Miscarriage (Early Pregnancy Loss)

Descriptive text is not available for this image BASICS

DESCRIPTION

  • Miscarriage, also known as early pregnancy loss (EPL) or spontaneous abortion (SAb), is the failure or loss of a pregnancy before 13 weeks’ gestational age (WGA).
  • Related terms
    • Anembryonic gestation: gestational sac on ultrasound (US) without visible embryo after 6 WGA
    • Complete abortion: entire contents of uterus expelled
    • Ectopic pregnancy: pregnancy outside the uterus
    • Embryonic or fetal demise: cervix closed; embryo or fetus present in the uterus without cardiac activity
    • Incomplete abortion: abortion with retained products of conception, generally placental tissue
    • Induced or therapeutic abortion: evacuation of uterine contents or products of conception medically or surgically
    • Inevitable abortion: cervical dilatation or rupture of membranes in the presence of vaginal bleeding
    • Recurrent abortion: three or more consecutive pregnancy losses at <15 WGA
    • Threatened abortion: vaginal bleeding in the 1st trimester of pregnancy
    • Septic abortion: a spontaneous or therapeutic abortion complicated by pelvic infection; common complication of illegally performed induced abortions
  • Synonym(s): SAb
    • Missed abortion and blighted ovum are used less frequently in favor of terms representing the sonographic diagnosis.

EPIDEMIOLOGY

Predominant age: increases with advancing age, especially >35 years; at age 40 years, the loss rate is twice that of age 20 years.

Incidence

  • Threatened abortion (1st-trimester bleeding) occurs in 20–25% of clinical pregnancies.
  • Between 10% and 15% of all clinically recognized pregnancies end in EPL, with 80% of these occurring within 12 weeks after last menstrual period (LMP) (1).
  • When both clinical and biochemical (β-hCG detected) pregnancies are considered, about 30% of pregnancies end in EPL.
  • One in four people with a uterus will have an EPL during their lifetime (1).

ETIOLOGY AND PATHOPHYSIOLOGY

Chromosomal anomalies (50% of cases), congenital anomalies, trauma, maternal factors: uterine abnormalities, infection (toxoplasma, other viruses, rubella, cytomegalovirus, herpesvirus), maternal endocrine disorders, hypercoagulable state

Genetics

Approximately 50% of 1st-trimester EPLs have significant chromosomal anomalies, with 50% of these being autosomal trisomies and the remainder being triploidy, tetraploidy, or 45X monosomies.

RISK FACTORS

Most cases of EPL occur in patients without identifiable risk factors; however, risk factors include the following: chromosomal abnormalities, advancing maternal age, uterine abnormalities, and maternal chronic disease (antiphospholipid antibodies, uncontrolled diabetes mellitus, polycystic ovarian syndrome, obesity, hypertension, thyroid disease, renal disease); other possible contributing factors include smoking, alcohol intake, cocaine use, infection, and luteal phase defect.

GENERAL PREVENTION

  • Insufficient evidence supports the use of aspirin and/or other anticoagulants, bed rest, hCG, immunotherapy, uterine muscle relaxants, or vitamins for general prevention of EPL, before or after threatened abortion is diagnosed.
  • By the time the hemorrhage begins, half of pregnancies complicated by threatened abortion already have no fetal cardiac activity.
  • In threatened abortion, oral progestogens may reduce the risk of EPL (RR 0.73, 95% CI 0.59–0.92) and possibly increase the rate of live birth (RR 1.07, 95% CI 1–1.15).
  • Antiphospholipid syndrome: The combination of unfractionated heparin and aspirin reduces risk of EPL in women with antiphospholipid antibodies and a history of recurrent abortion.

Descriptive text is not available for this image DIAGNOSIS

HISTORY

  • The possibility of pregnancy should be considered in a reproductive-aged person with a uterus who presents with nonmenstrual vaginal bleeding.
  • Vaginal bleeding
    • Characteristics (amount, color, consistency, associated symptoms), onset (abrupt or gradual), duration, intensity/quantity, and exacerbating/precipitating factors
    • Document LMP if known: It allows calculation of estimated gestational age.
  • Abdominal pain/uterine cramping, as well as associated nausea/vomiting/syncope
  • Rupture of membranes
  • Passage of products of conception
  • Prenatal course: toxic or infectious exposures, family or personal history of genetic abnormalities, past history of ectopic pregnancy or EPL, endocrine disease, autoimmune disorder, bleeding/clotting disorder

PHYSICAL EXAM

  • Orthostatic vital signs to estimate hemodynamic stability
  • Abdominal exam for tenderness, guarding, rebound, bowel sounds (Peritoneal signs are more likely with ectopic pregnancy.)
  • Speculum exam for visual assessment of cervical dilation, blood, and products of conception (confirms diagnosis of EPL)
  • Bimanual exam to assess for uterine size–dates discrepancy and adnexal tenderness or mass

