**Core Concept**
Recurrent abortion, also known as recurrent miscarriage or habitual abortion, refers to the loss of three or more consecutive pregnancies before 20 weeks of gestation. The underlying causes can be **anatomical**, **hormonal**, **immune**, or **genetic**.

**Why the Correct Answer is Right**
Since the correct answer is not specified, let's discuss the common causes of recurrent abortion, which include **uterine anomalies**, **hormonal imbalances** (such as luteal phase defect), **immune disorders** (like antiphospholipid syndrome), and **genetic factors** (including parental chromosomal abnormalities).

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option, it's challenging to provide a detailed explanation. However, common incorrect options might include factors that are not directly related to recurrent abortion, such as **infections** or **lifestyle factors**, which can cause individual miscarriages but are not typically associated with recurrent losses.
**Option B:** Similarly, without the specific option, it's difficult to provide a detailed explanation. However, factors like **advanced maternal age** can increase the risk of miscarriage but are not a direct cause of recurrent abortion.
**Option C:** Again, without the specific option, it's challenging to provide a detailed explanation. However, factors like **previous history of trauma** might be included, which is not a direct cause of recurrent abortion.
**Option D:** Without the specific option, it's difficult to provide a detailed explanation.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **antiphospholipid syndrome** is a well-established cause of recurrent abortion, and testing for this condition is often part of the evaluation for recurrent pregnancy loss.

**Correct Answer:** D. Hyperthyroidism