Obstetric highlights elmar p. sakala

USMLE Step 2 — Lesson 1 OBSTETRIC

Highlights

USMLE Step 2

Elmar P. Sakala, MD, MPH

Discrepant Fundal Size

Case #1

• A 20 y/o woman comes to the out-pt prenatal clinic for a new OB visit.

• She is 30 wks gest by LMP.

• Fundal measurement is 24 cm.

Fundus smaller than dates

Differential Diagnosis


Think of 3 uterine compartments:

o Fetal: fetal demise, IUGR

o Amniotic fluid: oligohydramnios

o Placental: molar preg

Diagnosis


Obtain OB ULTRASOUND:

o Fetal: cardiac motion, fetal biometry (BPD, HC, AC, FL)

o Amniotic fluid: 4-quad AFI <5 cm

o Placental: texture, appearance

Etiology

Intrauterine Growth Restriction

SYMMETRIC IUGR:

o BPD, HC, AC, FL are less than expected due to growth potential: e.g. aneuploidy, 1st trimester infection

ASYMMETRIC IUGR:

o AC is less than expected due to nutritional supply e.g. hypertension, preeclampsia

Etiology

Oligohydramnios

• Premature membrane rupture

• Urinary tract anomaly

• Placental insufficiency

• Meds: indomethacin, ACE inhibitors

Management


• Details are specific to the problem identified.

Case #2

• A 20 y/o woman comes to the out-pt prenatal clinic for a new OB visit.


• Fundal measurement is 35 cm.

Fundus larger than dates



Think of 4 compartments:

o Fetal: multiple fetuses, macrosomia

o Amniotic fluid: polyhydramnios

o Placental: molar preg, fetal hydrops, infection

o Uterine: leiomyomas

Diagnosis


Obtain OB ULTRASOUND:

o Fetal: # of fetuses; fetal biometry (BPD, HC, AC, FL) shows macrosomia

o Amniotic fluid: 4-quad AFI >25 cm

o Placental: texture, appearance

o Uterus: leiomyomas

Etiology

Polyhydramnios

• Fetal GI tract: TE fistula, duod atresia

• Fetal NTD: spina bifida, anencephaly

• Fetal hydrops: immune, nonimmune

• Diabetes mellitus: poor glucose control

Management


• Details are specific to the problem identified.

USMLE Step 2 — Lesson 2 FIRST Trimester Bleeding

Case #3

• A 25 y/o woman comes to the out-pt prenatal clinic for a return OB visit.

• She has had vaginal bleeding with no cramping.



First trimester bleeding

• Threatened abortion

• Missed abortion

• Inevitable abortion

• Incomplete abortion

• Completed abortion

• Molar pregnancy

• Ectopic pregnancy

Diagnosis


SYMPTOMS

o Bleeding? Passed tissue? Contractions?

Diagnosis


SYMPTOMS:


PELVIC EXAMINATION

o Cervical lesion? Internal cervical os dilated?

Diagnosis


SYMPTOMS:


PELVIC EXAMINATION

o Cervical lesion? Internal cervical os dilated?

ULTRASOUND:

o Gest sac? Embryo? Cardiac motion?

Diagnosis & Management

THREATENED abortion

Characteristics:

o Bleeding: minimal

o Cramping: none or minimal

o Internal cervical os: closed

o Ultrasound: normal findings

Management:

o Conservative management


MISSED abortion

Characteristics:

o Bleeding: none

o Cramping: none

o Internal cervical os: closed

o Ultrasound: non-viable pregnancy

Management:

o Scheduled D&C, RhoGAM if Rh-


INEVITABLE abortion

Characteristics:

o Bleeding: YES

o Cramping: YES

o Internal cervical os: dilated

o Tissue passed: none

o Ultrasound: POC remains in uterus

Management:

o Emergency D&C, RhoGAM if Rh-


INCOMPLETE abortion

Characteristics:

o Bleeding: YES

o Cramping: YES


o Tissue passed: YES

o Ultrasound: POC remains in uterus

Management:

o Emergency D&C, RhoGAM if Rh-


COMPLETED abortion

Characteristics:

o Bleeding: Minimal

o Cramping: Minimal


o Tissue passed: YES

o Ultrasound: Normal uterus stripe

Management:

o Observation; serial quantitative β-hCG (to r/o ectopic)


