Final answer:
McDonald's sign during pregnancy is characterized by the enlargement and softening of the cervix. It is one of the many changes occurring in a woman's body, including weight gain, the sensation of fetal movements, and skin changes.
Step-by-step explanation:
A probable sign of pregnancy, McDonald's sign is characterized by enlargement and softening of the cervix. This physical change is among the various physiological and anatomical adaptations that a woman's body undergoes during pregnancy. Pregnancy weight gain primarily occurs in the breasts and abdominal region. As the pregnancy progresses, especially during the second and third trimesters, the uterus expands rapidly contributing to increased abdominal size. The mammary glands also prepare for breastfeeding influenced by elevated hormone levels including prolactin.
Common signs of advancing pregnancy include the sensation of fetal movements felt by the mother, typically starting between weeks 16-20, known as quickening. The skin may show changes such as stretch marks and increased melanin production leading to areas of darkening, including the areolas. Maternal blood volume also increases significantly to accommodate the growing fetal demands.