Women & Infants’ Fertility Center Blog

Unexplained Infertility Explained

Written by Women & Infants Fertility Center | April 18, 2022

What do you do when all the tests are normal, but you still aren’t pregnant? Unexplained infertility affects roughly 15 to 30 percent of couples seeking fertility help. Dr. Carol Wheeler shares what we do when everything is right, but still going wrong.

The Diagnosis Is … Complicated

To make the diagnosis of unexplained infertility, our patients have a complete infertility evaluation including semen analysis, and evaluation of the uterine cavity and fallopian tubes, as well as confirmation of regular ovulation and normal ovarian reserve. Patients under 35 years of age have all this testing done after one year of trying to conceive without success and for patients over age 35, after six months of inability to conceive. We also confirm that there are no underlying medical conditions such as uncontrolled thyroid disease.

After all of this testing, everything can still appear to be normal. Everything should be working properly but, for an unknown reason, is not. “Unexplained” does not mean a couple is never going to get pregnant, it just means it’s taking longer than it should and we don’t know why. We review with patients a number of options to improve the chance of pregnancy, going from the simplest to the most complex.

Time Limits

Before we enter into treatment, we tell patients that anything we do to try to treat unexplained infertility needs a time limit. We usually do one of the treatment options for three months, then re-evaluate to try to understand why it doesn’t seem to be working, and then we move on to another option.

Timing and Frequency For Pregnancy

It may seem obvious, but some patients are not having intercourse frequently enough or aren’t timing their intercourse correctly. Some couples are only having sex once or twice a month and that may not be sufficient for them to achieve a pregnancy.

Because younger patients have a higher chance of success with simple measures than do older patients in their mid to late 30s, we often recommend that younger patients use at-home ovulation predictor kits and have intercourse every other day around their most fertile time for a few more months.



This is because female egg quality begins to decline progressively around age 35. If a patient is 39, we don’t want to spend six months on timing intercourse when there are more aggressive options we may need to turn to for those patients.

Of course, most of the couples who come see us have been timing their intercourse with ovulation kits and already increased the frequency of their intercourse. They’ve done all of that and are still having no luck.

Related Reading: Is Your Ovulation Calculator Lying to You?  

How About a Combo?

Most of the patients we see do a combination of oral fertility drugs and an intrauterine insemination (IUI). This is an excellent option for many of our patients. This treatment involves five days of taking a medication like clomiphene citrate or letrozole. Most patients know these medications by their brand names of Clomid or Femara. They stimulate ovulation in women who have normal hormones by often leading to more predictable ovulation and multiple eggs being released.

This lets us closely monitor ovulation and then perform an IUI at the best possible time. During an IUI, we place sperm directly into the uterus to help a woman get pregnant. Sometimes sperm have difficulty getting to the uterus, so IUI concentrates the sperm and places sperm closer to the eggs during the time of ovulation, thus increasing the chances of pregnancy.

Related Reading: Blessed Three Times Over, Aided by IUI and Meds

Finally For Unexplained Infertility, IVF

In vitro fertilization (IVF) works extremely well for unexplained infertility. What we don’t know in terms of determining what is causing the infertility is whether there is a problem with the sperm getting to the egg or the sperm and egg interaction. IVF can help us identify the problem as well as treat it. When performing IVF, the fertilization takes place in a lab, where we can see what occurs when the sperm and egg come together.

Many of our patients with unexplained infertility have very high pregnancy rates with IVF. They generally have healthy sperm and eggs and a normal uterus. So, when the eggs and sperm come together during IVF, it leads to a successful pregnancy.

The bottom line is just because it is unexplained that does not mean it is untreatable. We do have treatment options that give women a good chance of achieving a pregnancy.