Yellow discharge with a sweet smell during pregnancy can be caused by various factors. One possibility is an increase in vaginal discharge, which is common during pregnancy due to hormonal changes. As long as the discharge is not accompanied by itching, burning, or any other discomfort, it is usually considered normal. However, if you experience any of these symptoms or are concerned about the odor or color of the discharge, it's best to consult your healthcare provider for a proper evaluation. They can determine if there is an infection present or if further investigation is needed. It's always better to err on the side of caution when it comes to your health and the health of your baby.