Being able to see or palpate fetal parts is absolutely normal in term pregnancy specially in women who are thin or have very weak abdominal muscle tone. To promote normal delivery your wife must walk for at least 30 to 40 minutes daily before taking food and if your doctor suggests prenatal exercises, she can also do those. Give her a well balanced diet, rich in vitamins and proteins and restrict her fat and dry fruit intake. Ultrasound is safe in pregnancy and as many as desired by your obstetrician can be undertaken for her.