STDs pose special risks for pregnant women and their babies. These infections can cause:
Most frequently a baby becomes infected during delivery, while passing through an infected birth canal. However, a few of these infections can cross the placenta and infect the baby.
It is important for a pregnant woman to find out whether she has an STD. During an early prenatal visit, her health care provider will screen her for some of these infections, including HIV (the virus that causes AIDS) and syphilis. Some STDs can be cured with drug treatment, but not all. However, if a woman has an STD that cannot be cured, steps usually can be taken to protect her baby.
What is chlamydia?
Chlamydia is a bacterium. A chlamydial infection contracted before or during pregnancy can cause reproductive problems. About 2.8 million new cases of this infection occur yearly in the United States in both sexes, making this one of the most common STDs (1). It is most frequent in people under age 25.
Chlamydia usually causes no symptoms, although a minority of infected women experience vaginal discharge and burning on urination (2). Untreated, chlamydia can spread to the upper genital tract (uterus, fallopian tubes and ovaries), resulting in pelvic inflammatory disease (PID), often with a superinfection with other bacteria. PID can damage a woman's fallopian tubes and lead to ectopic pregnancy or infertility.
About 10 percent of pregnant women in the United States are infected with Chlamydia (3). Untreated, they face an increased risk of premature rupture of the membranes (PROM) (bag of waters) and preterm delivery (3). Babies of untreated women often become infected during vaginal delivery. Infected babies can develop eye infections and pneumonia, which require treatment with antibiotics.
The Centers for Disease Control and Prevention (CDC) recommends that all pregnant women be screened for chlamydia infection at the first prenatal visit (4). Testing is done on a urine sample or vaginal fluid obtained with a swab. Chlamydial infection can be cured with antibiotics that prevent complications for mother and baby. Partners of an infected women also should be treated, because the infection can be passed back and forth between sexually active couples.
What is gonorrhea?
Gonorrhea is a common bacterial infectious disease that causes reproductive problems much like those caused by chlamydia. In the United States, about 600,000 new cases occur each year (4). Like infection with chlamydia, gonorrhea often causes no symptoms in infected women, although some experience vaginal discharge, burning on urination or abdominal pain. Many infected women also develop PID. Unlike chlamydial infection, gonorrhea in men causes intense burning on urination and even obstruction of urinary flow.
Pregnant women with untreated gonorrhea are at increased risk for miscarriage, PROM and premature delivery. Their babies frequently contract this infection during vaginal delivery. It can affect their eyes and joints and even cause life-threatening blood infections. Antibiotics offer effective treatment.
The CDC recommends that all pregnant women who are at risk for gonorrhea or live in an area where it is common should be tested at the first prenatal visit (4). Testing can be done on a urine sample or vaginal fluid taken with a swab. Treatment with antibiotics is usually effective and prevents complications. Because gonorrhea and chlamydia often occur together, health care providers test individuals with one of these infections for the other.
What is syphilis?
Syphilis is an STD caused by a bacterium that can cross the placenta and infect the fetus. This infection is among the most serious STDs, although it is substantially less common than the other STDs. In 2005, about 1,300 women in the United States were diagnosed with this infection (5).
Syphilis begins with a hard, painless sore called a "chancre" that usually occurs in the genital or vaginal area. Without treatment, infected individuals develop a rash, fever and other symptoms months later. If still untreated, years later some infected individuals can develop heart problems, brain damage, blindness, insanity and death.
Without treatment, syphilis during pregnancy can result in fetal or infant death in up to 40 percent of cases (5). It also can result in preterm delivery. Some infected infants show no symptoms at birth, but without immediate antibiotic treatment, they develop brain damage, blindness, hearing impairment, bone and tooth abnormalities and other problems.
The CDC recommends that all women have a blood test to screen for syphilis during the first prenatal visit (4). A single injection (shot) of penicillin can cure syphilis if a woman has had the STD for less than a year; other women require longer periods of treatment (4). When a pregnant woman is treated before the third trimester of pregnancy (about 28 weeks of pregnancy), her baby usually is not be harmed by the infection (6).
