eMedicine Specialties > Emergency Medicine > Obstetrics & Gynecology
Abortion, Missed: Differential Diagnoses & Workup
Updated: Jun 15, 2006
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
| Abortion, Complete | Abortion, Threatened |
| Abortion, Complications | Pregnancy, Ectopic |
| Abortion, Incomplete | |
| Abortion, Inevitable | |
| Abortion, Septic |
Workup
Laboratory 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.
More on Abortion, Missed |
| Overview: Abortion, Missed |
 Differential Diagnoses & Workup: Abortion, Missed |
| Treatment & Medication: Abortion, Missed |
| Follow-up: Abortion, Missed |
| Multimedia: Abortion, Missed |
| References |
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References
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Further Reading
Keywords
miscarriage, blighted ovum, anembryonic pregnancy, fetal demise, spontaneous abortion, missed abortion, threatened abortion, complete abortion, incomplete abortion, inevitable abortion, pregnancy loss, utero death of the embryo, utero death of the fetus, chromosomal anomalies, septate uterus, luteal phase insufficiency, hypothyroidism, hypoprolactinemia, polycystic ovarian syndrome, anembryonic pregnancy, subchorionic hematoma, subchorionic hemorrhage, subchorionic bleeding, endovaginal ultrasound, transabdominal ultrasound
