Which of the following sonographic finding confirms intra uterine pregnancy: (A) An echogenic rim along one side of decidua., (B) Two concentric echogenic rings surrounding the sac., (C) A sac positioned eccentrically within endometrium., (D) All of the above.
Answer is D. Normal gestational sac implants eccentrically in the endometrium.
Anechoic center surrounded by single echogenic rim = intra-decidual sign.
Two concentric rings echogenic surrounding sac = Double decidual sign.