Eduovisual
Pregnancy, Childbirth & Puerperium
Preterm labor: diagnosis and management
— Contractions without documented cervical change = "threatened preterm labor," not true PTL.
— Preterm birth subcategories: late preterm 34–36 6/7, moderate 32–33 6/7, very preterm 28–31 6/7, extremely preterm <28 weeks.
— Pregnant patient 20–36 weeks reporting menstrual-like cramping, low back pain, pelvic pressure, increased vaginal discharge, spotting, or rhythmic tightening.
— Vague symptoms are common; low threshold for evaluation because earliest tocolytic and corticosteroid window is the most impactful.
— Prior spontaneous preterm birth (strongest modifiable predictor).
— Short cervical length (<25 mm before 24 wk by TVUS).
— Multiple gestation, polyhydramnios, uterine anomalies (septate, bicornuate), prior cervical procedures (LEEP, cone).
— Infection: bacteriuria/UTI, BV, chorioamnionitis, periodontal disease, STIs.
— Short interpregnancy interval (<18 mo), tobacco/cocaine use, low BMI, Black race, age <18 or >35, late/no prenatal care.
Board pearl: The single strongest predictor of recurrent preterm birth is a prior spontaneous preterm delivery <37 weeks — this drives both progesterone prophylaxis and serial cervical length surveillance starting at 16 weeks.
— Rhythmic abdominal tightening every few minutes, sometimes painless.
— Low, dull back pain that comes and goes — frequently mistaken for musculoskeletal.
— Pelvic pressure ("baby feels like it's falling out").
— Change in vaginal discharge: mucoid, watery, blood-tinged ("bloody show").
— Menstrual-like cramping.
— Gush or continuous leak of fluid → suspect PPROM (preterm premature rupture of membranes), changes management drastically.
— Heavy bleeding → rule out abruption or previa before pelvic exam.
— Fever, foul discharge, uterine tenderness → chorioamnionitis, contraindicates tocolysis and mandates delivery.
— Decreased fetal movement → assess fetal status before focusing on contractions.
— Exact GA by best obstetric dating (LMP confirmed by first-trimester US is most reliable).
— Parity, prior preterm births and GA at delivery, prior cesarean, cervical procedures.
— Current pregnancy: singleton vs multifetal, placental location, GBS status, prior cervical length, 17-OH progesterone or vaginal progesterone use.
— Prenatal labs: blood type/Rh, GBS, infection screen, glucose tolerance.
— Tobacco, cocaine, methamphetamine (vasoconstriction → abruption, PTL).
— Recent UTI symptoms, dental infection, recent intercourse, group B Strep history.
— Domestic violence screening — abdominal trauma is a Step 3 mandatory ask in any pregnant patient with new contractions or bleeding.
— Braxton-Hicks: irregular, non-progressive, relieved by hydration/position change, no cervical change.
— True PTL: regular, increasing in intensity and frequency, with cervical change.
Key distinction: Painless cervical dilation in the mid-trimester (16–24 wk) with bulging membranes and no contractions is cervical insufficiency, not preterm labor — management is emergency cerclage, not tocolysis.
— Vitals (maternal HR, BP, temp, RR, SpO2) — tachycardia + fever raises concern for chorioamnionitis or sepsis.
— Continuous external fetal monitoring (EFM) + tocodynamometer — quantify contraction frequency, duration, fetal HR baseline and variability.
— Leopold maneuvers for fetal lie/presentation.
— Sterile speculum exam BEFORE digital exam if PPROM possible.
— Inspect for pooling of amniotic fluid in posterior fornix.
— Nitrazine test: amniotic fluid turns paper blue (pH >6.5).
— Ferning on dried slide under microscope.
— Inspect cervix visually for dilation, effacement, bleeding, prolapsed cord, or visible membranes.
— Obtain GBS, gonorrhea/chlamydia, and wet mount swabs if not recent.
— Document dilation (cm), effacement (%), station (–3 to +3), consistency, position.
— In PPROM, digital exams increase infection risk and should be deferred unless delivery is imminent.
— Fundal height to corroborate GA.
— Uterine tenderness → think abruption or chorioamnionitis.
— Tense, board-like uterus with vaginal bleeding → placental abruption until proven otherwise.
— Reassuring: baseline 110–160, moderate variability, accelerations, no late/recurrent variable decels.
