Intrauterine infection, also known as intra-amniotic infection or chorioamnionitis, is an infection that develops inside the uterus during pregnancy. This condition can affect the amniotic fluid, the placenta, and the membranes surrounding the baby. Prompt attention is required to minimize potential risks to both the expectant mother and the developing fetus.
How Infections Occur
Infections can reach the uterus through several pathways. The most common is an ascending infection from the vagina or cervix, where bacteria like Group B streptococcus or E. coli travel upwards. The membranes normally act as a barrier, but if they rupture prematurely, bacteria can enter more easily.
Another route is transplacental transmission, where pathogens from the mother’s bloodstream cross the placenta to infect the fetus. Certain viruses and bacteria can spread this way. Medical procedures, such as amniocentesis, also present a less frequent pathway for bacteria to enter the uterus.
The risk of infection increases with prolonged rupture of membranes, especially if it occurs before full term. A long labor or multiple vaginal examinations after the water has broken can also contribute to the risk. The presence of certain bacteria in the vagina, such as those causing bacterial vaginosis or sexually transmitted infections, can also raise the likelihood of an intrauterine infection.
Recognizing the Signs
Recognizing the signs of an intrauterine infection is important for timely medical intervention. In the expectant mother, common indicators include a fever, particularly after the water has broken or during labor. The mother may also experience abdominal pain or tenderness in the uterus.
Other maternal signs can include an unusually fast heart rate, a foul-smelling or discolored vaginal discharge. While some women may not have obvious symptoms, these signs warrant immediate medical evaluation.
For the fetus, an increased heart rate, known as fetal tachycardia, can be a sign of infection. A normal fetal heart rate is typically between 110 and 160 beats per minute, so a sustained rate above this range may indicate a problem. Decreased fetal movement might also be observed, signaling a need for prompt assessment.
Potential Health Impacts
Intrauterine infections can lead to various health impacts for both the mother and the baby. For the mother, risks include preterm labor and premature birth. There is also an increased likelihood of postpartum infections, such as endometritis (an infection of the uterine lining), and in severe cases, sepsis (a life-threatening systemic response to infection).
Mothers may also face an increased risk of needing a cesarean delivery, excessive bleeding after birth, or developing blood clots. Placental abruption, where the placenta separates from the uterus, can also occur.
For the baby, potential consequences include premature birth and developing infections such as sepsis, pneumonia, or meningitis. There is also a risk of respiratory distress, which can lead to chronic lung disease. Neurological complications, such as cerebral palsy, seizures, or developmental delays, may arise due to the inflammatory response impacting fetal brain development. In the most severe cases, an intrauterine infection can lead to stillbirth.
Diagnosis, Treatment, and Prevention
Diagnosing an intrauterine infection typically involves evaluating clinical signs in the mother, such as fever, uterine tenderness, and an elevated maternal white blood cell count. In some cases, laboratory tests on maternal blood or amniotic fluid, obtained through amniocentesis, may be performed to confirm the presence of infection.
Treatment usually involves the prompt administration of broad-spectrum antibiotics, often given intravenously, to combat the infection. Medications to lower fever may also be provided. Delivery of the baby is often recommended as soon as possible once an infection is diagnosed, with the safest option, whether induced labor or a cesarean, determined by the medical team.
Preventive measures include maintaining good hygiene and addressing any existing maternal infections, such as urinary tract infections or sexually transmitted infections, in a timely manner. For women with preterm prelabor rupture of membranes, prophylactic oral antibiotics may be prescribed to reduce the risk of infection. Universal screening for Group B streptococcus between 35 and 37 weeks of gestation, with antibiotic prophylaxis during labor for positive cases, also contributes to prevention.