Obstetrical Emergencies

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Preeclampsia

• Clinically defined as hypertension and proteinuria during pregnancy. • Treatment of severe hypertension (SBP >160, DBP >110 mmHg) include the following medications:

Severe hypertension in pregnancy

Eclampsia — weight-based dosing

Magnesium first-line; benzos if Mg fails. Calcium gluconate for toxicity.

Weight70 kg
  • Magnesium Sulfate — Loading
    Eclamptic seizure / severe preeclampsia prophylaxis
    First-line
    IVOnset Within minsDur ~30 min plasma
    Dose
    4-6 g IV
    Infuse over 15-20 min
    Volume: 12.0 mL @ 0.5 g/mL (50%)
    • • Watch for loss of DTRs, RR <12, urine output <30 mL/hr
  • Magnesium Sulfate — Maintenance
    First-line
    IV infusion
    Dose
    1-2 g/hr IV
    Continue 24 hr postpartum or post-seizure
    Volume: 20.0 mL @ 0.1 g/mL (10%)
  • Magnesium Sulfate — IM (no IV)
    Alternative
    IM
    Dose
    10 g IM
    5 g in each buttock; then 5 g q4h
    Volume: 20.0 mL @ 0.5 g/mL (50%)
    • • Use only if IV access unavailable
  • Lorazepam(Ativan)
    Refractory eclamptic seizure (Mg failed)
    Alternative
    IV
    Dose
    4.0 mg IV
    0.1 mg/kg (max 4 mg)
    Volume: 2.0 mL @ 2 mg/mL
  • Midazolam(Versed)
    Refractory seizure, no IV access
    Alternative
    IV/IM/IN
    Dose
    10.0 mg IV/IM
    0.2 mg/kg (max 10 mg)
    Volume: 2.0 mL @ 5 mg/mL
  • Calcium Gluconate
    Magnesium toxicity (loss DTRs, RR<12)
    Rescue
    IVOnset Mins
    Dose
    1 g IV
    Over 5-10 min; may repeat
    Volume: 10.0 mL @ 100 mg/mL (10%)
    • • Stop magnesium infusion immediately
    • • Support airway/ventilation

Eclampsia

• Pregnancy related hypertension + generalized seizure activity • Treat seizures initially with Magnesium Sulfate • Continued seizures may require benzodiazepines or phenytoin as described in Seizure / Status Epilepticus category • Treat hypertension as outlined in Preeclampsia category

Eclampsia — seizure management

Magnesium toxicity — rescue protocol

Therapeutic Mg level for eclampsia prophylaxis: 4-8 mg/dL. Toxicity correlates with serum level — but treat the patient, not the number.

Symptoms / signs present
Calcium gluconate — rescue dose
1-2 g IV (10-20 mL of 10%)

Adult: 1 g (10 mL of 10%) over 5-10 min; repeat to 2 g if no improvement. Use 2 g for severe / arrest.

70 kg
  • • Push slowly — rapid IV calcium → bradycardia/arrest
  • • Avoid same line as ceftriaxone (precipitation)
  • • Calcium chloride 1 g = ~3× elemental Ca vs gluconate (use only via central line if available)

Postpartum Hemorrhage (PPH)

• Defined as blood loss >1000 mL OR blood loss with signs/symptoms of hypovolemia within 24 hr of delivery. • Causes — the 4 T's: Tone (uterine atony, ~70%), Trauma (lacerations), Tissue (retained products), Thrombin (coagulopathy). • Initial: bimanual uterine massage, large-bore IV × 2, type & cross, activate massive transfusion if needed, call OB.

PPH — uterotonics & adjuncts

Oxytocin first; escalate by mechanism. Check contraindications before each.