— Non-reassuring tracing in PTL workup escalates urgency toward delivery rather than tocolysis.
CCS pearl: On a CCS case of suspected preterm labor, your first three orders should be continuous fetal monitoring, IV access with crystalloid bolus, and sterile speculum exam — before labs return, before tocolytics, and before any digital exam if rupture is on the differential.
— CBC (leukocytosis suggests infection; anemia changes resuscitation).
— Urinalysis + urine culture — UTI/pyelonephritis is a classic preterm labor trigger.
— Urine drug screen (cocaine/meth strongly associated with PTL and abruption).
— GBS culture if not done within 5 weeks — drives intrapartum antibiotic prophylaxis.
— Cervical/vaginal swabs: GC/CT, wet mount for BV/trich.
— Type & screen, especially if Rh-negative or bleeding.
— Sterile speculum: pooling + nitrazine + ferning = clinical PROM.
— Equivocal cases: commercial immunoassays (PAMG-1/AmniSure, IGFBP-1/Actim PROM).
— Avoid digital exams until rupture excluded.
— CL <20 mm before 30 weeks → high probability of preterm delivery within 7 days.
— CL ≥30 mm → very low likelihood; supports observation/discharge.
— CL 20–29 mm → consider fetal fibronectin to refine risk.
— Performed between 22 0/7 and 34 6/7 weeks, on intact membranes, no recent intercourse or digital exam (within 24 h).
— High negative predictive value (~99%) for delivery within 7–14 days when negative.
— Positive fFN is less specific — use to rule out, not rule in.
— Confirm GA, fetal presentation, estimated fetal weight, amniotic fluid index, placental location, anomalies.
— Multiple gestation status (chorionicity already known ideally).
Board pearl: The combination of negative fFN + cervical length ≥30 mm gives a <2% chance of delivery within 7 days — a classic Step 3 "safe to discharge with close follow-up" stem.
— Indicated when clinical chorioamnionitis is uncertain but suspected (e.g., PPROM with maternal tachycardia but no fever).
— Send fluid for Gram stain, glucose (<14 mg/dL suggests infection), WBC, culture, and lactate.
— A positive result mandates delivery, not continued expectant management.
— Renal/pelvic ultrasound if pyelonephritis suspected (hydronephrosis, stones).
— Right upper quadrant ultrasound if abdominal pain mimics cholecystitis or HELLP.
— MRI without contrast preferred over CT for non-OB abdominal pathology when feasible.
— BMP, LFTs, uric acid, LDH, haptoglobin, peripheral smear, urine protein/creatinine ratio or 24-h urine, platelet count.
— Rule out HELLP as a delivery indication masquerading as PTL.
— Fibrinogen <200 mg/dL in pregnancy is abnormal and points to DIC/abruption.
— Trends matter; a shortening cervix on serial TVUS in a high-risk patient supports admission and intervention even with equivocal contractions.
— If status unknown and delivery looks imminent, intrapartum PCR can guide antibiotic prophylaxis.
— In extreme prematurity (<26 wk), confirm absence of lethal anomalies before committing to aggressive resuscitation plans — informs counseling with neonatology.
Key distinction: Clinical chorioamnionitis (Triple I) is a clinical diagnosis — maternal fever ≥39.0 °C alone, or ≥38.0 °C plus fetal tachycardia, maternal leukocytosis, or purulent cervical discharge. Once diagnosed, delivery + broad-spectrum antibiotics is the rule regardless of GA; tocolysis is contraindicated.
— Regular contractions + cervical change or + short CL or + positive fFN with symptoms → admit.
— Contractions without cervical change, CL ≥30 mm, negative fFN → observe 4–6 h, reassess, discharge with precautions.
— Contraindications to tocolysis: chorioamnionitis, non-reassuring fetal status, severe preeclampsia/eclampsia, significant abruption with maternal/fetal instability, lethal fetal anomaly, intrauterine fetal demise, advanced labor (≥4 cm dilation often), GA ≥34 weeks (relative).
— Otherwise, the goal is to buy 48 hours for corticosteroid effect and maternal transfer.
— <24 weeks: Counsel with neonatology re: periviability; individualize resuscitation; corticosteroids from 22 0/7 if active resuscitation planned.
— 24 0/7–33 6/7 weeks: Betamethasone, tocolysis ×48 h, MgSO4 for neuroprotection <32 wk, GBS prophylaxis if indicated.
