If a yeast infection goes untreated during pregnancy, it can potentially lead to complications. The infection may persist or worsen, causing more severe symptoms, such as intense itching, redness, swelling, and discomfort. There is also a risk of passing the infection to the baby during delivery, which can result in oral thrush or a diaper rash. It is important to seek medical attention and follow the recommended treatment if a yeast infection is suspected during pregnancy.