Final answer:
Fetal movement, typically felt as quickening, is first noticed by women during weeks 16-20 of pregnancy, in the second trimester.
Step-by-step explanation:
Women first feel fetal movement, commonly known as quickening, during approximately weeks 16-20 of pregnancy. This occurs in the second trimester, a time when the fetus grows and limb movements become stronger, although space restrictions within the uterus limit these movements. The term quickening describes the initial moments when a pregnant individual becomes aware of the fetus moving inside the womb. These initial movements might feel like flutters or gentle swishes and increase in intensity and frequency as the fetus develops.