Recurrent abortion in 1st trimester, investigation of choice:
**Core Concept**
Recurrent abortion in the first trimester can be caused by various factors, including anatomical, hormonal, and immunological abnormalities. The investigation of choice should aim to identify the underlying cause of recurrent pregnancy loss.
**Why the Correct Answer is Right**
The investigation of choice for recurrent abortion in the first trimester is **karyotyping and chromosomal analysis**. This is because chromosomal abnormalities are a common cause of recurrent pregnancy loss, particularly in women under the age of 35. The most common chromosomal abnormalities associated with recurrent pregnancy loss are **aneuploidy** (e.g., triploidy, trisomy 16) and **balanced translocations**. Karyotyping involves examining the chromosomes of both partners to identify any abnormalities that may be contributing to the recurrent pregnancy loss.
**Why Each Wrong Option is Incorrect**
* **Option A:** Hysterosalpingography (HSG) is an imaging test used to evaluate the shape of the uterine cavity and the patency of the fallopian tubes. While HSG may be useful in evaluating uterine anomalies, it is not the investigation of choice for recurrent abortion in the first trimester.
* **Option B:** Endometrial biopsy is used to evaluate the endometrium for abnormalities such as atrophy, hyperplasia, or cancer. However, endometrial biopsy is not typically used to investigate recurrent abortion in the first trimester.
* **Option C:** This option is missing.
**Clinical Pearl / High-Yield Fact**
Chromosomal abnormalities are a common cause of recurrent pregnancy loss, particularly in women under the age of 35. Couples experiencing recurrent pregnancy loss should undergo karyotyping and chromosomal analysis to identify any underlying chromosomal abnormalities.
**Correct Answer: C. Karyotyping and chromosomal analysis.**