SEPTIC abortion

Characteristics:

o History: Non-sterile uterine instrumentation

o Bleeding: Minimal

o Cervical os: purulent discharge

o Uterus: tender

o Vital Signs: Fever, tachycardia

Management:

o Admit; cultures; IV gent & clindamycin; gentle D&C

SECOND Trimester Loss

Case #4

• A 25 y/o woman (G2 P1Ab1) at 18 wks gest presents to the hospital maternity unit

with pelvic pressure but NO contractions.

• On exam membranes are bulging to the introitus.

Second trimester loss


Second trimester loss

o Incompetent cervix

o Mullerian anomaly

o Submucus leiomyoma


Incompetent Cervix

Characteristics:

o Painless cervical dilation.

o Non-viable gest age.

o Delivery of immature normal fetus that dies.

Management:

o Cervical cerclage (emerg now if possible; scheduled at 14 wks next

pregnancy)

Cervical CERCLAGE


Mullerian anomaly

History:

• Regular contractions with cervical dilation.

• Non-viable gestational age.

• Delivery of immature normal fetus that dies.

Diagnosis: Hysteroscopy or HSG

Management: Hysteroscope resection if thin uterine septum; laparotomy if thick septum


Submucus leiomyoma

History:

• 2nd trim demise occurs without explanation.

• Non-viable gestational age.

• Delivery of stillborn normal fetus.

Diagnosis: Hysteroscopy or HSG

• Management: Hysteroscope resection.

THIRD Trimester Bleeding

Case #5

• A 25 y/o G2 P1Ab1 woman presents to the hospital maternity unit with painful vaginal

bleeding.


• Fetal heart tones are present.

THIRD trimester bleeding


THIRD trimester bleeding

• Abruptio placenta

• Placenta previa

• Vasa previa

• Uterine rupture


Abruptio Placenta

Findings:

o PAINFUL vag bleeding with uterus not relaxing between UCs.

o Assoc with PIH, cocaine, trauma, DIC

Sono: Normally implanted placenta

Management:

o Depends on gest age, status of Mom & fetus.

Normal

Placental

Implantation

- Fundal

- Anterior - Posterior

Overt

ABRUPTIO

Placenta

Concealed

ABRUPTIO

Placenta


Placenta previa

Findings:

o PAINLESS vaginal bleeding.

o Assoc with prev PP, twins,multiparity, AMA

Sono: placenta in lower uterine segment Types: Low-lying, partial, complete

Management:

o Depends on gest age, status of Mom & fetus.

Low

Lying

Placenta

Previa

Partial

Placenta

Previa

Total

Central

Placenta

Previa


Vasa previa

Findings:

o PAINLESS vaginal bleeding.

o Assoc with twins,accessory placental lobe

o Bleeding is fetal blood!

Triad: AROM, vag bleeding, fetal bradycardia

Management:

o Immediate cesarean on diagnosis!

VASA

Previa

TEST TAKING WORKSHOP

Barbara J. Irwin, BSN, RN


Uterine rupture

Findings:

o PAINFUL vaginal bleeding with UCs.

o Assoc: prev classical CS, XS oxytocin, trauma.

o Non-reassuring fetal monitor pattern.

Types: Complete, incomplete

Management:

o Immediate cesarean delivery on diagnosis!

USMLE Step 2 — Lesson 3 Postdates Pregnancy

Case #6

• A 24 y/o multigravida comes to the out-pt office for a return OB visit.

