Hi,
Welcome to ehealthforum,
Consider going ahead with the scheduled repeat ultrasound scan as recommended by your treating doctor/gynecologist. If the abdominal distension is more compared to the corresponding gestational age, other causes like twin or multiple pregnancy, Hydatidiform mole, larger than normal baby, etc should be ruled out. Further management would be suggested based on examination and evaluation findings. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet.
Take care.