Controlled ovarian hyperstimulation

When ovulated follicles are fertilised in vivo, whether by natural or artificial insemination, there is a very high risk of a multiple pregnancy.

In contrast, ovulation induction is ovarian stimulation without subsequent IVF, with the aim of developing one or two ovulatory follicles.

Response prediction based on ovarian reserve confers substantially higher live birth rates, lower total costs and more safety.

[5] The following table defines antral follicles as those about 2–8 mm in diameter:[6] The incidence of poor ovarian response in IVF ranges from 10 to 20%.

[13] A meta-analysis came to the result that the optimal daily recombinant FSH stimulation dose is 150 IU/day in presumed normal responders younger than 39 years undergoing IVF.

[16] Recombinant FSH (rFSH) appears to be equally effective in terms of live birth rate compared to any of the other types of gonadotropin preparations irrespective of the protocol used for ovulation suppression.

Clomifene, in addition to gonadotropins, may make little or no difference to the live birth rate but may lower the probability of ovarian hyperstimulation syndrome.

[19] A systematic review showed that using clomifene citrate in addition to low dose gonadotropin (in a GnRH antagonist protocol as described in the following section) resulted in a trend towards better pregnancy rates and a greater number of oocytes retrieved when compared with a standard high-dose FSH regime.

[21] Using low dose human chorionic gonadotropin (hCG) to replace FSH during the late follicular phase in women undergoing hyperstimulation as part of IVF may make little or no difference to pregnancy rates, and possibly leads to in an equivalent number of oocytes retrieved, but with less expenditure of FSH.

[22] Before ovarian stimulation with antagonist protocols, pretreatment with combined oral contraceptive pills probably reduces the rate of live birth or ongoing pregnancy, while it is uncertain whether pretreatment with progesterone only has any effect on live birth or ongoing pregnancy rates.

[23] Findings are conflicting, but metformin treatment as a complement in IVF cycles may reduce the risk of ovarian hyperstimulation syndrome and increase live birth rates.

[14] There is a concomitant monitoring, including frequently checking the estradiol level and, by means of gynecologic ultrasonography, follicular growth.

OHSS occurs when, following a "trigger" injection for final oocyte maturation, excessive VEGF production by numerous follicles acts systemically.

Nomogram for the starting dosage of FSH preparation as estimated from age, antral follicle count (AFC) and endogenous serum FSH taken day 3 of the menstrual cycle . [ 5 ] An example is given in the nomogram, wherein an age of 32 years and an AFC of 12 gives a point on the middle line that, when continued to an FSH of 5 IU/L, results in a starting FSH dosage of almost 200 IU/L.
Nomogram for the starting dosage of FSH as estimated from age, anti-Müllerian hormone (AMH) and endogenous serum FSH taken day 3 of the menstrual cycle (same as previous nomogram but with AMH instead of AFC) [ 5 ]