DIFFERENTIAL DIAGNOSIS

  • Ectopic pregnancy: potentially life-threatening; must be considered in any woman of childbearing age with abdominal pain and vaginal bleeding
  • Physiologic bleeding in normal pregnancy (implantation bleeding)
  • Subchorionic bleeding
  • Cervical polyps, neoplasia, and/or inflammatory conditions
  • Hydatidiform mole pregnancy
  • hCG-secreting ovarian tumor

DIAGNOSTIC TESTS & INTERPRETATION

Initial Tests (lab, imaging)

  • Quantitative hCG
    • Particularly useful if intrauterine pregnancy (IUP) has not been documented by US
    • Serial quantitative serum hCG measurements can assess viability of the pregnancy. Serum hCG should rise at least 53% every 48 hours through 7 weeks after LMP. An inappropriate rise, plateau, or decrease of hCG suggests abnormal IUP or possible ectopic pregnancy.
  • Complete blood count (CBC) with differential
  • Cultures: gonorrhea/chlamydia
  • US exam to evaluate fetal viability and to rule out ectopic pregnancy
    • hCG >2,000 mIU/mL necessary to detect IUP via transvaginal US (TVUS), >5,500 mIU/mL for abdominal US
    • TVUS criteria for nonviable intrauterine gestation: 7-mm fetal pole without cardiac activity or 25-mm gestational sac without a fetal pole, IUP with no growth over 1 week, or previously seen IUP no longer visible
    • Structures and timing: with TVUS, gestational sac of 2 to 3 mm generally seen around 5 WGA; yolk sac by 5.5 WGA; fetal pole with cardiac activity by 6 WGA

Follow-Up Tests & Special Considerations

  • In the case of vaginal bleeding with no documented IUP and hCG <2,000 mIU/mL, follow serum hCG levels weekly to zero.
  • If levels plateau, consider ectopic pregnancy or retained products of conception. If levels are very high, consider gestational trophoblastic disease.
  • If initial hCG level does not permit documentation of IUP by TVUS, follow serum hCG in 48 hours to document appropriate rise.
  • Repeat US once hCG is at a level commensurate with visualization on US (see above).
  • Provide the patient with ectopic precautions in interim: worsening abdominal pain, dizziness/syncope, nausea/vomiting.
  • In a pregnancy of unknown location with hCG rise <53% in 48 hours, offer methotrexate for treatment of presumed ectopic pregnancy.

Diagnostic Procedures/Other

  • Fetal heart tones can be auscultated with Doppler US. starting between 10 and 12 WGA in a viable pregnancy.
  • In threatened abortion, fetal cardiac activity at 7 to 11 WGA is 90–96% predictive of continued pregnancy (1).

Descriptive text is not available for this image TREATMENT

GENERAL MEASURES

  • Discuss contraception plan at the time of diagnosis of EPL, as ovulation can occur prior to resumption of normal menses.
  • Expectant management (“watchful waiting”) is 90% effective for incomplete abortion, although it may take several weeks for the process to be complete (1). This approach is only recommended in the 1st trimester and is more effective in women with symptoms of impending pregnancy loss.

MEDICATION

  • Rates of complete miscarriage and of need for surgical evacuation are equivalent with expectant management and medication.
  • Long-term conception rate and pregnancy outcomes are similar for women who undergo expectant management, medical treatment, or surgical evacuation.
  • Infection rates are lower with medical versus surgical management.

First Line

  • Misoprostol: most common agent for inducing passage of tissue in incomplete abortion or embryonic demise
    • Off-label use; has not been submitted to the FDA for consideration for use in treatment of early pregnancy failure; recognized by the World Health Organization (WHO) as a life-saving medication for this indication
    • Efficacy: Complete expulsion of products of conception in 71% by day 3 and 84% by day 8.
    • Efficacy depends on route of administration, gestational age of pregnancy, and dose.
    • Recommended dose is 800 mcg vaginally; alternate regimens include the WHO regimen of 600 mcg sublingually q3h for up to 3 doses; multidose regimens and oral dosing (including buccal and sublingual) may result in increased side effects.
    • The addition of mifepristone 200 mg, if available, given 24 hours before misoprostol increases the efficacy to 83.8% (ARR 16.7%, 95% CI 7.1–26.3%) (2)[A].
  • Common adverse effects include abdominal pain/cramping, nausea, and diarrhea. Pain increases at higher doses but is manageable with oral analgesia.
  • Recommended for stable patients who decline surgery but do not want to wait for spontaneous passage of products of conception.

Second Line

Patients with evidence of anemia should receive iron supplementation.

ISSUES FOR REFERRAL

Patients should be monitored for up to 1 year for the development of pathologic grief. There is an insufficient evidence to support counseling to prevent development of anxiety or depression related to grief following EPL.

ADDITIONAL THERAPIES

Rh immunoglobulin is not required for Rh-negative patients with EPL in the 1st trimester.

