Chadwick's sign during pregnancy is primarily influenced by which hormone?

• A. Progesterone
• B. Estrogen
• C. Prolactin
• D. Oxytocin

Answer: (B)

Chadwick's sign is the bluish discoloration of the cervix, vagina, and labia, which is an early indicator of pregnancy. This sign occurs due to increased blood flow and vascular engorgement in the pelvic region, a physiological change driven largely by the influence of estrogen. During pregnancy, estrogen levels rise significantly, leading to enhanced blood circulation and the engorgement of blood vessels, which results in the bluish tint associated with Chadwick's sign.

Other hormones play important roles during pregnancy but do not specifically cause this vascular change. Progesterone primarily supports the maintenance of pregnancy and prepares the endometrium for implantation, while prolactin is mainly involved in breast development and milk production. Oxytocin plays a crucial role during labor and breastfeeding but is not involved in producing Chadwick's sign. Understanding the role of estrogen in promoting correct blood flow and vascular changes helps clarify why it is the primary hormone associated with this sign in pregnancy.