It is generally safe to have sex at 4 weeks into pregnancy, but it's important to consult with your healthcare provider first. In most cases, as long as there are no complications or high-risk factors involved, sexual activity can be enjoyed without harm to the baby. However, every pregnancy is unique, so it's crucial to get personalized advice from your doctor.
As for the best positions during intercourse, many women find that being on top allows them more control and reduces pressure on their abdomen. Side-by-side positions can also be comfortable and provide intimacy while minimizing discomfort. Ultimately, communication with your partner and listening to your body's comfort levels are key in finding the best position for you during this stage of pregnancy.