Early pregnancy loss (EPL) often presents with bleeding and/or cramping. It can also be an incidental finding on ultrasound or can be discovered when fetal heart tones are not heard as expected after 10 weeks gestational age. Ultrasound is almost always used to assess for viability before recommending treatment. There have been several recent studies looking at transvaginal ultrasound measurements and their predictive value for EPL. The most rigorous studies were both conducted by Abdullah and colleagues, and they analyzed the pregnancies of 1,060 women with pregnancies of uncertain viability.¹ ²
According to their criteria, EPL can be diagnosed in the following circumstances.
- With a crown rump length (CRL) visible that is greater than or equal to 5.3 mm without cardiac activity present, EPL can be diagnosed with a false positive rate of 0%.¹
- Without visible CRL, measure mean sac diameter (MSD). A MSD of 21mm or greater without a visible embryo, with or without the presence of a yolk sac, has 100% specificity for early pregnancy loss.
- An empty sac of a smaller size, with no development of a yolk sac or embryo 7 or more days later also indicates a non-viable pregnancy.
A subsequent paper published in 2013 by Doubilet has even more stringent criteria for diagnosing EPL. These criteria were adopted by the Society of Radiologists in Ultrasound “Guidelines for Transvaginal “Ultrasonographic Diagnosis of Early Pregnancy Loss. The rationale for these stricter criteria is to avoid misdiagnosing a viable pregnancy, but unfortunately they assumed that all pregnancies are desired. They would only call a pregnancy non-viable for a CRL >7mm with no fetal heart activity or a gestational sac with a MSD of 25 or greater and no yolk sac. They also recommend two weeks between ultrasounds demonstrating no growth if the above criteria are not met. Each institution must decide which criteria to follow, and may choose to be flexible, taking into account the individual woman’s pregnancy desires.
Abdallah Y et al. Limitations of current definitions of miscarriage using mean gestational sac diameter and crown-rump length measurements: a multicenter observational study. “Ultrasound Obstet Gynecol.” 2011 Nov;38(5):497-502.
Abdallah Y, Daemen A, Guha S et al. Gestational sac and embryonic growth are not useful as criteria to define miscarriage: a multicenter observational study. “Ultrasound Obstet Gynecol “2011b;38:503-9.
Insights into abortion and miscarriage care is a publication of the Reproductive Health Access Project and Innovating Education in Reproductive Health, a project of the Bixby Center for Global Reproductive Health, UCSF. The Reproductive Health Access Project and Innovating Education in Reproductive Health do not accept funding from pharmaceutical companies. We do not promote specific brands of medication or products. The information in the Insights is unbiased, based on science alone.