— 34 0/7–36 6/7 weeks (late preterm): Single course of betamethasone if no prior course and delivery likely within 7 days; tocolysis generally not recommended.
— ≥37 weeks: No longer preterm; manage as term labor.
— If current facility lacks appropriate NICU level for the GA, arrange maternal transport while stable — safer than neonatal transport after birth.
Step 3 management: For a patient at 30 weeks in confirmed PTL, your "core bundle" orders are: (1) IM betamethasone 12 mg q24h ×2, (2) IV magnesium sulfate for neuroprotection, (3) tocolytic for 48 h, (4) GBS prophylaxis per status, (5) NICU and neonatology consult, (6) maternal transfer if not at a Level III facility.
— Betamethasone 12 mg IM q24h ×2 doses (preferred) or dexamethasone 6 mg IM q12h ×4.
— Indicated 24 0/7–33 6/7 weeks at risk of delivery within 7 days; considered from 22 0/7 if resuscitation planned.
— Late preterm (34 0/7–36 6/7): single course if no prior course and delivery expected within 7 days — reduces neonatal respiratory morbidity.
— Rescue course: one additional course if >14 days since first course, before 34 wk, and delivery again likely within 7 days.
— Benefits: ↓ RDS, IVH, NEC, neonatal death.
— <32 weeks and delivery anticipated within 24 h.
— Typical: 4–6 g IV load over 20–30 min, then 1–2 g/h, usually for up to 12–24 h.
— Reduces cerebral palsy risk. Monitor DTRs, respirations, urine output, magnesium level; calcium gluconate is the antidote for toxicity.
— Nifedipine (CCB) — first line for most; 20–30 mg PO load then 10–20 mg q4–6h. Avoid with hypotension; do not combine with magnesium (risk of profound hypotension/neuromuscular blockade).
— Indomethacin (NSAID) — preferred <32 weeks; 50–100 mg load then 25–50 mg q4–6h. Avoid >32 wk (premature ductus closure, oligohydramnios). Limit to 48 h.
— Terbutaline (β-agonist) — SC 0.25 mg; black-box: no prolonged use, no oral terbutaline (maternal cardiac events, death). Short-term tocolysis only.
— Atosiban (oxytocin antagonist) — not FDA-approved in US.
— Penicillin G IV (or ampicillin); cefazolin for low-risk penicillin allergy; clindamycin/vancomycin by susceptibility for anaphylaxis-risk allergy.
Board pearl: Tocolytics do not improve neonatal outcomes by themselves — their job is to buy 48 hours so corticosteroids and magnesium can work, and to allow transport to a facility with appropriate NICU level.
— History-indicated cerclage (12–14 wk): ≥1 prior second-trimester loss attributed to painless cervical dilation, or prior cerclage.
— Ultrasound-indicated cerclage (before 24 wk): singleton, prior spontaneous preterm birth <34 wk, and CL <25 mm on TVUS.
— Exam-indicated ("rescue") cerclage: painless dilation with visible/bulging membranes <24 wk, no infection, no labor.
— Contraindications: active labor, chorioamnionitis, PPROM, significant bleeding, lethal anomaly, IUFD.
— Cerclage is not effective in multiple gestations and may be harmful.
— Vertex preterm singleton: vaginal delivery preferred when feasible.
— Preterm breech, especially <32 wk: cesarean generally preferred due to head-entrapment risk and limited evidence for vaginal preterm breech.
— Periviable (<25 wk): mode individualized; cesarean only if maternal indication or after explicit decision for active neonatal resuscitation, given maternal morbidity risk.
— Recommended in vigorous preterm neonates; ↓ IVH, transfusion need.
— Antenatal consult to counsel on survival/morbidity by GA, document shared decision-making.
— Confirm NICU bed availability before tocolysis fails or transfer window closes.
CCS pearl: For periviable PTL (22–25 wk), order a formal neonatology consult and document parental counseling about resuscitation goals before committing to cesarean for fetal indications — this is both an ethics and exam expectation on Step 3.
— Avoid β-agonist tocolytics (terbutaline) in maternal arrhythmia, hyperthyroidism, severe hypertension; risk of pulmonary edema, MI.
— Nifedipine preferred but watch BP in cardiac patients; avoid concurrent magnesium.
