Emerson et al listed criteria for various types of early gestation as seen on endovaginal sonography (EVS). The authors are from the University of Tennessee.
Categories of early gestation:
(1) viable and intrauterine
(2) failed and intrauterine
intrauterine gestational sac
double sac sign or embryonic structure
>= 1 cm
no yolk sac
> 1.5 cm
no fetal pole
no cardiac activity
< 1 cm
neither double sac sign nor embryonic structures
intrauterine sac abnormally low in the uterus
extrauterine gestational sac
with or without embryonic structures
large amount of pelvic fluid
separate from uterus and ovary
originating from ovary
• An ectopic gestation should have either an empty uterus or abnormal endometrial fluid.
• Nothing = empty uterus AND no adnexal gestational sac AND no adnexal mass.
• In the implementation the combination of intrauterine gestational sac, diameter > 1.5 cm, and cardiac activity was added as evidence of a viable pregnancy. This was to balance criteria for a failed gestation.
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Specialty: Obstetrics & Gynecology, Pedatrics