The Normal First Trimester


Normal Embryology of the Embryonic Period

Normal Ultrasound Parameters during the First Trimester

The Pathology of Trophoblastic Invasion

The Uterus prior to visualization of the gestational sac

The Decidua

The Gestational Sac

The Yolk Sac

The Embryo (normal appearance from 5 to 12 weeks of gestation)

The Membranes - amnion, chorion, and their cavities

Multiple Pregnancies

Estimation of Gestational Age

Maternal serum bhCG levels

MSS (Maternal serum marker screen) or Triple Test

Video Images