Weight70 kg
  • Oxytocin(Pitocin)
    Uterine atony (70% of PPH)
    First-line
    IV / IMOnset <1 min IVDur ~1 hr
    Dose
    10-40 units IV
    In 500-1000 mL NS/LR, infuse rapidly. IM 10 units if no IV.
    • • Avoid undiluted IV bolus → hypotension
  • Methylergonovine(Methergine)
    If oxytocin inadequate
    Alternative
    IMOnset 2-5 minDur ~3 hr
    Dose
    0.2 mg IM
    May repeat q2-4h
    Volume: 1.0 mL @ 0.2 mg/mL
    Contraindicated: HTN; Preeclampsia; Cardiovascular disease
  • Carboprost(Hemabate)
    Refractory atony
    Alternative
    IMOnset 5-15 minDur ~2 hr
    Dose
    250 mcg IM
    Repeat q15-90 min, max 8 doses (2 mg)
    Volume: 1.0 mL @ 250 mcg/mL
    • • Side effects: diarrhea, fever, bronchospasm
    Contraindicated: Asthma
  • Misoprostol(Cytotec)
    When injectables contraindicated/unavailable
    Alternative
    PR / SLOnset 10-20 minDur ~2 hr
    Dose
    800-1000 mcg PR
    or 600-800 mcg SL
    Volume: 0.01 mL @ 200 mcg tab
  • Tranexamic Acid (TXA)
    Adjunct — give within 3 hr of bleeding onset
    Rescue
    IVOnset ImmediateDur ~3 hr
    Dose
    1 g IV
    Over 10 min. (15 mg/kg = 1000 mg, capped at 1 g.) Repeat 1 g if bleeding continues after 30 min.
    Volume: 10.0 mL @ 100 mg/mL

Uterotonics for PPH

TXA timing calculator (3-hr window)

0 min1 hr (best)3 hr (cutoff)
120 min remaining in window
Recommendation
GIVE 1 g IV NOW

Maximum mortality benefit when given within the first hour (CRASH-2/WOMAN trials).

Standard TXA dose
  • • 1 g IV over 10 min (over ~1 mL/min for trauma; faster acceptable in PPH)
  • • May repeat 1 g if bleeding continues after 30 min
  • • Pediatric: 15 mg/kg (max 1 g) over 10 min

Shoulder Dystocia

• Inability to deliver fetal shoulders after head delivery — true obstetric emergency. • Call for help immediately (OB, pediatrics, anesthesia). • HELPERR mnemonic: H — Call for Help E — Evaluate for Episiotomy L — Legs (McRoberts maneuver — hyperflex maternal hips) P — Suprapubic Pressure (NOT fundal pressure) E — Enter (rotational maneuvers — Rubin II, Woods screw, reverse Woods) R — Remove posterior arm R — Roll patient to hands/knees (Gaskin maneuver) • Avoid fundal pressure — worsens impaction.

Shoulder dystocia — uterine relaxation

Adjunct ONLY after HELPERR maneuvers fail and uterine tone is preventing manipulation. Do not delay maneuvers for drug.

Weight70 kg
  • Nitroglycerin
    Fastest uterine relaxation; preferred in dystocia
    First-line
    IV / SLOnset 30-90 secDur 1-2 min
    Dose
    50-200 mcg IV
    Or 400 mcg SL spray; may repeat q1-2 min × 3
    Volume: 2.0 mL @ 100 mcg/mL
    • • Brief duration ideal — relaxes then resolves quickly
    • • Have IV fluids ready for hypotension
    Contraindicated: Maternal hypotension (SBP <100); PDE5 inhibitor in last 24 hr
  • Terbutaline(Brethine)
    Use if no IV access or NTG unavailable
    Alternative
    SC / IVOnset 5-15 min SCDur 1-4 hr
    Dose
    0.25 mg SC
    Or 0.125-0.25 mg IV slow push; may repeat q15-30 min
    Volume: 0.25 mL @ 1 mg/mL
    • • Slower onset than NTG — less ideal in true dystocia
    • • Maternal tachycardia, hyperglycemia
    Contraindicated: Maternal tachyarrhythmia; Uncontrolled hyperthyroidism
  • Magnesium Sulfate
    Last-resort uterine relaxation if others fail
    Rescue
    IVOnset Mins
    Dose
    4 g IV
    Over 5-10 min (faster than eclampsia load)
    Volume: 8.0 mL @ 0.5 g/mL (50%)
    • • Have calcium gluconate at bedside
    • • Watch for maternal respiratory depression

Umbilical Cord Prolapse

• Cord palpated/visualized in vagina before fetus — true emergency, immediate delivery required. • Elevate presenting part off cord with examiner's hand (do not remove until C-section). • Place mother in knee-chest or steep Trendelenburg position. • Fill bladder with 500-700 mL saline via Foley to elevate fetal head. • Provide O2, IV fluids, tocolytic (terbutaline 0.25 mg SC) if uterine contractions. • Emergency C-section unless vaginal delivery imminent.

