Premature birth, defined as a birth that occurs before 37 weeks of gestation, can bring a host of challenges for both the baby and the healthcare team. While clinical evaluations and physical assessments are the first steps in diagnosing prematurity, medical laboratory tests play a critical role in understanding the baby’s condition, identifying potential complications, and guiding care after birth. In this blog, we’ll explore the key laboratory tests that help diagnose prematurity, monitor health risks, and ensure the best outcomes for preterm infants.
1. Blood Tests for Infection or Inflammation
Infections and inflammation are common triggers of preterm labor. Several blood tests can help identify these underlying factors, allowing healthcare providers to manage risks and intervene early.
· C-Reactive Protein (CRP): This is a marker of inflammation in the body. Elevated CRP levels may suggest an infection or inflammatory process, both of which can increase the risk of preterm birth.
· White Blood Cell Count (WBC): A high WBC count can indicate an ongoing infection or inflammatory response, particularly in cases of chorioamnionitis (infection of the fetal membranes), which is a leading cause of preterm birth.
· Urine Cultures: Urinary tract infections (UTIs) are common during pregnancy and can lead to preterm labor if left untreated. Urine cultures are often performed to check for infections, particularly if a woman has symptoms like pain during urination or fever.
· Vaginal or Endocervical Cultures: These tests help identify bacterial infections such as Group B Streptococcus (GBS), Chlamydia, or Gonorrhea, which can increase the risk of preterm premature rupture of membranes (PPROM) and subsequent preterm birth.
2. Complete Blood Count (CBC): Assessing Overall Health
A complete blood count (CBC) is one of the most commonly performed laboratory tests on preterm infants. It provides a snapshot of the infant’s overall health, detecting conditions like anemia, infection, or blood clotting disorders. For example:
Anemia of Prematurity: Preterm infants often have lower red blood cell counts and may require transfusions.
Leukocytosis: An elevated white blood cell count may signal infection or inflammation.
Thrombocytopenia: A low platelet count, which can occur in premature infants, increases the risk of bleeding and may require treatment.
3. Bilirubin Levels: Monitoring for Jaundice
Jaundice (yellowing of the skin and eyes) is common in preterm infants because their liver is often too immature to process bilirubin, a byproduct of red blood cell breakdown. A bilirubin blood test helps determine the levels of this substance in the blood.
Total Serum Bilirubin (TSB): High bilirubin levels can lead to a condition called kernicterus (a type of brain damage), so close monitoring and potential treatment (like phototherapy) are necessary for preterm infants with jaundice.
4. Glucose and Electrolyte Testing: Monitoring for Hypoglycemia
Premature infants are at higher risk for hypoglycemia (low blood sugar), which can lead to seizures, brain injury, or other complications if not addressed. Blood glucose tests are performed regularly in premature infants to monitor for low blood sugar, especially in the first few days after birth.
Electrolyte Imbalances: Premature babies are also more prone to electrolyte imbalances (like low sodium or potassium), which can affect heart and kidney function. Blood tests to check electrolyte levels are a routine part of neonatal care.
Conclusion
Premature birth presents significant challenges, but medical advances in diagnostic testing allow healthcare providers to better manage preterm pregnancies and the infants born early. Laboratory tests, from amniocentesis to blood gas analysis, offer essential insights into fetal lung maturity, the risk of preterm labor, infection, and the immediate health of the newborn. By combining clinical evaluation with these diagnostic tools, doctors can make more informed decisions and provide the best possible care for both the baby and the mother.