Preterm prelabor rupture of membranes is defined as spontaneous rupture of membranes before which gestational threshold?

• A. After 37 weeks of gestation and before labor.
• B. Before 37 weeks of gestation and before labor.
• C. During labor only.
• D. Any rupture of membranes after viability.

Answer: (B)

The main idea is that preterm prelabor rupture of membranes happens when the membranes break before labor begins in a pregnancy that is not yet term. The defining timeframe is before 37 completed weeks of gestation and prior to the onset of labor. So this option is the best because it includes both conditions: rupture occurring before labor and before 37 weeks. If rupture happens after 37 weeks, it’s PROM at term. If rupture occurs during labor, it’s not prelabor rupture. Using viability as the threshold doesn’t specify the gestational age cutpoint and could include or exclude pregnancies inconsistently.