Intraamniotic infection is infection and resulting inflammation of the tissues around the fetus, such as the fluid that surrounds the fetus (amniotic fluid), the placenta, the membranes around the fetus, the fetus, or a combination.
Intraamniotic infection increases the risk of problems in a pregnant 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 medications to lower body temperature, and delivery is scheduled as soon as possible.
Risk factors for intraamniotic infection
Intraamniotic infection typically develops when bacteria from the vagina enter the uterus and infect the tissues around the fetus. Many different kinds of bacteria normally live in the vagina. Usually these do not cause a vaginal infection, but if they spread to the uterus, they can cause a uterine infection. 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.
Intraamniotic infection is also more likely if
The membranes around the fetus rupture too soon (called prelabor rupture of the membranes).
There is a long delay between rupture of the membranes and delivery of the baby. The longer the delay, the more likely intraamniotic infection is to develop.
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).
Bacteria that can cause infections are in the genital tract. 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.
Doctors or midwives do many pelvic examinations in women with ruptured membranes. Such examinations may introduce bacteria into the vagina and uterus.
Labor lasts a long time.
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 a woman’s vagina and attached to the fetus’s scalp.
Complications of intraamniotic infection
Intraamniotic infection can increase the risk of the following problems in the fetus or newborn:
Preterm delivery or preterm prelabor rupture of the membranes (rupture of the membranes before 37 weeks of pregnancy)
Too little oxygen in the blood around the time of delivery
Infections, such as a bodywide infection (sepsis), pneumonia, or meningitis
Death
Intraamniotic infection can cause as well as result from preterm delivery or preterm prelabor rupture of the membranes.
Intraamniotic infection can increase the risk of the following problems in a woman:
Need for a cesarean delivery
Bleeding after delivery (postpartum hemorrhage)
A collection of pus (abscess) around the uterus
Infection of incisions made during delivery
Rarely, if an intraamniotic 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 of Intraamniotic Infection
Intraamniotic infection usually causes fever and often causes abdominal pain and a vaginal discharge that can be foul-smelling. The mother and fetus may have a rapid heart rate. However, some women do not have typical symptoms.
Diagnosis of Intraamniotic Infection
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 intraamniotic infection is suspected when women have a fever and at least one other 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 prelabor rupture of membranes occurs, doctors consider the possibility of infection even if women do not have typical symptoms.
Treatment of Intraamniotic Infection
Antibiotics
Medications to lower body temperature
Delivery
Delivery should not be delayed once the diagnosis is made.
If labor has not started, labor may be started with medications (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.
Prevention of Intraamniotic Infection
If a woman has preterm prelabor rupture of the membranes, doctors do pelvic examinations only if necessary.
Doctors usually also give a woman antibiotics intravenously and by mouth to help the pregnancy last longer and reduce the risk of problems in the fetus.
Doctors screen pregnant patients for group B streptococcus at 35 to 37 weeks of pregnancy. People who screen positive are given antibiotics during labor.
