<P> Embryonic age: 18 weeks old . </P> <Ul> <Li> The fetus reaches a length of 20 cm (8 inches). </Li> <Li> Lanugo covers the entire body . </Li> <Li> Eyebrows and eyelashes appear . </Li> <Li> Nails appear on fingers and toes . </Li> <Li> The fetus is more active with increased muscle development . </Li> <Li> "Quickening" usually occurs (the mother and others can feel the fetus moving). </Li> <Li> The fetal heartbeat can be heard with a stethoscope . </Li> </Ul> <Li> The fetus reaches a length of 20 cm (8 inches). </Li> <Li> Lanugo covers the entire body . </Li>

When does the fetal stage begin and end