Engaging in sexual activity during the 11th week and 3rd day of pregnancy is generally considered safe for most women. However, it is important to consult with your healthcare provider to ensure that there are no specific concerns or complications related to your individual pregnancy. In most cases, as long as there are no medical conditions or previous complications, sexual intercourse should not pose a risk to the developing fetus. It is important to communicate openly with your partner about any discomfort or changes you may experience during sex, and if necessary, make adjustments or try different positions that are more comfortable for you. Remember, every pregnancy is unique, so it's always best to consult with your healthcare provider for personalized advice based on your specific circumstances.