Pregnancy Complications - USMLE Step 2

SECTION 1

Historical Context & Motivation

Throughout most of human history, pregnancy was among the most dangerous physiological states a woman could experience, with maternal mortality rates exceeding 1,000 per 100,000 live births in pre-industrial societies. The recognition and classification of pregnancy complications as distinct clinical entities — rather than an inevitable consequence of childbearing — has been one of the great triumphs of modern medicine. Understanding the historical trajectory of obstetric care provides important context for why current screening protocols, diagnostic thresholds, and management algorithms exist in their present forms.

1843 • Oliver Wendell Holmes & Puerperal Fever

Holmes published his landmark essay arguing that puerperal fever was contagious and transmitted by the hands of attending physicians, laying groundwork for infection control in obstetrics.

1897 • Eclampsia Classification Formalized

The distinction between preeclampsia and eclampsia was formally codified, enabling differentiated management strategies based on seizure activity and end-organ damage.

1940s • Rh Isoimmunization Discovered

Landsteiner and Wiener identified the Rh factor, explaining erythroblastosis fetalis and eventually leading to the development of RhoGAM prophylaxis in 1968.

1970s • Magnesium Sulfate for Seizure Prophylaxis

Randomized controlled trials established magnesium sulfate as the gold standard for eclamptic seizure prevention, replacing prior barbiturate regimens with far superior maternal and fetal outcomes.

2013 • ACOG Redefines Hypertensive Disorders

The American College of Obstetricians and Gynecologists published updated criteria removing the requirement for proteinuria in diagnosing preeclampsia, instead emphasizing end-organ dysfunction as the defining feature.

Despite these advances, pregnancy complications remain a leading cause of maternal morbidity and mortality worldwide. The central challenge for clinicians — and for USMLE Step 2 examinees — is the ability to rapidly identify, classify, and initiate appropriate management for conditions that can progress from stable to life-threatening within hours. This lesson systematically addresses the highest-yield pregnancy complications, equipping you with the diagnostic frameworks and clinical reasoning skills tested on board examinations.

SECTION 2

Core Principles & Classification

Pregnancy complications can be organized into several overarching categories based on the primary pathophysiological mechanism and the trimester in which they most commonly present. A structured classification schema helps clinicians prioritize differential diagnoses when a pregnant patient presents with symptoms such as bleeding, hypertension, or altered fetal status. The following foundational concepts underpin every major obstetric complication and are essential to clinical decision-making.

Hypertensive Disorders

A spectrum ranging from gestational hypertension to preeclampsia with severe features, eclampsia, and HELLP syndrome. The unifying feature is endothelial dysfunction secondary to abnormal placentation.

Hemorrhagic Complications

Includes placenta previa, placental abruption, vasa previa, and postpartum hemorrhage. Rapid hemodynamic assessment and source identification are critical.

Gestational Diabetes Mellitus

Characterized by insulin resistance that exceeds the adaptive capacity of pancreatic β-cells, resulting in glucose intolerance first recognized in pregnancy. Screening occurs at 24–28 weeks with a glucose challenge test.

Ectopic & Molar Pregnancies

First-trimester complications including ectopic pregnancy (most commonly tubal) and gestational trophoblastic disease. Both require prompt recognition to prevent life-threatening hemorrhage or malignancy.

Preterm Labor & PPROM

Spontaneous labor before 37 weeks or preterm premature rupture of membranes (PPROM). Management depends on gestational age, with key decision points around the thresholds of viability and fetal lung maturity.

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KEY TAKEAWAY

Think of pregnancy complications like a triage system in an emergency department. Just as ED physicians categorize patients by acuity (immediate, emergent, urgent, non-urgent), you can stratify obstetric complications by their time-to-intervention window. Eclamptic seizures and placental abruption with fetal distress demand immediate intervention (minutes), while gestational diabetes and mild preeclampsia allow for deliberate outpatient management over weeks. The board exam frequently tests whether you can correctly triage the urgency of a clinical scenario.

