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Intra-Amniotic Infection

(Chorioamnionitis)

By

Antonette T. Dulay

, MD, Main Line Health System

Last full review/revision Aug 2019| Content last modified Aug 2019
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NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
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Intra-amniotic infection is infection of the tissues around the fetus, such as the fluid that surrounds the fetus (amniotic fluid), the placenta, the membranes around the fetus, or a combination.

  • Intra-amniotic infection increases the risk of problems in the woman and in the fetus.

  • Women usually have a fever and often have pelvic pain and a vaginal discharge.

  • Usually, doctors can diagnose the infection by doing a physical examination, but sometimes amniotic fluid must be analyzed.

  • Women are given antibiotics and drugs to lower body temperature, and delivery is scheduled as soon as possible.

Pregnancy complications, such as intra-amniotic infection, are problems that occur only during pregnancy. They may affect the woman, the fetus, or both and may occur at different times during the pregnancy. However, most pregnancy complications can be effectively treated.

Intra-amniotic infection typically develops because bacteria from the vagina enter the uterus and infect the tissues around the fetus. Normally, mucus in the cervix, the membranes around the fetus, and the placenta prevent bacteria from causing infection. However, certain conditions can make it easier for bacteria to breach these defenses. For example, the membranes around the fetus may rupture too soon (called premature rupture of the membranes). Rarely, infection occurs when internal fetal monitoring is done. For this procedure, doctors monitor the fetus by inserting an electrode (a small round sensor attached to a wire) through the woman’s vagina.

The more time that passes between when the membranes rupture and delivery occurs, the more likely intra-amniotic infection is to develop, particularly if doctors or midwives do many pelvic examinations. Such examinations may introduce bacteria into the vagina and uterus.

Having bacteria that can cause infections in the genital tract also makes intra-amniotic infections more likely. Women may not know that these bacteria are present, particularly if they have not had routine prenatal care, when tests for these bacteria would have been done.

Intra-amniotic infection is also more likely if

  • Labor starts early (preterm labor).

  • The amniotic fluid contains meconium (the dark green stool that is produced by the fetus before birth and that is usually only expelled after birth).

  • Labor lasts a long time.

Intra-amniotic infection can increase the risk of the following problems in the fetus:

  • Preterm delivery or preterm premature rupture of the membranes (intra-amniotic infection can cause as well as result from these problems)

  • Too little oxygen in the blood around the time of delivery

  • Infections, such as a bodywide infection (sepsis), pneumonia, or meningitis

  • Death

Intra-amniotic infection can increase the risk of the following problems in the woman:

Rarely, if an intra-amniotic infection is not treated, women may develop septic shock (life-threatening low blood pressure caused by a serious bodywide response to infection), disseminated intravascular coagulation (a blood clotting disorder that causes blood clots and bleeding), and acute respiratory distress syndrome.

Symptoms

Intra-amniotic infection usually causes fever and often causes abdominal pain and a discharge that can be foul-smelling. The heart rate of the fetus and the woman may be rapid. However, some women do not have typical symptoms.

Diagnosis

  • A doctor's evaluation

  • A complete blood count

  • Sometimes amniocentesis

Doctors do a physical examination and a complete blood count (which includes a white blood cell count).

An intra-amniotic infection is suspected when women have a fever and there is another typical symptom, such as a fast heart rate in the fetus or a foul-smelling discharge or an abnormally high white blood cell count in the woman. If the diagnosis is still unclear, doctors can remove a sample of the amniotic fluid and analyze it (amniocentesis).

If preterm labor or premature preterm rupture of membranes occurs, doctors consider the possibility of infection even if women do not have typical symptoms.

Prevention

If women have preterm premature rupture of the membranes, doctors do pelvic examinations only if necessary.

Doctors usually also give these women antibiotics intravenously or by mouth to help the pregnancy last longer and reduce the risk of problems in the fetus.

Treatment

  • Antibiotics

  • Drugs to lower body temperature

  • Delivery

Women with an intra-amniotic infection are given antibiotics intravenously. They are also given drugs such as acetaminophen to lower body temperature.

Delivery should not be delayed once the diagnosis is made.

If labor has not started, labor may be artificially started (induced).

Immediate cesarean delivery is not usually necessary if the mother and fetus are stable and if antibiotics are given while labor is being induced.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
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