— Peripartum cardiomyopathy and pulmonary edema risk rises with tocolytics + corticosteroids + IV fluids — limit crystalloid to ~125 mL/h.
— Magnesium clears renally → toxicity risk with CrCl <30; reduce maintenance dose, follow Mg levels q6h, monitor DTRs and respirations.
— NSAIDs (indomethacin) worsen renal function and BP — avoid in preeclampsia or renal disease.
— Tocolysis generally contraindicated; delivery is the treatment.
— Steroids still given for fetal lung maturity if GA <34 wk and delivery not imminent within hours.
— Betamethasone causes transient hyperglycemia for 3–5 days; anticipate insulin requirement increases.
— Use sliding-scale or insulin infusion in poorly controlled cases.
— Indomethacin generally fine; avoid in aspirin-sensitive asthma.
— Terbutaline can worsen tachycardia but is bronchodilatory.
— Pyelonephritis, appendicitis, periodontal infection — treat the source; uterine activity often resolves.
— Suspected chorioamnionitis → deliver, no tocolysis.
— Cocaine/meth: rule out abruption; tocolysis after stabilization.
— Opioid use disorder: continue methadone or buprenorphine; do not abruptly taper.
Key distinction: Magnesium toxicity order — loss of DTRs first (~9–12 mg/dL), then respiratory depression (~12–18), then cardiac arrest (>25). Stop infusion, give calcium gluconate 1 g IV, support ventilation.
— Twins and higher-order multiples account for a disproportionate share of PTL; median GA at delivery ~36 wk for twins, ~32 wk for triplets.
— 17-OH progesterone and cerclage are NOT effective in multifetal pregnancies for prevention.
— Vaginal progesterone may be considered with short cervix in twins (evolving evidence).
— Magnesium neuroprotection and antenatal steroids: same indications by GA.
— Higher baseline PTL risk; also at risk for poor prenatal care attendance.
— Step 3 ethical layer: minors can usually consent to their own prenatal and labor care in most US states without parental consent (state-specific); document.
— Higher rates of comorbidities (HTN, DM) drive iatrogenic preterm delivery more than spontaneous PTL.
— Begin vaginal progesterone (200 mg suppository nightly) or — where still used — 17-OH progesterone caproate in selected patients starting 16 weeks (note: 17-OHPC has been withdrawn from US market; vaginal progesterone is current default).
— Serial TVUS cervical lengths every 1–2 wk from 16 to 24 wk.
— Decision framework: antenatal steroids, MgSO4, tocolysis, cesarean for fetal indication, active neonatal resuscitation — each is optional and contingent on shared decision-making.
— Survival without major morbidity rises sharply each week: ~30% at 23 wk → >70% at 25 wk in modern NICUs.
— Expectant management with latency antibiotics: ampicillin + azithromycin IV ×48 h, then amoxicillin PO ×5 d.
— Steroids, MgSO4 if <32 wk, no tocolysis after 34 wk.
Board pearl: 17-OH progesterone caproate (Makena) was withdrawn from the US market in 2023 after the PROLONG trial failed to confirm benefit — current first-line prevention for recurrent spontaneous PTL is vaginal progesterone in singletons with prior PTB or short cervix.
— Respiratory distress syndrome (RDS) — surfactant deficiency; mitigated by antenatal steroids.
— Intraventricular hemorrhage (IVH) — especially <32 wk; reduced by steroids, MgSO4, delayed cord clamping.
— Necrotizing enterocolitis (NEC) — favored by formula feeding; human milk protective.
— Retinopathy of prematurity (ROP) — driven by oxygen exposure and immaturity; screening per AAP.
— Bronchopulmonary dysplasia (BPD) — chronic oxygen need at 36 wk PMA.
— Sepsis (early-onset GBS, E. coli) — empiric ampicillin + gentamicin.
— Hypoglycemia, hypothermia, hyperbilirubinemia, feeding intolerance.
— Long-term: cerebral palsy, developmental delay, learning disabilities, vision/hearing impairment.
— Tocolytic adverse events: pulmonary edema (β-agonists, especially with fluid overload), hypotension (nifedipine), maternal arrhythmia (terbutaline), platelet dysfunction and renal effects (indomethacin).
— Magnesium toxicity: loss of DTRs, respiratory depression, cardiac arrest — antidote calcium gluconate.
— Chorioamnionitis → endometritis, sepsis, postpartum hemorrhage (atony in infected uterus).
