Final answer:
The primary estrogen is estradiol during regular menstruation, estriol is dominant during pregnancy, and estrone is the main estrogen during menopause. These estrogens play vital roles in the body's reproductive functions and the transition through menopause. correct answer is -regular menstruation .
Step-by-step explanation:
The primary form of estrogen during regular menstruation is estradiol. During pregnancy, the primary estrogen is estriol, and during menopause, the form largely found is estrone.
Estrogens are critical for various reproductive functions in women, with different forms being predominant during various life stages. During regular menstruation, the ovaries mainly produce estradiol, which assists in endometrial regrowth and regulation of the menstrual cycle. During pregnancy, the placenta takes over estrogen production, with estriol being the main form to support the pregnancy and prepare the body for childbirth. When a woman reaches menopause, ovarian estrogen production decreases significantly, and the primary estrogen is estrone, which is formed in the body's peripheral tissues. Estrone becomes the leading form of estrogen because it can be produced without direct ovarian function. This change in hormone balance can contribute to various menopausal symptoms such as hot flashes, night sweats, mood swings, and changes in hair distribution. It's worth mentioning that the drop in progesterone levels during menopause can also lead to conditions like uterine fibroids, irregular bleeding, and an increased risk of developing endometrial cancer. Therefore, understanding these hormonal changes is crucial for managing health before, during, and after the transition into menopause.