## **Core Concept**
The use of combined oral contraceptives (COCs) postpartum is influenced by the need to balance contraceptive efficacy with the risks of estrogen exposure, particularly thromboembolic events. For non-breastfeeding mothers, the primary concern is the risk of pregnancy and the timing of initiation of COCs in relation to postpartum physiological changes.

## **Why the Correct Answer is Right**
The correct answer, **C. 3 weeks**, reflects the general recommendation that for non-breastfeeding mothers, combined oral contraceptives can typically be started about 3 weeks postpartum. This timing allows for the reduction of postpartum hemorrhage risk and does not significantly interfere with the normal physiological changes that occur after delivery. Starting COCs too early could potentially interfere with the natural coagulation changes that occur postpartum, but by 3 weeks, the risk of thromboembolic events starts to decrease, making it safer to initiate COCs.

## **Why Each Wrong Option is Incorrect**
- **Option A: Immediately** - Starting COCs immediately postpartum might increase the risk of thromboembolic events due to the already heightened state of coagulation in the postpartum period.
- **Option B: 1 week** - This might still be too early for initiating COCs due to ongoing physiological changes and potential increased risk of venous thromboembolism.
- **Option D: 6 weeks** - While some guidelines suggest waiting until after the 6-week postpartum check-up, for non-breastfeeding mothers, starting at 3 weeks is often considered safe and effective in preventing pregnancy.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the initiation of COCs postpartum should be balanced against the risks and benefits for each individual, including the risk of pregnancy and thromboembolic events. For breastfeeding mothers, the concern is also about the potential effects of estrogen on milk supply and infant exposure, typically recommending progestin-only contraceptives earlier.

## **Correct Answer: C. 3 weeks.**