AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

The most common complication of pregnancy is spontaneous abortion. Spontaneous abortion is categorized as threatened, inevitable, incomplete, complete, or missed. Abortion can be categorized further as sporadic or recurrent. By definition, a missed abortion is in utero death of the embryo or fetus before the 20th week of gestation with retained products of conception. Missed abortions also may be referred to as blighted ovum, anembryonic pregnancy, or fetal demise.

Pathophysiology

The timing of a spontaneous abortion suggests its pathophysiology. Genetic anomalies (trisomies); hormonal abnormalities; and infectious, immunologic, and environmental factors usually result in first-trimester loss. Anatomic factors usually are associated with second-trimester loss.

Frequency

United States

Many pregnancies are not viable, with an estimated loss of 50% before the first missed menstrual period. These pregnancies usually are not clinically recognized. Classic spontaneous abortion is defined as a clinically recognized (ie, by blood test, ultrasound) pregnancy loss before the 20th week of gestation. Estimates place frequency at 10-15% of pregnancies.

International

A report from the United Kingdom by Pandya utilizing ultrasound screening at 10-13 weeks of gestation revealed 2.8% of pregnancy failure with 62.5% missed abortions and 37.5% anembryonic pregnancies. The prevalence was higher in women with a history of vaginal bleeding.

Mortality/Morbidity

Surveillance data of pregnancy-related deaths from 1987 through 1990 revealed a total of 1459 deaths in the US. Of these deaths, spontaneous and induced abortions accounted for 5.6%.

Race

Surveillance data for pregnancy-related deaths (1987-1990) demonstrated more deaths followed ectopic pregnancy and spontaneous and induced abortion among African American women than among Caucasian women. Fourteen percent of pregnancy-related deaths among black women were due to ectopic pregnancies; 7% were due to abortions. Among white women, data showed that 8% of pregnancy-related deaths were due to ectopic pregnancies; 4% were due to abortions.

Age

• Age and increased parity affect a woman's risk of miscarriage. In women younger than 20 years, miscarriage occurs in an estimated 12% of pregnancies. In women older than 20 years, miscarriage occurs in an estimated 26% of pregnancies.
• Age primarily affects the oocyte. When oocytes from young women are used to create embryos for transfer to older recipients, implantation rates and pregnancy rates mimic those seen in younger women; the number of miscarriages and chromosomal anomalies decreases, suggesting that the uterus is not responsible for poor outcomes in women of advanced reproductive age.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• The patient history should include the following:
• • Last menstrual period (LMP)
  • Estimated length of gestation
  • Ultrasound results, if previously performed (especially presence of fetal cardiac activity)
  • Bleeding (eg, degree, duration, presence/passage of tissue): Bleeding may be quantified roughly by the number of pads soaked per hour or day. An average pad absorbs approximately 20-30 mL of blood.
• The patient's pregnancy symptoms may regress. Pregnancy test results may become negative and fetal heartbeat may not be detected.

Physical

• Vital signs usually are within reference ranges. Rarely, ecchymosis is noted on the skin in cases of associated coagulation disorder.
• Abdominal examination may or may not reveal a palpable uterus. If palpable, the uterus usually is small for the presumed gestational age.
• Fetal heart tones are inaudible or unseen on ultrasound.
• The cervical os is closed upon pelvic examination. The uterus may feel soft and enlarged.

