It is generally safe to drink raspberry tea during the third trimester of pregnancy, including at 31 weeks. Raspberry leaf tea is believed to have several potential benefits for pregnant women, including toning the uterus and potentially reducing labor complications. However, it is important to consult with your healthcare provider before adding any new herbal teas or supplements to your diet, especially if you have any pre-existing medical conditions or concerns about potential interactions with other medications you may be taking. Your healthcare provider will be able to provide personalized advice based on your specific situation and medical history. If they give you the green light, you can enjoy raspberry tea in moderation as part of a balanced diet.