Master the Boards: Obstetrics Flashcards
The Goodell sign is one of the first signs of pregnancy seen on physical exam. What is it?
Softening of the cervix in first 4 weeks
Describe the Chadwick sign?
Blue discoloration of vagina and cervix (6-8 wks GA)
Describe chloasma
“mask of pregnancy” seen on face (hyperpigmentation) at 16wks GA
What happens to B-hCG levels in each of the first three trimesters?
1: doubles every 48hrs
2: declines
3: slowly increases to a plateau level
Physiologic changes in pregnancy - Cardiology
CO:
BP:
CO: Increases (increased HR)
BP: Decreases (lowest at 24-28wks)
Physiology changes in pregnancy - Renal
GFR:
BUN:
Creatinine:
GFR: Increases (due to higher plasma volume)
BUN: Decreases
Creatinine: Decreases
Physiologic changes in pregnancy - Hematology
Hct:
Coaguability:
HCT: Decreases from dilutional effect
Coaguability: Hypercoaguable, increased fibrinogen, normal PT/PTT/INR
What is the most accurate way to measure gestational age in first trimester?
Ultrasound
Define Braxton-Hicks contractions
Sporadic contractions occurring in third trimester which do not open the cervix
At what GA is the 1 hour glucose load challenge done?
24-28 weeks
What drug is used in the medical management of an ectopic pregnancy and what is one major side effect?
Methotrexate
Hepatotoxicity
What is the difference between an inevitable and threatened abortion?
Both have intact products of conception and uterine bleeding.
Inevitable: cervix is dilated
Threatened: cervix is closed
What medication is used in medical abortion?
Misoprostol: Prostaglandin E1 analog
A women presents at 29 weeks gestation with contractions and cervical changes. You determine she is in preterm labor. Her cervix is 4cm dilated. Do you stop the contractions or continue on?
Continue with labor. Dilation of the cervix to 4cm or beyond is an indication to continue with labor.
A patient presents in preterm labor at 28 weeks gestation but the fetus is small (
Betamethasone to increase surfactant production. Also give tocolytics to slow uterine contractions so that betamethasone has time to work.
What are three tocolytics you may use to slow uterine contractions or stop preterm labor?
Magnesium sulfate
Calcium-channel blockers
Terbutaline (Beta-adrenergic receptor agonist)
What is one of the first signs of magnesium sulfate toxicity?
What are more serious side effects you hope to prevent?
Early sign: depression of DTRs
Serious effects: respiratory depression and cardiac arrest
When checking for premature rupture of membranes, what does amniotic fluid:
1) do on nitrazine paper
2) look like when dried on a slide
1) Blue
2) Ferning appearance
Premature or even prolonged rupture of membranes puts patients at risk for what serious infection?
If the infection is present, what is the management?
Chorioamnionitis
Immediately delivery
(Antibiotic coverage usually includes azithromycin and additional gram positive coverage)
A pregnant patient presents with bleeding in her third trimester. Before proceeding with determining if she will need to deliver immediately, what test should be done?
Transabdominal ultrasound. Prior to any digital exam an US needs to rule out placenta previa because digital exam may cause more separation and worsen the bleeding.
What is vasa previa?
Subtype of placenta previa where the fetal vessels are actually in close proximity to the cervical os.
Should all placenta previas or abruptions be delivered immediately?
In which cases should they be (3)?
No.
Massive hemorrhage
Cervical dilation > 4cm
Fetal distress
When they are delivered, it should be through a C-section
Define placenta accreta, increta, and percreta.
Placenta accreta: attaches to superficial uterine wall
Placenta increta: attaches to myometrium
Placenta percreta: invades uterine serosa, bladder wall, or rectum wall
Uterine tetany and DIC are complications of what cause of third trimester bleeding?
Placental abruption
What are the major risk factors of placental abruption?
Maternal hypertension
Maternal cocaine use and smoking
Which patients are at greater risk of uterine rupture, those with previous classic C-sections (vertical incision) or low transverse C-sections?
Those with classic (verticl) incisions
What is the management of a uterine rupture?
Immediate laparotomy because the fetus may not be in the uterus but free-floating in the abdomen
In hemolytic disease of the newborn, since the BM is not very mature, where are RBCs made?
Liver and spleen (extramedullary production)
What BP meds may be used to treat chronic hypertension?
What BP med is used in the acute treatment of eclampsia?
Chronic HTN: Methyldopa, Labetalol, Nifedipine
Eclampsia: Hydralazine
Should you ever tell a pregnant patient to lose weight?
No
What are risk factors for fetal macrosomia (>4500g)?
Maternal diabetes
Post-term pregnancy
Advanced maternal age
Above what fetal weight should C-section be performed?
4500g
What cause the following decelerations:
Early
Late
Variable
Early: Head compression
Late: Uteroplacental insufficiency
Variable: Umbilical cord compression
After what level of cervical dilation does the latent phase of stage 1 become the active phase?
4 cm
Why shouldn’t an asthmatic patient receive prostaglandin?
It may provoke bronchospasm
Name one cervical ripening agent
Prostaglandin E2
Failure of labor to progress is often said to be due to the 3 P’s. What are they?
Power: Inadequate uterine contractions
Passenger: Fetus too big
Passage: Pelvis too small
C-section for latter too, oxytocin for inadequate contractions
Prior to attempting external cephalic version for suspected breech presentation what should be done?
Ultrasound to confirm position
What is the McRobert’s maneuver?
Flexion of maternal hips in suspected shoulder dystocia to open pelvic canal wider
Uterine atony accounts for 80% of postpartum hemorrhage. What is the mechanism by which atony leads to hemorrhage?
Contractions normally help tamponade bleeding from vessels via compression. No contractions means they are more prone to bleed.
What are bimanual compression and massage and oxytocin all used for?
Stopping postpartum hemorrhage
What is the Nagel rule?
Estimates day of delivery. Take LMP, subtract 3 months, add 7 days.