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OBG · Labour and delivery: secondary arrest in active phase
Sample itemA primigravida at term has been in labour for 14 hours. The cervix has remained at 6 cm for 5 hours despite adequate contractions on an oxytocin infusion. The head is high with marked caput and 3+ moulding, and the fetal heart tracing is normal. What is the best management?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
D. Caesarean section
Arrest of dilatation despite adequate contractions with a high head, marked caput and severe moulding indicates cephalopelvic disproportion. Further oxytocin or waiting risks obstructed labour and uterine rupture, so delivery is by caesarean. Instrumental delivery is impossible with a high head and unfully dilated cervix.
Option by option
A. Mid-cavity forceps delivery
The cervix is only 6 cm dilated and the head is high, so forceps cannot be applied.
B. Wait for 4 more hours and review
Further waiting is unsafe because arrest with disproportion will not resolve.
C. Increase the oxytocin dose further
More oxytocin in disproportion increases the risk of uterine rupture and fetal injury.
D. Caesarean section (correct)
Correct. Failed progress in spite of good contractions, caput and severe moulding signals disproportion, requiring caesarean birth.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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