Obstetrics

Prenatal Care

GA (weeks) Testing
3 ~ 4 Pregnancy test
4 ~ 5 hCG 1000 ~ 1500 mIU/mL
Gestational sac
10 ~ 12 PAPP-A
Nuchal translucency
± Chorionic villus sampling (CVS)
16 ~ 20 Quad screening
± Amniocentesis
20 ~ 24 Level II ultrasonagraphy
24 ~ 28 100-g OGTT
26 ~ 28 ± RhoGAM
28 ~ 32 ± Corticosteroids
35 ~ 37 GBS culture

Classification of Gestational Ages (GA)

Classification GA (weeks)
Early preterm < 24
Preterm 24 ~ 34
Late preterm 34 ~ 37
Term 37 ~ 42
Postterm > 42

Causes of Size/Date Discrepancy

  • Inaccurate dating
  • Molar pregnancy
  • Multiple gestation
  • Macrosomia
  • Hydramnios
  • Obesity
  • Distended bladder
  • Adnexal mass

Quad Screening {HAEI}

  • hCG
  • AFP
  • Estriol
  • Inhibin A
  • Abortion
  • Ectopic pregnancy
  • Gestational trophoblastic diseases (GTD)
  • Aneuploidy

Etiology of Elevated AFP

  • Inaccurate dating
  • Germ cell tumors (GCT)
  • Endodermal sinus tumor (EST)
  • Embryonal carcinoma
  • Teratoma
  • Neural tube defects :: open
    • Anencephaly
    • Encephalocele
    • Spina bifida aperta
      • Meningocele
      • Myelomeningocele
  • Abdominal wall defects
    • Gastroschisis
    • Omphalocele
  • Fetal demise
  • Multiple gestation
  • Placental abruption

Etiology of Reduced AFP

  • Inaccurate dating
  • Trisomy 21 & 18
  • Fetal demise

Indications for Methotrexate in Ectopic Pregnancy

  • Gestational sac < 3.5 cm
  • hCG < 5000 mIU/mL
  • No fetal cardiac activity (FCA)

Classification of Pregnancy Loss [Miscarriage]

Condition Definition
Spontaneous abortion < 20 weeks / < 500 g
Intrauterine fetal demise (IUFD) [Stillbirth] > 20 weeks / > 500 g

Spontaneous Abortion

Type Bleeding POC Expulsion Cervical Os POC Presence FCA Management
Threatened + - Closed + + Pelvic rest
Inevitable + - Open + + Expectant / Medical / Surgical
Incomplete + + Open + - Expectant / Medical / Surgical
Missed - - Closed + - Expectant / Medical / Surgical
Complete + + Closed - - -
  • Product of conception (POC)
  • Fetal cardiac activity (FCA)

Management of Irreversible Spontaneous Abortion

  • Expectant management
  • Medical evacuation
    • Misoprostol
  • Surgical evacuation
    • Manual uterine aspiration (MUA) if < 12 weeks
    • Dilatation and curettage (D&C) if > 12 weeks

Management of Intrauterine Fetal Demise (IUFD)

  • Dilatation and curettage (D&C) if < 24 weeks
  • Labor induction if > 24 weeks / autopsy

Management of Induced Abortion

First Trimester

  • Medical abortion
    • Misoprostol
    • Misoprostol & Mifepristone
    • Misoprostol & Methotrexate
  • Manual uterine aspiration (MUA)

Second Trimester

  • Labor induction
  • Dilatation and curettage (D&C)

Gestational Trophoblastic Diseases (GTD)

  • Hydatidiform moles
    • Complete mole
    • Partial mole
  • Gestational trophoblastic neoplasia (GTN)
    • Choriocarcinoma
    • Invasive mole
    • Trophoblastic tumor
      • Placental-site trophoblastic tumor
      • Epithelioid trophoblastic tumor

Hydatidiform Moles

  Complete Mole Partial Mole
Karyotype 46,XX / 46,XY 69,XXX / 69,XXY / 69,XYY
hCG ↑↑↑↑ ↑
Uterine Size ↑ -
Choriocarcinoma 2% Rare
Fetal Parts - +
Components 2 sperms & 0 egg 2 sperms & 1 egg

Multiple Gestation

Type Cleavage #Placenta #Sac
Dichorionic diamniotic (DCDA) Before Morula 2 2
Monochorionic diamniotic (MCDA) Morula ~ Blastocyst 1 2
Monochorionic monoamniotic (MCMA) After blastocyst 1 1

Presentation of Preeclampsia

Mild Preeclampsia

  • BP > 140/90 mmHg
  • Proteinuria > 0.3 g/d

Severe Preeclampsia

  • BP > 160/110 mmHg
  • Headache
  • Visual disturbances
  • Epigastric pain
  • ↑ Liver enzymes
  • Platelet count ≤ 100,000/µL
  • Creatinine > 1.1 mg/dL
  • Pulmonary edema

HELLP Syndrome

  • Hemolysis :: microangiopathic
  • ↑ Liver enzymes
  • ↓ Platelet count

Management of Preeclampsia and Eclampsia

Condition Management
Mild preeclampsia Delivery at 37 weeks
Severe preeclampsia Delivery at 34 weeks
Magnesium sulfate
Antihypertensives
Corticosteroids
Eclampsia Delivery
Magnesium sulfate
Antihypertensives

