Uterine problems can cause infertility or miscarriage. A (fairly) normal uterine cavity and endometrial lining are necessary in order to conceive and maintain a pregnancy.
There are several conditions related to the cavity or the lining that can cause problems.
- When a woman has her menses (period) the endometrial lining of the uterus and some associated blood is shed. Then a new lining is regenerated over the next few weeks or so and eventually becomes receptive to implantation of an embryo.
- If no embryo implants, her body recognizes that she is not pregnant and it sheds the uterine lining and starts the regeneration process over again.
Problems of the uterus and uterine lining that can cause or contribute to reproductive problems such as infertility or recurrent miscarriage:
- Uterine Polyps
- Uterine Fibroids (proper medical terminology is myoma or leiomyoma)
- Intrauterine adhesions - scar tissue within the uterine cavity, also called Asherman's Syndrome. This can interfere with conception, or can increase the risk of a miscarriage.
- Congenital uterine malformations, such as a bicornuate uterus, a T-shaped uterus, or a uterine septum
- Luteal phase defect - an uncommon condition that involves inadequate development of the microscopic and cellular changes in the endometrial lining of the uterus after ovulation and exposure to the hormone progesterone.
- Thin endometrial lining - this is also uncommon. We like to see a lining of at least 8mm in thickness when measured by ultrasound at the time of maximal thickness during the cycle (see above ultrasound picture of an 11.2 mm lining).
There is some debate about “how thin is too thin”, as well as to “how thick is too thick”.
- In general, 8-13 mm is good, less than 6 is potentially a problem, and greater than 15 or so might possibly reduce chances for successful pregnancy.
During IVF treatment, the uterine lining starts at about 3mm thick at the end of the menstrual period. After estrogen levels rise sufficiently, the lining of the uterus thickens by about 1mm each day during IVF.
Hysteroscopy is a surgical procedure that involves insertion of a narrow telescope-like instrument through the vagina and cervix into the cavity of the uterus (endometrial cavity). The cavity is then distended with fluid (such as salt water) and can be visualized through the scope. This procedure allows us to see any defects inside the cavity.
Ultrasound is a very useful tool for evaluating the pelvis and the uterus and its lining, or endometrium. 3D ultrasound, a newer technology, is particularly good at helping doctors to characterize the shape of the uterine cavity.
