Couples who have unexplained infertility have several options for trying to improve their
odds of conceiving. These treatments can be used at any age. If you are 35 years old or
over, which of these treatments has the highest chance for success? Lets see what the data says
First off, what is unexplained infertility? This is a phrase used to describe patients who have
infertility but all of their testing has come back normal. At a minimum, in order to be diagnosed
as having unexplained infertility, a sperm collection should be done to look at your partner
to document the presence of numerous moving sperm. On your side, blood tests and ultrasounds
should be performed to assess your ovarian reserve, ovulation, and thyroid function
and a hysterosalpingogram should be completed to evaluate the uterus and fallopian tubes. In some
cases, testing may also involve looking inside the abdomen for endometriosis or scar tissue.
Couples with unexplained infertility can be divided into two groups. Group 1 are people
who actually have a specific cause for their infertility, it just hasn’t been discovered yet.
Doctors are identifying new causes for infertility all the time. We may not know what is causing your
infertility today, but we may tomorrow. Group 2 are people that truly don’t have anything
medically wrong with them but they have just been statistically unlucky to that point. Given a long
enough period of time, many people in this group will get pregnant on their own without treatment.
As a fertility doctor, there are a variety of treatments that I can offer to patients
to help shorten the time it takes to achieve a pregnancy. Fertility medications are commonly
used for this purpose in order to get multiple eggs to develop. There are two oral fertility
medications that can be used for unexplained infertility: Clomid and Letrozole. For people
with unexplained infertility, Clomid works better than letrozole. I talk about that in this video.
In addition to using fertility medication, many fertility doctors will also perform a procedure
to get more sperm up into the fallopian tubes. This is known as IUI or intrauterine insemination.
How well does Clomid and IUI work if you are 35 or older? This study is the largest to look at
pregnancy rates using Clomid and IUI. In this study, people who were 35–37 years old had a
pregnancy rate that was just over 9% for each completed Clomid cycle. That means on a given try,
about 1 in 11 people this age would become pregnant on a single attempt with Clomid.
For patients aged 38–40 years, that rate was a bit lower at 7.3% or about 1 in 13 people.
Another group of fertility medications are given as injections. These are called
gonadotropins. These shots can also increase the number of eggs that mature at one time
and can also be combined with an IUI for couples with unexplained infertility.
At my fertility center, IVF1, we have treated people with injections of fertility meds and IUI
over 800 times in people who were 35 and over. In people aged 35 to 37, the pregnancy rate was 16.7%
per try. In 38 to 40 years olds it was 15.8%
IVF is also used as a treatment for unexplained infertility. In order to determine the
pregnancy rate in older people specifically with unexplained infertility, we turned to the US IVF
database. In their online database, the pregnancy rates are broken down by age. You can also filter
the patients based on their diagnosis. We looked at those patients that had “unknown factor” as
their diagnosis and that were attempting pregnancy using their own eggs and did not have chromosome
testing of their embryos. For people aged 35 to 37, the live birth rate for a single embryo
transfer in 2019 was 30.6%. For 38 to 40 year olds it was 19.2%. If the embryos were tested first,
then the chance for a live birth was 44% for 35 to 37 years olds and 35% for 38 to 40 year olds.
Our Infertility TV Bottom Line is this, if you are 35 years of age or older and have
unexplained infertility, the treatment with the highest chance for pregnancy is
IVF. Embryo testing gives the highest chance. Transferring untested embryos is second best.
The 3rd best treatment utilizes fertility injections with IUI.
The 4th best is Clomid and IUI and the least successful treatment is Letrozole.