Spontaneous Abortion (Threatened)MANAGEMENT

OBSTETRIC PRESENTATIONS · 12 SECTIONS

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610 items

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Cardiovascular Presentations71▾

Respiratory Presentations52▾

Neurological Presentations83▾

Gastrointestinal Presentations74▾

Genitourinary and Reproductive Presentations48▾

Infectious Disease Presentations148▾

Trauma Presentations89▾

Toxicologic Presentations80▾

Psychiatric Presentations26▾

Musculoskeletal and Rheumatologic Presentations96▾

Dermatology Presentations23▾

Environmental and Exposure Presentations27▾

Hematologic and Oncologic Presentations36▾

Pediatric-Specific Presentations19▾

Endocrine and Metabolic Presentations45▾

ENT and Maxillofacial Presentations27▾

Ophthalmologic Presentations19▾

Obstetric Presentations23▾

Chorioamnionitis Eclampsia Ectopic Pregnancy (Ruptured)Ectopic Pregnancy (Unruptured)HELLP Syndrome Hyperemesis gravidarum Peripartum cardiomyopathy Placenta previa Placental abruption Postpartum Endometritis Postpartum hemorrhage Postpartum infection Preeclampsia Preeclampsia-eclampsia Preterm labor Sepsis in pregnancy Septic abortion Shoulder dystocia Spontaneous Abortion (Incomplete)Spontaneous Abortion (Missed)Spontaneous Abortion (Threatened)Threatened-inevitable-incomplete abortion Umbilical cord prolapse

Systemic and Miscellaneous Presentations17▾

01Approach to the Critical Patient/attcp36

Hemodynamic instability

›Unstable patient triggers

›Tachycardia HR > 100 bpm

›May indicate hemorrhage or ruptured ectopic

›Serial vitals every 5-15 minutes

›Hypotension SBP < 90 mmHg

›Immediate large-bore IV access x2

›Crystalloid resuscitation 1-2 L NS or LR bolus

›Orthostatic changes

›Indicates significant volume depletion

›Active hemorrhage assessment

›Ruptured ectopic exclusion

›Peritoneal signs mandate emergent surgical consult

›Rebound tenderness

›Guarding

›Free fluid on bedside ultrasound in unstable patient

›Emergent OB/GYN activation

›Prepare for operative intervention

Immediate priorities

›Time-critical actions

›IV access and type and screen in all hemodynamically unstable patients

›Two large-bore peripheral IVs

›Blood products if hemorrhagic shock

›Bedside point-of-care ultrasound for IUP confirmation

›Cannot-miss: exclude ectopic pregnancy before all other management

›Transvaginal ultrasound preferred over transabdominal for first trimester

›Rh(D) status determination

›Anti-D immunoglobulin required if Rh-negative and unsensitized

02History/hx86

Bleeding characterization

›Bleeding features

›Onset and duration

›Acute vs. gradual

›Hours to days

›Color and character

›Bright red vs. brown old blood

›Spotting vs. pad-soaking

›Volume quantification

›Number of pads soaked per hour

›Heavy bleeding >1 pad/hour combined with cramping has HR 5.03 for pregnancy loss

›Passage of tissue or clots

›Tissue passage suggests inevitable or incomplete abortion

›Clot passage indicates significant hemorrhage

Pain assessment

›Pain characterization

›Location

›Midline cramping consistent with threatened abortion

›Unilateral pain raises concern for ectopic pregnancy

›Character

›Cramping vs. sharp vs. constant

›Peritoneal quality suggests rupture

›Severity and trajectory

›Escalating pain is concerning feature

›Shoulder tip pain suggests diaphragmatic irritation from hemoperitoneum

Gestational timing and context

›Pregnancy dating

›Last menstrual period

›Gestational age calculation

›Concordance with prior ultrasound

›Prior ultrasound dating

›Viability confirmation if available

›Crown-rump length measurement

›Triggers for current episode

›Post-coital bleeding

›Trauma or exertion

Associated symptoms

›Protective and concerning features

›Nausea and vomiting

›Presence is protective; associated with lower miscarriage risk of approximately 9.7%

