2 - Female Reproductive Physiology (Luteal Phase, Oral Contraceptives, Pregnancy)

What happens to the follicle after ovulation?

ruptured follicle becomes corpus luteum, primarily producing progesterone

What happens to the endometrium in luteal phase?

• becomes secretory and implantation-ready

• glands become tortuous & begin storing glycogen

• stroma (connective tissue) becomes edematous

• spiral arteries become more coiled

What happens to the cervical mucus in luteal phase?

thickens, less abundant

• tenacious, nonelastic, makes sperm passage less favorable

• protects potential pregnancy

What happens to basal body temperature in luteal phase?

rises after ovulation

• due to progesterone

• retrospective clue that ovulation has occurred

What happens to the FSH & LH in luteal phase?

remain suppressed

What follows if pregnancy does not occur?

• copus luteum begins to regress, has a lifespan of 10-14 days

• estradiol & progesterone fall abruptly

• menses follows

• follicles for next cycle are being recruited

Define menses

loss of hormonal support promotes prostaglandin production → causes uterine contraction and spiral artery vasospasm → superficial endometrium becomes ischemic and breaks down

What is the effect of estrogen on endometrium?

proliferation - builds the lining; promotes mitosis & cell division

What is the effect of estrogen on the cervix?

thins & alkalinizes mucus, favors sperm passage

What is the effect of progesterone on endometrium?

differentiation - converts to secretory; opposes estrogen; stabilizes and matures tissue

What is the effect of progesterone on the cervix?

thickens mucus, blocks sperm passage

How do oral contraceptives work?

• suppressing FSH & LH prevents ovulation

• progestins thicken cervical mucus, blocking sperm passage

• endometrial changes reduce receptivity

What follows ovulation if fertilization does occur?

• embryo attaches to and begins to embed in the lining

• maternal endometrial tissue changes to support implantation = decidualization

What hormone is released by early embryos?

human chorionic gonadotropin (hCG) this is what is detected by pregnancy tests

What is the effect of hCG?

acts like LH on the corpeus luteum, keeping it alive instead of regressing

What happens to progesterone & estrogen in pregnancy?

stay elevated

Early pregnancy depends on what for hormone support?

corpus luteum

How does hormone source of the embryo change as pregnancy continues?

placenta becomes the main hormone source & progesterone & estrogen continue to rise

• this suppresses new follicle development & ovulation

• supports uterus & breast