— Iatrogenic preterm cesarean morbidity: hemorrhage, infection, implications for future placentation (accreta).
— NICU separation, postpartum depression risk doubles with preterm birth — screen at every postpartum visit with Edinburgh or PHQ-9.
— Preterm birth accounts for the largest single share of newborn hospitalization costs in the US.
Step 3 management: A patient on magnesium + nifedipine who develops dyspnea and crackles is presenting with pulmonary edema — stop both agents, give supplemental O2, IV furosemide, sit upright, check Mg level, obtain CXR/ECG, and consider switching tocolytic class.
— Magnesium toxicity with respiratory compromise.
— Pulmonary edema from tocolytics + fluids.
— Septic shock from chorioamnionitis or pyelonephritis.
— HELLP with hepatic hematoma, DIC, or AKI.
— Massive abruption with hemorrhagic shock and DIC.
— Periviable PTL (22–25 wk).
— Multiple gestation in PTL.
— Suspected accreta or anomalous placentation.
— Recurrent or refractory PTL despite tocolysis.
— Complex maternal disease (cardiac, renal transplant, lupus, sickle cell).
— Any expected delivery <34 wk.
— Anomalous fetus.
— Documented shared decision-making for periviable resuscitation.
— Default rule: transfer mother before delivery if local NICU level is insufficient.
— Level I: well-newborn nursery.
— Level II: ≥32 wk and ≥1500 g.
— Level III: <32 wk or <1500 g, requires sustained ventilatory support.
— Level IV: subspecialty surgical neonatal care.
— Admit: confirmed PTL with cervical change, PPROM, abruption, infection, non-reassuring tracing.
— Discharge with close follow-up (24–72 h): contractions resolved, no cervical change, CL ≥30 mm and/or fFN negative, reassuring fetal status, reliable patient and access to care.
CCS pearl: On a CCS case, ordering "transfer to tertiary-care center with Level III NICU" for a 27-week PTL patient before her cervix dilates to 6 cm is rewarded; waiting until she is in advanced labor and the baby must transfer postnatally is penalized for delayed disposition.
— Irregular, non-progressive, painless or mildly uncomfortable, no cervical change. Resolve with hydration and rest. Reassurance + return precautions.
— Painless cervical dilation in the second trimester, often with bulging membranes; no or minimal contractions.
— Management: emergency or history-/US-indicated cerclage, not tocolysis.
— Rupture without labor. Pooling, ferning, nitrazine positive.
— Management: latency antibiotics, steroids, MgSO4 <32 wk, deliver at 34 wk or sooner for infection/non-reassuring status.
— Painful vaginal bleeding, tense/tender uterus, frequent low-amplitude contractions, possible non-reassuring tracing, ± DIC.
— Cocaine, trauma, HTN, prior abruption are risks. Management: stabilize, deliver if maternal/fetal compromise.
— Painless bleeding; previa diagnosed on US; vasa previa presents with bleeding at rupture with fetal bradycardia.
— No digital exam until placenta location confirmed.
— Fever, fetal/maternal tachycardia, uterine tenderness, leukocytosis. Deliver + broad-spectrum antibiotics (ampicillin + gentamicin ± clindamycin for cesarean).
— Sharp, lateralized lower abdominal pain with movement; no contractions, no cervical change.
— Recheck GA dating — a misdated pregnancy at "35 weeks" may actually be 38 wk; tocolysis is inappropriate.
Key distinction: Painful contractions with bleeding + rigid uterus = abruption (clinical diagnosis; ultrasound often misses it); painless bleeding without contractions = previa (US confirms). Both are bleeding emergencies but the management priorities diverge.
— Cystitis / pyelonephritis — dysuria, frequency, CVA tenderness, fever; pyelo is a major PTL trigger. Treat with IV ceftriaxone until afebrile 24–48 h, then PO; avoid nitrofurantoin near term and sulfa in third trimester.
— Nephrolithiasis — flank pain radiating to groin; renal/pelvic US, then low-dose CT if needed.
— Appendicitis — pain often higher and more lateral in pregnancy as uterus displaces appendix; MRI preferred imaging if US non-diagnostic. Surgical emergency.
— Cholecystitis / cholelithiasis — RUQ pain, Murphy sign, US-diagnosed; laparoscopic cholecystectomy can be done in any trimester (second trimester ideal).