SECTION 3

Visual Overview of Hypertensive Disorders in Pregnancy

The hypertensive disorders of pregnancy represent a continuum of disease severity, driven by abnormal trophoblastic invasion of the spiral arteries during the first and early second trimesters. The following diagram illustrates the spectrum of hypertensive disease, the diagnostic criteria distinguishing each entity, and the key management decision points that clinicians must navigate.

The spectrum of hypertensive disorders progresses from left (gestational hypertension) to right (eclampsia/HELLP). Note how the delivery timing threshold decreases with increasing severity: 37 weeks for gestational HTN/mild preeclampsia, 34 weeks for severe features, and immediate delivery for eclampsia regardless of gestational age. The bottom panels summarize universal pharmacological interventions and high-yield board pearls.

As shown in the diagram, the clinical progression from gestational hypertension to eclampsia is not always linear — patients may present de novo with severe features or HELLP syndrome without preceding mild disease. The overarching principle is that delivery is the definitive treatment for all hypertensive disorders of pregnancy. Every other intervention — magnesium sulfate for seizure prophylaxis, labetalol or hydralazine for acute blood pressure control, betamethasone for fetal lung maturity — serves only to stabilize the patient until delivery can be safely accomplished. The gestational age at which the risks of prematurity are outweighed by the risks of continuing the pregnancy defines the critical management threshold for each category.

SECTION 4

Pathophysiology & Mechanisms

Abnormal Placentation: The Root Cause

The pathophysiology of preeclampsia is fundamentally a two-stage disease model. In Stage 1, which occurs during the first trimester, there is incomplete remodeling of the maternal spiral arteries by invasive cytotrophoblasts. Normally, these fetal-derived cells transform the narrow, muscular spiral arteries into wide, low-resistance conduits capable of supplying the massive blood flow demands of the developing placenta. When this remodeling fails, the result is uteroplacental ischemia — a persistent state of relative hypoperfusion that generates oxidative stress within the placental bed.

In Stage 2, the ischemic placenta releases a cascade of anti-angiogenic factors — most notably soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin — into the maternal circulation. These factors antagonize pro-angiogenic molecules such as vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), causing widespread systemic endothelial dysfunction. This endothelial injury manifests as vasospasm, increased vascular permeability, and activation of the coagulation cascade, producing the clinical triad of hypertension, proteinuria, and edema.

Key Molecular Pathways

ANGIOGENIC IMBALANCE RATIO

sFlt-1 / PlGF ratio > 85 → high probability of preeclampsia

An elevated sFlt-1/PlGF ratio reflects the anti-angiogenic state. Although not yet standard of care in the United States, European guidelines incorporate this ratio into risk stratification. A ratio > 85 has a positive predictive value of ~37% for developing preeclampsia within 4 weeks, while a ratio ≤ 38 has a negative predictive value of ~99.3% for ruling it out within 1 week.

Placental Abruption Pathophysiology

In placental abruption, the fundamental mechanism is premature separation of the normally implanted placenta from the uterine wall. This begins with rupture of maternal decidual arteries, creating a retroplacental hematoma that progressively shears the placenta away from its blood supply. Risk factors include chronic hypertension, cocaine use, abdominal trauma, and prior abruption. The clinical presentation depends on the degree of separation: partial abruption may present with vaginal bleeding and a tender, rigid uterus, while a complete or concealed abruption can cause catastrophic hemorrhagic shock with a board-like abdomen and absent fetal heart tones. Couvelaire uterus — a pathological finding of myometrial infiltration by blood — can impair uterine contractility and worsen postpartum hemorrhage.

