Natural v/s Stimulated IUI
There are two forms of IUI:
- Natural cycle IUI without any hormonal stimulation.
- Medicated IUI
- Oral tablets with IUI
- Stimulated IUI
Natural IUI is the simplest form of IUI. It does not require the use of any fertility drugs. It is usually performed around the time of ovulation which could vary between day 12 and day 16 in a large number of women.
This is best suited for women who have a regular cycle where ovulation can be predictable. It is not as suitable for women with irregular cycles, since predicting ovulation is more difficult and it takes a longer time to detect it with a scan.
In those women having a natural cycle of IUI would be asked to come in for a scan between day eight and day ten to check for follicular growth, following which they would be monitoring the follicles using the LH test to check for ovulation. The surge of the LH hormone indicates that ovulation is imminent.
We generally prefer to give a trigger injection which would ensure that the eggs could be released and that if the LH test is positive, we would ask you to contact us as soon as possible, otherwise we generally would arrange for a scan in two to three days’ time to perform the trigger. The IUI is generally done the day after the LH surge when ovulation is likely to occur. The disadvantage of this treatment is that in some cases ovulation can be missed and the treatment would need to be stopped
Stimulated IUI may achieve a slightly better chance of pregnancy. This is by generally generating more than one follicle and though it would increase the chance of pregnancy, it also slightly increases the chance of multiple pregnancies .
Fertility drugs used are of two types, either using oral tablets or using injections. The oral tablets I use are called
- Clomiphene or
The injections are gonadotropins and these could be FSH and LH, the common names being
- Gonal F,
- Fostimon and
The use of these fertility drugs can be advantageous because they stimulate the ovaries to produce at least one egg in each cycle. This works extremely well in women with unexplained infertility as well as women with irregular cycles.
The advantage of using injections for medications are that through multiple studies, using stimulated IUI seems to give a much better success rate in heterosexual couples, while in same sex couples with regular cycles, it does not make a significant difference.
We prefer to use stimulated IUI cycles in heterosexual relationships, as the success rates at present seem to be higher with the injections.