SURGERY/OTHER PROCEDURES

  • Uterine aspiration (suction dilation and curettage [D&C] or manual uterine aspiration [MUA], also known as manual vacuum aspiration [MVA]) is the conventional treatment.
  • Indications: septic abortion, heavy bleeding, hypotension, persistent IUP after medical or expectant management, patient’s choice
  • Risks (all rare): anesthesia (usually local), uterine perforation, intrauterine adhesions, cervical trauma, infection that may lead to infertility or increased risk of ectopic pregnancy
  • When compared with expectant management, surgical intervention leads to fewer days of vaginal bleeding, with a lower risk of incomplete abortion and heavy bleeding and a similar risk of infection, but with a higher cost. It is appropriate to prioritize the patient's preference in determining management.
  • Vacuum aspiration (manual or electric) is considered preferable to sharp curettage, as aspiration is less painful, takes less time, involves less blood loss, and does not require general anesthesia. The WHO supports use of suction curettage over rigid metal curettage.
  • Although data from induced abortions suggest that antibiotic prophylaxis with doxycycline 200 mg in a single dose reduces the already rare risk of postprocedure infection, data are insufficient to support use of antibiotics before aspiration for EPL.

COMPLEMENTARY & ALTERNATIVE MEDICINE

A systematic review of Chinese herbal medicine alone and in conjunction with Western medicine showed benefit over Western medicine alone in achieving continued viability at 28 weeks (number needed to treat [NNT] = 4.8 pregnancies with combined therapy). However, the available studies did not meet international standards for reporting quality.

ADMISSION, INPATIENT, AND NURSING CONSIDERATIONS

  • If the patient has orthostatic vital signs, initiate resuscitation with IV fluids and/or blood products, if needed.
  • Hemodynamically unstable patients may require IV fluids and/or blood products to maintain BP.

Descriptive text is not available for this image ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

All patients should be offered follow-up in 2 to 6 weeks to monitor for resolution of bleeding, return of menses, and symptoms related to grief, as well as to review the contraception plan.

Patient Monitoring

  • If EPL occurs in setting of previously documented IUP and abortion is completed with resumption of normal menses, it is not necessary to check or follow serum hCG to 0.
  • After medical management, confirm complete expulsion with US or serial serum β-hCG.
  • If pregnancy is not immediately desired, offer effective contraception. Immediate insertion of an intrauterine device is both acceptable and safe.
  • If pregnancy is desired, provide preconception counseling. There is no evidence that it is necessary to wait a certain number of cycles before attempting conception again.

DIET

NPO if patient will undergo D&C under general anesthesia

PATIENT EDUCATION

PROGNOSIS

  • Prognosis is excellent once bleeding is controlled.
  • Recurrent miscarriage: prognosis depends on etiology; up to 70% rate of success with subsequent pregnancy

COMPLICATIONS

  • D&C or MUA: uterine perforation, bleeding, adhesions, cervical trauma, and infection that may lead to infertility or increased risk of ectopic pregnancy. Bleeding and adhesions are more common with D&C than with MUA; all complications are rare.
  • Retained products of conception

Authors

Clara M. Keegan, MD

REFERENCES

  1. Prine LW, MacNaughton H. Office management of early pregnancy loss. Am Fam Physician. 2011;84(1):75–82.  [PMID:21766758]
  2. Schreiber CA, Creinin MD, Atrio J, et al. Mifepristone pretreatment for the medical management of early pregnancy loss. N Engl J Med. 2018;378(23):2161–2170.  [PMID:29874535]

ADDITIONAL READING

American College of Obstetricians and Gynecologists. ACOG practice bulletin No. 200; early pregnancy loss. Obstet Gynecol. 2018;132(5):e197–e207.  [PMID:30157093]

Descriptive text is not available for this image SEE ALSO

Descriptive text is not available for this image CODES

ICD10

  • O03.9 Complete or unspecified spontaneous abortion without complication
  • O03.4 Incomplete spontaneous abortion without complication
  • O02.1 Missed abortion
  • O20.0 Threatened abortion
  • N96 Recurrent pregnancy loss
  • O02.0 Blighted ovum and nonhydatidiform mole

SNOMED

  • 17369002 Miscarriage (disorder)
  • 156072005 Incomplete miscarriage (disorder)
  • 156073000 Complete miscarriage (disorder)
  • 54048003 Threatened abortion (disorder)
  • 35999006 Blighted ovum (disorder)
  • 16607004 Missed abortion (disorder)

CLINICAL PEARLS

  • Any pregnant woman with abdominal pain and/or vaginal bleeding must be evaluated to rule out ectopic pregnancy, which is potentially life-threatening.
  • As all options have similar long-term outcomes, patient’s preference should determine whether management is expectant, medical, or procedural.

Last Updated: 2026

© Wolters Kluwer Health Lippincott Williams & Wilkins