Which first-trimester condition increases the risk of spina bifida?

• A. Hypothermia
• B. Hyperthermia
• C. Fever
• D. Dehydration

Answer: (B)

During early pregnancy, the neural tube forms and closes very early in gestation. When maternal core temperature is elevated during this critical window—such as with a fever or prolonged exposure to hot environments—the higher temperature can disrupt neural tube closure. Heat can interfere with cell division and crucial signaling pathways, including those involving folate-dependent processes, increasing the risk of neural tube defects like spina bifida. This is why hyperthermia is the associated condition. Hypothermia or dehydration do not have the same established link to neural tube closure in this context, and fever reflects the presence of elevated temperature. To reduce risk, avoid situations that raise core temperature in early pregnancy, treat fever appropriately, stay hydrated, and maintain adequate folate intake.