›Loss of pregnancy symptoms may indicate demise

›Dizziness and syncope

›Suggests significant hemorrhage

›Vasovagal response vs. hemodynamic instability

›Fever and purulent discharge

›Raises concern for septic abortion

›Requires immediate broad-spectrum antibiotics

Obstetric history

›Prior pregnancy outcomes

›Previous miscarriages

›Strongest predictor of recurrence

›Risk: 11% with no prior → 42% with ≥3 prior miscarriages

›Prior ectopic pregnancies

›Increased risk of recurrence

›Prior salpingotomy or salpingectomy

›Assisted reproductive technology

›IVF or IUI pregnancies

›Higher rate of monitoring and earlier viability assessment

›Prior uterine surgery

›Myomectomy, D&C, cesarean section

›LEEP increases mid-trimester loss risk

Risk factors

›Patient-level risk factors

›Advanced maternal age

›Risk: 12% age 20-29, 20% at age 35, 40% at age 40, 65% at age ≥45

›Chromosomal abnormalities account for approximately 50% of early pregnancy losses

›Prior miscarriage number

›Risk increases approximately 10% per additional miscarriage

›Recurrent pregnancy loss defined as ≥2 consecutive miscarriages

›Smoking and alcohol use

›Both independently increase miscarriage risk

›Alcohol: any consumption during pregnancy associated with increased risk

›Body mass index extremes

›Obesity BMI >24.9 or underweight BMI <18.5

›Associated with increased early pregnancy loss

›Medical comorbidities

›Antiphospholipid syndrome

›Thyroid autoantibodies and subclinical hypothyroidism

›Poorly controlled diabetes

Past medical and family history

›Relevant history

›Autoimmune conditions

›Antiphospholipid syndrome

›Systemic lupus erythematosus

›Endocrine disorders

›Thyroid disease

›Polycystic ovary syndrome

›Thrombophilias

›Factor V Leiden

›Prothrombin gene mutation

›Family history of recurrent pregnancy loss

›Chromosomal rearrangements in approximately 2-5% of couples with RPL

›Balanced translocations

03Physical Exam/exam55

Vital signs

›Hemodynamic status

›Heart rate

›Tachycardia >100 bpm indicates hemorrhage risk

›Serial trending in active bleeders

›Blood pressure

›Hypotension SBP <90 mmHg is emergency

›Orthostatic change >20 mmHg systolic

›Temperature

›Fever >38.0 C raises concern for septic abortion

›Normal temperature does not exclude early infection

›Oxygen saturation

›Baseline monitoring in hemodynamically unstable patients

Abdominal exam

›Abdominal findings

›Uterine tenderness

›Midline tenderness with cervical motion tenderness suggests infection

›Uterine size discrepancy ≥4 weeks from dates predicts nonviable pregnancy

›Peritoneal signs

›Rebound tenderness suggests ruptured ectopic

›Guarding requires urgent surgical evaluation

›Adnexal masses

›Palpable adnexal mass suggests ectopic or corpus luteum cyst

›Tenderness localizing to one side raises ectopic concern

Speculum examination

›Cervical os assessment

›Os status

›Closed os = threatened abortion (definition requires closed os)

04Differential Diagnosis/ddx46

Life-threatening diagnoses

›Cannot-miss diagnoses

›Ectopic pregnancy (ICD-10: O00.9)

›1-2% of all pregnancies; accounts for 6% of maternal deaths

›Unilateral pain, adnexal mass, hCG above discriminatory zone without IUP

›Discriminatory zone 1,500-3,000 mIU/mL; IUP should be visible on TVUS above this level

›Ruptured ectopic with hemoperitoneum

›Peritoneal signs, hemodynamic instability, free fluid on ultrasound

›Requires emergent surgical intervention

›Septic abortion (ICD-10: O03.0)

›Fever, uterine tenderness, leukocytosis, purulent discharge

›Potentially life-threatening; requires IV antibiotics and often surgical evacuation

