**Core Concept**
Pregnancy can lead to changes in the growth rate of certain CNS tumors due to hormonal fluctuations, particularly estrogen and progesterone. This is a critical consideration for managing CNS tumors in pregnant women.

**Why the Correct Answer is Right**
Pinealomas, specifically germinomas, are known to show increased growth during pregnancy. This is attributed to the high levels of estrogen and progesterone, which stimulate the growth of these tumors. Germinomas are a type of germ cell tumor that originate in the pineal gland or the suprasellar region. They are highly sensitive to sex hormones, leading to accelerated growth during pregnancy.

**Why Each Wrong Option is Incorrect**
**Option A:** Meningiomas are a type of brain tumor that are often associated with pregnancy. However, they do not typically show increased growth during pregnancy. Instead, they may stabilize or even regress due to hormonal changes.

**Option B:** Glioblastomas are aggressive brain tumors that are not typically influenced by pregnancy. Their growth rate is more closely related to genetic mutations and tumor biology rather than hormonal fluctuations.

**Option C:** Craniopharyngiomas are benign brain tumors that occur near the pituitary gland. While they can cause problems during pregnancy, their growth rate is not typically increased by hormonal changes.

**Clinical Pearl / High-Yield Fact**
It's essential for clinicians to be aware of the potential effects of pregnancy on CNS tumor growth, as this can impact management decisions and patient outcomes.

**Correct Answer: D. Germinomas.