At 31 weeks pregnant, you are approximately seven months and one week pregnant. Pregnancy is typically measured in weeks rather than months, as months have varying lengths. The standard calculation is that pregnancy lasts about 40 weeks, or roughly nine months. At this stage, your baby is continuing to grow and develop, and you may be experiencing symptoms such as fatigue, back pain, and frequent urination. Consult with your doctor for personalized advice and care during your pregnancy.