What Does the Uterus Do?
As one of the most well-known female reproductive organs, the uterus nourishes and houses the baby as it grows and develops during pregnancy.
During every menstrual cycle, hormones cause the lining of the uterus (called the endometrium) to thicken and mature preparing for implantation of a developing embryo. If a woman doesn’t get pregnant, the uterine lining is shed through the process of menstruation.
The health of the uterus represents a critical component in fertility. The size, shape and structure of your uterus can impact your ability to achieve a pregnancy or carry a fetus full-term. For instance, uterine fibroids or polyps can distort the endometrial cavity making it difficult for implantation to occur.
There are other factors that can impact your uterus and ultimately your fertility, including thyroid problems, hormonal issues, adhesions/scar tissue, infections, or cancer.
Some types of uterine abnormalities increase the risk of miscarriage and require treatment, but others may not cause any problems with pregnancy at all.
Through a thorough assessment, CCRM’s fertility specialists can determine if any uterine problems exist and also if treatment will be required.
Evaluating the Uterus
The current gold standard for assessing the uterus is hysteroscopy. With this method, a thin scope is inserted into the vagina and moved gently into the cervix and then the uterus. Next, the uterine cavity is distended with either carbon dioxide or a sterile clear fluid solution. The hysteroscope has a light and a camera at the end so we can clearly see those areas on a monitor. If we think it will be helpful, we take a small sample of tissue (endometrial biopsy) for analysis.
Additional techniques for evaluating the uterine cavity include:
- Pelvic examination
- Hysterosalpingogram (HSG): An x-ray procedure during which dye is introduced into the uterus through the cervix and passed through the fallopian tubes.
- Saline infusion sonohysterography (SIS): a sterile saline solution is infused into the uterine cavity through a small catheter at the same time. By distending the uterine cavity with the saline solution, visualization is significantly enhanced.
- Magnetic resonance imaging (MRI): MRI scans use strong magnetic fields and radio waves to produce a detailed image of the inside of your body. This technique is used for adenomyosis and congenital uterine abnormalities.
Throughout the years, we have learned that there are certain times when the endometrium in the uterus is “receptive” to implantation. If the timing isn’t right, the embryo will not implant.
A popular test, known as the endometrial receptivity array (ERA) test, initially showed promise in accurately determining if the uterus was receptive to implantation. The ERA test requires a biopsy of the uterine lining and analysis of 200+ genes that are believed to play a role in the endometrium becoming receptive. In a July 2018 study, it was found that “performing the ERA test in a mock cycle prior to a frozen embryo transfer does not seem to improve the ongoing pregnancy rate in good prognosis patients.”
At CCRM, we’ve been researching the development of a test that has great promise in helping to predict the optimal time for implantation. Twenty-hours ahead of embryo transfer, we retrieve a very small sample of the fluid in the uterus. Then the molecules in the fluid sample are analyzed to determine if they are “toxic” or “receptive” to implantation. By finding the best time for embryo transfer, we can increase the likelihood of a successful outcome.
So far, our ongoing research on endometrial receptivity has been very encouraging. Stay tuned for ongoing developments as we hope that this test could improve upon the personalized treatment for each patient in our care and increase our patients’ chances achieve their goal of a healthy baby.