**Core Concept**
Post-term pregnancy refers to a gestation period that extends beyond 42 weeks. This condition is associated with various risks to the mother and the fetus, including increased likelihood of certain complications. The risks in post-term pregnancy are primarily related to the decreased amniotic fluid volume and the increased placental resistance.

**Why the Correct Answer is Right**
The correct answer is related to the decreased risks associated with post-term pregnancy. Typically, post-term pregnancies are associated with an increased risk of stillbirth, meconium aspiration syndrome, and cord prolapse. However, one of the exceptions is the risk of **hydramnios** (excessive amniotic fluid). Post-term pregnancies are more commonly associated with **oligohydramnios** (decreased amniotic fluid volume).

**Why Each Wrong Option is Incorrect**
* **Option A:** Stillbirth is a well-known risk in post-term pregnancies. The risk of stillbirth increases significantly after 42 weeks of gestation due to placental insufficiency and decreased fetal movement.
* **Option B:** Meconium aspiration syndrome is also a risk in post-term pregnancies. The increased intrauterine pressure and decreased fetal movement can cause the fetus to pass meconium into the amniotic fluid, which can then be aspirated by the fetus during delivery.
* **Option C:** Cord prolapse is another risk in post-term pregnancies. The decreased amniotic fluid volume can cause the umbilical cord to prolapse into the birth canal, which can lead to fetal compromise.

**Clinical Pearl / High-Yield Fact**
It is essential to recognize the risks associated with post-term pregnancy and to monitor patients closely for signs of fetal compromise. Regular ultrasound assessments and fetal monitoring can help identify potential complications early, allowing for timely intervention.

**Correct Answer:** D.