In the early ’90s, we identified, quantified and published widely on the importance of the pattern and thickness of the uterine lining (endometrium) in determining outcome following in vitro fertilization (IVF). Women in whom the thickness of the endometrium had an abnormal ultrasound pattern and measured less than 9mm around the time of egg retrieval were far less likely to achieve an IVF pregnancy than their counterparts with normal uterine linings.

Women in the following situations tended to have “poor uterine linings”:

had experienced previous infection of the uterus;
had multiple fibroid tumors in the wall of the uterus;
had repeatedly used the fertility drug Clomiphene for more than three treatment cycles in a row; and,
whose mothers had taken a drug known as DES while pregnant with them.

These findings were soon corroborated by other researchers, leading to routine ultrasound assessment of the uterine lining prior to and during IVF cycles becoming common practice.

Hitherto, the relative inability to improve the development of the uterine linings in women with “poor endometrial development,” through the administration of fertility drugs or estrogen has often prevented such women from conceiving.

In 1997, we attempted to improve the quality of the uterine lining by prescribing nitroglycerine skin patches to women with compromised endometrium. Nitroglycerine promotes the production of nitric oxide (NO), which causes dilatation of uterine blood vessels and, in so doing, dramatically improves uterine blood flow. It was hoped that through this mechanism, the delivery of estrogen would be improved along with development of the uterine lining. Nitroglycerine therapy has since helped many women with compromised endometrial development make successful journeys from infertility to family.

One of the major draw backs associated with the use of nitroglycerine is that associated unpleasant side effects, such as severe headaches, nausea, and fluctuations in blood pressure, have led to it being poorly tolerated.

Viagra (Sildenafil), like nitroglycerine, also triggers production of NO and improves blood flow to specific organs. In fact, it is by dramatically increasing muscular blood flow that Viagra produces penile erection, which has led to its successful use in the treatment of male impotence; and without major side effects.

It was against this background, that in 1998, in collaboration with a pharmacist, Dr. Sher and co-workers incorporated Viagra into vaginal suppositories to improve uterine absorption, and began testing the effect of such treatment on uterine blood flow and endometrial development in women with a history of poor uterine linings.

The results were impressive. Treatment with Viagra suppositories produced a rapid and profound improvement in uterine blood flow as measured by Doppler ultrasound. No side effects were reported and more than 80% of the patients experienced a vast improvement in endometrial development. And more than 50% of these women achieved viable pregnancies on their first IVF attempt.