• She is now 42½ wks gest by LMP. Her first prenatal visit was 6 weeks ago.

• Her fundal height measures 41 cm.

• FHT are 145 beats/min. BP is 125/75.

POSTDATES pregnancy

Level of Question Difficulty

• Recall Recognition

• Comprehension

• Application

• Analysis

Diagnosis

POSTDATES pregnancy

• >42 weeks amenorrhea

(assuming ovulation occurred on day 14)

• >294 days amenorrhea

(assuming ovulation occurred on day 14)

• >280 days postconception

(time of conception is known)

Diagnosis

POSTDATES pregnancy

• Based on Amenorrhea 6-12% (false)

• Based on Conception 3-5% (true)

Hazards

POSTDATES pregnancy

PERINATAL

MORTALITY

3-fold

Fetus in Postdates Preg?

Key question: Placental Function?

75% Maintained

MACROSOMIA

Syndrome

Difficult Labor

& Delivery

Forceps, Vacuum

Shoulder Dystocia

Birth trauma

Cesarean Section

25% Deteriorates

DYSMATURITY

Syndrome

Placental

Insufficiency

Acidosis

Meconium aspiration

Oxygen deprivation

Cesarean Section

POSTDATES pregnancy

First Question to ask:

How much confidence do you have in the GESTATIONAL AGE?

Confirming gest age

POSTDATES pregnancy

• Menstrual history

sure; planned preg; normal cycle; no Ocs

• Clinical landmarks

uterine size & FHT<12 wk; quickening

• Sonogram dating

CRL <12 wk (+ or - 5d); BPD 12-18 wk (+ or - 7d)

Differential Diagnoses

POSTDATES pregnancy

• Dates sure

o cervix favorable

• Dates sure

o cervix Unfavorable

• Dates unsure

POSTDATES Management

Dates FIRM - Cx FAVORABLE

• 1 Induce labor: AROM, oxytocin

• Intrapartum EFM looking for:

o VARIABLE decels

umbilical cord compression

o LATE decels

placental insufficiency


What about MECONIUM?

• Incidence:

4 times more common

• Mechanism:

bowel function or acidosis


What about MECONIUM?

Management:

• Amnioinfusion

• Suction pharynx

• Tracheal aspiration


Dates FIRM - Cx Unfavorable

• 1 Induce labor: prostaglandin E2

• Await spont labor looking for:

o NSTs reactive 2/week

o AFIs > 5-8 cm 2/week


Dates UNSURE

• Await spont labor looking for:

NSTs reactive 2/week

AFIs > 5-8 cm 2/week

Hypertension in Pregnancy

HYPERTENSION in Preg

Effect of normal

physiologic changes of pregnancy

Case #7

• A 21 y/o primigravida at 32 wks gest comes for a routine OB visit.

• Her BP sitting is 155/95; repeat reading was 145/90.

• Urine dipstick protein is 3+.

• No previous history of HTN.




o Mild preeclampsia

o Severe preeclampsia

o Eclampsia

o HELLP syndrome

o Chronic HTN

MILD preeclampsia

SEVERE preeclampsia

ECLAMPSIA

Can be RAPID progression!

Preeclampsia should be renamed:

Diffuse

VASOSPASTIC

Disease of Pregnancy

AGGRESSIVE Management GUIDELINES:

• MAINTAIN BP diastolic 90-100 mm Hg

• Prevent CONVULSIONS with MgSO4

• Initiate DELIVERY rapidly


MILD Preeclampsia Findings:

• HTN > 140/90; proteinuria 1-2+; edema.

• Hemoconcent ( H&H, uric acid, BUN, creat)

• No Symptoms (HA, epig pain, visual ∆).

• No Signs (DIC, cyan, oliguria, pulm edema).

Management:

• Conservative – in hospital if < 36 wks gest

• Aggressive – if > 36 wks gest, IV MgS04


SEVERE Preeclampsia Findings:

• HTN > 160/110; proteinuria 3-4+; edema

• Any Symptoms (HA, epig pain, visual ∆).

