**Core Concept**
In primigravidae (first-time pregnant women), maternal height is a key predictor of fetal growth and delivery outcomes. A height below a certain threshold is associated with increased risk of complications such as intrauterine growth restriction, preterm birth, and obstetric trauma due to limited pelvic dimensions and reduced uterine capacity.

**Why the Correct Answer is Right**
The standard cutoff for height in primigravidae to assess potential obstetric risk is **less than 140 cm**. Women below this height are considered at higher risk for poor fetal growth and delivery complications due to smaller pelvic size and reduced uterine space. This threshold is based on clinical guidelines and population studies showing that shorter stature correlates with smaller birth canals and lower delivery success rates.

**Why Each Wrong Option is Incorrect**
Option B: 145 cm – This is above the standard threshold and does not indicate increased risk in primigravidae.
Option C: 150 cm – This is well above the threshold and considered normal, with no significant obstetric risk.
Option D: 135 cm – While below 140 cm, it is not the standard cutoff; the official threshold used in clinical practice is 140 cm, not 135 cm.

**Clinical Pearl / High-Yield Fact**
Always assess maternal height in first-time pregnancies—height <140 cm increases risk of fetal growth restriction and difficult deliveries. This is a key screening criterion for obstetric risk assessment in primigravidae.

✓ Correct Answer: A. 140 cm