Fetal tachycardia is defined as foetal heart rate greater than–

Correct option is D

Sol. Fetal tachycardia is defined as a fetal heart rate (FHR) exceeding 160 beats per minute for more than 10 minutes. It may be caused by maternal fever, fetal infection, hypoxia, or maternal medications. A normal FHR ranges from 110 to 160 bpm. When it consistently exceeds 160 bpm, it requires careful evaluation to rule out fetal distress or intrauterine infections like chorioamnionitis.
Explanation of each option:
· (a) 120–140 beats/min – Incorrect. This range falls within the normal variation of fetal heart rate and does not indicate tachycardia.
· (b) 140–160 beats/min – Incorrect. Although it's on the higher side of normal, it's still considered acceptable and not classified as tachycardia.
· (c) 150–170 beats/min – Incorrect. Though 170 bpm may indicate tachycardia, the definition begins clearly at >160 bpm, not within this broad overlapping range.
· (d) 160–180 beats/min – Correct. This range is above the upper normal limit. Tachycardia starts at >160 bpm, so this is the medically accepted definition.