Physiology of Pregnancy Flashcards
Human Placental Lactogen (hPL)
• Composition
• How do levels change throughout pregnancy?
• Function?
Composition:
• hPL is a PEPTIDE hormone without any carbohydrate component
Change in levels:
• Levels increase steadily throughout pregnancy
Function:
• hPL increases blood glucose (increased Gluconeogenesis, decreased glucose uptake)
• hPL increases lipolysis
Human Placental Lactogen (hPL)
•Is it needed to maintain pregnancy?
• Why might this cause Ketones in the urine?
• Consequences of XS hPL on the fetus?
NOT Needed to maintain pregnancy
- Ketone are typically seen in the urine of women in L and D because of increased lipolysis (anti-insulin action) of hPL
- Exposure of the fetus to hyperglycemic condition can lead to hyperinsulinemia (causing post-partum hypoglycemia) and macrosomia (from xs nutrients and insulin (anabolic))
What cells are responsible for the release of hCG?
Syncytiotrophoblasts
What are the 3 (maybe 4) primary functions of hCG?
- Prolongs the life of the corpus luteum
- Increases steroid production
- Diagnostic test for pregnancy
- May help depress mom’s immune system
What are the 2 main mediators secreted from the placenta?
• what are their functions?
- Estrogen - stimulates the endometrium and controls uterine blood flow
- Progesterone - affects tubal mobility, endometrial maturation, blood flow, relaxes muscle, INHIBITS LYMPHOCYTE MEDIATED rejection
When do hCG levels max out during pregnancy?
• how high to they get?
Max out at ~ 8 wks
They get up to around 100,000. Much higher than this and you should consider hydatidiform mole or choriocarcinoma
What is Hegar’s sign?
• when does it occur?
• what causes it?
Lower Uterine Segment Softening
• occurs around wk 6
Cause:
• Increased Volume in veins without a significant increase in plasma proteins (decreased intrvascular oncotic pressure) as well has increased hydrostatic pressure from the fetus pressing on the intraabdominal veins
What is Chadwick’s sign?
• when does it occur?
• what causes it?
Bluish Discoloration
• occurs wk 6-8
Cause:
Increased Vascularity
What is Goodell’s sign?
• when does it occur?
Cervical Softening
• Occurs at week 8
What histological changes do we see in the cervix during pregnancy?
Replacement of squamous epithelium with columnar epithelium
At how many weeks should the uterus be roughly the size of a baseball?
• Softball?
8 wks - baseball
10 wks - softball
At how many weeks of pregnancy does the uterus go from being a pelvic organ to an intraabdominal organ?
• when does it get to the umbilicus?
12 wks - crosses pelvic brim
20 wks - Fetus should be to umbilicus
When will be fetus be just below the xiphoid?
36 wks
During what week of pregnancy are aldosterone levels at their highest?
34 wks
What happens to PTH levels in pregnancy?
• Total and free ionized Calcium levels?
PTH increases
Total calcium decreases but FREE CALCIUM IS THE SAME
T or F: in addition to multiple hydatidiform moles, choriocarcinomas, and erythroblastosis, multiple gestations can also cause increases in hCG.
True, more fetus => more placenta => more hCG
What happens to maternal thyroid function in pregnancy?
TSH levels may decrease early in pregnancy due to suppression by hCG
TSH levels them rise to normal with an ENLARGED thyroid that is needed because there is more TBG
BMR increases but free T3 and T4 are NORMAL
(free T4 actually falls late in pregnancy, don’t know why)
What is the normal amount of weight gained during pregnancy?
24 lbs (1st - 2, 2nd - 11, 3rd - 11)
What factors increase a pregnant woman’s susceptibility to UTIs?
- Increased Renal BF => Increased GFR => increased glycosuria
- Ureters dilated from increased pressure at the pelvic brim => decreased tone and peristalisis
combine these two and you get stasis + glucose in urine => way more likely to get UTI
What volumes and capacities decrease in pregnancy?
• which increase?
• Which do not change?
Decrease:
Reduced RV => Reduced TLV => Reduced FRC (expiratory reserve vol.)
Increased:
Tidal Volume
Unchanged:
IRV - inspiratory reserve volume, Vital Capacity
Basically you just exhale more with each breath and you have less RV
What is the compensation in pregnancy that leads to increased TV and respiratory alkalosis?
- Widening of subcostal angle
- Increased Diphragmatic Excursion (pushes more air out)
- Tidal volume increased
- Minute ventilation increased
- pO2 increasd pCO2 decreased
- Respiratory alkalosis
What do you get a widely split S1 with S3 + soft mid-systolic flow murmur in pregnancy?
More anemia during pregnancy (caused by increase in blood volume that is not compensated completely by increase in RBCs)
What changes do we wee in cardiac output with pregnancy?
Increased SV + NL or inc HR => higher CO (peaks at 30-32 wks)
Increased SV with Decreased TPR => lower BP
Explain what causes increased RBCs in pregnancy?
increase hPL => increaed EPO => increased erythroid hyperplasia => increased reticulocytes
Although this compensation is effective, its not good enough to overcome the 45% increase in plasma volume in pregnancy