Causes

• Genetic factors account for approximately 5% of spontaneous abortions. Trisomies commonly are encountered, with trisomy 16 accounting for approximately a third of chromosomal abnormalities in early pregnancy.
• Anatomic: Congenital or acquired anatomic factors reportedly occur in 10-15% of women who have histories of recurrent spontaneous abortions.
• • Congenital anatomic lesions include müllerian duct anomalies (eg, septate uterus, diethylstilbestrol [DES]-related). A septate uterus has been associated with some cases of missed abortion.
  • Acquired lesions include intrauterine adhesions (synechiae), leiomyoma, and endometriosis.
• Endocrine factors potentially contribute to recurrent abortion in 10-20% of cases.
• • Luteal phase insufficiency (abnormal corpus luteum function with insufficient progesterone production) is implicated as the most common etiologic factor in endocrine abnormalities contributing to spontaneous abortion.
  • Hypothyroidism, hypoprolactinemia, poor diabetic control, and polycystic ovarian syndrome are recognized contributing factors to pregnancy loss.
• Infectious
• • A presumed infectious etiology may be found in 5% of cases.
  • Bacterial, viral, parasitic, fungal, and zoonotic infections are associated with recurrent spontaneous abortion.
• Immunologic
• • Immunologic factors contribute in as many as 60% of recurrent spontaneous abortions.
  • Both the developing embryo and the trophoblast may be considered immunologically foreign to the maternal immune system.
  • Antiphospholipid antibody syndrome generally is responsible for more second-trimester pregnancy losses than first-trimester losses.
• Miscellaneous
• • Miscellaneous factors account for as many as 3% of recurrent spontaneous abortions.
  • Many other contributing factors are implicated in sporadic and recurrent spontaneous abortions. Environment, drugs, placental abnormalities, medical illnesses, and male-related causes are noted.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• Complete blood count with differential and platelet count
• Blood type and Rh
• Qualitative and quantitative beta-human chorionic gonadotropin
• • An anembryonic pregnancy is a gestation in which embryonic development does not occur.
  • This pregnancy occurs with or without evidence of early normal trophoblast growth and function, as indicated by adequately rising beta-human chorionic gonadotropin (hCG) levels.
• Coagulation panel (if coagulation disorder is suspected)
• Factor XIII and fibrinogen

Imaging Studies

• Sonography is the most accurate diagnostic modality for the confirmation of a viable pregnancy during the first trimester.
• Sonographic signs suggestive of a nonviable pregnancy include the following:
  • Irregular gestational sac (ie, gestational sac >25-mm mean sac diameter [MSD] on transabdominal ultrasound; >16-mm MSD on endovaginal ultrasound without a detectable embryo)
  • Nonliving embryo (embryo without a heartbeat)
  • Presence of abnormal hyperechoic material within the uterine cavity (see Images 2-3)
• Consider the sonographic diagnosis of early pregnancy failure in relationship to developmental stage.
• • Subclinical or preclinical loss: This occurs within the first 2 weeks after conception. Sonographic evidence of pregnancy does not exist at this stage.
  • Loss at 5-6 weeks: Loss at this stage is based upon gestational sac characteristics. Abnormal gestational sac size is the most reliable indicator of abnormal outcome. Gestational sacs should be 5-mm MSD by the fifth gestational week. An abnormally large gestational sac, as determined by high-frequency endovaginal sonography (HFEVS), is observed when the MSD is more than 8 mm without a demonstrable yolk sac or is more than 16 mm without a demonstrable embryo (see Image 2).
  • Loss at 7-8 weeks: Sonographic evidence is based upon demonstration of an abnormal embryo or gestational sac.
  • Loss at 9-12 weeks: Sonographic diagnosis of embryonic demise usually is made on demonstration of an abnormal embryo. Sonographic evidence of an embryo lacking cardiac activity is the most specific indicator of embryonic demise.
• Caution is advised in the diagnosis of embryonic demise. Determination of whether the viewed structure is the embryo is critical, as no other morphologically recognizable structures, other than a heartbeat, exist at this stage of development. The embryo must be scanned thoroughly for evidence of a heartbeat.
• • Most recommendations call for 2 independent examiners to view the embryo, either concurrent with the ED visit or at follow-up.
  • Most sonographers recommend repeating the scan within 3-7 days to determine if normal development is occurring.
  • On follow-up, a falling beta-human chorionic gonadotropin (hCG) level, as well as abnormal fetal development, confirms embryonic demise.
• Sonography also can identify presence of a subchorionic hematoma or hemorrhage (ie, bleeding between the endometrium and the gestational sac).
• • A subchorionic hemorrhage is the most commonly identified source of first-trimester bleeding, appearing on sonography as a crescent-shaped hypoechoic area next to the gestational sac.
  • Subchorionic hemorrhage encompasses a spectrum of sonographic findings. Subchorionic fluid can be classified in relation to gestational sac size and length of gestation. Subchorionic bleeding is present when pulsation of the subchorionic fluid is noted.
  • Size of the subchorionic hemorrhage should be taken into consideration, as greater size relates to an increased risk of spontaneous abortion. Subchorionic fluid and bleeding in combination with clinical bleeding is associated with embryonic death (see Image 3).
  • Subchorionic bleeding can be demonstrated using color Doppler imaging.
• Endovaginal ultrasound should be applied whenever possible to limit image distortion due to patient habitus or an overdistended bladder.

