In a longitudinal study published in Scientific Reports, researchers investigate the effect of maternal physical activity on the size and growth of the yolk sac during early pregnancy. To this end, ...

Learn what a viable pregnancy is, and how health care providers use strict ultrasound criteria to diagnose a nonviable pregnancy. Medically reviewed by Alyssa Dweck, MS, MD, FACOG A viable pregnancy ...

Poor prognosticators: calcified yolk sac and expanded amnion sign. Transvaginal sagittal grayscale ultrasound image in a 27-year-old pregnant patient shows an 8-mm embryo (calipers) without cardiac ...

Rachael has a degree in Zoology from the University of Southampton, and specializes in animal behavior, evolution, palaeontology, and the environment. Rachael has a degree in Zoology from the ...