Miscarriage variants

›Types of pregnancy loss

›Threatened abortion (ICD-10: O20.0)

›Vaginal bleeding with closed os and confirmed viable IUP

›25% of all pregnancies; 10-20% progress to complete miscarriage

›Inevitable abortion (ICD-10: O03.9)

›Open cervical os; loss cannot be prevented

›May still have fetal cardiac activity

›Incomplete abortion (ICD-10: O03.4)

›Partial passage of products of conception

›Open os with retained tissue on ultrasound

›Missed abortion (ICD-10: O02.1)

›No fetal cardiac activity, closed os, no active bleeding

›Often asymptomatic until spotting occurs

›Complete abortion (ICD-10: O03.9)

›Complete passage of products, closed os, no tissue on ultrasound

05Laboratory Tests/lt51

Beta-hCG

›Quantitative beta-hCG interpretation

›Serial trending requirement

›Minimum 48-hour interval for meaningful interpretation

›Normal rise ≥49% over 48 hours for initial hCG <1,500 mIU/mL

›ACOG Practice Bulletin No. 193 guideline

›Discriminatory zone

›1,500-3,000 mIU/mL: IUP should be visible on transvaginal ultrasound above this threshold

›hCG above discriminatory zone without IUP requires ectopic exclusion

›Abnormal trends

›Plateau or suboptimal rise suggests ectopic or nonviable pregnancy

›Falling hCG with open os and passed tissue consistent with complete abortion

Serum progesterone

›Progesterone as viability predictor

›Low progesterone threshold

›<35 nmol/L is strongest predictor of miscarriage in threatened abortion (OR 26.3)

›Frontiers in Medicine 2025 prospective cohort data

›Utility in triage

›Can guide management and counselling when ultrasound is inconclusive

›Levels >60 nmol/L associated with viable IUP in most cases

›Limitations

›Not universally available as point-of-care test

›Should not replace ultrasound as primary diagnostic tool

Blood type and antibody screen

›Rh status

›Required in all first trimester bleeding

›Rh-negative unsensitized patients require anti-D immunoglobulin

›ACOG Practice Bulletin No. 200 recommendation

06Diagnostic Tests/dt59

Scoring Systems

›Prognostic scoring for threatened abortion

›No validated single scoring tool is universally adopted

›Combination of clinical features used for risk stratification

›Serum progesterone, hCG trend, and ultrasound findings together provide best prognosis

›Key prognostic factors with quantified risk

›Fetal cardiac activity at 8 weeks: live birth probability approaches 97-98% (Lancet 2021)

›Heavy bleeding with cramping: HR 5.03 for pregnancy loss vs. no symptoms (Human Reproduction 2016)

›Prior miscarriage number: strongest independent predictor

›Uterine size discrepancy ≥4 weeks from dates: predictor of nonviable pregnancy

›PRISM trial risk stratification

›Women with bleeding and ≥1 prior miscarriage: highest benefit from progesterone

›Women with bleeding and ≥3 prior miscarriages: 15% absolute increase in live births with progesterone

MRI

›MRI in threatened abortion

›Indications

›Not first-line for threatened abortion evaluation

›Role when ultrasound is technically limited or inconclusive

›Uterine anomaly characterization when septate uterus or fibroid suspected

›MRI findings relevant to miscarriage

›Subchorionic hemorrhage extent and location

›Uterine anomalies: arcuate, septate, bicornuate uterus

›Fibroids: location relative to implantation site

›Limitations in first trimester

›Limited fetal detail in early first trimester

›Ultrasound is preferred for all primary first trimester assessments

›Gadolinium contrast is contraindicated in pregnancy unless benefits outweigh risks

