OB Meds

Question 1

Oxytocin MOA

Answer 1

Binds to oxytocin receptors in myometrium,
increasing intracellular Ca and
stimulating uterine contractions

Question 2

Half-Life of Oxytocin?

Answer 2

1-6min

Question 3

MOA Methylergonovine (Methergine)

Answer 3

Increases uterine contraction force and
frequency

Question 4

Dose of Methergine

Answer 4

0.2mg IM

Question 5

Caution/Contraindication of Methergine

Answer 5

HTN, Preeclampsia

Question 6

MOA of Carboprost

Answer 6

Stimulates smooth muscle and uterine
contractions (synthetic prostanglandin)

Question 7

Dose of Carboprost

Answer 7

250mcg IM

Question 8

Caution/Contraindication of Carboprost

Answer 8

Asthma

Question 9

MOA of Misoprostol

Answer 9

Produces uterine contractions (prostaglandin
E1)

Question 10

Metabolism of Misoprostol?

Answer 10

Gut parietal cells,
CYP450

Question 11

Dose of Misoprostol

Answer 11

1000 mcg rectal

Question 12

Pharmacologic C-Section Goals

Answer 12

*Stable hemodynamics
*Limiting cardiac and respiratory
depressant drugs that cross the
placenta
* Birth of a health baby
* Minimizing bleeding

Question 13

Pregnancy results in changes in maternal
anatomy and physiology such as?

Answer 13

• Increased maternal metabolic demands
• Biochemical alterations from the fetus
• Mechanical effects of an enlarging uterus

Question 14

Pregnancy-induced changes in the cardiovascular system include:

Answer 14

–Increased blood volume
– Increased cardiac output
– Decreased vascular resistance
– Supine hypotension

Question 15

What is the mechanism behind increased intravascular volume in pregnancy? This change likely induced by?

Answer 15

-begins to increase in the first trimester of pregnancy as the result of increased production of renin, angiotensin,
and aldosterone, which together promote sodium absorption and water retention

-Likely induced by Progesterone

Question 16

By term gestation, the plasma volume increases approximately _____ , and the red cell volume increases about ______

Answer 16

50%

25%

Question 17

Any hgb level less an _____ g/dL even at term is considered anemia?

Answer 17

11

Question 18

Why does physiologic anemia of pregnancy not cause a reduction in oxygen delivery?

Answer 18

Because of a coincident increase in cardiac output

Question 19

Estimated blood loss in vaginal delivery

Answer 19

300-500mL

Question 20

Estimated blood loss in C-Section delivery

Answer 20

800-1,000mL

Question 21

Gestational thrombocytopenia is thought to result from a combination of? Plt count does not usually drop below?

Answer 21

Hemodilution and accelerated platelet turnover

70,000

Question 22

What clotting factors are increased and decreased during pregnancy?

Answer 22

Thrombogenic factors such as VII, VIII, and X, von Willebrand factor, and fibrinogen are increased,

whereas protein S and antithrombin III are
decreased

Question 23

In spite of mild thrombocytopenia, pregnancy is a?

Answer 23

a hypercoagulable state with increased clotting and decrease in fibrinolytic capacity

Question 24

True or False: Neuraxial blockade does not alter uterine blood flow in the absence of maternal hypotension

Answer 24

True

Question 25

True or False: Newer studies showed the use of phenylephrine is not only effective in preventing hypotension but also is associated with less fetal acidosis and base deficit than the use of ephedrine

Answer 25

True