Glossary of Sonographic and Obstetric Terms

Amniocentesis - Health test of the fetus by analyzing the chromosomes in the amniotic fluid obtained by inserting a needle through the abdomen into the pregnancy.

Embryo - The fertilized ovum until the end of week 8.

Fetus - The embryo from the beginning of week 9 to birth.

Gender - Sex determination (boy or girl).

Genital tubercle - The early phallus.

Labioscrotal swelling - Two folds that form the scrotum in the male or labia in the majora in the female.

LMP - Dating to the pregnancy from the first day of the LMP is called gestation.

Menstrual age - The true age of the fetus (fertilization age) is two weeks less than gestational fetal age is the number of weeks from conception 12 weeks gestational age is 10 weeks of fetal age.

Phallus - Precursor of the clitoris or penis.

Placenta - The organ between the fetus and mother for nutrients and gaseous exchange.

Trimester - The nine calendar months of gestation is divided into 3-month periods called trimesters.

True age - Age from the date of fertilization. Gestation is 38 weeks.

Ultrasound - High frequency low energy sound vibrations passed through tissues to determine and present as a visual display the location and size of areas within the body.

Uterus - Womb.

*Color photographs and glossary (with permission) from: A Color Atlas of Life Before Birth, Dr. M. England, Year Book Medical Publishers.