This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
A 32-year-old G3P20L2 presents to the obstetrician's office for a routine OB visit at 30 weeks. She has had no complications during the pregnancy and has had regular prenatal care. Her gestational age is confirmed with a first-trimester sonogram. During the routine OB visit, the fundal height measures 35 cm. All of the following can explain the size-date discrepancy except 
Select and explain. 
A. The 5-cm difference is within the error for fundal height measurements, B. Leiomyomas, C. Polyhydramnios, D. Fetal macrosomia
A: The 5-cm difference is within the error for fundal height measurements
Answer: A: The 5-cm difference is within the error for fundal height measurements 
Explanation: (Gabbe, 2/e, p 230.) Uterine fibroids, polyhydram- nios (excessive amniotic fluid), fetal macrosomia, and twin gestation are all plausible explanations of why the uterine size would measure larger than expected for the patient's dates. It is unlikely, but possible, that a twin gestation would have been missed with an early sonogram. The fundal height in centimeters has been found to correlate with gestational age in weeks with an error of 3 cm from 16 to 38 weeks.