begins with a high initial FSH dose, then gradually decreases.  

The choice of protocol depends on the doctor’s preference and the assisted reproduction center’s approach.