— Constipation, gastroenteritis, GERD — common pregnancy-related GI complaints, no cervical change.
— HELLP, AFLP, intrahepatic cholestasis of pregnancy — RUQ pain, elevated LFTs, ± pruritus.
— Round ligament pain, symphysis pubis dysfunction, sciatica.
— Herpes zoster, shingles dermatomal pain mistaken for visceral.
— Ovarian torsion — sudden, severe unilateral pain ± nausea; Doppler US. Often requires laparoscopy.
— Degenerating fibroid — focal uterine tenderness, low-grade fever, conservative management with acetaminophen ± short NSAID course.
— Pulmonary embolism — pregnancy is hypercoagulable; dyspnea, tachycardia. Workup: CXR → lower-extremity Doppler → V/Q or CTPA. Anticoagulate with LMWH.
Board pearl: A pregnant patient with fever, flank pain, and "contractions" is pyelonephritis until proven otherwise — treat the infection aggressively, and the contractions often resolve without tocolytics.
— Document the index PTL details: GA at delivery, suspected etiology (infection, abruption, idiopathic, iatrogenic), cervical length history, prior interventions.
— Counsel: recurrence risk ~15–30% after one prior spontaneous PTL; higher with earlier index delivery and short interpregnancy interval.
— Recommend ≥18 months between delivery and next conception; <6 months doubles PTL risk.
— Discuss contraception before discharge — LARC (IUD, implant) ideal; postplacental IUD if available.
— Singleton with prior spontaneous PTB <37 wk → vaginal progesterone 200 mg nightly from 16 to 36 wk; serial TVUS cervical lengths every 1–2 wk from 16 to 24 wk.
— Short CL <25 mm before 24 wk → vaginal progesterone (with or without prior PTB).
— Prior PTB + short CL → consider cerclage.
— 17-OHPC is no longer used in the US.
— Smoking cessation (counseling + nicotine replacement if needed).
— Treat BV and asymptomatic bacteriuria, periodontal care.
— Optimize maternal nutrition, BMI, glycemic control, BP.
— Address substance use disorders (referral, MAT for OUD).
— Screen and treat STIs preconceptionally.
— Preterm birth (and preeclampsia) confer increased lifetime cardiovascular risk — counsel about long-term BP, lipid, glucose surveillance and lifestyle modification.
— Ensure NICU graduate clinic, audiology, ophthalmology (ROP), and early-intervention referrals are in place before discharge.
Step 3 management: At the 6-week postpartum visit after preterm delivery, your "secondary prevention" order set includes: contraception (LARC preferred), depression screen, BP check, glycemic follow-up if gestational DM, plan for vaginal progesterone in any future pregnancy from 16 wk, and smoking-cessation counseling.
— Continuous EFM + toco during active intervention; intermittent thereafter if stable.
— MgSO4 monitoring: DTRs hourly, respirations, urine output (≥30 mL/h), Mg level if symptoms or renal impairment.
— Glucose checks q4–6 h × 3–5 days after betamethasone, especially in DM.
— Daily CBC, temperature curve in PPROM; vigilance for chorioamnionitis.
— Twice-weekly NST/BPP after 32 wk in stable PPROM.
— Follow-up within 3–7 days with OB; immediate return for new bleeding, leaking fluid, regular contractions, fever, decreased fetal movement.
— Activity modification individualized; strict bed rest is NOT recommended (no benefit, ↑ VTE risk).
— Continue vaginal progesterone if indicated.
— Serial TVUS cervical lengths every 1–2 wk from 16 to 24 wk.
— Growth ultrasounds q3–4 wk in third trimester if growth restriction concerns.
— Influenza, Tdap (27–36 wk), COVID-19, RSV (32–36 wk) vaccinations on schedule.
— Fetal kick counts after 28 wk.
— Recognition of preterm labor symptoms.
— Contraindication of smoking, illicit drugs, alcohol.
— Mental health: anticipate NICU stress, postpartum depression screening.
— Document discussions about mode of delivery, neonatal resuscitation thresholds (especially periviable), breastfeeding plans, postpartum contraception.
Board pearl: Bed rest does not prevent preterm birth and may worsen outcomes via VTE, deconditioning, and depression — recommending it on a Step 3 stem is a distractor; the correct answer is targeted progesterone, cerclage when indicated, and treatment of modifiable risks.
