## **Core Concept**
HSG (hysterosalpingography) is a radiologic procedure to investigate the shape of the uterine cavity and the shape and patency of the fallopian tubes. It involves the injection of a contrast agent into the uterus, which then leaks out through the fallopian tubes if they are patent. The procedure is typically performed to evaluate infertility, recurrent miscarriages, and suspected tubal occlusion.

## **Why the Correct Answer is Right**
The ideal time for performing HSG is between day 7 and day 10 of a regular menstrual cycle. This timing is chosen to avoid interfering with a potential early pregnancy and to minimize the risk of disrupting an early conception. Performing HSG during the follicular phase also provides a clearer image due to the relatively thin endometrium.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option suggests a period that might be too early or too late in the cycle for optimal HSG performance, potentially interfering with an early pregnancy or being performed during a less ideal phase of the menstrual cycle.
- **Option B:** Similar to option A, this timing might not be optimal for HSG as it could still pose risks to an early pregnancy or not provide the best conditions for tubal assessment.
- **Option D:** This timing might be too close to ovulation or too late in the cycle, potentially increasing the risk of performing the procedure during an early pregnancy or encountering a thicker endometrium.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that HSG should be performed after a negative pregnancy test and before ovulation in a regular menstrual cycle, ideally between days 7-10. This timing helps ensure that the patient is not pregnant and minimizes potential disruptions to a menstrual cycle or early pregnancy.

## **Correct Answer:** . Between days 7-10 of menstrual cycle.