**Core Concept**
Listeriosis is a zoonotic infection caused by Listeria monocytogenes, which can be transmitted to humans through contaminated food, particularly unpasteurized dairy products and undercooked poultry. This infection poses a significant risk to pregnant women, especially during the third trimester and early postpartum period, due to its potential to cause fetal harm.

**Why the Correct Answer is Right**
Listeriosis in pregnancy is associated with a higher risk of preterm labor, fetal demise, and neonatal sepsis. The pathogenesis of listeriosis involves the bacterium's ability to invade the placenta, leading to an inflammatory response and subsequent fetal injury. The clinical presentation of listeriosis in pregnancy is often nonspecific, making it essential for healthcare providers to maintain a high index of suspicion, particularly in women with a history of consuming high-risk foods.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately reflect the current understanding of listeriosis in pregnancy. The risk of transmission is not solely dependent on the severity of the maternal infection.
**Option B:** This option is incorrect as it oversimplifies the pathogenesis of listeriosis in pregnancy. The bacterium's ability to invade the placenta is a critical factor in fetal injury.
**Option C:** This option is incorrect as it does not acknowledge the significant risk of listeriosis in pregnancy, particularly during the third trimester and early postpartum period.

**Clinical Pearl / High-Yield Fact**
The Centers for Disease Control and Prevention (CDC) recommend that pregnant women avoid consuming high-risk foods, such as unpasteurized dairy products, undercooked poultry, and raw sprouts, to minimize the risk of listeriosis.

**Correct Answer:** D