Pregnancy/OB

Question 1

Stage 1 Labor

Answer 1

Onset of labor until cervix is completely dilated (10cm)

LATENT PHASE = contractions become stronger, longer and more coordinated

ACTIVE PHASE = begins at 3-4cm dilation and is when the rate of cervical dilation is at its max

• Strong, regular contractions
• Without epidural minimal expected rates of cervical dilation are 1.2cm/hr for nulliparous woman and 1.5cm/hr for parous woman in active phase

Question 2

Stage 2 Labor

Answer 2

From complete cervical dilation through the delivery of the fetus

Due to combination of force of uterine contractions and the pushing efforts of the mother

Normally lasts < 2hr in nulliparous woman and <1hr in parous woman Epidural can prolong these times by ~1hr

Question 3

Stage 3 Labor

Answer 3

Begins after the delivery of the baby and ends with delivery of the placenta and membranes

Should not last > 30 min

Question 4

Baseline Fetal Heart Rate

Answer 4

Approximate HR during a 10 min tracing

(Normal ~110-160 bpm)

BRADYCARDIA (<110) can be caused by maternal hypothermia, certain meds, congenital heart block, or fetal distress

TACHYCARDIA (>160) most commonly d/t maternal fever

Question 5

Short Term Variability in Fetal HR Monitoring

Answer 5

Change in fetal HR from one beat to the next and can only be accurately determined when an internal scalp-electrode is placed

Normal ~6-25 beats/min

Question 6

Long Term Variability (Fetal HR)

Answer 6

Waviness of the baseline HR over 1 min (Normal ~3-5 cycles/min)

DECREASED variability can be due to fetal sleep cycles, CNS depressant drugs, congenital neuro abnormalities, prematurity, and acidemia 2/2 hypoxemia

Question 7

Fetal HR Monitoring: Accelerations

Answer 7

Increase in fetal HR of 15 beats/min or more for at least 15 seconds

Presence of accelerations whether they are spontaneous, in response to contractions, fetal movement, or stimulation of fetus virtually ensures fetal arterial pH is >7.2

Question 8

Late deceleration (fetal HR)

Answer 8

Gradual reduction in fetal HR that starts at or after the peak of a contraction and has a gradual return to baseline

Manifestation of uteroplacental insufficiency. A common cause is maternal hypotension d/t epidural or uterine hyperstimulation d/t oxytocin

Can also be due to conditions that reduce placental circulation like maternal HTN, DM, prolonged pregnancy, and placental abruption

Question 9

Early Decelerations (Fetal HR)

Answer 9

Coincides with a contraction in onset of fetal HR decline and return to baseline

D/t increased vagal tone caused by compression of fetal head

Question 10

Variable Declerations (Fetal HR)

Answer 10

Abrupt decrease in fetal HR, usually followed by abrupt return to baseline that occurs variable with respects to contraction

Caused by umbilical cord compression during contractions and is generally unconcerning

Question 11

Recommended labs at initial prenatal visit

Answer 11

CBC

HBsAg, HIV, & RPR

Urinalysis + Urine culture

Rubella antibody

Blood type and Rh status

PAP Smear and chlamydia screen

Question 12

Trisomy Screening

Answer 12

10-13 wk: NT, hCG, and PAPP-A

2nd Trimester (16-18wk): AFP + estriol +hCG +/- inhibin A

Question 13

Gestational DM Screen

Answer 13

1-hr glucose tolerance test (50g) @ 26-28wk

If abnormal, do 3-hr tolerance test (100g, check @ 1, 2, and 3 hr)

Question 14

Pregnancy Category B

Answer 14

Animal studies have shown no harm to a fetus but human studies not available

OR

animal studies have shown harm to a fetus but studies in pregnant women have NOT shown harm

Question 15

Pregnancy Category C

Answer 15

Animal studies have shown adverse fetal effects and there are NO adequate studies in humans

OR

No animal studies have been conducted AND no adequate studies in humans

Question 16

Pregnancy Category D

Answer 16

human studies have shown potential adverse fetal effects BUT benefits of therapy may outweight potential risks

Question 17

Bupropion (Wellbutryin, zyban)

Answer 17

Blocks uptake of NE and/or dopamine, can be used for smoking cessation

Contraindicated in pt with eating disorders, MOAI use in last 2 wk, or hx of seizures

Caution in pt with coronary heart disease d/t possible cardiotoxicity and possible prolongation of QRS –> arrhythmia

Question 18

Verenecline (Chantix)

Answer 18

Partial nicotinic receptor agonist –> reduced cravings, withdrawal symptoms and increases smoking cessation x3 compared to placebo

Can have neuropsych effects and possible cardiac events.

Common Side Effects = nausea, trouble sleeping, and abnormal, vivid, or strange dreams

Question 19

4 Causes of Post-partum Hemorrhage

Answer 19

TONE (uterine Antony) - 70% of cases

• Risks = prolonged labor, prolonged use oxytocin, large baby
• Management: biannual uterine compression and massage, admin oxytocin

TRAUMA: cervical, vaginal, or perineal lacerations, uterine inversion

TISSUE: retained placenta or membranes

THROMBIN (coagulopathies)

Question 20

Postpartum changes in uterine size

Answer 20

Immediately postpartum: ~1kg and size of 20-wk pregnancy

End of 1st postpartum week: ~12wk size and palpable at pubic symphysis

Usually will be normal size by 6wk postpartum

Question 21

Normal vaginal bleeding post-partum

Answer 21

Heavier bleeding immediately after delivery

Brown/blood-tinged lochia ~1wk

Yellow or white lochia ~4-6wk

Question 22

Pharmacologic tx options for postpartum hemorrhage

Answer 22

Methylergonovine (C/I in pt with HTN or preeclampsia)

Carboprost (C/I in pt with asthma)

Misoprostol (GI side effects)