• Any Signs (DIC, cyanosis, oliguria, pulmon edema).

Management:

• Conservative – in ICU if 26-33 wks gest if only HTN & proteinuria present;

hydralazine; MgS04; steroids.

• Aggressive – if <26 or >33 wks, or symptoms/signs; MgS04; steroid.


ECLAMPSIA

Findings:

• HTN > 140/90; proteinuria; edema

• New onset of generalized convulsions.

• May occur ante/intra/postpartum.

Management:

• Conservative – NEVER.

• Aggressive – as soon as diagnosis is made; hydralazine; IV MgS04; steroids.


HELLP syndrome

Findings:

• Hemolysis, Elev Liver enyz, Low Platelets.

• Other findings of preeclampsia.

• May occur ante/intra/postpartum.

Management:

• Conservative – NEVER.

• Aggressive – as soon as diagnosis is made; hydralazine; IV MgS04; steroids.


CHRONIC hypertension

Findings:

• Pre-existent HTN or HTN prior to 20 wks that persists past 6 wks PP.

• Proteinuria is variable.

Management:

• Conservative – Aldomet is drug of choice

• Aggressive – if superimposed preeclampsia; hydralazine; MgS04, steroids

Aggressive in-patient:

• Mild PIH : > 37 wks

• Severe PIH < 26 wks

• Severe PIH > 34 wks

• Severe PIH maternal jeopardy

• Severe PIH fetal jeopardy

• Chr HTN with PIH.. any GA

• Eclampsia………… any GA

• HELLP…………….. any GA

Glucose Intolerance in Pregnancy

Case #8

•

A 36 y/o multigravid at 28 wks gest.

•

•

1 hr 50 g glucose is 165 mg/dl.

•

•

3 hr 100 g OGTT is F-90; 1hr- 190 ; 2-hr 165 ; 3-hr 145 .

•

•

Urine dipstick glucose is 3+.

•

•

• DIABETES in Pregnancy


DIABETES in Pregnancy

• Gestational diabetes

• Type 1 diabetes mellitus

• Type 2 diabetes mellitus

Diagnosis

GESTATIONAL diabetes Findings:

o 2 of 4 values abnormal on 3 hr 100 g OGTT.

o Onset > 20 wks gestation (if true GDM)

o Onset any time during pregnancy.

o Due to hPL, placental insulinase, cortisol.

o No in fetal anomalies (if true GDM).

o Resolves after delivery (if true GDM).

Diagnosis

TYPE 1 diabetes mellitus Findings:

o Onset prior to pregnancy.

o Due to islet cell destruction.

o Plasma insulin level is .

o Fetal anomalies may be .

o Unable to achieve nonPG euglycemia without insulin.

Diagnosis

TYPE 2 diabetes mellitus Findings:

o Onset prior to pregnancy.

o Due to insulin resistance.

o Plasma insulin level is .

o Fetal anomalies may be .

o Is able to achieve nonPG euglycemia without insulin.

EUGLYCEMIA management

All Preg Glucose Intolerance

• Diet: ADA diet ( complex CHO). • Educ: Mom re glucose control.

• Exercise: Regular, consistent

• Targets: FBS 60-90; 1 hr PP <140

• Insulin: NPH & Reg human insulin if euglycemia not achieved with diet; split dose of

2/3 AM & 1/3 PM.