Gestational Diabetes Mellitus: Metabolic Mechanism

Normal pregnancy induces progressive insulin resistance mediated by placental hormones including human placental lactogen (hPL), cortisol, progesterone, and tumor necrosis factor-α. In most women, pancreatic β-cells compensate by increasing insulin secretion. Gestational diabetes mellitus (GDM) develops when β-cell reserve is insufficient to overcome this physiological resistance. The resulting maternal hyperglycemia drives fetal hyperinsulinemia via facilitated diffusion of glucose across the placenta, producing fetal macrosomia, neonatal hypoglycemia, and increased risk of shoulder dystocia during delivery.

SECTION 5

Detailed Classification of Antepartum Hemorrhage

Antepartum hemorrhage — defined as vaginal bleeding after 20 weeks of gestation — is among the most clinically urgent presentations in obstetrics. The three major etiologies are placenta previa, placental abruption, and vasa previa. Distinguishing among them rapidly is a cornerstone of obstetric emergency management and a favorite topic of board examiners.

Side-by-side comparison of the three major causes of antepartum hemorrhage. Note the critical clinical distinguishers: placenta previa presents with painless bright red bleeding and a non-tender uterus; placental abruption presents with painful dark bleeding and a rigid uterus; and vasa previa presents with bleeding at membrane rupture accompanied by sudden fetal bradycardia.

Feature	Placenta Previa	Placental Abruption	Vasa Previa
Bleeding character	Painless, bright red	Painful, dark red (may be concealed)	Painless, occurs at ROM
Uterine tone	Soft, non-tender	Rigid, board-like	Soft, non-tender
Fetal status	Usually reassuring	Often non-reassuring	Rapid fetal distress/demise
Diagnosis	Transabdominal ultrasound	Clinical; US insensitive	Transvaginal US with Doppler
Key risk factors	Prior C-section, multiparity, prior previa	HTN, cocaine, trauma, prior abruption	Velamentous cord insertion, low-lying placenta, IVF
Delivery	Planned C-section 36–37 wk	Emergent delivery	Planned C-section 34–35 wk

Comparison of the three major causes of antepartum hemorrhage

SECTION 6

Worked Clinical Vignette

The following clinical vignette demonstrates the systematic approach to diagnosing and managing a pregnancy complication, mirroring the format and reasoning expected on USMLE Step 2 CK.

Clinical Vignette: 32-Year-Old G2P1 at 34 Weeks with Headache and Elevated BP

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Step 1 — Identify Key Clinical Features

A 32-year-old G2P1 at 34 weeks of gestation presents to labor and delivery with a severe headache and blurred vision. Her blood pressure is 168/110 mmHg. She has 3+ proteinuria on dipstick. Labs reveal platelets 88,000/μL, AST 245 U/L, ALT 312 U/L, creatinine 1.3 mg/dL, and LDH 680 U/L. The key findings to extract are: hypertension, visual symptoms (cerebral involvement), thrombocytopenia, elevated liver enzymes, elevated creatinine, and elevated LDH suggestive of hemolysis.

Severe hypertension + cerebral symptoms + thrombocytopenia + elevated LFTs + hemolysis markers
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Step 2 — Formulate the Diagnosis

This presentation fulfills criteria for preeclampsia with severe features based on multiple criteria: SBP ≥ 160 mmHg, DBP ≥ 110 mmHg, platelet count < 100,000/μL, hepatic transaminases > 2× the upper limit of normal, and cerebral symptoms (headache and visual disturbance). Additionally, the combination of hemolysis (elevated LDH), elevated liver enzymes, and low platelets meets the diagnostic triad for HELLP syndrome.

Diagnosis: Preeclampsia with severe features / HELLP syndrome
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Step 3 — Initiate Immediate Stabilization

The immediate priorities are (1) seizure prophylaxis with intravenous magnesium sulfate — loading dose of 4–6 g IV over 15–20 minutes followed by a maintenance infusion of 1–2 g/hour; and (2) acute blood pressure control with IV labetalol (20 mg initial dose, escalating as needed) or IV hydralazine (5–10 mg IV). The target is to reduce SBP to < 160 and DBP to < 110 to prevent maternal stroke or abruption while avoiding precipitous drops that could compromise uteroplacental perfusion.

