Pregnancy complications

• Pregnancy complications may need special medical care.
• Common problems include anemia, diabetes and bleeding.
• Ask your provider about the signs of serious complications.

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Abnormalities of the female reproductive organs can cause infertility, miscarriage, premature birth (before 37 completed weeks of pregnancy) and other pregnancy complications. Reproductive tract abnormalities can be congenital (present at birth) or acquired (develop later in life).

Many women with reproductive tract abnormalities have no symptoms and do not know they have an abnormality. Some women with reproductive tract abnormalities are able to become pregnant and have normal, full-term pregnancies. Others may learn that they have a reproductive tract abnormality if they have difficulty becoming pregnant or develop pregnancy complications. In some cases, treatment can improve the chances for a healthy pregnancy.

What are congenital uterine abnormalities?
The uterus is a hollow muscular organ shaped like an upside-down pear. The narrow, lower end of the uterus is called the cervix. About 3 in 100 women are born with an abnormality in the size, shape or structure of the uterus (1). In the female embryo, the uterus is formed from two small tubes called Mullerian ducts. At about 10 weeks gestation, these two tubes come together and fuse, forming a single uterine cavity. When the Mullerian ducts do not fuse at all or fuse incompletely, a uterine abnormality can result.

Some women with a congenital uterine abnormality have normal, full-term pregnancies. However, these abnormalities can increase the risk of a number of reproductive problems, including:

• Miscarriage (pregnancy loss that occurs before 20 weeks of pregnancy)
• Premature birth
• Poor fetal growth
• Abnormal presentation, such as breech position (the baby is in a position other than head down)
• Cesarean birth

The risk may be different for each one of these problems, depending on the specific uterine abnormality.

Congenital uterine abnormalities include:

• Septate uterus. This is the most common congenital uterine abnormality and is most commonly associated with adverse pregnancy outcomes, especially miscarriage (1, 2). In a septate uterus, the uterus is divided into two sections by a band of muscle or tissue. This tissue is the remainder of the joined Mullerian tubes, which the body did not break down and absorb as it should have.
• Bicornate uterus. In this condition, the uterus has two partially or completely joined cavities, instead of one large cavity. This abnormality is caused by incomplete fusion of the Mullerian tubes.
• Didelphic uterus (double uterus). The Mullerian tubes fail to join, resulting in two separate uterine cavities and two cervices. Each uterine cavity may be smaller than normal.
• Unicornate uterus. One Mullerian duct fails to form, resulting in absence of half of the uterus.

How are congenital uterine abnormalities diagnosed?
Congenital uterine abnormalities usually are diagnosed using imaging tests. Sometimes more than one of these tests is needed to distinguish between uterine abnormalities. It is important to make the correct diagnosis because certain uterine abnormalities (such as septate and bicornate uterus) appear similar on some imaging tests but are treated differently. Imaging tests include (1, 3):

• Vaginal ultrasound. A tampon-sized probe is placed in the vagina. The probe uses sound waves to show pictures of the uterus and other pelvic organs. A new form of ultrasound, called three-dimensional ultrasound, is highly accurate in diagnosing uterine abnormalities.
• Sonohysterogram. The health care provider inserts salt water into the uterus through the cervix and then performs a vaginal ultrasound. The salt water allows a clearer picture of the uterine cavity.
• Hysterosalpingogram. The health care provider inserts a dye into the cervix and then follows the path of the dye with a uterine x-ray. This exam shows the condition of the cervix, the uterine cavity and fallopian tubes. This test uses radiation and cannot distinguish between septate and bicornate uterus.
• Magnetic resonance imaging (MRI). This test uses strong magnets and a computer to create detailed images of organs. It provides a clear picture of the uterine cavity and is highly accurate in diagnosing most uterine abnormalities, including septate and bicornate uterus.

How are congenital uterine abnormalities treated?
Some congenital uterine abnormalities can be corrected with surgery. The provider may recommend surgery for a woman who has a congenital uterine abnormality and a history of miscarriage or premature birth. Surgery usually is not recommended if the woman has no history of pregnancy problems because some women with uterine abnormalities have normal, full-term pregnancies.

