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first time Mums often don't feel the baby move until around 20 weeks, second time around you are more 'tuned in' and feel it earlier. However the baby has plenty of room to move and as you can only feel it if it touches the front of the uterus (just under the skin where the nerve endings are) you will not feel much especially if the placenta is at the front as well.
Spotting in the second trimester needs to be evaluated by your doctor or clinic. The fact that you feel fetal movement is good. Call your doctor!.
I think in the second trimester.
During the 4th month, the first month of the second trimester, the greatest amount of fetal growth occurs.
It is an incision into the uterus done during a cesarean section, open fetal surgery , and some second-trimester abortions
The fetal infection rate is above 60% if maternal infection occurs during the third trimester, but the most severe fetal complications occur with first-trimester infection.
There major phases of antenatal development are commonly divided into three trimesters. The first trimester involves embryogenesis. The second and third trimester involves fetal development. The pregnancy is considered viable from the third trimester onwards.
Phantom fetal movement is perceived movement when there is no fetus in utero, or if the fetus has not actually moved.
Late in the third trimester
I am four months pregnant with my second child, and I feel fetal movement in my abdomen a little to the left of my navel. Once you are farther along with your pregnancy, you should be able to feel movement pretty much anywhere in your stomach area.
Organogenesis occurs within the first trimester of fetal development.