Understanding the Uterus: A main player during pregnancy

By Teri Brown

If you’re a woman, chances are you’ve already met your uterus in one form or another. Usually, it isn’t a pleasant experience. It comes in the form of your period or painful cramps. Most of the time, the only occasion we really pay attention to our uterus is when we are trying to get, or have already gotten, pregnant.

Dr. Deborah Wilson, an OB/GYN in private practice in Scottsdale, Ariz., says though the exact size of the uterus varies from woman to woman, it generally falls within a certain range. “The uterus is tiny when a girl is born, not much larger than an adult thumb,” says Dr. Wilson. “Women who have never been pregnant generally have smaller uteri than women who have been pregnant. A normal uterus can weigh as little as 30 grams (.06 pounds) and as much as 100 grams (.22 pounds).

Dr. Wilson says many women, as they age, develop abnormalities that enlarge the uterus.

What Is the Uterus Made Of?

According to Dr. Wilson, the uterus is made of smooth muscle lined with glands. The smooth muscle is designed to contract during labor, orgasm and menstruation. “The glands grow thicker during the month with the stimulation of ovarian hormones and finally shed off during the menstrual cycle if no pregnancy occurs,” says Dr. Wilson. “The cervix is the portion of the uterus that extends into the vagina. It is made of fibro-muscular tissue and is designed to dilate in order to allow the baby to exit the uterus.”

The Function of the Uterus In Pregnancy

Dr. Danne Young-Hawkins from Total Concept Healthcare in Logan, Utah, says the uterus is not only where babies grow, but it has other important roles as well. “It also plays a role in blood flow to the ovaries, support of the vagina, bladder and rectum and, for some women, can be important for normal sexual function,” says Dr. Young. “For instance, some women at risk of premature labor are asked to be careful about intercourse because the contractions of orgasm can trigger contractions. Those contractions can be an important part of a woman’s sexual experience when she isn’t pregnant as well.”

The uterus has a lining that thickens up in response to hormones produced by the ovaries. If pregnancy doesn’t occur, then one of the hormones that prepares the lining for a growing baby will also help the lining come off, which results in a period.

“When a woman becomes pregnant, blood flow increases to the uterus and the uterus increases in size, continuing to enlarge with the baby,” says Dr. Young. “After the baby is born, the uterine muscle fibers start to contract, and over the course of eight to 10 weeks it shrinks back to just a little bigger than it was before she got pregnant.”

Think of the uterus as a baby incubator. It expands to accommodate the baby and also works with the placenta to supply the baby with nutrients. When it’s time for the baby to be born, the uterus contracts to expel the baby and the placenta. It then shrinks back down and gets ready to start the whole cycle again.

Problems with the Uterus

“One of the most common problems that a woman has with her uterus is excessive bleeding,” says Dr. Young. “A lot of women have to use a pad and a tampon every couple of hours lasting for days. For many women, their periods keep them from living a normal life.”

Women can have problems with weakness of vaginal tissue, which causes other problems such as bladder leakage, the feeling that something is falling out, pressure in the vagina and even problems with sex.

“Another problem is pelvic pain that can be caused by infection, growths like fibroids or ovarian tumors, diseases like endometriosis and/or pain from nearby organs like the bowel or bladder,” says Dr. Young.

A uterus can also develop hyperplasia, which is the thickening and crowding of the lining cells. According to Dr. Wilson, this can cause heavy or irregular bleeding and generally occurs in women who are in their 40s and 50s. If not treated, hyperplasia can develop into cancer of the uterine lining. This is called endometrial carcinoma and can often be cured if caught early. Cancer of the uterine muscle is called leiomyosarcoma and is a very deadly cancer, although rare.

Tips for keeping your uterus healthy

Dr. Wilson gives the following tips for keeping your uterus healthy:

• Regular physician visits are essential. A pap smear is done to check for abnormal cells on the cervix. An internal exam is done to check for abnormalities of the uterus such as fibroid tumors or cancer of the uterus.
• Report any abnormal bleeding to your doctor. Abnormally heavy or irregular bleeding is often the first sign that a woman is developing fibroid tumors, adenomyosis or hyperplasia.
• Report any pain to your doctor. Fibroid tumors can affect up to 50 percent of women and, although they are generally benign, can cause serious bleeding and pain. Fibroids can affect women of any age but are most common in the 30s and 40s. We do not know what causes fibroids, but they tend to run in families. If your mother and sisters had fibroids, you are likely to have them also.
• Uterine cancer occurs more frequently in women who are overweight. A low-fat diet and exercise are your best bet in preventing cancer of the uterus.