MgSO₄ 4–6 g IV load → 1–2 g/hr maintenance; Labetalol 20 mg IV or Hydralazine 5–10 mg IV for BP control
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Step 4 — Administer Corticosteroids for Fetal Lung Maturity

At 34 weeks, the fetus is preterm and would benefit from antenatal corticosteroids if delivery can be safely delayed by 48 hours. Administer betamethasone 12 mg IM × 2 doses, 24 hours apart. However, in the setting of HELLP syndrome, delivery should not be significantly delayed solely for steroid benefit if the maternal condition is unstable or deteriorating. In this case, if the patient stabilizes on magnesium and antihypertensives, a brief delay of up to 48 hours may be reasonable with close monitoring.

Betamethasone 12 mg IM × 2 doses (24 hours apart) — but do not delay delivery if maternal condition worsens
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Step 5 — Plan Definitive Treatment: Delivery

The definitive treatment for HELLP syndrome and severe preeclampsia is delivery. At 34 weeks with HELLP, delivery is indicated regardless of fetal lung maturity status. The mode of delivery depends on cervical favorability and fetal presentation — induction of labor with continuous fetal monitoring is appropriate if the cervix is favorable and there is no evidence of fetal distress. If the cervix is unfavorable or there is non-reassuring fetal status, cesarean delivery is the preferred approach. Postpartum monitoring must continue for at least 48–72 hours, as HELLP syndrome can worsen or first present after delivery. Continue magnesium sulfate for 24–48 hours postpartum.

Delivery at 34 weeks; continue MgSO₄ for 24–48 hours postpartum; monitor platelets and LFTs for nadir

SECTION 7

Management Comparison: Timing of Delivery

One of the most commonly tested decision points in obstetric management is determining when to deliver. The balance between the risks of prematurity and the risks of continuing a complicated pregnancy is at the heart of obstetric care. The following table consolidates delivery timing recommendations for the major pregnancy complications, organized by the condition and its severity.

Condition	Recommended Delivery Timing	Key Considerations
Gestational HTN	37 0/7 weeks	Monitor for progression to preeclampsia; weekly labs and BPs
Preeclampsia without severe features	37 0/7 weeks	Expectant management with twice-weekly monitoring; betamethasone if <37 wk
Preeclampsia with severe features	34 0/7 weeks (or sooner if unstable)	MgSO₄ + antihypertensives; corticosteroids; may delay 48h for steroids if stable
Eclampsia	Immediate after stabilization	Stabilize seizures with MgSO₄ first; delivery regardless of GA
HELLP syndrome	Immediate (may delay 24–48h if stable)	Platelet nadir usually 24–48h postpartum; transfuse if <20,000 or active bleeding
Placenta previa (stable)	36–37 weeks (C-section)	Hospitalize for recurrent bleeding; no digital cervical exams; type and screen
Placental abruption	Emergent	Vaginal delivery if stable and vertex; C-section if unstable or non-reassuring FHR
GDM (diet-controlled)	39–40 6/7 weeks	No indication for early induction unless additional risk factors
GDM (insulin-requiring)	39 0/7 weeks	Antenatal testing from 32 weeks; consider early delivery if poorly controlled
PPROM (<34 weeks)	34 0/7 weeks	Latency antibiotics (ampicillin + azithromycin); corticosteroids; monitor for chorioamnionitis

Summary of delivery timing recommendations for major pregnancy complications

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KEY TAKEAWAY

Think of delivery timing like risk-benefit analysis in pharmacotherapy. Just as a drug's therapeutic benefit must outweigh its side effects, the benefits of removing the fetus from a hostile intrauterine environment must outweigh the risks of prematurity. The specific gestational age thresholds (34 weeks for severe preeclampsia, 37 weeks for mild preeclampsia, etc.) represent the evidence-based tipping points where this balance shifts in favor of delivery. On the boards, knowing these thresholds cold is as important as knowing drug dosages.

