system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: INTRODUCTION, MATERIALS AND METHODS. Meshes: Adult, Biomarkers, Chromosomes, Human, Pair 10, Chromosomes, Human, Pair 7, Female, Humans, Pregnancy, Pregnancy Trimester, First, Trisomy, Ultrasonography, Prenatal, Yolk Sac.
user
Is the yolk sac a new marker for chromosomal abnormalities in early pregnancy? Context: Abnormal yolk sac size is associated with fetal miscarriage. This is a case report of two pregnancies with abnormal yolk sacs. In one case, a twofold sac was found; in the other case, the yolk sac was not of spherical form.
assistant
Currently available publications demonstrate a correlation between abnormal yolk sac size and miscarriage. However, in both cases a trisomy was confirmed. It should therefore be discussed whether form and size of the yolk sac could be a marker for chromosomal abnormalities of the fetus.