Final answer:
Positive signs of pregnancy include a noticeable enlargement of the abdomen, weight gain in specific areas like the breasts and abdominal region, increased maternal blood volume, and hormonal changes. Symptoms like nausea, heartburn, and frequent urination also accompany pregnancy, along with possible skin changes such as stretch marks and chloasma.
Step-by-step explanation:
Pregnancy is associated with various positive signs that indicate its presence. The second and third trimesters of pregnancy bring about dramatic anatomical and physiological changes in the maternal body. One of the most notable is the enlargement of the abdominal region, which is accompanied by an overall weight gain encompassing the growth of the fetus, expanded uterus, amniotic fluid, and placenta.
Breast tissue development and a significant rise in blood volume also contribute to this weight increase. However, it is interesting to note that only a small part of this weight gain, approximately 2.3 kg (5 lbs), is attributed to fat storage, which supports the metabolic demands of breastfeeding.
Other common symptoms throughout pregnancy may include nausea, heartburn, and frequent urination. The maternal blood volume increases by 30 percent, and the respiratory minute volume goes up by 50 percent, reflecting the increased demands of the growing fetus. The skin also undergoes changes such as the development of stretch marks and increased melanin production.
A critical aspect of pregnancy monitoring is the presence of hormonal changes that can impact various body systems. The anterior pituitary gland notably enlarges and increases its secretion of essential hormones like thyrotropin and prolactin, vital for adaptation during pregnancy. The anticipation of a positive pregnancy test, which signifies the successful conception after a period of trying, is a moment of joy for many prospective parents.
Nevertheless, pregnancy can also present with challenges such as changes in skin condition, including the possible appearance of chloasma, referred to as the "mask of pregnancy."