07Disposition/dispo31

Emergency department disposition

›Disposition decision framework

›Admission indications

›Hemodynamic instability not responding to resuscitation

›Suspected or confirmed ruptured ectopic

›Septic abortion requiring IV antibiotics

›Severe hemorrhage requiring transfusion

›Surgical intervention required

›Observation indications

›Heavy bleeding with initial hemodynamic stability

›Serial hCG monitoring required in ED setting

›Ultrasound unavailable and ectopic not yet excluded

Discharge criteria

›Safe discharge requirements

›Hemodynamic stability

›Vital signs within normal limits

›Bleeding slowing or stopped at time of discharge

›Ectopic excluded

›IUP confirmed on ultrasound or hCG below discriminatory zone with plan for serial monitoring

›Adnexal pathology excluded

›Follow-up arranged

›OB/GYN or early pregnancy unit within 48-72 hours

›Repeat hCG and/or ultrasound planned if viability not yet confirmed

›Return precautions provided

›Patient understands red flag symptoms

›Reliable method of return to care

Follow-up planning

›Post-discharge monitoring

08Treatment/t80

Expectant management

›Expectant management principles

›Primary approach for threatened abortion with viable IUP

›Majority of patients with threatened abortion do not require specific intervention

›Emotional support and clear follow-up plan are essential components

›Bed rest

›No proven benefit on pregnancy outcomes

›Not recommended; may increase thromboembolic risk

›AFP 2019 review confirms no evidence of benefit

›Activity restrictions

›Avoidance of intercourse and tampon use until bleeding resolves

›Pelvic rest until cleared by provider

›Monitoring parameters

›Serial beta-hCG every 48 hours if viability uncertain

›Repeat ultrasound at 7-14 days

Progesterone therapy

›Vaginal micronized progesterone

›Indication

›Women with early pregnancy bleeding AND history of ≥1 prior miscarriage

›PRISM trial (NEJM 2019) demonstrates benefit in this subgroup

›Dosing

›Vaginal micronized progesterone 400 mg twice daily

›Continued to 16 weeks gestation

›Efficacy data

›5% absolute increase in live births in women with bleeding and ≥1 prior miscarriage

›15% absolute increase in live births in women with ≥3 prior miscarriages

›No proven benefit in women with threatened miscarriage and no prior miscarriage history (Cochrane 2021)

›Contraindications

›Undiagnosed vaginal bleeding without IUP confirmed

›Suspected ectopic pregnancy

›Alternatives not recommended

›Oral dydrogesterone: not shown to reduce miscarriage rate vs. placebo (Human Reproduction 2021)

›Combined oestrogen and progesterone: insufficient evidence

Rh immunoglobulin

›Anti-D immunoglobulin administration

›Indication

›Rh-negative unsensitized women with first trimester vaginal bleeding

›ACOG Practice Bulletin No. 200 guideline

›Dosing

›250 mcg (1250 IU) intramuscular in first trimester

›Administer within 72 hours of bleeding episode

›Timing considerations

›Particularly important later in first trimester (after 8-10 weeks)

