Fertility FAQ - Unexplained Infertility

My husband and I are frustrated not knowing why we can’t conceive. We don’t know what to do next. Can you explain possible causes for couples like us?

Unexplained infertility is frustrating for both the couple and the provider. It is estimated that up to 10% of couples with infertility will have no explanation. We have ongoing research that suggests implantation failure may be part of this scenario.

When the male has normal sperm and the female has open tubes, ovulatory cycles and normal hormone profile, we must look beyond the usual causes. The good news for these couples is that this often represents a form of inflammation that can be diagnosed and treated effectively.

We usually recommend that women with unexplained infertility have a careful evaluation for endometriosis. In an ongoing study of couples with unexplained infertility, we find that the vast majority have stage I or II (minimal or mild) stages of endometriosis. Once diagnosed, most of these couples conceive on their own without further treatment.

Unfortunately, many couples are not diagnosed early and, therefore, may have problems even during in vitro fertilization (IVF). Our philosophy is to diagnose our patients first and then start treatment. We believe this has made a big difference in our high success rates in couples with unexplained infertility.

I have a three-year-old and had no trouble getting pregnant the first time. We are trying for a second child and nothing is happening. What is going on?

Infertility after a previous successful pregnancy is called secondary infertility. Even though you may be in great health, subtle anatomic and hormonal issues, as well as age factors, could be contributing to your difficulty. For example, up to 40% of women in their reproductive years develop fibroid tumors in their uterus. Fibroids are benign muscle tumors that can distort the shape of the uterus and prevent embryos from implanting. Others may have hormone issues, like an underactive thyroid gland (hypothyroidism), that can affect the ovaries’ ability to release eggs and make hormones.

One of the most subtle causes of secondary infertility is reproductive aging. As women get older, their ovaries contain fewer eggs that require stronger signals from the pituitary gland to ovulate. When the eggs are released, they tend to not fertilize as easily and may produce embryos that stop growing. Outwardly, this may show up as infertility. Aging factors seem to become more important as women approach the age of 40 and beyond.