Can Letrozole increase the chance of triplets?

Question

Hi doctor,

We have been undergoing a cycle of Letrozole as we are trying to conceive (TTC). I have a unicornuate uterus and currently, on day 16, I have three follicles: one at 19mm, one at 18mm, and one at 14mm. I am likely to ovulate tomorrow. However, the 14mm follicle has not grown since day 12.

What is the likelihood of having multiples?
Does the 14mm follicle have a mature egg, and will it release?

We are very eager to try, but we want to avoid the possibility of ending up with triplets.

Please help.

Thank you.

Answer 1

Hi,

Welcome to icliniq.com.

I am truly sorry you are feeling this way.

I get that you have mixed feelings about the fertility journey you are going through right now with a unicornuate uterus (not fully developed uterus), which requires special pregnancy planning in addition to other factors. There are increased chances of multiples if you are having Letrozole cycles, as opposed to natural ones, since several follicles can develop, although chances depend on how old you are, how well you respond to the medication, and the number of mature follicles.

A follicle that measures about 18 to 20 mm is considered to be mature, meaning that it is likely that it will release an egg. It is less likely that a 14 mm follicle on day 16 has matured, but not impossible for it to continue developing or ovulating, considering that follicle development varies from woman to woman.

Two mature follicles mean an increased chance of twins, while triplets, though rare, are possible when three follicles release viable eggs. Having two mature follicles does increase the possibility of twins, while triplets from a Letrozole cycle are much less common but can occur if three follicles release viable eggs.

Because you have a unicornuate uterus, it is especially important to discuss your follicle numbers with your fertility specialist before triggering ovulation or proceeding with timed intercourse, as they can advise whether the cycle is safe to continue based on your ultrasound findings and personal risks. Your doctor can help balance the chance of conception with reducing the chance of a high-order multiple pregnancy.

I wish you the best as you move forward with your TTC (trying to conceive) journey.

Thank you.