**Blighted Ovary: An Explainer**

**Core Concept**
A blighted ovum, also known as an anembryonic pregnancy, is a type of early pregnancy loss characterized by the absence of fetal development within a gestational sac. This condition occurs when the fertilized egg fails to implant or develop properly, leading to a non-viable pregnancy.

**Why the Correct Answer is Right**
The correct answer is not provided, but we can discuss the condition. A blighted ovum is typically diagnosed during the first trimester of pregnancy, often between 6-10 weeks, through ultrasound examination. In this condition, the gestational sac appears empty or contains a non-viable embryo, whereas the embryo itself is absent. The exact cause of a blighted ovum is often unknown, but it may be related to chromosomal abnormalities in the embryo, hormonal imbalances, or uterine abnormalities.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a blighted ovum is not a type of ectopic pregnancy, which occurs when the embryo implants outside the uterus.

**Option B:** This option is incorrect because a molar pregnancy is a type of abnormal gestation characterized by an overgrowth of trophoblastic tissue, whereas a blighted ovum lacks fetal development.

**Option C:** This option is incorrect because a blighted ovum is not characterized by an abnormal fetal position or presentation.

**Clinical Pearl / High-Yield Fact**
A blighted ovum is a type of early pregnancy loss that often presents with nonspecific symptoms such as abdominal pain, vaginal bleeding, or a missed period. Ultrasound examination is essential for diagnosing this condition, and it is crucial to rule out other causes of early pregnancy loss, such as ectopic pregnancy or miscarriage.

**Correct Answer:** A. Blighted ovum