SECTION 8

Connections to Advanced Obstetric Management

The foundational pregnancy complications covered in this lesson serve as gateways to more complex clinical scenarios tested on higher-level examinations and encountered in residency training. Understanding how these conditions interconnect and overlap is essential for developing the nuanced clinical judgment demanded of practicing obstetricians.

Step 2 Foundation	Advanced Extension
Preeclampsia pathophysiology (sFlt-1, PlGF)	Biomarker-guided management; angiogenic factor assays for risk stratification; aspirin prophylaxis in high-risk populations
Magnesium sulfate for seizure prophylaxis	Neuroprotection for preterm neonates <32 weeks; MgSO₄ dosing in renal insufficiency; pharmacokinetic considerations
Gestational diabetes screening (GCT/GTT)	Continuous glucose monitoring in pregnancy; early screening in high-risk populations; postpartum metabolic syndrome prevention
Placenta previa and abnormal placentation	Placenta accreta spectrum disorders (accreta, increta, percreta); multidisciplinary surgical planning; interventional radiology for hemorrhage control
PPROM management	Periviable counseling (<24 weeks); amnioinfusion; fetal lung maturity testing; microbiome-informed antibiotic selection

Step 2 foundations and their advanced clinical extensions

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Placenta Accreta Spectrum: The Rising Epidemic

With rising cesarean delivery rates worldwide, the incidence of placenta accreta spectrum (PAS) disorders has increased dramatically — now occurring in approximately 1 in 272 pregnancies. PAS represents abnormal trophoblastic invasion beyond the decidua basalis: accreta (invasion to the myometrium), increta (into the myometrium), and percreta (through the serosa and into adjacent organs). A patient with placenta previa overlying a prior cesarean scar has a dramatically elevated risk. Delivery requires a multidisciplinary team including maternal-fetal medicine, gynecologic oncology, urology, and interventional radiology, with massive transfusion protocol activation.

As you progress through your clinical training, you will encounter patients in whom multiple pregnancy complications coexist — for example, a woman with chronic hypertension who develops superimposed preeclampsia with HELLP syndrome and an abruption precipitated by the hypertensive crisis. The ability to manage these layered clinical scenarios begins with a firm command of the individual entities and their pathophysiological links, which is precisely what Step 2 examinations assess.

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

A 28-year-old primigravida at 32 weeks of gestation has a blood pressure of 148/96 mmHg on two occasions 4 hours apart, with no proteinuria and normal laboratory values. What is the most likely diagnosis, and what distinguishes this condition from preeclampsia according to current ACOG criteria?

Show answer

The most likely diagnosis is gestational hypertension, defined as new-onset hypertension (SBP ≥ 140 or DBP ≥ 90 mmHg) after 20 weeks of gestation without proteinuria and without features of end-organ dysfunction. The key distinction from preeclampsia under current ACOG 2013 guidelines is that preeclampsia requires either proteinuria (≥ 300 mg/24 hours or protein-to-creatinine ratio ≥ 0.3) OR evidence of end-organ dysfunction (thrombocytopenia, renal insufficiency, elevated liver enzymes, pulmonary edema, or cerebral/visual symptoms). Importantly, proteinuria alone is no longer required if other end-organ findings are present. Gestational hypertension patients should be monitored closely, as up to 25% will progress to preeclampsia.

Question 2: BASIC CALCULATION

A 30-year-old G3P2 at 26 weeks undergoes a 50 g glucose challenge test (GCT) with a 1-hour result of 152 mg/dL. She then undergoes a 3-hour 100 g oral glucose tolerance test (GTT) with the following results: fasting 98 mg/dL, 1-hour 192 mg/dL, 2-hour 168 mg/dL, 3-hour 138 mg/dL. Using the Carpenter-Coustan criteria, does this patient meet the diagnostic threshold for gestational diabetes mellitus?

