A 29-year-old pregnant client at 32 weeks presents to the prenatal clinic for a routine visit. Fundal height measures 4 cm smaller than expected for gestational age. An ultrasound is performed and reveals a fetus with estimated weight below the 10th percentile for gestational age, confirming intrauterine growth restriction (IUGR). Which underlying complication is the most likely cause of the fetal growth restriction (IUGR)?

Rationale: A. HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) can complicate pregnancy but is more commonly associated with preeclampsia and maternal morbidity; it is not the primary cause of IUGR. B. Uteroplacental insufficiency is the most common cause of IUGR, as it results in reduced oxygen and nutrient delivery to the fetus, leading to growth restriction and fetal weight below the 10th percentile. C. Maternal gestational diabetes usually causes macrosomia (large-for-gestational-age infants), not growth restriction. D. Polyhydramnios (excess amniotic fluid) is not a direct cause of IUGR; it may be associated with other fetal anomalies or maternal conditions.