Understanding the Medical Terminology used in Ultrasound Reports during Pregnancy

Confusion and apprehension in understanding medical terms of pregnancy used by your doctor and in test reports, scan reports are often seen in most of the pregnant women.

Here are a few terms often used in pregnancy which may help you in having a clearer idea on what the test, scan reports mean and your doctor says.

Terms from used in an ultrasound scan report during pregnancy:

LMP – Last Menstrual Period which is the first day of bleeding in last period.
EDD – Expected Date of Delivery is calculated according to LMP. Most accurate estimate of EDD is given by an ultrasound in 5-18 weeks of gestational age. Earlier an ultrasound is done, more accurate EDD can be estimated.
Gestational age – duration of pregnancy that is calculated from LMP.
Gestational sac – a large fluid filled sac like structure surrounding the embryo. It is usually the first component of pregnancy that can be visualized even before detecting an embryo on a transvaginal ultrasound scan as early as 5th week of pregnancy.
Fetus – baby in the womb from 9th week of pregnancy till delivery.
Fetal/embryonic pole – embryo which takes the shape of a curve with a head at one end and a tail like structure at the other end. A fetal pole usually starts getting detected from 5 ½ – 6 ½ weeks of pregnancy on an ultrasound scan.
Blighted ovum- a gestational sac without a fetal pole that may indicate a miscarriage.
CRL (Crown Rump Length) – length of the fetal pole from head to tail and of fetus in later weeks of pregnancy measured on an ultrasound scan.
Femoral Length (FL) – length of thigh bone of the baby.
BiParietal Diameter (BPD) – distance between sides of head of the baby.
Head Circumference (HC) – circumference of head of the baby.
Abdominal Circumference (AC) – circumference of abdomen of the baby.

FL, BPD, HC and AC values are computed to produce EFW (estimated weight of the baby) which helps in determining if the baby growing well according to the gestational age.

Fetal heart rate – heart rate of the baby according to an ultrasound scan.
Cephalic presentation – Head of the baby occupies the lower pole of the uterus, that is in the direction of legs of the mother.
Breech presentation – Limbs of the baby occupies the lower pole of the uterus, that is in the direction of legs of the mother.
Placenta – a disc shaped mass located on the back wall in the upper half of uterus from 10th week of pregnancy and produces progesterone hormone which prevents uterine contractions, maintaining healthy pregnancy and prevents miscarriage.
Low lying placenta – placenta that is situated in the lower half of uterus (normally situated in upper half of uterus).
Placenta previa – Low lying placenta that partially or completely covers the opening of cervix or womb at the end of pregnancy. This increases the risk of bleeding during pregnancy, miscarriage and the baby is usually delivered by cesarean section.
IUGR – IntraUterine Growth Restriction indicates the baby is small for gestational age.
AFI – Amniotic Fluid Index that is calculated based on levels of amniotic fluid in womb. Normal AFI is 8-18.