Acute tocolysis

Buy time for emergent delivery — relax uterus.

Weight70 kg
  • Terbutaline(Brethine)
    Acute tocolysis
    First-line
    SCOnset 5-10 minDur 1-4 hr
    Dose
    0.25 mg SC
    May repeat in 15-30 min
    Volume: 0.25 mL @ 1 mg/mL
    • • Maternal tachycardia, hyperglycemia
    Contraindicated: Maternal tachyarrhythmia; Uncontrolled hyperthyroid
  • Nitroglycerin
    Tocolysis if terbutaline contraindicated
    Alternative
    IV / SLOnset 1-2 minDur 5-10 min
    Dose
    50-100 mcg IV
    or 400 mcg SL spray; repeat q1-2 min
    Volume: 1.0 mL @ 100 mcg/mL
    Contraindicated: Maternal hypotension
  • Magnesium Sulfate
    If hemodynamically stable, slower onset
    Alternative
    IVOnset Mins
    Dose
    4 g IV
    Over 20 min, then 1-2 g/hr
    Volume: 8.0 mL @ 0.5 g/mL (50%)

Emergency Delivery (Precipitous Labor)

• Indicated when delivery is imminent and transfer not feasible. • Position mother — semi-recumbent with hips flexed. • Support perineum, control head delivery (avoid precipitous expulsion). • Check for nuchal cord — reduce over head or clamp/cut if tight. • Deliver anterior shoulder (gentle downward traction) then posterior shoulder. • Clamp cord ~2 cm and ~5 cm from infant after 30-60 sec delayed clamping (if vigorous). • Deliver placenta with gentle cord traction + suprapubic pressure (Brandt-Andrews maneuver). • Inspect placenta for completeness; assess for lacerations. • Initiate oxytocin after delivery to prevent PPH.

HELLP Syndrome

• Severe variant of preeclampsia: Hemolysis, Elevated Liver enzymes, Low Platelets. • Presents with RUQ/epigastric pain, nausea/vomiting, malaise, headache; hypertension may be mild or absent. • Labs: schistocytes on smear, LDH >600, AST/ALT >2× ULN, platelets <100k, haptoglobin low, indirect bili elevated. • Complications: DIC, abruption, hepatic hematoma/rupture, AKI, pulmonary edema, stroke. • Management: stabilize BP (see Preeclampsia), magnesium for seizure prophylaxis, transfuse platelets if <20k or <50k with bleeding/surgery, dexamethasone may improve labs, definitive treatment is delivery — emergent OB consult.

Ectopic Pregnancy

Reproductive-age woman + abdominal pain / vaginal bleeding / syncope + positive βhCG = ectopic until proven otherwise.

Workup
  • Quantitative βhCG, CBC, type & screen (Rh status)
  • TVUS: look for IUP (gestational sac + yolk sac). Free fluid in cul-de-sac + adnexal mass = highly concerning
  • Discriminatory zone: IUP should be visible on TVUS when βhCG >1500–2000 mIU/mL
  • Coags + crossmatch 2 units PRBC if unstable or large hemoperitoneum
First-line treatment
  • UNSTABLE (hypotension, peritonitis, large free fluid): 2 large-bore IVs, IV crystalloid, blood, NPO → emergent OB/Gyn for laparotomy/laparoscopy
  • STABLE + confirmed unruptured ectopic AND mass <3.5 cm AND no FHR AND βhCG <5000: Methotrexate 50 mg/m² IM × 1 (per OB) with day 4 & 7 βhCG follow-up
  • RhoGAM if Rh-negative (50 mcg <12 wk, 300 mcg ≥12 wk) within 72 h
  • Pain control: IV fentanyl or morphine; antiemetic PRN
Red flags / Do not miss
  • Hemodynamic instability, syncope, shoulder-tip pain (diaphragmatic irritation from hemoperitoneum)
  • Peritoneal signs / rebound / guarding
  • Heterotopic pregnancy (especially after IVF) — IUP does NOT exclude ectopic
  • Cervical, interstitial, or cesarean-scar ectopic — high rupture risk, consult OB urgently
  • MTX contraindicated: rupture, instability, hepatic/renal disease, immunodeficiency, breastfeeding, PUD
Disposition
  • Surgical / unstable: OR with OB/Gyn
  • Medical management: admit or close OB follow-up with strict return precautions, no NSAIDs/folate while on MTX