Anomaly detection

Type 1 & 2 Diabetes Mellitus

Most common anomalies

• NTD defects

• CHD defects

• Sacral agenesis

Anomaly detection


13-14 wk Sono anencephaly

16-18 wk MSAFP NTD

18-22 wk Focused sono other anomalies

22-24 wk Fetal echo cardiac anomalies

( if first trimester Hb A1C)

Anomaly PREVENTION


• Preconception

EUGLYCEMIA

• Preconception

FOLIC ACID 4 mg po /day

USMLE Step 2 — Lesson 4: Medical Complications of Pregnancy CARDIAC Disease in Pregnancy

Cardiac Disease in Preg

Effect of normal physiologic changes of pregnancy

Physiology of Pregnancy Cardiac

Formula for

Cardiac OUTPUT? (Volume of blood pumped by heart in 1 minute)


Formula for

Cardiac OUTPUT?

(Volume of blood pumped by heart in 1 minute)

HR x SV

(Heart Rate x Stroke Volume)


IF HR & SV

THEN

Cardiac Output

Case #9

• A 40 y/o multigravida at 18 wks gest comes to the out-pt clinic.

• History of rheumatic fever.

• SOB with mild activity.

• Pulse: 110/min; parasternal heave;

Gr 4/6 pandiastolic murmur.


Significant Diagnoses


• Mitral stenosis

• Eisenmenger’s syndrome

• Marfan’s syndrome

• Tetralogy of Fallot


Mitral STENOSIS Findings:

• Most common acquired heart disease.

• Problem: narrow valve diastolic filling.

• Results: LA Atrial fib, SBE, emboli.

CARDIAC Cycle: Diastole/Systole



Factors worsening

MITRAL STENOSIS?

• heart rate

• blood volume

• heart rate

• blood volume

Normal changes of PREGNANCY?

Factors worsening MITRAL STENOSIS:

heart rate

blood volume

Normal changes of PREGNANCY:

MITRAL STENOSIS:

Do not go well together

Normal changes of PREGNANCY:


Mitral STENOSIS

Findings:

o Most common acquired heart disease.

o Problem: narrow valve diastolic filling.

o Results: LA Atrial fib, SBE, emboli.

Management:

o Watch decompensation: PND, syncope, JVD.

o Avoid fluid overload: Na+ diet, diuretics.

o Avoid tachycardia: anemia, exercise, sedation.

o Vag delivery; invasive monitoring; SBE prophylax


STENOTIC lesions are tolerated

POORLY.

USMLE Step 2 — Lesson 5: Management of Labor Abnormal

Labor

ABNORMAL LABOR

STAGES of NORMAL LABOR

Case 12

• A 32 y/o multigravida at 39 wks gest in the maternity unit has UCs every 3-4

minutes.

• Her cervix is 1-2 cm dilated and has been the same for the past 16 hours.

• Fetal monitor strip is reassuring.

ABNORMAL labor

Significant Diagnoses

ABNORMAL labor

• Prolonged latent phase

• Prolonged active phase

• Active phase arrest

• Arrest of descent


Prolonged LATENT phase Findings:

• Cervical dilation < 3 cm with UCs present.

• No labor progress >14 hrs in multipara.

• No labor progress >20 hrs in primipara

Cause:

• Injudicious analgesia, hypo/hypertonic UCs.

Management:

• Therapeutic rest or sedation; avoid cesarean.

Causes of ACTIVE phase problems:

• PELVIS

• Passenger

• Powers

PROBLEMS with MATERNAL

BONY PELVIS

How much can you change PROBLEMS with

MATERNAL BONY PELVIS?


MATERNAL BONY PELVIS?

NONE!


• Pelvis

• PASSENGER

• Powers

PROBLEMS with IN-UTERO FETAL

ORIENTATION

Nomenclature for IN-UTERO FETAL ORIENTATION

• Fetal LIE

• Fetal PRESENTATION

• Fetal POSITION

• Fetal ATTITUDE

• STATION

Terms to remember:

Orientation of Fetus In-utero

Fetal LIE Relationship between long axis of the

fetus & long axis of mother

Most common: LONGITUDINAL

Terms to remember:


PRESENTATION Portion of fetus overlying the pelvic inlet

Most common: CEPHALIC

Terms to remember:


POSITION Relationship between a reference point on the presenting fetal part & maternal bony

pelvis

Most common: OCCIPUT ANTERIOR

Terms to remember:


ATTITUDE Degree of flexion or extension

of fetal head

Most common: VERTEX

Terms to remember:


STATION Degree of descent of the presenting part through birth canal

(Expressed in cm above or below maternal ischial spine)

How much can you change PROBLEMS with IN-UTERO FETAL ORIENTATION?

