Lecture 16: Pregnancy Hormones and Birth Control (copy)

What is conception defined as?

either fertilization or implantation

Where does fertilization often occur?

the oviduct

What is the structure that forms after 3-4 days after fertilization?

the blastocyst

How many days does implantation take?

7-10 days

During implantation, what do embryo synctiotrophoblast cells do?

invade the uterine wall

During implantation, what do the uterine stromal cells do?

forms a cup over the blastocyst (which is called a decidua)

True or False: After implantation, the embryo is now in contact with componentstrue in maternal circulation.

true

Implantation occurs at peak of what?

peak of progesterone release from the ovary

True or False: The uterus must have been exposed to just the right amount of estrogen and progesterone for implantation to occur.

true

What does corpus luteum do?

secretes high amounts of progesterone and low levels of estrogen during the first trimester

What does CL maintain and inhibit?

• maintains pregnancy

• inhibits ovulation

What secretes human chorionic gonadotropin (hCG)? What does this do?

syncytiotrophoblasts secrete hCG to maintain CL until the placenta is functional

When does the placenta secrete estrogen and progesterone?

starting around 5 weeks

True or False: The structures of LH and hCG are similar.

true

What happens when hCG binds to LH receptors on the corpus luteum? What is this phenomenon called?

• to extend the functional life span of the corpus luteum

• maternal recognition of pregnancy

What is the LH receptors?

LHR or LHCGR

When is hCG detectable?

as early as 7-8 days after fertilization

How accurate is the hCG pregnancy test?

a positive test by the time of the next expected menstruation is 98% correct

What is the role of estrogen during pregnancy?

• promotes growth and vascular development of endometrium and other portions of the reproductive tract

• promotes development of mammary glands

What is the role of progesterone during pregnancy?

• promote development of endometrium

• inhibit highly coordinated uterine contractility (helping prevent premature birth)

• promotes development of mammary glands

What does hPL stand for?

human placental lactogen from the placenta

True or False: Prolactin from the maternal anterior pituitary increases as well.

true

Which hormone maintains pregnancy?

progesterone

Which hormone enhances myometrial excitability?

estrogens

Which hormone increases before labor?

prostaglandins

Does placental prolactin increase or decrease?

increase

What causes uterine contractions and thus facilitates labor?

oxytocin

Which hormone increases and leads to collagen degradation?

relaxin

What is the function of glucocorticoids in pregnancy?

is the integrator of fetal organ development

Which hormones are involved in the fetal adrenal cortex?

CRH-ACTH-glucocorticoids

What is the function of birth control?

• inhibit ovulation

• make cervical mucous thick

What are the types of hormonal birth control?

• IUD

• minipill (only contains progestin)

• the pill (contains estrogen and progestin)

• arm implants

• depo-provera shot

• emergency contraception like Plan-B control

What are the types of non-hormonal birth control?

• condoms

• internal condoms

• diaphragm

• cervical cap

• birth control sponge

What is Plan B?

levonoregstrel

When is Plan B most effective up to?

3 days

What does Plan B do?

• blocks ovulation

• prevents fertilization

• may impair receptivity

What is ella made of?

ulipristal acetate

What is ella?

a selective progesterone receptive modulator

What does ella do?

inhibits or delays folliculogenesis (blocking ovulation) and steroidogenesis

When is ella most effective up to?

5 days

True or False: Emergency contraception cannot interrupt an established pregnancy.

true