›Lower urgency but still recommended in early first trimester per ACOG

›Exemptions

›Rh-positive patients do not require anti-D

›Already sensitized patients do not benefit

Medications to avoid

›Harmful medications in threatened abortion

›NSAIDs

›Associated with increased miscarriage risk

›Avoid ibuprofen, naproxen, ketorolac

›Use acetaminophen if analgesia required

›Anticoagulants and aspirin

›Not shown to reduce early pregnancy loss except in antiphospholipid syndrome

›Do not initiate empirically

›Ergotamines and uterotonics

›Contraindicated in viable pregnancy

Septic abortion management

›Septic abortion treatment protocol

›Empiric antibiotic therapy

›Broad-spectrum IV antibiotics within 1 hour of diagnosis

›Ampicillin-sulbactam 3 g IV every 6 hours

›Piperacillin-tazobactam 3.375 g IV every 6 hours as alternative

›Add metronidazole 500 mg IV every 8 hours for anaerobic coverage if needed

›Clindamycin-based regimen

›Clindamycin 900 mg IV every 8 hours plus gentamicin 5 mg/kg IV once daily

›Alternative for penicillin-allergic patients

›Surgical evacuation

›Urgent suction curettage once patient hemodynamically stabilized

›OB/GYN consultation for operative planning

›Septic shock management

›Crystalloid resuscitation 30 mL/kg IV

›Vasopressors if refractory hypotension: norepinephrine 0.01-0.5 mcg/kg/min

Heavy hemorrhage management

›Hemorrhage management protocol

›Resuscitation

›Two large-bore peripheral IVs

›Tranexamic acid 1 g IV over 10 minutes if severe bleeding

›Packed red blood cells for hemoglobin <70 g/L or hemodynamic instability

›Uterotonic agents if incomplete abortion with ongoing bleeding

›Oxytocin 10 units IM after tissue passage confirmed

›Misoprostol 600-800 mcg sublingual for medical management of incomplete abortion

›Surgical options

›Suction curettage for incomplete abortion with ongoing hemorrhage

›Manual vacuum aspiration as office procedure if stable

09Special Populations/sp44

Pregnancy

›Pregnancy-specific management considerations

›Gestational age impact on management

›<6 weeks: fetal cardiac activity may not yet be detectable on TVUS

›6-8 weeks: fetal cardiac activity first reliably detected; if absent, repeat in 7-14 days

›>8 weeks with confirmed cardiac activity: live birth probability 97-98%

›IVF pregnancies

›Higher monitoring frequency due to patient anxiety and investment

›Same diagnostic criteria apply for viability assessment

›Progesterone supplementation often already part of IVF protocol

›Multiple gestation

›Vanishing twin phenomenon may cause bleeding without jeopardizing surviving twin

›Separate fetal viability assessment required for each conceptus

›Subchorionic hemorrhage management

›Expectant management standard

›Serial ultrasound monitoring for hematoma evolution

›Large hematomas associated with worse outcomes

Geriatric

›Considerations in advanced reproductive age

›Maternal age ≥35 years

›Advanced maternal age (AMA) status affects counselling

›Chromosomal abnormalities increasingly common with advancing age

›Risk at 40 years is approximately 40%; at ≥45 years approximately 65%

›Perimenopause overlap

›Age ≥40: distinguish threatened abortion from perimenopausal irregular bleeding

›Positive pregnancy test mandatory before attributing bleeding to menopause

›Comorbidity burden

›Higher prevalence of hypertension, diabetes, thyroid disease with age

10Background/b58

Epidemiology

›Prevalence and incidence

›Threatened abortion frequency

›Occurs in approximately 25% of all recognized pregnancies

›10-20% of threatened abortions progress to complete miscarriage

›BioMed Research International 2019; Cochrane 2018

›Overall miscarriage risk

›Pooled risk of miscarriage across all recognized pregnancies is approximately 15.3%

›Lancet 2021 systematic review (Quenby et al.)

›Recurrent pregnancy loss

›Affects approximately 1-2% of couples attempting conception

›Defined as ≥2 consecutive pregnancy losses

›Maternal age distribution

›Risk rises from 12% at age 20-29 to 65% at age ≥45

›Exponential increase after age 35 driven by chromosomal aneuploidy

Pathophysiology

›Mechanisms of pregnancy loss

›Chromosomal abnormalities

›Account for approximately 50% of all early pregnancy losses

›Most commonly trisomies (especially trisomy 16), monosomy X, triploidy

›Random de novo events in sporadic miscarriage

›Implantation and placentation defects

›Subchorionic hemorrhage from defective trophoblastic invasion

›Inadequate decidualization at implantation site

›Uterine anatomic factors: fibroids, polyps, septate uterus

›Hormonal insufficiency

›Corpus luteum progesterone production supports early pregnancy until placental takeover at 8-10 weeks

›Low serum progesterone <35 nmol/L associated with OR 26.3 for miscarriage

11Patient Discharge Instructions/pdi36

copy discharge instructions

›Diagnosis and explanation

›Threatened miscarriage: bleeding in early pregnancy with a closed cervix and a baby still visible on ultrasound