Procedures

• Transabdominal ultrasound of the pelvis provides an overall view of the pelvic structures. A full bladder is required as a sonographic window.
• Endovaginal ultrasound gives a detailed view of the endometrium of the uterus, ovaries, adnexa, and cul-de-sac. An empty bladder is preferred.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Emergency Department Care

Treatment may vary depending upon gestational age as follows:

• First trimester
• • Most patients abort spontaneously.
  • Coagulation defects secondary to a dead fetus are rare.
  • Expectant management or suction curettage may be performed.
• Second trimester
• • The uterus is emptied by dilatation and evacuation.
  • Alternatively, the uterus is emptied by induction of labor.

Consultations

• Consult an obstetrician/gynecologist (OB/GYN), especially for difficult diagnoses and follow-up care.
• Ultrasonographic findings may aid in determining the need for consultation (see Images 2-3).

FOLLOW-UP

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Further Outpatient Care

• In the case of expectant management, advise the patient to return to the ED or to contact an OB/GYN if severe cramping, bleeding, fever, and/or passage of tissue occur.
• Ultrasound findings, in association with presence or absence of significant clinical bleeding, may aid in determination of urgent versus routine follow-up (see Images 2-3).

Transfer

• Transfer patients with evidence of a coagulation disorder to a higher level of care.

Complications

• Coagulation defects may be associated with a retained dead fetus.

Prognosis

• The prognosis for a successful pregnancy depends upon the etiology of previous spontaneous abortion(s).
• • Correction of an endocrine abnormality in women with recurrent abortion has the best prognosis for a successful pregnancy (>90%).
  • In women with an unknown etiology of prior losses, the probability of achieving successful pregnancies is 40-80%.
  • The live-birth rate after documentation of fetal cardiac activity at 5-6 weeks of gestation in women with a history of 2 or more unexplained spontaneous abortions is approximately 77%.

Patient Education

• Advise the patient to return to the ED upon occurrence of any of the following:
• • Bleeding from gums
  • Epistaxis
  • Skin ecchymosis
  • Profuse vaginal bleeding or passage of tissue
  • Severe pelvic pain
  • Temperature above 38°C (100.4°F)
• For excellent patient education resources, visit eMedicine's Pregnancy and Reproduction Center and Procedures Center. Also, see eMedicine's patient education articles Miscarriage, Abortion, and Dilation and Curettage (D&C).

MISCELLANEOUS

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Special Concerns

• Offer grief counseling to all patients who have had a miscarriage.

MULTIMEDIA

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  This endovaginal ultrasonogram reveals an irregular gestational sac with an amorphic fetal pole. No fetal cardiac activity was noted. This image represents a missed abortion or fetal demise.
	View Full Size Image
Media type:  Image

Media file 2:  This flowchart details a diagnostic algorithm based on sonographic findings in early pregnancy, using high-frequency endovaginal sonography (HFEVS) of more than 5 megahertz (MHz). The algorithm continues in Image 3.
	View Full Size Image
Media type:  Graph

