Uterus During Pregnancy

When a baby girl is born she has a uterus size of just a little larger than an adult thumb. By adulthood the uterus changes in size and can weigh a little over half a pound (0.6 pounds) or 30 grams to as much as 0.22 pounds or 100 grams. The changes in a uterus during pregnancy are monumental and women who have been pregnant generally never have the smaller uterus they had before conceiving. It's not uncommon for older post menopausal women to develop abnormalities in the uterus that makes it bigger.

Where is the Uterus?

The uterus is in a woman's abdomen and one end opens to the vagina through the cervix. The pear-shaped muscle is located between the bladder and the rectum. The other end is connected to the fallopian tubes where the egg(s) travel down towards the uterus when they're released by the ovaries.

The uterus is usually tilted forwards but is sometimes tilted backwards. This is called a retroverted uterus, tilted uterus or tipped uterus. Most women have a uterus that tipped toward the bladder. A retroverted uterus tips towards the spin. Statistics indicate that approximately 1 in 3 and as many as 1 in 5 women have a tilted uterus.

A tipped uterus doesn't affect fertility or fetal development. Women can easily get pregnant with a retroverted uterus and the tilt typically rights itself around the week 10 or week 12 of the pregnancy.

What is the Uterus?

The uterus is a smooth muscle lined with glands that change in size with hormonal changes. These glands cause the endometrium of the uterus to become blood rich and grow thick in preparation for a possible pregnancy. It averages 6.7 millimeters thick and is shed when no pregnancy occurs. The cervix is the opening of the uterus to the vagina and it's made of fibro-muscular tissue that's supple enough to dilate and allow a baby's head to pass through during labor.

Potential Medical Problems

Crowding and thickening of the lining cells of the uterus can develop in women in their 40s and 50s. This condition is called hyperplasia and can cause uterus cancer of the lining if not properly treated. Signs of hyperplasia include heavy or irregular bleeding. When the uterine muscle gets cancer it's called leiomyosarcoma and is rare by extremely deadly.

The uterus can also get non-cancerous growths called fibroids. Fibroids can cause pain and bleeding with some women experiencing bleeding between periods and excessive pain during their periods. They can also make sexual intercourse painful and can affect fertility and a woman's ability to conceive. Some women don't have any signs of fibroids and the condition may only be discovered during a medical exam.

Endometriosis is another health problem associated with the uterus. This happens when the lining that should grow inside the uterus forms outside the uterus instead. Women who have endometriosis tend to have pelvic pain, lower back pain, painful periods, pain during sexual intercourse and infertility.

Uterus Changes During Pregnancy

Your uterus changes drastically in size during pregnancy to accommodate your growing baby. When your baby reaches full term, your uterus will be bigger than five times its original size with a capacity of 500 times more than before you conceived. It'll be 15 times heavier on its own without the baby and the placenta. After you give birth, the uterus immediately starts contracting to shrink itself. One week after delivery it'll weigh about 1.5 pounds but two weeks after birth it'll be down to 11 ounces. By the six week after pregnancy it'll be back to its pre-pregnancy weight of 2.5 ounces.

Uterus Prolapse and Pregnancy

Sometimes pregnancy, repeated pregnancies or one or more vaginal births can cause the strength of the pelvis muscles and special ligaments that hold the uterus in place to weaken. This causes the uterus to fall into the vaginal canal in a condition called uterus prolapse. Sometimes lack of estrogen, normal aging, obesity, severe constipation or a chronic cough can cause the connective tissue of the vagina to weaken. Occasionally the cause of this is a pelvic tumor.

There is no treatment unless the symptoms become bothersome. Treatment can include devices placed inside the vagina to hold the uterus in place.