›Many pregnancies with early bleeding continue to term

›Your cervix is closed and your pregnancy is currently still present

›Bleeding in early pregnancy is common, occurring in up to 1 in 4 pregnancies

›Many cases do not result in pregnancy loss

›Close monitoring is required to confirm the pregnancy is continuing normally

›Activity instructions

›Activity restrictions

›No sexual intercourse, tampons, or douching until bleeding has fully resolved and cleared by your provider

›Pelvic rest until your next appointment

›Light normal activity is acceptable; bed rest is not required

›Medications

›Continue prenatal vitamins and folic acid

›If progesterone has been prescribed, take as directed

›Avoid ibuprofen (Advil, Motrin) and other anti-inflammatory medications

›Use acetaminophen (Tylenol) only if pain relief is needed

›Follow-up instructions

›Scheduled follow-up

›Return to your OB/GYN or early pregnancy clinic in 48-72 hours for repeat blood tests

›A repeat ultrasound may be needed in 7-14 days to confirm your pregnancy is growing normally

›If fetal heartbeat was seen on ultrasound, your chance of ongoing pregnancy is very good

›Return to emergency department immediately if

›Red flag symptoms requiring emergency return

›Heavy bleeding: soaking more than 1 pad per hour for 2 or more hours

›Passage of tissue or clots

›Severe or worsening abdominal or pelvic pain

12References/r28

Guidelines and key sources

›ACOG Practice Guidelines

›ACOG Practice Bulletin No. 200: Early Pregnancy Loss. Obstetrics and Gynecology. 2018. Committee on Practice Bulletins-Gynecology

›Management framework for all types of early pregnancy loss

›Rh immunoglobulin recommendations

›ACOG Practice Bulletin No. 193: Tubal Ectopic Pregnancy. Obstetrics and Gynecology. 2018. Committee on Practice Bulletins-Gynecology

›hCG discriminatory zone criteria

›Management of ectopic pregnancy

›ACR Appropriateness Criteria

›ACR Appropriateness Criteria: First Trimester Vaginal Bleeding. 2025 Update. Laifer-Narin SL, Fruauff A, et al. Journal of the American College of Radiology. 2025

›Transvaginal ultrasound as first-line imaging

›ACR Appropriateness Criteria: Acute Pelvic Pain in the Reproductive Age Group. 2023 Update. Brook OR, Dadour JR, Robbins JB, et al. Journal of the American College of Radiology. 2024

Landmark trials and systematic reviews

›Progesterone trials

›Coomarasamy A, Devall AJ, Cheed V, et al. A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy (PRISM). New England Journal of Medicine. 2019

›5% absolute live birth increase in women with bleeding and prior miscarriage

›15% absolute increase in ≥3 prior miscarriage subgroup

›McLindon LA, James G, Beckmann MM, et al. Progesterone for Women With Threatened Miscarriage (STOP Trial). Human Reproduction. 2023

›No benefit in unselected threatened miscarriage population without prior miscarriage history

›Devall AJ, Papadopoulou A, Podesek M, et al. Progestogens for Preventing Miscarriage: A Network Meta-Analysis. Cochrane Database of Systematic Reviews. 2021

›Confirms benefit limited to high-risk subgroups

›Epidemiology and prognosis

›Quenby S, Gallos ID, Dhillon-Smith RK, et al. Miscarriage Matters: The Epidemiological, Physical, Psychological, and Economic Costs of Early Pregnancy Loss. Lancet. 2021

›Pooled miscarriage risk 15.3%; once cardiac activity confirmed at 8 weeks, live birth 97-98%

›Sapra KJ, Buck Louis GM, Sundaram R, et al. Signs and Symptoms Associated With Early Pregnancy Loss. Human Reproduction. 2016

›Heavy bleeding with cramping HR 5.03 for pregnancy loss

›Ku CW, Tan YB, Tan MMT, et al. A Risk Prediction Model of Spontaneous Miscarriage in Women With Threatened Miscarriage. Frontiers in Medicine. 2025

›Serum progesterone <35 nmol/L OR 26.3 for miscarriage

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Reviewed by SymptomDx Medical Team · Last reviewed August 18, 2026

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