Show answer

Yes, this patient meets criteria for gestational diabetes mellitus. The Carpenter-Coustan criteria require two or more abnormal values on the 3-hour GTT. The thresholds are: fasting ≥ 95 mg/dL, 1-hour ≥ 180 mg/dL, 2-hour ≥ 155 mg/dL, and 3-hour ≥ 140 mg/dL. In this case, the fasting value (98 ≥ 95), 1-hour value (192 ≥ 180), and 2-hour value (168 ≥ 155) are all abnormal — that is three abnormal values, which exceeds the two-value threshold. The 3-hour value (138 < 140) is normal. With three of four values abnormal, this is a clear diagnosis of GDM. The initial GCT screen was positive at 152 mg/dL (threshold ≥ 130 or ≥ 140 depending on institutional cutoff), appropriately triggering the confirmatory GTT.

Question 3: INTERMEDIATE

A 35-year-old G4P3 at 33 weeks presents with sudden onset of constant, severe abdominal pain. She has a history of chronic hypertension treated with labetalol. On examination, her uterus is firm and tender, with blood pressure 175/112 mmHg. A small amount of dark vaginal bleeding is noted. The fetal heart rate tracing shows recurrent late decelerations with minimal variability. What is your diagnosis, and outline your immediate management steps in order of priority.

Show answer

The diagnosis is placental abruption in the setting of chronic hypertension with superimposed hypertensive crisis. The clinical triad of painful vaginal bleeding, a rigid tender uterus, and non-reassuring fetal heart tracing is classic. Management priorities in order: (1) Establish two large-bore IV lines and begin aggressive fluid resuscitation with crystalloid; (2) Draw stat labs including CBC, coagulation studies (PT, PTT, fibrinogen), type and crossmatch for at least 4 units pRBCs — abruption can precipitate DIC; (3) Begin emergent cesarean delivery given the non-reassuring fetal status (recurrent late decelerations with minimal variability indicate fetal acidemia); (4) Administer IV labetalol or hydralazine for acute blood pressure control; (5) Activate massive transfusion protocol if hemodynamically unstable; (6) Be prepared for postpartum hemorrhage secondary to Couvelaire uterus. Note that betamethasone for fetal lung maturity, while ideal at 33 weeks, should not delay delivery in this hemodynamically unstable scenario with fetal distress.

Question 4: APPLIED

A 29-year-old G1P0 at 30 weeks is admitted with preeclampsia with severe features (BP 162/108, platelets 92,000, AST 188). After stabilization with IV magnesium sulfate and labetalol, her blood pressure is controlled at 142/88, and she is asymptomatic. The fetal heart rate tracing is category I. The attending plans to administer betamethasone and attempt to delay delivery. Four hours later, the nurse calls you because the patient's respiratory rate is 10/min, patellar reflexes are absent, and urine output has been 15 mL over the last 2 hours. What complication has occurred, and what is the immediate treatment?

Show answer

This patient is exhibiting signs of magnesium sulfate toxicity. The classic triad of findings is: loss of deep tendon reflexes (patellar reflexes absent), respiratory depression (RR 10/min), and oliguria (15 mL in 2 hours). The therapeutic range for magnesium is 4–7 mEq/L. Loss of patellar reflexes occurs at approximately 8–10 mEq/L, respiratory depression at 10–12 mEq/L, and cardiac arrest at >12 mEq/L. The reduced urine output is particularly concerning because magnesium is renally excreted, so oliguria perpetuates toxicity. Immediate management: (1) Stop the magnesium sulfate infusion immediately; (2) Administer the antidote — calcium gluconate 1 g IV (10 mL of 10% solution) pushed slowly over 3 minutes; (3) Monitor respiratory status closely and provide supplemental oxygen; prepare for endotracheal intubation if respiratory arrest is imminent; (4) Check a stat serum magnesium level; (5) Ensure adequate IV fluid resuscitation to promote renal excretion. This patient's pre-existing renal impairment (creatinine was elevated) likely contributed to magnesium accumulation, and the infusion rate should have been reduced accordingly.

