Tuesday, August 16, 2011
How your doctor decides the dose of your IVF meds
When you do your IVF treatment, a very important decision the doctor needs to make is - What should your starting dose of HMG / FSH ( brand names for these key IVF meds include Repronex; Gonal-F; Follistim) be for optimal super ovulation? This is a key decision because this determines how many follicles you’re likely to grow. If he selects a dose which is too low , you may not have enough eggs or embryos. And if he selects a dose which is too high, you may grow too many follicles and end up with OHSS.
We do have rules of thumb for this, but as with any biological system , it’s very hard to predict how a patient will respond finally, and we need to acknowledge that some of this is trial & error.
As a general rule for most young patients, the starting dose is 3 amp of Menogon , which is 225 IU. This will then be tweaked, based on various factors for example, for very young patients who are less than 25 we would start with 2 amps; for patients who have polycystic ovarian disease we’d start with 2 amps; for patients who are more than 35 , we’d start with 4; and for those who are more than 38 , we’d start with 6.
The starting dose needs to be modified based on various fahttp://www.blogger.com/img/blank.gifctors, and the variables which need to be considered are:http://www.blogger.com/img/blank.gif
your Day 3 FSH and E2 levels;
your AMH level;
your antral follicle count ; and
your ovarian response in the past
If you’ve done an IVF cycle earlier , this provides us with a useful base line, based on which we can then decide what the starting dose for this cycle will be.
Other factors , such as past history of endometriosis or ovarian surgery would cause us to increase the starting dose. Similarly patients with a history of ovarian hyperstimulation ( OHSS) in the past would cause us to reduce the dose.
No matter what the starting dose is , the fact remains that after 6 days of super ovulation , when we do an ultrasound scan , this is a key moment of truth which will tell us whether we have selected the right dose or not. Based on the scan result ( and sometimes doctors will do a blood estradiol level as well to check your ovarian response) , we may then need to either continue the same dose ; or reduce it ; or increase it , depending on your ovarian response.