Ectopic — Methotrexate (per OB)

Endometriosis

• Ectopic endometrial tissue → cyclic pelvic pain, dysmenorrhea, dyspareunia, infertility. • ER role: pain control, rule out other causes (ectopic, torsion, PID, appendicitis). • Workup: pelvic exam, βhCG, UA, pelvic US (often normal — diagnosis is laparoscopic). • Treatment: NSAIDs first-line, hormonal suppression (OCPs, progestins) — outpatient OB-Gyn referral.

Medications in Pregnancy

• Always weigh maternal benefit vs. fetal risk; consult pharmacy/OB when unclear. • Generally SAFE: Acetaminophen, Penicillins/Cephalosporins, Azithromycin, Clindamycin, Nitrofurantoin (avoid 1st tri & near term), Metronidazole, Ondansetron, Diphenhydramine, Heparin/LMWH, Insulin, Methyldopa, Labetalol, Hydralazine, Nifedipine. • AVOID / TERATOGENIC: ACE inhibitors / ARBs, Warfarin, Methotrexate, Misoprostol (unless for PPH/labor), Isotretinoin, Tetracyclines, Fluoroquinolones (relative), Aminoglycosides (relative), Statins, NSAIDs (after 20 wk — oligohydramnios; after 30 wk — premature ductal closure), Sulfonamides (near term). • Imaging: ultrasound and MRI without gadolinium are preferred; single CT with shielding is acceptable when needed.

Ovarian Cysts / Ovarian Torsion

• Most simple cysts <5 cm are physiologic and resolve. • Concerning: cyst >5 cm, sudden severe unilateral pelvic pain, N/V, peritoneal signs. • OVARIAN TORSION is a surgical emergency: sudden-onset sharp unilateral pelvic pain, N/V, palpable adnexal mass. • Workup: βhCG, CBC, UA, pelvic US with Doppler (decreased/absent flow suggests torsion but normal flow does NOT rule out). • Management: NPO, IV fluids, pain control (morphine/fentanyl), antiemetics, immediate OB-Gyn consult for laparoscopy if torsion suspected.

Pelvic Inflammatory Disease (PID)

Sexually active patient with pelvic/lower-abdominal pain — diagnose empirically; treat early to prevent infertility, ectopic, and TOA.

Workup
  • Minimum criteria (any one): cervical motion tenderness, uterine tenderness, OR adnexal tenderness
  • βhCG (always — rules out pregnancy/ectopic and changes regimen)
  • NAAT for GC/Chlamydia, wet mount, GC/CT culture if available
  • CBC, UA, HIV / syphilis / HBV screen
  • Pelvic ultrasound if severe pain, palpable mass, fever, or no improvement at 48–72 h — rule out tubo-ovarian abscess (TOA)
First-line treatment
  • OUTPATIENT (CDC 2021): Ceftriaxone 500 mg IM × 1 (1 g if ≥150 kg) + Doxycycline 100 mg PO BID × 14 d + Metronidazole 500 mg PO BID × 14 d
  • INPATIENT: Ceftriaxone 1 g IV q24h + Doxycycline 100 mg IV/PO q12h + Metronidazole 500 mg IV/PO q12h (alt: Cefoxitin 2 g IV q6h + Doxycycline)
  • Pregnancy: admit, IV regimen, OB consult; AVOID doxycycline — substitute azithromycin per OB
  • Pain control + antiemetics; remove IUD only if no improvement in 48–72 h
  • Treat all sexual partners from prior 60 days; abstain × 7 d after therapy
Red flags / Do not miss
  • Tubo-ovarian abscess on US — admit, IV antibiotics, possible drainage
  • Pregnancy + PID — admit
  • Peritonitis, sepsis, or unable to tolerate PO — admit
  • Failed outpatient therapy at 48–72 h — reassess, image, admit
  • Fitz-Hugh–Curtis syndrome (perihepatitis): RUQ pain mimicking cholecystitis
Disposition
  • Outpatient if mild–moderate, tolerating PO, reliable follow-up in 48–72 h
  • Admit if pregnant, TOA, severe illness, surgical abdomen not excluded, or failed outpatient therapy

