Intrapartum Fever - Causes, Management, and Consequences

Introduction

Intrapartum means during labor. Intrapartum fever is when the maternal oral temperature is greater than 102 degrees Fahrenheit (F). Oral temperature is preferred as it correlates better with intrauterine temperature. It occurs due to infectious or noninfectious etiology. The maternal and newborn consequences depend on the cause. Maternal fever is a strong risk factor for neonatal brain disease (encephalopathy), brain paralysis, and death. Hence, maternal fever is associated with significant neonatal outcomes. However, the exact cause of intrapartum fever is unknown.

What Are the Causes of Intrapartum Fever?

It is hypothesized that maternal inflammation releases inflammatory cytokines (mediators). It is because the hypothalamus is set at a higher temperature by the internal pyrogens (fever-causing substances). Pyrogens are produced by specific cytokines such as interleukin (IL)-1, IL-6, tumor necrosis (TNF)-alpha, and TNF-beta. The various causes are infectious and noninfectious.

1. Infectious: The most common infection-related causes are:

• Intraamniotic infection (IAI).

• Urinary tract infection.

• Respiratory tract infection (Influenza).

• Dengue fever and COVID-19.

• Any pre-existing infection that presents as fever during labor.

2. Non-infectious: Most cases of intrapartum fever are related to the noninfectious category. Non-infectious causes include:

• Neuraxial anesthesia (epidural and spinal anesthesia).

• An increased surrounding temperature of the delivery room.

• Dehydration.

• Increased Metabolism.

IAI and neuraxial anesthesia are the most frequent causes of intrapartum fever.

• IAI - It is also called chorioamnionitis. Chorioamnionitis is a serious infection during pregnancy. It happens when the mucous plug breaks long before the due date. The clinical signs are fever, cervix tenderness, increased maternal heart rate (greater than 100 beats per minute), increased fetal heart rate (greater than 160 beats per minute), and foul-smelling vaginal discharge. Maternal fever is the most crucial sign of chorioamnionitis. Chorioamnionitis is attributed to about 20 percent of newborns with brain paralysis.

• Neuraxial Anesthesia: Epidural and spinal anesthesia comprise neuraxial anesthesia. These are given in the body’s back, following which they numb the lower part of the body. Analgesics (painkillers) are also delivered through the same route during delivery. Epidural analgesics are associated with intrapartum fever. Studies report that it is an independent risk factor for the same.

What Are the Risk Factors for Intrapartum Fever?

The risk factors are:

1. Past History: A past childbirth history is very important. A nulligravid (a female who was never pregnant) patient is at higher risk of developing an intrapartum fever. Other risk factors are a previous cesarian section, preterm birth, gestational diabetes, hypertension, and platelet disorder.

2. Antepartum Factors: Antepartum is before childbirth. The antepartum risk factors include maternal obesity, current hypertension, and gestational diabetes.

3. Intrapartum Factors: Labor induction, prolonged labor, multiple vaginal examinations, exposure to intrauterine devices, and prolonged membrane rupture are the intrapartum risk factors. Membrane rupture is when the mucous plug (water) breaks. Membrane rupture of more than four hours is significantly associated with intrapartum fever. Labor induction with Oxytocin and mode of delivery are notable factors. Further, women who deliver through a cesarian section are more likely to develop an intrapartum fever.

4. Newborn Factors: Apgar is a test done for about five minutes after childbirth for infant assessment. A score of above seven is considered normal. An Apgar score of less than seven may be linked with intrapartum fever. The presence of meconium (first stools of the newborn) is another risk factor. The nuchal cord is when the umbilical cord gets wrapped around the fetus’s neck in the uterus. A positive nuchal cord potentiates the risk of intrapartum fever.

How Is the Diagnosis of Intrapartum Fever Made?

A meticulous history taking and physical examination is necessary. Special attention should be given to abdominal tenderness and the nature of the amniotic fluid. The investigations done are:

1. Routine Investigations: Complete blood count (CBC), blood culture, urine culture, and examination are performed based on the suspected cause. A vaginal swab is an additional useful test. It is done in the case of early membrane rupture.

2. Immunoassays: Immunoassays are tests done to detect a specific viral antigen. It is especially done in pandemic situations such as COVID-19. Real-time polymerase chain reaction (RT-PCR) is more useful, if available. Antigen detection is also done for dengue fever. These are vital for the immediate detection and management of intrapartum fever.

3. Biological Markers: IL-8 is a reliable maternal serum marker to detect intrapartum fever. Also, C-reactive protein (CRP) is an inflammatory marker raised in fever. However, raised CRP is non-specific and unpredictable.

What Is the Management of Intrapartum Fever?

A senior obstetrician’s opinion is crucial in intrapartum fever management. An important point to remember is to start antibiotics in all cases of intrapartum fever. Various measures incorporated for intrapartum fever management are:

1. General Measures: Adequate hydration is important to treat and prevent dehydration. The main aim is to lower the room temperature during delivery. It can be done by removing blankets, applying a cool wet towel to the skin, and providing paracetamol (antipyretic).

2. Antibiotics: Broad-spectrum antibiotics are started in all patients. The exception is those patients with a pre-existing infection. Healthcare workers must check the oral temperature of a woman in labor every four hours. However, the blood pressure, heart rate, and respiratory rate should be assessed every fifteen minutes during labor and after childbirth.

3. Intraamniotic Infection Management: It is the inflammation of the amniotic fluid, placenta, and decidua (maternal uterine tissue). Amniotic fluid gram staining, culture, or placental tissue study are done to detect IAI. Maternal CRP and elevated white blood cell counts can also be done. However, they have low sensitivity and specificity. Obstetricians should start all IAI patients on intravenous antibiotics.

What Are the Consequences of Intrapartum Fever?

The maternal consequences are:

1. Abnormal labor.

2. Increased chances of cesarian delivery.

3. Postpartum hemorrhage (bleeding after childbirth).

4. Postpartum uterine infection.

When a laboring woman has a fever, fetal infection is one of the major concerns. Once the microbes enter the fetal environment, they induce an inflammatory response. Septicemia (infection in the blood), meningitis, and pneumonia are the short-term effects. On the other hand, the long-term fetal consequences are:

1. Neonatal (newborn) seizures.

2. Stillbirths.

3. Hyaline membrane disease (also called infant respiratory distress syndrome where babies need extra oxygen to survive).

4. Early infant death.

5. Birth asphyxia (newborn suffocates due to lack of oxygen).

6. Neonatal brain disease and paralysis.

Conclusion

Due to varied causes, the management of intrapartum fever is complex. It involves a multidisciplinary team including the obstetrician, microbiologist, physician, and anesthetist. The neonatology team should also be informed and involved in all cases of intrapartum fever. Further studies are needed to discover methods for immediate fever management and prevent neonatal sequelae.