**Core Concept**
Elevated serum prolactin levels in a pregnant woman can be a normal physiological adaptation to pregnancy, with levels often peaking at around 50-150 ng/mL due to the stimulation of prolactin secretion by human chorionic gonadotropin (hCG).

**Why the Correct Answer is Right**
The patient is pregnant, and the elevated prolactin level is likely a physiological response to the hCG produced by the placenta. This is a common phenomenon during pregnancy, and routine obstetric care is the appropriate management. The elevated prolactin level does not indicate a pathological process, such as a prolactinoma, which would require further investigation.

**Why Each Wrong Option is Incorrect**
**Option B:** A CT scan of the sella turcica is not indicated in this case, as the elevated prolactin level is likely due to physiological adaptation to pregnancy, not a pituitary adenoma.
**Option C:** Repeat measurements of serum prolactin are not necessary, as the elevated level is likely a normal physiological response to pregnancy.
**Option D:** Bromocriptine, a dopamine agonist, is used to treat hyperprolactinemia due to a prolactinoma, but it is not indicated in this case where the elevated prolactin level is likely due to physiological adaptation to pregnancy.

**Clinical Pearl / High-Yield Fact**
Physiological hyperprolactinemia during pregnancy is a common phenomenon, and routine obstetric care is the appropriate management. This is an important distinction to make, as elevated prolactin levels in a non-pregnant woman may indicate a pathological process, such as a prolactinoma.

**✓ Correct Answer: A. Routine obstetric care**