Studies suggest that more than 80 percent of women with septate uterus have successful pregnancies after surgical removal of the septum (1). Surgery for this abnormality generally can be done during hysteroscopy. In a hysteroscopy, the provider inserts a thin, telescope-like instrument through the vagina and cervix into the uterus to see inside the uterine cavity. The provider inserts a small instrument through the hysteroscope to remove the septum. Surgery to correct bicornate uterus and other congenital uterine abnormalities involves more extensive surgery through an incision (cut) in the abdomen.

What are acquired uterine abnormalities?
Acquired uterine abnormalities are those that develop later in life. Acquired uterine abnormalities that affect pregnancy include:

• Fibroids
• Uterine adhesions (scars)
• Cervical insufficiency and short cervix

What are fibroids?
Fibroids are benign (non-cancerous) growths made up of muscle tissue. They range from pea-size to 5 to 6 inches across. About 20 to 40 percent of women develop fibroids during their reproductive years, most frequently in their 30s and 40s (4). Many women with fibroids have no symptoms, while others have symptoms such as (5):

• Heavy menstrual bleeding
• Anemia (resulting from heavy menstrual bleeding)
• Abdominal or back pain
• Pain during sex
• Difficulty urinating or frequent urination

The health care provider may first detect fibroids during a routine pelvic exam. The diagnosis can be confirmed with one or more imaging tests.

Do fibroids cause pregnancy complications?
Small fibroids usually do not cause problems during pregnancy and usually require no treatment. However, fibroids occasionally break down during pregnancy, resulting in abdominal pain and low-grade fever. Treatment includes bedrest and pain medication. Multiple or large fibroids may need to be surgically removed, generally before pregnancy, to avoid potential complications associated with pregnancy. Due to pregnancy hormones, fibroids sometimes grow larger during pregnancy. Rarely, large fibroids may block the uterine opening, making a cesarean birth necessary.

Most women with fibroids have healthy pregnancies. However, fibroids can increase the risk of certain pregnancy complications, including (2, 5):

• Infertility
• Miscarriage
• Preterm labor
• Abnormal presentation (such as breech position)
• Cesarean birth (usually due to breech position)
• Placental abruption (separation of the placenta from the wall of the uterus before birth)
• Heavy bleeding after birth

If the health care provider determines that a woman’s infertility or repeated pregnancy losses are probably caused by fibroids, he may recommend surgery to remove the fibroids. This surgery is called a myomectomy. In some cases, myomectomy can be done during hysteroscopy.

What are uterine adhesions?
Uterine adhesions, sometimes called Asherman syndrome, are scar tissue that can damage the uterine lining (endometrium). The damage may range from mild to severe. Causes of uterine adhesions can include (2, 6):

• D&C (dilation and curettage), which may be done after a miscarriage (this is a surgical procedure, in which the cervix is dilated and the uterus is emptied with suction or with an instrument called a curette)
• Other uterine surgery
• Severe infection of the uterine lining (endometritis)

Some women have no symptoms, while others may have light or infrequent menstrual periods. Adhesions can contribute to infertility, repeat miscarriage and premature birth (2, 6). Imaging tests and hysteroscopy can diagnose adhesions. Adhesions can be removed during hysteroscopy, improving the chances of a normal pregnancy (2).

What are cervical insufficiency and short cervix?
Cervical insufficiency (sometimes called incompetent cervix) refers to a cervix that opens too early during pregnancy, usually without pain and contractions. This usually occurs in the second or early third trimester of pregnancy, resulting in late miscarriage or premature birth. A woman may be diagnosed with cervical insufficiency based largely on this history. There is no specific diagnostic test.

Medical experts do not always know why cervical insufficiency occurs. Factors that may contribute include (7):

• Uterine defects. Women with certain uterine defects, such as bicornate uterus, are more likely to have cervical insufficiency than women without these defects (1, 2).
• History of surgical procedures involving the cervix. These include LEEP (loop electrosurgical excision procedure), which is used to diagnose and treat abnormal cells found during a Pap test.
• Injuries during a previous birth
• Short cervix. The shorter the cervix, the more likely the woman is to have cervical insufficiency. In some cases, a short cervix can be congenital.