PID — Outpatient regimen (CDC 2021)

• Ceftriaxone 500 mg IM × 1 (1 g if ≥150 kg) • PLUS Doxycycline 100 mg PO BID × 14 days • PLUS Metronidazole 500 mg PO BID × 14 days

PID — Inpatient regimen

• Ceftriaxone 1 g IV q24h + Doxycycline 100 mg IV/PO q12h + Metronidazole 500 mg IV/PO q12h • Alternative: Cefoxitin 2 g IV q6h + Doxycycline 100 mg IV/PO q12h • Continue IV until clinical improvement, then transition to PO doxy + metro to complete 14 days.

Pelvic Ultrasound — ER pearls

• First-trimester bleeding/pain: confirm IUP (gestational sac with yolk sac inside uterus). Pseudosac alone ≠ IUP. • Discriminatory zone: TVUS should see IUP at βhCG >1500-2000; transabdominal at >5000-6000. • Findings: yolk sac at ~5.5 wk TVUS, fetal pole at 6 wk, cardiac activity at 6-6.5 wk. • Free fluid in cul-de-sac + positive βhCG without IUP = ectopic until proven otherwise. • Doppler for ovarian torsion (limited sensitivity), tubo-ovarian abscess, retained products.

Pregnancy Wheel / Dating Calculator

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Pregnancy Dating — Reference

• EDD (Naegele's rule): LMP + 7 days − 3 months + 1 year (assumes regular 28-day cycle = LMP + 280 d). • Gestational age = weeks since LMP. Conception ≈ LMP + 14 d. • First-trimester ultrasound (CRL) is the most accurate dating method (±5–7 days through 13+6 wk). • Trimesters: 1st = 0–13+6 wk, 2nd = 14–27+6 wk, 3rd = 28 wk–delivery. • Viability ~23–24 wk; term 37–41+6 wk; postterm ≥42 wk.

RhoGAM & Rh-Negative Patients

• Rh(D)-negative pregnant patients with bleeding, trauma, or any pregnancy loss/termination should receive Rh immune globulin (RhoGAM) to prevent alloimmunization. • <12 wk gestation: 50 mcg (mini-dose) IM. • ≥12 wk gestation: 300 mcg IM within 72 hours of exposure. • Trauma in 2nd/3rd trimester: also obtain Kleihauer-Betke to assess for large fetomaternal hemorrhage requiring additional doses. • Postpartum: 300 mcg IM within 72 hr of delivery if neonate is Rh-positive.

Rh Immune Globulin (RhoGAM)

STD / STI — Common ER regimens (CDC 2021)

• Gonorrhea (uncomplicated): Ceftriaxone 500 mg IM × 1 (1 g if ≥150 kg). If chlamydia not excluded: + Doxycycline 100 mg PO BID × 7 days. • Chlamydia: Doxycycline 100 mg PO BID × 7 days. (Pregnancy: Azithromycin 1 g PO × 1.) • Trichomoniasis: Metronidazole 500 mg PO BID × 7 days (women) or 2 g PO × 1 (men). • Syphilis (1°/2°/early latent): Benzathine PCN G 2.4 million units IM × 1. • Syphilis (late latent / unknown duration): Benzathine PCN G 2.4 million units IM weekly × 3. • Genital herpes (first episode): Acyclovir 400 mg PO TID × 7-10 days OR Valacyclovir 1 g PO BID × 7-10 days. • Empiric ER coverage for cervicitis/urethritis: Ceftriaxone 500 mg IM + Doxycycline 100 mg PO BID × 7 d. • Treat partners; report per state law; offer HIV/syphilis/HBV/HCV screening.

Spontaneous Abortion (Miscarriage)

• Pregnancy loss <20 wk gestation. Subtypes: – THREATENED: bleeding, closed os, viable IUP. – INEVITABLE: bleeding, open os, products not yet passed. – INCOMPLETE: partial passage of POC, open os. – COMPLETE: all POC passed, closed os, empty uterus on US. – MISSED: fetal demise without bleeding/expulsion. – SEPTIC: infection + retained POC — emergency. • Workup: βhCG (quant), CBC, type & Rh, pelvic US, pelvic exam. • Management: hemodynamic stabilization, RhoGAM if Rh-negative, OB consult for D&C if heavy bleeding/incomplete/septic, pain control, emotional support, outpatient OB follow-up.

