Role of Sonography in Obstetrics, Part I - Vocabulary Flashcards

A set of vocabulary flashcards covering key terms and concepts from the notes on the role of sonography in obstetrics.

Sonography (Obstetric)

Primary imaging tool to evaluate the developing fetus during pregnancy; assesses fetal development, growth, and well‑being to guide obstetric management.

Obstetric ultrasound

Ultrasound examination used to evaluate pregnancy, fetal development, and related maternal factors; aids prenatal diagnosis and parental education.

Fetal well‑being biophysical evaluation

Biophysical assessment after 28 weeks including amniotic fluid volume, fetal tone, body movements, breathing, and heart rate patterns.

Fetal biometry

Measurement of fetal size by ultrasound to estimate gestational age and monitor growth.

Intrauterine growth restriction (IUGR)

Fetal growth below expected standards for gestational age; monitored with serial ultrasound measurements.

Macrosomia

A fetus with abnormally large size for gestational age.

Indications for obstetric ultrasound

Clinical reasons to perform ultrasound, such as dating, growth assessment, bleeding, pain, and evaluation of fetal presentation, anomalies, or placenta.

Estimation of gestational age

Dating a pregnancy using menstrual dates or ultrasound measurements to determine fetal age and timing of delivery.

Uteroplacental insufficiency

Inadequate placental blood flow causing potential fetal growth restriction or distress.

Serial cervical length evaluation

Repeated measurement of cervical length to assess risk of preterm birth.

Ultrasound guidance for amniocentesis

Use of ultrasound to guide needle away from placenta and fetus during amniocentesis, increasing safety and success.

Multiple gestation

Pregnancy with more than one fetus; management may be altered accordingly.

Fetal presentation

Position of the presenting part relative to the birth canal (e.g., cephalic, breech) important for delivery planning.

Ectopic pregnancy

Pregnancy implanted outside the uterus; ultrasound helps confirm location and viability.

Hydatidiform mole (molar pregnancy)

Gestational trophoblastic disease; ultrasound aids diagnosis and distinction from fetal death.

Cervical cerclage

Surgical stitch to reinforce the cervix; ultrasound aids timing and placement in incompetent cervix.

Suspected fetal death

Clinical suspicion of fetal demise; rapid ultrasound evaluation supports management decisions.

Suspected uterine abnormality

Possible leiomyomata or congenital uterine anomalies detected by ultrasound.

Fetal growth assessment with amniotic fluid measurement

Evaluation of fetal growth and amniotic fluid volume to identify oligohydramnios or polyhydramnios.

Placental location evaluation (placenta previa)

Assessment of placental position to identify previa and guide delivery planning.

Fetal weight estimation

Ultrasound‑based calculation to estimate fetal weight to inform delivery timing and method.

Aneuploidy risk screening

Assessment for abnormal fetal chromosome number (e.g., trisomies); may involve ultrasound markers and biochemical screening.

First trimester examination (76801)

Ultrasound before 13 weeks 6 days evaluating uterus, cervix, adnexa, gestational sac, embryo, dating by size, and documenting chorionicity/amnionicity.

First trimester risk assessment (76813)

Nuchal translucency measurement and crown‑rump length for aneuploidy screening.

18 weeks standard examination

Second trimester standard exam evaluating gestational age by biometry, fetal number, placental position, cardiac activity, amniotic fluid, and fetal anatomy.

Limited obstetric sonography (76815)

Focused exam answering a specific clinical question (e.g., presentation, placental location, cervical length, amniotic fluid).

Repeat obstetric examination (76816)

Similar to standard exam; includes biometry for growth assessment and possible re‑evaluation of anatomy.

Specialty obstetric sonography (76811)

Targeted exam with in‑depth fetal anatomy views; often used when anomaly is suspected.

Chorionicity and amnionicity

Number of chorions and amniotic sacs in multiple gestations; should be documented.

Gravidity

Number of pregnancies a woman has had, including the current one.

Parity

Number of pregnancies carried to viability; expressed as a P sequence (e.g., P0000 indicates term, preterm, abortion, living children).

Last menstrual period (LMP)

First date used to date pregnancy; standard reference point in dating.

Naegele’s rule

EDD = LMP − 3 months + 7 days (used to calculate expected delivery date).

Trimester

Pregnancy divided into three roughly 13‑week periods; first, second, and third trimesters.

ALARA principle

As Low As Reasonably Achievable; minimize ultrasound energy and dwell time to reduce exposure.

Doppler ultrasound safety

Use of Doppler to assess fetal/metal circulation; prefer pulsed wave in fetus; minimize exposure, especially in early pregnancy.

RDMS

Registered Diagnostic Medical Sonographer; certification ensuring appropriate training and competency.

Documentation standards

Permanent records of measurements and findings; labeled images and written reports maintained in patient records.

Quality control and infection control

Protocols ensuring equipment performance, safe practice, and prevention of infection in the imaging laboratory.