Media file 3:  This flowchart outlines a diagnostic algorithm based on the initial endovaginal sonographic finding of an intrauterine embryo. The chart incorporates fetal cardiac activity, crown-rump length (CRL), presence of subchorionic hemorrhage (SCH), and uterine or adnexal masses with the clinical presentation (spotting vs bleeding) to aid in making clinical decisions.
	View Full Size Image
Media type:  Graph

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Follow-up
• Miscellaneous
• Multimedia
• References

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• Brown DL, Doubilet PM. Transvaginal sonography for diagnosing ectopic pregnancy: positivity criteria and performance characteristics. J Ultrasound Med. Apr 1994;13(4):259-66. [Medline].
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• Dickey RP, Olar TT, Curole DN, et al. Relationship of first-trimester subchorionic bleeding detected by color Doppler ultrasound to subchorionic fluid, clinical bleeding, and pregnancy outcome. Obstet Gynecol. Sep 1992;80(3 Pt 1):415-20. [Medline].
• Doubilet PM, Benson CB. Embryonic heart rate in the early first trimester: what rate is normal?. J Ultrasound Med. Jun 1995;14(6):431-4. [Medline].
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• Hill JA. Sporadic and recurrent spontaneous abortion. In: Kistner RW, ed. Kistner's Gynecology: Principles and Practice. 6th ed. Mosby-Year Book;1995:33-365.
• Inbal A, Muszbek L. Coagulation factor deficiencies and pregnancy loss. Semin Thromb Hemost. Apr 2003;29(2):171-4. [Medline].
• Kaplan BC, Dart RG, Moskos M, et al. Ectopic pregnancy: prospective study with improved diagnostic accuracy. Ann Emerg Med. Jul 1996;28(1):10-7. [Medline].
• Koonin LM, MacKay AP, Berg CJ, et al. Pregnancy-related mortality surveillance--United States, 1987-1990. Mor Mortal Wkly Rep CDC Surveill Summ. Aug 8 1997;46(4):17-36. [Medline].
• Levi CS, Dashefsky SM, Lyons EA. First trimester ultrasound. In: McGahan JP, Goldberg BB, eds. Diagnostic Ultrasound - A Logical Approach. Lippincott-Raven Publishers;1998:141.
• Levi CS, Lyons EA, Lindsay DJ. Early diagnosis of nonviable pregnancy with endovaginal US. Radiology. May 1988;167(2):383-5. [Medline].
• Lockshin MD. Pregnancy loss in the antiphospholipid syndrome. Thromb Haemost. Aug 1999;82(2):641-8. [Medline].
• Nyberg DA, Cyr DR, Mack LA, et al. Sonographic spectrum of placental abruption. AJR Am J Roentgenol. Jan 1987;148(1):161-4. [Medline].
• Nyberg DA, Laing FC, Filly RA. Threatened abortion: sonographic distinction of normal and abnormal gestation sacs. Radiology. Feb 1986;158(2):397-400. [Medline].
• Pandya PP, Snijders RJ, Psara N. The prevalence of non-viable pregnancy at 10-13 weeks of gestation. Ultrasound Obstet Gynecol. Mar 1996;7(3):170-3. [Medline].
• Sairam S, Khare M, Michailidis G. The role of ultrasound in the expectant management of early pregnancy loss. Ultrasound Obstet Gynecol. Jun 2001;17(6):506-9. [Medline].
• Sauer MV. Pregnancy wastage and reproductive aging: the oocyte donation model. Curr Opin Obstet Gynecol. Jun 1996;8(3):226-9. [Medline].
• Scott JR. Early pregnancy loss. In: Danforth's Obstetrics and Gynecology. 7th ed. Lippincott-Raven Publishers;1994:175-185.
• Scroggins KM, Smucker WD, Krishen AE. Spontaneous pregnancy loss: evaluation, management, and follow-up counseling. Prim Care. Mar 2000;27(1):153-67. [Medline].
• Simpson JL, Mills JL, Holmes LB, et al. Low fetal loss rates after ultrasound-proved viability in early pregnancy. JAMA. Nov 13 1987;258(18):2555-7. [Medline].

Article Last Updated: Jun 15, 2006