## Core Concept
The Hysterosalpingogram (HSG) 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 material through the cervix, which then flows into the uterus and fallopian tubes, allowing for their visualization on X-ray. Given its invasive nature and the use of radiation and contrast, certain conditions are considered contraindications.

## Why the Correct Answer is Right
Option is the correct answer because pregnancy is a relative contraindication rather than an absolute one. HSG is generally avoided in pregnancy due to the exposure to radiation and the potential risk to the fetus. However, in certain situations, it might be considered if the benefits outweigh the risks. On the other hand, active pelvic infection, suspected or confirmed pregnancy (in some contexts), and severe iodine allergy are typically considered absolute or strong contraindications.

## Why Each Wrong Option is Incorrect
- **Option A:** Active pelvic infection is an absolute contraindication because introducing a foreign substance into the uterus in the setting of an active infection could exacerbate the infection and lead to serious complications such as sepsis.
- **Option B:** Suspected or confirmed pregnancy is often listed as an absolute contraindication due to the risks associated with radiation exposure to the fetus.
- **Option D:** Severe iodine allergy is an absolute contraindication because the contrast material used in HSG contains iodine, and administering it to someone with a severe allergy could result in an anaphylactic reaction.

## Clinical Pearl / High-Yield Fact
A key point to remember is that while pregnancy is often cited as a contraindication, it's more nuanced; the critical concern is the potential harm to a developing fetus from radiation. HSG should ideally be performed in the follicular phase of the menstrual cycle to minimize the chance of early pregnancy.

## Correct Answer: C.