The normal cycling of estrogen that occurs in a fertile female involves an increase in estrogen level before the release of an egg cell from the ovary.

Ovulation occurs around the 14th day of a typical 28-day menstrual cycle.

After ovulation, estrogen levels decrease back to a basal level and then slowly increase again in a continuous cycle until they peak before ovulation.

When a woman takes the birth control pill, this cycling of estrogen is prevented. Instead, her body is exposed to one continuous low dose of estrogen. Low estrogen levels can lead to increased risk of osteoporosis.

This risk might lead you to the following:

Taking the birth control pill leads to increased risk of osteoporosis.

Questions

1. Assume the ovaries of a fertile woman produce a total of 49 mg of estrogen every cycle. Assume that the basal level of estrogen produced is 1 mg/day except during the increase, plateau, and decrease that occur on days 11, 12, and 13, respectively. How many days during a 28-day cycle is a woman producing a basal level of estrogen?
2. What is the total combined mg amount of estrogen that a woman produces during all the days she is producing estrogen at the basal level?
3. How much estrogen must she produce in the 3 days before ovulation (days 11, 12, and 13)?
4. Pharmaceutical companies design birth control pills that mimic the bone-protecting effects of the normal female menstrual cycle. Even though most birth control packs have placebo pills that contain no estrogen and allow for natural menstruation, assuming that a woman takes the birth control pill every day of the month, how many mg of estrogen should be found in each pill?
5. Consider your answers to questions 1–4 and explain why the original statement bolded above sounds right, but isn’t.