title: Ratio of gestational sac volume to crown-rump length in early pregnancy.
abstract: The sine qua non of fetal well-being in the first trimester is considered to be the presence of fetal cardiac activity. Despite fetal viability, some pregnancies might have a sac that is too large or small for the gestational age, even in the first trimester. As a first step in evaluating this hypothesis, a nomogram was constructed for the ratio of normal sac volume to crown-rump length.
mesh_terms: D000328:Adult; D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D014463:Ultrasonography