How much can you change PROBLEMS with IN-UTERO FETAL ORIENTATION?

Very little!


• Pelvis

• Passenger

• POWERS

PROBLEMS with INADEQUATE UTERINE CONTRACTIONS

Assessment of POWERS

Criteria for ADEQUACY of UTERINE CONTRACTIONS

• DURATION - 45-60 seconds

• FREQUENCY - every 2-3 minutes

• INTENSITY - > 50 mm Hg


INADEQUATE CONTRACTIONS?

How much can you change

PROBLEMS with INADEQUATE CONTRACTIONS?

Considerable!


• Pelvis

• Passenger

• POWERS


• Pelvis

• Passenger

• POWERS <- The only parameter that can be modified

Only CORRECTABLE Cause of ACTIVE phase problems:

Inadequate POWERS

IV OXYTOCIN


ACTIVE phase ARREST Findings:

• Cervical dilation > 3 cm with UCs present.

• NO Labor progress in multipara.

• NO Labor progress in primipara

Cause:

• Pelvic, Passenger, Powers.

Management:

• IV oxytocin (if inadequate UCs) or cesarean.


Prolonged ACTIVE phase Findings:

• Cervical dilation > 3 cm with UCs present.

• Labor progress <1.5 cm/hr in multipara.

• Labor progress <1.2 cm/hr in primipara

Cause:


Management:

• IV oxytocin (if inadequate UCs) or cesarean.


ARREST of DESCENT Findings:

• Cervical dilation is 10 cm or “complete”.

• Delivery not take place in spite of adequate maternal pushing efforts.

• Duration > 30 min in multip or >60 min in primip.

Cause:


Management:

• IV oxytocin, vacuum extractor, forceps or CS.

Intrapartum Fetal Monitoring

Case 13

• A 27 y/o primigravida at 41 wks gest is in labor in the maternity unit.

• She is 5 cm dilated, 100% effaced with UCs every 2-3 minutes.

• The EFM shows a baseline FHR of 140/min with decels: sudden drops of 40

beats/min lasting 15 seconds with rapid return.

ABNORMAL fetal monitor

Differential Diagnoses


• Early decelerations

• Variable decelerations

• Late decelerations


EARLY deceleration Findings:

• Onset of the deceleration is simultaneous with the onset of the contraction.

• End of the decelerations is simultaneous with the end of the contraction.

• Deceleration is a mirror image of the contraction.

Cause:

• Vagal stimulation; fetal head compression.

Management:

• Observation – no clinical significance.


VARIABLE deceleration Findings:

• Onset of the deceleration is variable with the onset of the contraction.

• End of the decelerations is variable with the end of the contraction.

• Sudden drops with rapid return to baseline.

Cause:

• Vagal stimulation; Umbil cord compression.

Management:

• Observation if mild-mod; worrisome if severe.


LATE deceleration

Findings:

• Onset of the deceleration is late in relation to the onset of the contraction.

• End of the decelerations is late in relation to the end of the contraction.

• Gradual drops with gradual return to baseline.

Cause:

• Uteroplacental insufficiency.

Management:

• All are worrisome!

Generic Interventions


• Decrease uterine activity

• Correct hypotension

• Change maternal position

• Administer high flow O2

• Vag exam r/o prolapsed cord

We have covered

The HIGHLIGHTS of

Obstetrics

USMLE Step 2

This brings us to

The END of the SESSION

BEST WISHES on the EXAM!

Obstetric highlights elmar p. sakala

Health & Medicine

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