The first movements of the fetus, known as "quickening," and the appearance of hair on its head, occur at different times during gestation. The first movements of the fetus are usually felt by the mother between 18 to 25 weeks of gestation. This can vary from woman to woman and pregnancy to pregnancy. Initially, the movements may feel like flutters or gentle taps, and as the fetus grows, the movements become more pronounced and noticeable. As for the appearance of hair on the fetus's head, it typically occurs around the 14th to 16th week of gestation. This is a developmental milestone when the hair follicles start forming, and fine hair, known as lanugo, begins to grow on the fetus's body, including the scalp. The lanugo hair helps regulate the fetus's body temperature and usually sheds before birth. Therefore, the appearance of hair on the fetus's head is observed earlier in gestation compared to the first movements, which are felt later in the second trimester.