Opioids given during labor for pain relief may cause which of the following side effects on the fetus?

• A. Fetal tachycardia
• B. Decreased FHR variability
• C. Variable decelerations
• D. Fetal growth restriction

Answer: (B)

Opioids given during labor can cross the placenta and cause fetal central nervous system depression. This leads to reduced autonomic control of the fetal heart, which dampens beat-to-beat fluctuations in heart rate. The result is decreased fetal heart rate variability, a pattern often associated with fetal sedation or distress from the analgesia.

Other options aren’t the typical direct effect of labor opioids. Fetal tachycardia can occur for various reasons like infection or hypoxia, but it isn’t the expected effect of opioid exposure. Variable decelerations arise from intermittent umbilical cord compression, not from drug effect. Fetal growth restriction is a chronic condition related to long-term factors, not an acute side effect of analgesia during labor.