1. Normal 5-week intrauterine pregnancy (IUP)
Normal 5-week intrauterine pregnancy (IUP). A: Transvaginal (TV) sonogram of 4-week, 6-day pregnancy demonstrating 5-mm anechoic sac (arrow) within decidua. B: Transabdominal (TA) sonogram of 5-week IUP (arrow) as depicted on magnified transverse scan. Normal 5-week IUP. C: TVS of 7- to 8-mm sac (arrow) of 5-week IUP. D: TVS US of 5-week IUP appearing as anechoic area within the thickened decidualized endometrium. E: TVS of 5-week, 6-day intrauterine pregnancy in a retroflexed uterus, demonstrating an embryo/yolk sac complex (arrowhead). F: Magnified transverse TAS of 5- to 6-week IUP showing concentric layers of decidua (arrow) and a "double bleb." G: TVS of 4-week IUP. The endometrium has undergone decidualization and the "chorionic sac" is just a few millimeters in size. H: Magnified TVS showing developing gestational sac of approximately 4 × 6 mm and surrounding choriodecidua in this 5-week pregnancy.
Source: TRANSVAGINAL SONOGRAPHY OF EARLY INTRAUTERINE PREGNANCY, Sonography in Obstetrics and Gynecology: Principles & Practice, 7e
Citation: Fleischer AC, Toy EC, Lee W, Manning FA, Romero RJ. Sonography in Obstetrics and Gynecology: Principles & Practice, 7e; 2014 Available at: Accessed: December 17, 2017
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