Chapter 50 - OB Measurements and Gestational Age Flashcards
measurement at the level of the stomach, left portal vein, and left umbilical vein
abdominal circumference (AC)
fetal parameters of size and proportionality expressed as age
age range analysis (ARA)
absence of one (cyclops) or both eyes
anophthalmos
average of multiple fetal parameters’ ages
average age (AA)
refers to the shape of the cerebellum when a spinal defect is present (cerebellum is pulled downward into the foramen magnum)
“banana” sign
measurement that includes both fetal orbits at the same time to predict gestational age
binocular distance (BD)
fetal transverse cranial diameter at the level of the thalamus and cavum septum pellucidum
biparietal diameter (BPD)
fetal head is relatively wide in the transverse diameter and shortened in the anteroposterior diameter
brachycephaly
see gestational sac
chorionic sac
most accurate measurement for determining gestational age; made in the first trimester
crown-rump length (CRL)
the heart rate before the early 9th week of gestation (after the LMP)
embryonic heart rate (EHR)
measurement of the femoral diaphysis
femur length (FL)
structure that is normally found within the uterus and contains the developing embryo
gestational sac
used in the first trimester to estimate appropriate gestational age with menstrual dates
gestational sac diameter
the method whereby the fetus is categorized into small, average, or large growth percentile
growth-adjusted sonar age (GASA)
measurement from the humeral head to the distal end of the humerus
humeral length
condition in which the orbits are spaced far apart
hypertelorism
condition in which the orbits are close together
hypotelorism
condition in which the fetus is not growing as fast as normal; usually considered as being malnourished or abnormal
intrauterine growth restriction (IUGR)
the first day of the LMP is used as the start date for human pregnancies
last menstrual period (LMP)
occurs with spina bifida; frontal bones collapse inward
“lemon” sign
small eyes
microphthalmos
the condition of having a relatively high cranial vault with a high or peaked appearance; it is caused by molding of the cranium, exaggerating the vertical axis, or in more severe cases by premature closure of the coronal, sagittal, and lambdoidal sutures and with a vertical index above 77
oxycephaly
flattening of the vertex of the skull; it is often associated with cranial molding, flattening the top of the skull, and compensatory exaggeration of the biparietal diameter
platycephaly
a normal fetus that measures smaller than dates
small for gestational age (SGA)
failure of the vertebrae to close
spina bifida
fetal head is relatively narrow in the transverse plane and elongated in the anteroposterior plane
dolichocephaly