Fetal Complications of Gestational Diabetes

  • Polyhydramnios
  • Macrosomia
  • ß-cell hyperplasia
  • Hypoglycemia
  • Polycythemia

Indications for Intrapartum GBS Prophylaxis

  • Fever
  • History of GBS-affected neonates
  • Preterm labor
  • Rupture of membranes (ROM) > 18 hours
  • Urine culture
  • Vaginal culture

Management of Prelabor Rupture of Membranes (PROM)

  • Delivery at 34 weeks
  • Corticosteroids if < 34 weeks
  • Antibiotics if < 34 weeks
    • Penicillinase-sensitive penicillin
    • Macrolides
  • Magnesium sulfate if < 32 weeks

Fetal Heart Rate (FHR)

Finding Definition Significance
Acceleration ↑ 15/min for 15 seconds ~ 2 minutes Reassuring
Early deceleration ↓ during a uterine contraction
Onset to nadir > 30 seconds
 Head compression
Late deceleration ↓ after a uterine contraction
Onset to nadir > 30 seconds		 Uteroplacental insufficiency
Variable deceleration ↓ 15/min for 15 seconds ~ 2 minutes
Onset to nadir < 30 seconds		 Cord compression

Fetal Heart Rate (FHR) Category III

  • Bradycardia
  • Recurrent late deceleration
  • Recurrent variable deceleration
  • Sinosoidal pattern

Management of Late Decelerations

  • Oxygen
  • Position :: left lateral decubitus
  • Tocolysis
  • Delivery

Biophysical Profile (BPP)

  • Nonstress test (NST): > 2 accelerations in 20 minutes
  • Amniotic fluid volume: AFI > 5 cm / the deepest vertical pool > 2 cm
  • Fetal breathing movements: breathing of > 30 seconds in 30 minutes
  • Fetal movements: > 3 movements in 30 minutes
  • Fetal tone: extension & flexion in 30 minutes

Amniotic Fluid Index (AFI)

Condition Definition
Oligohydramnios AFI < 5 cm
the deepest vertical pool < 2 cm
Normal AFI 5 ~ 25 cm
Polyhydramnios AFI > 25 cm

Sterile Speculum Exam

  • Pooling
  • Valsalva
  • Ferning
  • Nitrazine

Management of Preterm Labor

  • Delivery at 34 weeks
    • Tocolysis if < 34 weeks
    • Expectant management if > 34 weeks
  • Corticosteroids if < 34 weeks
  • Magnesium sulfate if < 32 weeks

Management of Postterm Pregnancy

  • Delivery at 41 weeks

Medications for Labor Induction

Mechanism Medication
PGE1 agonists Misoprostol
Oxytocin agonists Carbetocin

Medications for Tocolysis

Mechanism Medication
- MgSO4
Ca channel blockers Nifedipine
β2 agonists Terbutaline
Ritodrine
Oxytocin antagonists Atosiban
COX inhibitors Indomethacin
Nitrates Nitroglycerin

Contraindications to Tocolysis

  • Gestational age (GA) > 34 weeks
  • Advanced labor: dilation > 4 cm
  • Severe preeclampsia / eclampsia
  • Preterm prelabor rupture of membranes (PPROM)
  • Intraamniotic infection (IAI)
  • Intrauterine fetal demise (IUFD)
  • Non-reassuring fetal status

Etiology of Prolonged Labor

  • Cephalopelvic disproportion
    • Macrosomia
    • Unfavorable pelvis
  • Malpresentation
  • Uterine atony
  • Uterine rupture

Complications of Prolonged Labor

  • Postpartum hemorrhage
  • Chorioamnionitis
  • Endometritis
  • Perinatal asphyxia

Management of Shoulder Dystocia

  • McRoberts maneuver
  • Suprapubic pressure
  • Episiotomy
  • Woods screw maneuver
  • Rubin maneuver
  • Zavanelli maneuver

Classification of Perineal Lacerations

Degree Depth
1 Submucosa
2 Perineal body
3 Anal sphincter
4 Rectal mucosa

Indications for Cesarean Delivery

  • Prolonged labor
  • Cephalopelvic disproportion
    • Macrosomia
    • Unfavorable pelvis
  • Malpresentation
  • Non-reassuring fetal status
  • Placenta accreta
  • Placenta previa
  • Vasa previa
  • Cord prolapse
  • History of uterine surgery
  • Cervical cancer
  • Infection :: HSV & HIV

Etiology of Postpartum Hemorrhage {4T}

Mnemonic Etiology
Thrombin Coagulopathy
Tone Uterine atony
Uterine rupture
Tissue Plancental retention
Implantation site bleeding
Trauma Genitourinary tract

Empirical Antibiotics for Postpartum Endometritis

  • Clindamycin
  • Aminoglycosides

Indications for RhoGAM

  • Invasive prenatal diagnosis
    • Amniocentesis
    • Chorionic villus biopsy
  • Intrauterine procedures
  • External cephalic version (ECV)
  • Ectopic pregnancy
  • Molar pregnancy
  • Antepartum haemorrhage
  • Miscarriage after 12 weeks of gestation
  • Intrauterine fetal demise (IUFD)
  • Induced abortion
  • 24 ~ 28 weeks of gestation
  • Within 72 hours of delivery