We tend to focus on the very key component of viable egg cells in assisted reproductive technology. There's no doubt that "good eggs" are needed to make conception and pregnancy happen. A piece of the pregnancy puzzle that doesn't usually get as much attention is the impact of uterine health.
It makes sense, of course, that once an egg is fertilized, the resulting embryo needs a healthy place to implant and grow. The lining of the uterus, known as the endometrium, is that place. In cases of women with average to good fertility levels, the endometrium is primed for implantation by a variety of hormones relaying through her body. It's all part of the menstrual cycle. [Here's an explanation of how the endometrium works.] Timing is crucial -- both in natural and assisted conception -- because the lining is re-created and either used or sloughed off through menstruation on a cyclical basis, approximately every 28 days. If a woman's hormones are imbalanced, the result is sometimes an endometrium that's not ready to receive and nourish a conceived embryo. This can be a type of infertility.
We administer endometrium-enhancing medications -- such as progesterone supplementation -- to some patients, regardless of the assisted reproductive technique they're using to conceive. Ultrasound monitoring is used to view and gauge the health of the uterine lining, just as we use ultrasound to see how well a woman's ovaries are ovulating. Still, there's more to solving the pregnancy puzzle, and researchers have recently unveiled a new potential key.
A study of mice has resulted in the newly discovered connection between a protein called Hand2 and the control of the uterine lining's proliferation. The researchers' findings could eventually lead to more ways for fertility experts to help patients who have endometriosis or previously unexplained infertility.
Answering the question, "Why can't we get pregnant?" requires attention to many variables within each patient's situation. The responsive functioning of a woman's uterus is increasingly becoming the focal point of research. After all, there's a lot more to having a baby then simply creating an embryo.
~ Sonja Kristiansen