— Between 22 0/7 and 25 6/7 wk, decisions about antenatal steroids, MgSO4, cesarean for fetal indication, and active neonatal resuscitation should be made with explicit informed consent that reflects realistic survival and morbidity data.
— Document shared decision-making notes including survival statistics, expected NICU course, and parental values; revisit if conditions change.
— Respect parental refusal of cesarean for fetal indication at periviable GA — maternal autonomy is paramount.
— Minor pregnant patient: in most US states, pregnant minors can consent to care related to their pregnancy and their newborn without parental involvement — but practices vary by state; consult risk management.
— Patient with substance intoxication or altered capacity: if delivery is emergent and capacity is impaired, follow emergency exception to consent; involve surrogate when feasible.
— Intimate partner violence (IPV) during pregnancy: routine screening; offer resources but reporting to law enforcement generally requires patient consent (state-specific).
— Positive maternal/neonatal toxicology: many states mandate child welfare notification; know local law and document supportive interventions, not just punitive reporting.
— Maternal in-utero transfer is safer than neonatal transfer — failing to transfer in time is a recurring sentinel-event theme.
— Tocolytic + magnesium combinations are high-risk; standardized order sets, paired smart pumps, and bedside Mg toxicity protocols reduce errors.
— Look-alike/sound-alike risk: betamethasone vs dexamethasone dosing schedules differ; verify.
— Black patients have ~50% higher preterm birth rates than white patients; this is largely driven by structural racism, not biology. Step 3 may test recognition of this disparity and the duty to address it through equitable care models.
Key distinction: Maternal autonomy generally supersedes fetal interests in US law — even a competent pregnant patient refusing a recommended cesarean for fetal indications must have that decision respected, with rigorous informed-consent documentation.
Board pearl: If a Step 3 stem shows you a stable patient at 30 wk with regular contractions and 2 cm dilation, the single best next step is usually IM betamethasone — even before you choose a tocolytic, because steroids are what actually improve outcomes.
— 28-wk patient with cramping, CL 32 mm, fFN negative, no cervical change after 4 h observation. Next step: discharge home with OB follow-up in 3–7 days — not admission or tocolysis.
— Preeclamptic patient on MgSO4 develops loss of DTRs and RR 8. Next step: stop magnesium, give calcium gluconate 1 g IV, support ventilation, check Mg level.
— 28-wk PTL, no contraindications. Best tocolytic: indomethacin (preferred <32 wk).
— 33-wk PTL. Best tocolytic: nifedipine (avoid indomethacin >32 wk).
— 35-wk patient likely to deliver in 48 h, no prior steroid course. Next step: single course of betamethasone, no tocolysis, no MgSO4.
— Fever, fetal tachycardia, uterine tenderness, contractions. Next step: delivery + ampicillin + gentamicin, not tocolysis.
— Multipara with prior spontaneous PTB at 32 wk now at 14 wk. Next step: start vaginal progesterone at 16 wk and serial TVUS cervical lengths from 16–24 wk.
— 23-wk patient in PTL. Best next step: neonatology consult and shared decision-making about active resuscitation before committing to delivery mode.
— Fever, CVA tenderness, contractions. Next step: IV ceftriaxone, IV fluids, monitor — contractions usually resolve.
— Patient on MgSO4 receives nifedipine and becomes hypotensive. Cause: synergistic hypotension/NM blockade; avoid combination.
Step 3 management: Whenever the stem says "most likely to improve neonatal outcome," the answer is almost always antenatal corticosteroids — not the tocolytic, not the antibiotic, not the cerclage.
Preterm labor — defined as regular contractions with cervical change between 20 0/7 and 36 6/7 weeks — is managed by confirming the diagnosis (cervical exam, TVUS cervical length, fetal fibronectin), then deploying the evidence-based bundle of antenatal corticosteroids, magnesium sulfate for neuroprotection if <32 weeks, a 48-hour tocolytic to buy time, GBS prophylaxis, and in-utero transfer to an appropriate-level facility — while ruling out chorioamnionitis, abruption, and PPROM that mandate delivery instead of delay.
Board pearl: When in doubt on a Step 3 PTL stem, your highest-yield single order is betamethasone, followed by magnesium sulfate (if <32 wk) and maternal in-utero transfer to a Level III center — these three move the needle on neonatal outcomes far more than any tocolytic choice ever will.