Question 5: CRITICAL THINKING

A hospital in a resource-limited setting has a high rate of eclampsia-related maternal deaths. They currently diagnose preeclampsia based solely on the presence of hypertension and proteinuria and do not have access to 24-hour urine collection or sFlt-1/PlGF testing. A quality improvement team asks you to design a simplified screening and prevention protocol using only commonly available resources. What evidence-based interventions would you recommend for (a) identification of high-risk patients, (b) prevention of preeclampsia, and (c) management of impending eclampsia? Justify each recommendation.

Show answer

This question requires synthesis of multiple evidence-based strategies adapted to a resource-limited context. (a) Identification of high-risk patients: Use the ACOG risk factor stratification — history of preeclampsia, chronic hypertension, multifetal gestation, pregestational diabetes, renal disease, autoimmune disorders, and nulliparity. A urine dipstick protein-to-creatinine ratio (spot P/Cr ratio) can substitute for 24-hour urine and requires only a single voided specimen. Serial blood pressure monitoring at every prenatal visit is the most accessible screening tool. (b) Prevention: Low-dose aspirin (81–162 mg daily) initiated at 12–16 weeks in high-risk patients reduces preeclampsia risk by approximately 17% (USPSTF recommendation). This is among the most cost-effective interventions in obstetrics. Calcium supplementation (1.5–2 g daily) is recommended by WHO in populations with low dietary calcium intake and has been shown to reduce preeclampsia incidence by up to 50%. (c) Management of impending eclampsia: Magnesium sulfate is the single most important intervention — the Magpie Trial demonstrated a 58% reduction in eclampsia with MgSO₄ prophylaxis. The Pritchard regimen (IM loading and maintenance doses) can be administered without infusion pumps, making it feasible in resource-limited settings. Clinical monitoring of reflexes, respiratory rate, and urine output substitutes for serum magnesium levels. Oral nifedipine can manage hypertension without IV access. Finally, training traditional birth attendants to recognize warning signs (headache, visual changes, epigastric pain) and refer urgently is a proven strategy for reducing eclampsia mortality in low-resource contexts.

SUMMARY

Comprehensive Review

Summary

Pregnancy complications encompass a broad spectrum of disorders that threaten maternal and fetal well-being. The hypertensive disorders of pregnancy — including gestational hypertension, preeclampsia, eclampsia, and HELLP syndrome — arise from abnormal placentation and systemic endothelial dysfunction, managed with magnesium sulfate for seizure prophylaxis, labetalol or hydralazine for acute blood pressure control, and delivery as the definitive treatment. Antepartum hemorrhage is classified by three major etiologies: placenta previa (painless, bright red bleeding), placental abruption (painful, dark bleeding with a rigid uterus), and vasa previa (bleeding at rupture of membranes with rapid fetal decompensation).

Gestational diabetes mellitus results from insufficient β-cell compensation for the physiological insulin resistance of pregnancy, diagnosed via a two-step glucose screening protocol. Preterm premature rupture of membranes (PPROM) is managed with latency antibiotics and corticosteroids, with delivery at 34 weeks. Across all complications, the central clinical skill is matching the timing and mode of delivery to the severity of the condition and the gestational age: 37 weeks for mild disease, 34 weeks for severe preeclampsia/PPROM, and immediate delivery for eclampsia, HELLP syndrome, and significant placental abruption. Mastery of these decision thresholds, pharmacological interventions (including MgSO₄ monitoring and toxicity management with calcium gluconate), and the pathophysiological rationale underlying each condition is essential for success on USMLE Step 2 and for competent clinical practice.