The Long & Short IVF protocols are the stimulation protocols that are most commonly used, and the difference is GnRH down-regulation or not. A birth control pill (Lupron) controls the menstrual cycle and prevents ovulation in the Long Protocol, and both cycles then have stimulation from either follicle-stimulating hormone (FSH) or human menopausal gonadotropin (hMG).
An injection of human chorionic gonadotropin (hCG) is given before egg collection to mature the eggs in the ovaries fully, and progesterone is given after egg collection to mature the womb lining for implantation and maintain the pregnancy after a positive pregnancy test.
The whole cycle usually takes six weeks:
- 3-4 weeks of birth control pills (it allows for scheduling at the clinic)
- Five days before the end of this, the ovaries are “down-regulated” for two weeks with Lupron, which “switches” the menstrual cycle off. The advantages are more responsive to stimulation and a reduced risk of ovarian hyper-stimulation syndrome (OHSS)
- The woman has a period
- Daily stimulation injections follow this for about 8-12 days with FSH or hMG
- The ovaries are usually scanned every 2 -3 days until the leading follicle is over 18mm in diameter and the womb lining is over 8mm thick
- Estrogen levels are monitored with blood sampling
- When the follicles reach a mature size, a “trigger injection” of hCG induces the eggs to undergo the final maturation and detach from the follicle wall
- A GnRH antagonist injection can be given 36 hours before egg collection to prevent follicles from rupturing prematurely (it also helps to mature the follicles)
- The eggs are collected, fertilised and incubated
- Progesterone pessaries once the eggs are collected
- Embryo transfer is usually 3-5 days after egg collection
The Short protocol lasts four weeks and is without the GnRH down-regulation. It’s usually chosen after a poor response to a long protocol or for women with low ovarian reserve.
- Treatment starts with FSH or hMG stimulation on day 3 of the cycle (day 1 being the first day of the period) and lasts for around 11 days
- The ovaries are usually scanned every 2 -3 days until the diameter of the leading follicle is over 18mm, the womb lining is over 8mm thick, and blood estrogen levels are also monitored
- An hCG “trigger injection” is given to make the eggs undergo their final maturation and detach from the walls of the follicles
- A GnRH antagonist is injected 36 hours before egg collection to prevent premature ovulation and help the eggs mature
- The eggs are collected, fertilised and incubated in the laboratory
- Progesterone pessaries are needed once the eggs are collected
- Embryo transfer is usually 3-5 days later