Fig. 1.71: Twin pregnancy on Day 13. The two vesides are bi-latcial, one in each hom (anows).
Fig. 1.72: Twin pregnancy on Day 16. The two vesides are u-lateral and dose together.
Fig. 1.75: Twin pregnancy on Day 14. Only one embiyonic veside seems to be visib)c. In reiation to the last senńcc datę this yesicle is too large. The opposing walls of the two vcsicles arc hiddcn from view.
Fig. 1.74: Single pregnancy on Day 22. Due to the unfawrabk positioning of the ultrasound probc the cornmon membranę of allantois and yolk sac (anow) is depicted without the cra-biyo. A misinterpretation as a twin pregnancy is possMc