Abnormal fetal heart rate tracings and congenital fetal hypothyroidism.

Background: Fetal heart rate (FHR) monitoring is commonly used for fetal surveillance. Despite its widespread usage, there is still a disagreement about its value in predicting fetal distress.

Case: A 29-year-old woman in her first pregnancy was admitted for routine follow-up at 38 weeks gestation. The FHR tracing demonstrated severely reduced baseline variability. Due to non-reassuring FHR patterns accompanied by abnormal biophysical profile, the patient was scheduled for urgent Cesarean section. A newborn with congenital absence of the thyroid gland was delivered.

Conclusion: Severe reduced baseline variability might be an early sign for fetal hypothyroidism. Future research in this area may examine large populations of neonates with thyroid abnormalities in order to determine if abnormal FHR tracing can better predict congenital hypothyroidism.