Vaginal Bleeding (Non-pregnant)

• Always check βhCG first. • Causes: anovulatory (PCOS, perimenopause), structural (PALM: Polyp, Adenomyosis, Leiomyoma, Malignancy), coagulopathy, endometritis, trauma, IUD-related. • Workup: CBC, type & screen, coags, TSH, prolactin (if indicated), pelvic exam, pelvic US. • Acute heavy bleeding (hemodynamically unstable): IV fluids, transfuse, IV conjugated estrogens 25 mg q4-6h until bleeding stops (max 24 h), or high-dose OCP taper, TXA 1300 mg PO TID × 5 d, emergent OB-Gyn consult for D&C/balloon tamponade.

Vaginal Bleeding in Pregnancy

Approach by trimester. Any pregnant patient with bleeding gets βhCG, Rh status, and a bedside US.

Workup
  • Vitals + tilt; assess volume of bleeding (clots, pads/hr, syncope)
  • Quantitative βhCG, CBC, type & cross (≥2 units PRBC), Rh status, coags + fibrinogen
  • Kleihauer-Betke if >20 wk with trauma or suspected abruption
  • Bedside / formal US: confirm IUP, fetal cardiac activity, placental location (rule out previa BEFORE any digital/speculum exam in 2nd/3rd trimester)
  • Continuous fetal monitoring if ≥23 wk gestation
  • Speculum exam ONLY after previa excluded — assess cervix, source, products of conception
First-line treatment
  • 2 large-bore IVs, NPO, supplemental O2, left lateral tilt if >20 wk
  • IV crystalloid bolus; transfuse PRBCs early — activate MTP for hemorrhagic shock
  • RhoGAM if Rh-negative: 50 mcg <12 wk, 300 mcg ≥12 wk (within 72 h)
  • Immediate OB consult for: instability, abruption, previa with active bleeding, uterine rupture, vasa previa, preterm labor
  • 1st trimester stable + threatened AB: pelvic rest, OB follow-up, return precautions
  • Anti-D-confirmed ectopic / SAB management — see Ectopic / Spontaneous Abortion guides
Red flags / Do not miss
  • PLACENTA PREVIA — painless bright-red bleeding 2nd/3rd tri. NO digital or speculum exam until US excludes previa
  • PLACENTAL ABRUPTION — painful bleeding, tender/rigid uterus, fetal distress; bleeding may be concealed
  • UTERINE RUPTURE — sudden severe pain, loss of fetal station, hemodynamic collapse (esp. prior C-section/VBAC)
  • VASA PREVIA — painless bleeding with rupture of membranes + acute fetal bradycardia → emergent C-section
  • Ruptured ectopic, molar pregnancy (very high βhCG, hyperemesis, large-for-dates uterus, theca-lutein cysts)
  • DIC: oozing IV sites, prolonged PT/PTT, low fibrinogen — give cryoprecipitate, FFP, platelets
Disposition
  • Unstable / 2nd–3rd trimester bleeding / abruption / previa / rupture: OR with OB; admit to L&D
  • Stable 1st trimester threatened AB with confirmed IUP: discharge with OB follow-up + strict return precautions

Vaginitis

• BACTERIAL VAGINOSIS: thin gray-white discharge, fishy odor, clue cells, pH >4.5, + whiff test. Tx: Metronidazole 500 mg PO BID × 7 d OR 0.75% gel intravaginal × 5 d, OR Clindamycin 2% cream × 7 d. • CANDIDIASIS: thick white "cottage cheese" discharge, pruritus, pH normal (<4.5), pseudohyphae on KOH. Tx: Fluconazole 150 mg PO × 1 (avoid 1st trimester); topical azoles in pregnancy. • TRICHOMONIASIS: frothy yellow-green discharge, strawberry cervix, motile trichomonads. Tx: Metronidazole 500 mg PO BID × 7 d (treat partner). • Send NAAT/wet mount; consider GC/CT testing.