OB HESI Study Guide PDF

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OB HESI 

Menstrual Cycle o Length: varies for most women; average = 28 days o Timing of ovulation:  14 days between ovulation + beginning of the next menstrual cycle  Intercourse:  Sperm live ~3 days, egg lives ~24hr  So… do not have unprotected sex several days before anticipated ovulation + for 3 days after ovulation to prevent pregnancy o Objective signs of ovulation  Abundant, thin, clear cervical mucous; open cervical os; slight drop in basal temperature and then 0.5-1 degree rise o Hormones  Hypothalamus  Regulates hormones released by anterior pituitary  Produces GnRH – travels to ant. pituitary via portal blood; cause the cells in anterior pituitary gland to produce FSH + LH = important hormones!  These hormones travel to female ovaries (where eggs are produced) o Ovary: connects to the uterus via the Fallopian Tube  Has blood vessels; the hormones enter through these  Each ovary has many follicles; each month only some will begin to mature  Only ONE will ovulate – produces an egg  Pituitary gland: anterior and posterior o Cycle:  Beginning of menstrual cycle = shedding of uterine wall, period  2 phases – Follicular + Luteal  Follicular (day 0-14): o Increase in GnRH, increase in FSH + then slow drop in FSH; steady level of LH, increase in estrogen  WHY? FSH enters ovaries and stimulates follicle maturation of the primary follicles in the ovaries; some mature into secondary follicles – produce a hormone called ESTROGREN that inhibits LH  FSH is secreted primarily in response to LOW estrogen; when estrogen rises, FSH falls  This is why FSH initially increases but then drops  Estrogen:

1st 10 days: has negative feedback on pituitary gland inhibiting release of LH  Low concentrations of estrogen inhibits LH secretion  Importance: bone + muscle growth, endometrial growth, maintains secondary female characteristics, maintains breasts o After 10 days: estrogen levels continue to rise (as the follicles mature in the ovaries)  Positive feedback now  Stimulates the release of LH  Increase in GnRH + estrogen will stimulate LH secretion – big spike in LH! o Massive LH influx = triggers ovulation of the most mature follicle in the ovary  Ovulation of the follicle will release the oocyte (female egg) Luteal (day 14-28): o After ovulation LH drops back down, GnRH decreases, FSH goes back down (had a small spike d/t LH increase)  After the follicle ovulates, it turns into a corpus luteum (dead follicle)  Slowly degrades, but has a purpose! – secretes estrogen, inhibin, and progesterone o Inhibin: neg feedback; inhibits FSH (do NOT need any more follicles stimulated in luteal phase) o Progesterone: negative effect on hypothalamus; inhibits GnRH; stimulates endometrial growth (what sheds or where the egg implants in a pregnancy) o Estrogen also drops slightly o Inhibin (not present in follicular phase) – increases o Progesterone (low during ovulation) – increases o 21 days: inhibin + progesterone increase, estrogen still detectable o Corpus luteum degenerates, allowing a new set of follicles to mature – estrogen, inhibin, progesterone all decrease  This means progesterone cannot inhibit GnRH release… so a new menstrual cycle can occur! 

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Also… the decrease in progesterone and estrogen means that these hormones cannot maintain the endometrial lining in the uterus  the lining shed AKA you get your period, cycle continues!

Pregnancy o Signs of pregnancy  Missed period o Implantation spotting: bc some women experience this, they do not know they are pregnant (assume it is their period)  Nausea or morning sickness (AKA gravidarum)  Swollen/tender breasts  Fatigue/tiredness  Food cravings or aversions o High risk pregnancy  Less than 17 yo, older than 34yo  140, 3 hr test is done (fasting for this) o NO Coumadin during pregnancy; Heparin = drug of choice o Preeclampsia  High BP, proteinuria = key features; also edema + water retention  Goal: maintain uteroplacental perfusion + prevent seizure; Mag sulfate  Postpartum: delivery is “cure” but can still convulse up to 48 hrs post delivery o Mag sulfate:  Antidote = calcium gluconate  Signs of Toxicity = RR...