## **Core Concept**
The scenario describes a woman with a history of three consecutive second-trimester abortions. This history suggests a possible issue with cervical insufficiency or a uterine anomaly, but most importantly, it raises the concern for antiphospholipid syndrome (APS) or other thrombophilias, given the recurrent nature of the losses. Investigations should aim to identify a cause for these recurrent losses.

## **Why the Correct Answer is Right**
The correct answer, **. Antiphospholipid antibodies**, is appropriate because the presence of antiphospholipid antibodies is a known cause of recurrent pregnancy loss, particularly in the second trimester. Antiphospholipid syndrome (APS) is characterized by the presence of these antibodies along with a history of recurrent fetal loss, thrombosis, or other clinical manifestations. Testing for antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies, and anti-β2 glycoprotein I antibodies) is crucial in the evaluation of recurrent pregnancy loss.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While ultrasound of the uterus can help identify uterine anomalies that might contribute to pregnancy loss, it does not directly address a potential systemic cause like APS.
- **Option B:** Testing for thyroid function might reveal hypothyroidism, which can contribute to pregnancy loss. However, it is less directly related to second-trimester losses compared to APS.
- **Option C:** A detailed anatomy scan can provide valuable information on fetal anatomy but does not investigate the cause of recurrent pregnancy loss.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that antiphospholipid syndrome (APS) is a significant cause of recurrent pregnancy loss, particularly in the second trimester. Women with a history of recurrent pregnancy loss should be screened for APS, as this condition can be effectively treated with anticoagulation therapy to improve pregnancy outcomes.

## **Correct Answer:** . Antiphospholipid antibodies