What is bacterial vaginosis?
Bacterial vaginosis (BV), which affects 16 percent of pregnant women in the United States, is caused by an overgrowth of bacteria that occur naturally in the vagina (7). The cause of BV is not known, although it appears more common in women who have had multiple sexual partners. Some women with BV experience vaginal discharge that has an unpleasant odor, burning on urination and genital itching. Some women have no symptoms.
Studies suggest that BV may increase a woman's chances of PROM and preterm delivery (4). Women with symptoms of BV are treated with antibiotics to help reduce this risk. Some studies suggest that treating high-risk pregnant women with BV (even if they have no symptoms) may reduce their risk for preterm birth. Because treatment does not appear to reduce the risk of preterm delivery in low-risk women with symptomless BV, routine testing is not currently recommended (4).
What is trichomoniasis?
Trichomoniasis is a parasitic infection that causes yellow-green, foul-smelling vaginal discharge, genital itching and redness and, sometimes, pain during intercourse and urination. Each year 7.4 million individuals in this country become infected (8).
Ten percent of pregnant women in the United States have trichomoniasis (9). This STD may increase the risk of PROM and preterm delivery.
Trichomoniasis is diagnosed by testing vaginal fluid obtained with a swab. Treatment with a drug called metronidazole eliminates the infection, but it may not reduce the risk of preterm delivery (4, 8). A pregnant women should discuss with her provider whether or not she should be treated. If she is treated, her partner also should be treated.
What is genital herpes?
Genital herpes is a viral STD. Twenty-five percent of American women are infected, but most do not know it because they have no symptoms (10).
A small number of infected individuals develop blisters in the genital area that itch and become painful. Someone who contracts genital herpes for the first time also may develop fever, fatigue, swollen glands and body aches. The virus remains in the body forever and can cause repeated outbreaks of blisters. Providers usually diagnose herpes by looking at the sores. But in some cases, they may take a swab of the blisters for testing.
Fewer than 1 percent of women with a repeated outbreak of herpes at term pass the virus on to their babies (4). The risk is highest (30 to 50 percent) when the pregnant woman contracts herpes (whether or not she has symptoms) for the first time late in pregnancy (4). Some infected infants develop skin or mouth sores, which usually can be effectively treated with antiviral drugs. However, in spite of treatment, the infection sometimes spreads to the brain and other organs, resulting in brain damage, blindness, intellectual disabilities and even death. If a woman has symptoms of herpes at the time of delivery, her provider may recommend a cesarean section to protect her baby. Some women who have repeated outbreaks of herpes infection can be treated with an antiviral drug that may prevent such outbreaks (4).
What are genital warts?
Genital warts are pink, white or gray swellings in the genital area caused by a large group of viruses called human papillomaviruses (HPVs). Some of the viruses also increase the risk of cervical cancer. About 6.2 million individuals in this country become infected each year (11).
A vaccine against four major types of HPV is now routinely recommended for girls ages 11 to 12 years and girls and women between the ages of 13 and 26 who have not been previously vaccinated (11). This vaccine can prevent most cases of cervical cancer and genital warts. Pregnant women should not get the vaccine.
Genital warts often appear in small, cauliflower-shaped clusters that may itch or burn. About 1 percent of all sexually active adults have genital warts (11).
Sometimes pregnancy-related hormones cause genital warts to grow. Occasionally, they may grow so large that they block the birth canal, making a cesarean section necessary. Rarely, an infected mother can pass the virus on to her baby, causing warts to grow on the baby's vocal cords. A cesarean section is not recommended to protect the baby because this complication is rare, and the preventive effectiveness of cesarean delivery is not known.
If the warts grow large or make the woman uncomfortable, they can be safely removed during pregnancy with laser surgery or cryotherapy (freezing).
What is HIV?
HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immune deficiency syndrome). AIDS damages the immune system and threatens the lives of those who are infected, including mothers and babies. In the United States, 127,000 women are living with HIV (12). The majority were infected sexually, although intravenous drug use is another common source of the infection.
The CDC recommends that all pregnant women be tested for HIV early in pregnancy as part of the routine panel of prenatal tests (4). Women who learn that they carry the virus can get treatment to help protect their babies from contracting the infection. New drug treatments reduce the risk of a mother passing HIV to her baby to 2 percent or less, compared to 15 to 25 percent for untreated mothers (4).
What is hepatitis B?
Hepatitis B is one of several viruses that infect the liver. About 1 in every 500 to 1 in 1,000 pregnant women has hepatitis B at the time of delivery and can pass the infection on to her baby during labor and birth (13). In most cases, the risk is about 10 to 20 percent, though it can be higher if the woman has high levels of the virus in her body (14).
Symptoms of hepatitis B can range from mild to severe. Some infected individuals have no symptoms at all. Common symptoms include: jaundice (yellowing of skin), fatigue, nausea and vomiting, upper-abdominal discomfort and low-grade fever.
About 10 to 15 percent of individuals with hepatitis B do not clear the virus from their bodies and develop chronic hepatitis (14). These individuals are at increased risk for severe liver disease or liver cancer. Babies who are infected at birth usually develop chronic hepatitis B infection and face a high risk for serious liver disease and liver cancer as adults.
However, hepatitis usually can be prevented in babies. The Centers for Disease Control and Prevention (CDC) recommends that all pregnant women be screened for hepatitis B with a blood test (15). If the blood test shows a woman has hepatitis B, her baby should receive the hepatitis B vaccine and immune globulin (which contains hepatitis-fighting antibodies) within 12 hours of birth. This treatment prevents infection in more than 90 percent of babies at risk (15). The baby should have two more doses of the vaccine in the first 6 months of life. The CDC also recommends that all babies be vaccinated against hepatitis B before leaving the hospital and at 1 to 2 months and 6 to 18 months.
Besides sexual contact, hepatitis B can be spread by contact with blood or saliva of infected individuals (13). Women can help protect themselves from hepatitis B by following safe sex practices, avoiding illicit injected drugs, and not sharing personal care items that might have blood or saliva on them (razors, toothbrushes).
However, the best defense against hepatitis B is vaccination. The hepatitis B vaccine is considered safe in pregnancy (13, 15). Health care workers, public safety workers and others at high risk (such as women living with an infected partner) should consider getting the hepatitis B vaccine before or during pregnancy.
How can a pregnant woman protect her baby from STIs?
A pregnant woman can help protect her baby from STDs by making sure she doesn't contract one of these infections during pregnancy. The most effective prevention is having only one sexual partner who does not have an STD.
If her partner has a history of herpes and she does not, she should avoid intercourse during the third trimester when the risk of passing on the infection to the baby is highest (4). Throughout pregnancy, a woman should avoid intercourse when her partner has symptoms. He should use a condom even when he has no sores, because the infection may be active but cause no symptoms. Condoms also help to protect against HIV and other STDs.
A pregnant woman should contact her health care provider right away if she:
In this way she can be treated promptly, if necessary, to protect her health and that of her baby.
Does the March of Dimes support research on STIs in pregnancy?
The March of Dimes offers research grants aimed at answering these questions:
One grantee is seeking to identify genetic differences that may cause some pregnant women to be more susceptible to upper genital tract infections following BV. Because upper genital tract infections can increase the risk of preterm delivery, this study could lead to better ways to identify women at increased risk of preterm delivery, allowing early treatment to help prevent it.
Another grantee is analyzing how networks of genes in Chlamydia and other bacteria act to cause dangerous infections in newborns, such as meningitis and blood infection.
Other researchers are seeking to develop improved drug treatment for congenital herpes infections in order to prevent brain damage and lasting disabilities in newborns.
For more information