[Ultrasonography early in the pregnancy].
Salvesen
K A
KA
Blaas
H G
HG
Eik-Nes
S H
SH
D000328:Adult; D005260:Female; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D016216:Ultrasonography, Prenatal