Miscarriage and premature birth due to cervical insufficiency frequently happens again in another pregnancy. These problems can sometimes be prevented with a procedure called cerclage, in which the provider places a stitch in the cervix to keep it from opening too early. The provider removes the stitch when the woman is ready to give birth.

It is not always clear which women will benefit from cerclage. This is because there is no specific test for cervical insufficiency, and many women who have had a late miscarriage or early premature birth go on to have normal pregnancies without treatment. Some studies suggest that cerclage is most likely to be beneficial in women who have had three or more late miscarriages or premature births (7). In some cases, providers may monitor a woman suspected of having cervical insufficiency with repeated vaginal ultrasounds to see if her cervix is shortening or showing other signs that she may give birth soon. The provider may recommend cerclage if these changes occur.

Some women learn that they have a short cervix during a routine ultrasound. Most of these women do not end up having a premature birth. However, short cervix, especially a very short cervix (less than 15 millimeters), does increase her risk of premature birth (8, 9). Studies suggest that treatment with the hormone progesterone may help reduce the risk of premature birth in women with a very short cervix (8, 9). According to the American College of Obstetricians and Gynecologists (ACOG), progesterone treatment may be considered for these women (8). However, ACOG does not recommend routine cervical-length screening for low-risk women.

Does a retroverted (tipped) uterus pose pregnancy risks?
Almost never. About 20 percent of women have a uterus that tips slightly backward (10). This is considered a normal variant of uterine positioning in most women, though some women may develop a retroverted uterus due to fibroids or scar tissue in the pelvis. Generally, the uterus straightens by early in the second trimester and does not contribute to pregnancy complications.

At about 12 weeks of pregnancy, the top of the uterus normally extends past the pelvic cavity. Rarely, a retroverted uterus may become trapped in the pelvis. This is called uterine incarceration and can cause pain and difficulty passing urine (10). An ultrasound can diagnose retroverted uterus in women with these symptoms. Simple treatments, including bladder drainage, positioning exercises the woman can do at home, or gentle manipulation by the health care provider, usually can restore the uterus to its normal position. Occasionally, an untreated incarcerated uterus may contribute to second-trimester miscarriage.

What is polycystic ovary syndrome?
Polycystic ovary syndrome (PCOS) is a condition that affects a woman’s hormones and ovaries. PCOS affects up to 7 percent of women of childbearing age and is the leading cause of female infertility (12). Some women learn they have PCOS when they have problems becoming pregnant.

Women with PCOS have high levels of male hormones (androgens), which may interfere with normal ovarian function. Affected women often do not ovulate regularly. PCOS also affects other bodily systems, increasing a woman’s risk for diabetes and heart disease (11, 12). Signs and symptoms of PCOS include (11, 12):

• Irregular or absent menstrual periods
• Ovaries containing many small cysts (fluid-filled sacs)
• Increased facial hair
• Acne
• Weight gain or obesity
• Male-pattern baldness
• Abnormal blood sugar levels or diabetes
• High blood pressure

How is PCOS diagnosed?
There is no specific diagnostic test for PCOS. Diagnosis is usually based on:

• Signs and symptoms, including menstrual irregularities
• Physical examination
• Blood tests to check androgen and blood sugar levels
• Ultrasound of the ovaries

How is PCOS treated?
Women with PCOS who are overweight or obese should attempt to lose weight. Women who lose even 10 percent of their body weight can improve menstrual irregularities, lower androgen levels and reduce the risk of diabetes (11, 12). Weight loss also can improve fertility (11).

Women who do not wish to become pregnant right away can be treated with birth control pills. This treatment often helps regulate menstrual cycles and reduce androgen levels. In some cases, the woman may be treated with an oral diabetes drug called metformin (Glucophage), instead of or in addition to birth control pills. Metformin also helps reduce androgen levels and may help with weight loss.

