Table 2.
Current society guidelines for diagnosing spontaneous abortion.
| ACOG | ≤19 6/7 | First trimester |
| Non-viable, intrauterine pregnancy with either an empty gestational sac or a gestational sac containing an embryo or fetus without fetal heart activity within the first 12 6/7 weeks of gestation. | ||
| Findings diagnostic of spontaneous abortion (first trimester) | ||
| Crown-rump length (CRL) of 7 mm of greater and no heartbeat | ||
| Mean sac diameter of 25 mm or greater and no embryo | ||
| Absence of embryo with heartbeat 2 weeks or more after an ultrasound that showed a gestational sac without a yolk sac | ||
| Absence of embryo with heartbeat 11 days or more after an ultrasound that showed a gestational sac with a yolk sac | ||
| Second trimester | ||
| Spontaneous pregnancy loss after the first trimester and before 20 weeks gestation | ||
| [96] | ||
| NICE/RANZCOG/RCOG | Evaluation with transvaginal ultrasound | |
| If the mean gestational sac diameter is less than 25 mm and there is no visible fetal pole then perform a second ultrasound a minimum of 7 days after the first before making a diagnosis | ||
| If the mean gestational sac diameter is 25 mm or more and there is no visible fetal pole then seek a second opinion on the viability of the pregnancy and/or perform a second ultrasound a minimum of 7 days after the first | ||
| If the CRL is less than 7 mm and there is no visible heartbeat, perform a second ultrasound a minimum of 7 days after the first before making a diagnosis, and even more scans may be needed | ||
| If the CRL is 7 mm or more and there is no visible heartbeat, then one can seek a second opinion and/or perform a second ultrasound a minimum of 7 days after the first before making a decision regarding viability of the pregnancy | ||
| Evaluation with transabdominal ultrasound | ||
| If there is no visible heartbeat when the CRL is measured then record the size of the CRL and perform a second scan a minimum of 14 days after the first scan | ||
| Serum B-HCG should not be used alone to determine the viability of a pregnancy of unknown location. | ||
| [5] | ||
| SGOC | ≤23 6/7 | First trimester |
| Mean gestational sac diameter exceeds 8 mm without a yolk sac by transvaginal ultrasound | ||
| Mean gestational sac diameter exceeds 16 mm without an embryo by transvaginal ultrasound | ||
| Gestational sac greater than 20 mm without a yolk sac by transabdominal ultrasound | ||
| Gestational sac 25 mm without an embryo by transabdominal ultrasound | ||
| No cardiac activity in an embryo greater than 5 mm by transvaginal ultrasound or 9 mm by transabdominal ultrasound | ||
| Second Trimester | ||
| All spontaneous pregnancy losses from 13 weeks of gestation until the fetus reaches viability, 24 weeks gestation | ||
| [4] | ||