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 Prelabor Rupture of the Membranes (PROM) Prelabor rupture of the membranes is the leaking of amniotic fluid from around the fetus at any time before labor starts. After the membranes rupture, labor often soon follows. If labor does... read more ).
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.
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 Fetal monitoring Labor is a series of rhythmic, progressive contractions of the uterus that gradually move the fetus through the lower part of the uterus (cervix) and birth canal (vagina) to the outside world... read more 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 Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more ), pneumonia Overview of Pneumonia Pneumonia is an infection of the small air sacs of the lungs (alveoli) and the tissues around them. Pneumonia is one of the most common causes of death worldwide. The most common symptom of... read more , or meningitis Meningitis in Children Bacterial meningitis is a serious infection of the layers of tissue covering the brain and spinal cord ( meninges). Bacterial meningitis in older infants and children usually results from bacteria... read more
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:
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 Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more (life-threatening low blood pressure caused by a serious bodywide response to infection), disseminated intravascular coagulation Disseminated Intravascular Coagulation (DIC) Disseminated intravascular coagulation is a condition in which small blood clots develop throughout the bloodstream, blocking small blood vessels. The increased clotting depletes the platelets... read more (a blood clotting disorder that causes blood clots and bleeding), and acute respiratory distress syndrome Acute Respiratory Distress Syndrome (ARDS) Acute respiratory distress syndrome is a type of respiratory (lung) failure resulting from many different disorders that cause fluid to accumulate in the lungs and oxygen levels in the blood... read more .
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
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 Amniocentesis Prenatal testing for genetic disorders and birth defects involves testing a pregnant woman or fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including... read more ).
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
Medications to lower body temperature
Women with an intraamniotic infection are given antibiotics intravenously. They are also given medications to lower body temperature (preferably acetaminophen before delivery).
Delivery should not be delayed once the diagnosis is made.
If labor has not started, labor may be started with medications (induced Induction of Labor Induction of labor is the artificial starting of labor. Usually, labor is induced by giving the woman oxytocin, a drug that makes the uterus contract more frequently and more forcefully. The... read more ).
Immediate cesarean delivery Cesarean Delivery Cesarean delivery is surgical delivery of a baby by incision through a woman’s abdomen and uterus. In the United States, up to 30% of deliveries are cesarean. Doctors use a cesarean delivery... read more 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.