The exercise of pregnant women is different from that of ordinary people. Swimming can be said to be the safest and most effective for healthy pregnant women who are pregnant for 4 to 8 months. Swimming is more appropriate than underwater activities. Swimming for pregnant women does not necessarily require pregnant women to swim back and forth in the pool several times according to certain swimming strokes. The main purpose is to help pregnant women support 10 to 13 kg more than before pregnancy with the help of buoyancy of water, and at the same time, the resistance of water can reduce the chance of joint injury that gradually relaxes, making pregnant women safer in fitness. Whether you can swim or not, you'd better be accompanied by your family and fitness instructor. Those who can swim can choose backstroke or float in the water. Those who can't swim can walk, tap water and do aerobic exercise in the water. The advantage of water sports is that it has little burden on the body and it is easy to exercise the muscles of the waist and legs. Swimming can also significantly reduce low back pain during pregnancy, effectively correct abnormal fetal position, and promote the smooth delivery of pregnant women. Exercise bikes are also very suitable for pregnant women to practice. But it is not a spinning bike, but a horizontal fitness bike with good protection for knees, waist and back. The horizontal exercise bike has a backrest at the back and an armrest at the front. The legs do not push down, but push horizontally at 90 degrees with the upper body, which effectively supports the weight of pregnant women and minimizes the pressure on the lower abdomen when riding a bike. Pregnant women must consult a doctor before exercising. Pregnant women who are less than 4 months pregnant or more than 8 months pregnant are not suitable for fitness exercise, and should mainly take a walk.