Women who are having difficulty conceiving can be treated with medications that stimulate ovulation, usually starting with clomiphene citrate (Clomid, Serophene). If clomiphene treatment is not successful, the woman can be treated with injected fertility drugs (gonadotropins) or in vitro fertilization (IVF). In IVF, eggs are combined with sperm in the laboratory to create embryos which are transferred into the woman’s uterus. All fertility treatments increase the risk of multiple gestation (twins, etc.), which increases the risk for premature birth and other complications.

Does PCOS increase the risk of pregnancy complications?
Studies suggest that women with PCOS are at increased risk of gestational diabetes, preeclampsia (a pregnancy-related form of high blood pressure) and premature birth (11, 12, 13). Obesity also can increase the risk of these complications, so women with PCOS may be able to reduce their risk by reaching a healthy weight before they become pregnant. Women with PCOS should see their health care provider before pregnancy to make sure any health problems, such as diabetes, are under control, and that any medications they take are safe in pregnancy. When they become pregnant, they should go to all their prenatal appointments so that any complications can be diagnosed and managed before they become serious.

Does the March of Dimes support research on uterine and ovarian abnormalities and pregnancy?
The March of Dimes supports a number of grants on uterine and ovarian abnormalities and the pregnancy complications they may cause. One grantee is seeking to identify cell-to-cell signaling pathways that may help trigger shortening of the cervix before labor, in order to develop new treatments aimed at preventing premature birth. Another is studying the role of androgens in normal ovarian growth and fertility, in order to develop improved fertility treatments for PCOS.

References

1. Rackow, B.W. & Arici, A. (2007). Reproductive Performance of Women with Mullerian Anomalies. Current Opinion in Obstetrics and Gynecology, 19, 229-337.
2. Wold, A.S.D., Pham, N. & Arici, A. (2006). Anatomic Factors in Recurrent Pregnancy Loss. Seminars in Reproductive Medicine, 24 (1), 25-32.
3. Syed, I., Hussain, H.K., Weadock, W. & Ellis, J. (2008). Uterus, Mullerian Duct Abnormalities. EMedicine. Retrieved October 14, 2009.
4. Klatsky, P.C., Tran, N.D., Caughey, A.B. & Fujimoto, V.Y. (2008). Fibroids and Reproductive Outcomes: A Systematic Literature Review from Conception to Delivery. American Journal of Obstetrics and Gynecology, 198 (4), 357-366.
5. American College of Obstetricians and Gynecologists (ACOG). (2009). Uterine Fibroids. Retrieved October 14, 2009.
6. American Society for Reproductive Medicine. (2005). Patient’s Fact Sheet: Intrauterine Adhesions. Retrieved October 14, 2009.
7. American College of Obstetricians and Gynecologists (ACOG). (2003). Clinical Management Guidelines for Obstetrician-Gynecologists, Number 48: Cervical Insufficiency. Obstetrics and Gynecology, 102 (5), 1091-1099.
8. American College of Obstetricians and Gynecologists (ACOG). (2008). ACOG Committee Opinion, Number 419: Use of Progesterone to Reduce Preterm Birth. Obstetrics and Gynecology, 112 (4), 963-965.
9. Da Fonseco, E.B., Damiao, R. & Nicholaides, K. (2009). Prevention of Preterm Birth Based on Short Cervix: Progesterone. Seminars in Perinatology, 33 (5), 334-337.
10. O’Grady, J.P. (2008). Malposition of the Uterus. EMedicine. Retrieved November 9, 2009.
11. American College of Obstetricians and Gynecologists (ACOG). (2009). Clinical Management Guidelines for Obstetrician-Gynecologists, Number 108: Polycystic Ovary Syndrome. Obstetrics and Gynecology, 114 (4), 936-949.
12. U.S. Department of Health and Human Services. (2007). Polycystic Ovary Syndrome. Retrieved October 13, 2009.
13. Boomsma, C.M., Eijkemans, M.J.C., Hughes, E.G., Visser, G.H.A., Fauser, B.C.J.M., et al. (2006). A Meta-Analysis of Pregnancy Outcomes in Women with Polycystic Ovary Syndrome. Human Reproduction Update, 12 (6), 673-683.

March 2010