Pregnancy Physiology and Complications - Test 1 Flashcards
What are the five main functions of the placenta?
- Hormone production
- Protection from the maternal immune system
- Protection against infection
- Fetal nutrition
- Gas exchange
Which hormones are produced by the placenta?
hCG
Progesterone
Estrogen
Human placental lactogen (hPL)
Which placental hormone triggers hyperventilation in the mom?
Progesterone
Describe the subunits of the hCG glycoprotein and how they are physiologically and clinically relevant.
alpha subunit of hCG is identical to that of LH, FSH (helps to downregulate the HPG axis during pregnancy)
alpha subunit also mimicks TSH –> increased thyroid hormone synthesis in mom (but there is also increased thyroid binding globulin synthesis in the liver so free levels and TSH remain normal in most pregnant ladies)
beta subunit of hCG is specific to hCG
Which hormone triggers the nausea and vomiting common in early pregnancy?
hCG
What are the main physiologic effects of estrogen during pregnancy?
Estrogen causes enlargement of the uterus, breasts, and mammary ducts (its the hormone responsible for breast tenderness during pregnancy)
After fertilization, the corpus luteum is rescued by hCG, which then begins to synthesize _________ (hormone) until the syncitiotrophoblasts take over at ~7-10 weeks gestational age.
progesterone
By what mechanism does mifepristone terminate early pregnancy?
It is a progesterone antagonist; progesterone is necessary to maintain early pregnancy
Describe the physiologic effects of hPL in the fasting state and fed state, respectively.
Fasting state: hPL stimulates pancreatic secretion of insulin -> accelerated starvation w/ hypoglycemia (increased lipolysis helps maintain energy source for mom)
Fed state: hPL causes relative maternal insulin resistance -> higher circulating glucose levels to facilitate transfer to the fetus (worse in women w/ diabetes)
What is the recommended weight gain for a woman of normal BMI with a singleton pregnancy? What about for an obese woman?
Normal BMI: 25-35 pounds
Obese: 11-20 pounds
Name the two hormones that are responsible for loosening the connective tissue of the pelvic floor and vagina.
Relaxin and progesterone
What does the fundal height (in cm) correspond to? At 20 weeks gestation, the fundal height should be at the level of the ________ (anatomic landmark).
Fundal height corresponds to gestational age. At 20 weeks, fundal height should be at the level of the umbilicus.
What happens to aldosterone levels during pregnancy? What are the physiologic consequences of this?
Aldosterone levels increase –> fluid retention
Describe a normal arterial blood gas for a pregnant women.
pH: 7.4 - 7.45
pO2: 100mmHg (same as non-prego)
pCO2: 27 - 32 mmHg (vs. 40 in non-prego)
Bicarb: 18 - 21 mEq/L (vs. 24 in non-prego)
Describe the changes to respiratory rate, minute ventilation, and functional residual capacity that occur during pregnancy.
Why are pregnant women at increased risk of developing pyelonephritis?
Progesterone causes smooth muscle relaxation –> dilation of renal pelves, calyces, ureters –> increased stasis –> pyelonephritis
Would you expect creatinine levels to rise, or fall during pregnancy as compared to when not pregnant?
They should decrease because of increased renal blood flow (and GFR) due to relaxation of renal artery smooth muscle from progesterone.
Creatinine should be 0.7 or less in a pregnant woman.
Describe the normal physiologic effects on the cardiac system that occur during pregnancy.
Progesterone and relaxin dilate smooth muscle –> decreased systemic vascular resistance
Cardiac changes: resting HR increases, stroke volume increases, therefore cardiac output increases
Your pregnant patient comes in for a routine prenatal visit and has a BP of 146/96. She has no Hx of chronic HTN. Is this normal for a pregnant gal?
Not normal, BP should be low during pregnancy due to the smooth muscle effects of progesterone and relaxin. This is concerning for preeclampsia.
When supine, the uterus can pinch the ______, leading to decreased cardiac output and hypotension (this is why pregnant women should not lie on their backs! Left lateral decubitus position is best)
IVC