Obstetrical Ultrasound

1A fetal ultrasound is an imaging technique that uses sound waves to produce images of a baby in the uterus. The information gathered by a fetal ultrasound can help your health care provider evaluate your baby’s growth and development and determine how your pregnancy is progressing.

Why it’s done

A fetal ultrasound can be done at any point during pregnancy. Your health care provider may use a fetal ultrasound to:

Confirm the pregnancy and its location.
Some embryos develop in the fallopian tube instead of in the uterus. A fetal ultrasound can help your health care provider detect and treat a tubal (ectopic) pregnancy.

Determine your baby’s gestational age. 
Knowing the baby’s age can help your health care provider determine your due date and track various milestones throughout your pregnancy.

Confirm the number of babies. 
If your health care provider suspects a multiple pregnancy, an ultrasound may be done to resolve the question.

Assess fetal anatomy.
An ultrasound can help your health care provider assess the anatomy of your baby and identify various congenital abnormalities. early diagnosis may lead to early interventions that help to save or improve a baby’s life. fetal ultrasound has limitations. fetal ultrasound may not detect all birth defects.

Evaluate your baby’s growth.
Your health care provider can use ultrasound to determine whether your baby is growing at a normal rate.

Study the placenta.
Placental location and the maturity of the placenta can be evaluated.

Investigate new signs or symptoms.
If you’re bleeding or having other complications, an ultrasound may help your health care provider determine the cause.

Determine fetal position before delivery.

Fetal ultrasound cannot be done:

Just to determine the baby’s sex — this may be a bonus for curious parents when an ultrasound is done for medical reasons.

For the sole purpose of producing keepsake videos or pictures.


Medically indicated fetal ultrasounds are safe for both mother and baby. There are no adverse effects from fetal ultrasound on children followed for several years after birth.


A full bladder is required for obstetrical ultrasound examinations – one litre of fluid one hour prior to the ultrasound examination is required after 28 weeks of pregnancy – 500 ml of fluid one hour prior to the ultrasound examination is required do not void prior to your examination.

What you can expect:

During a standard fetal ultrasound, your sonographer will apply an ultrasound gel to your abdomen as you recline on an exam table. The sonographer will move the transducer over your abdomen in order to obtain all required information. Don’t worry if you cannot ‘see’ your baby, ultrasound images are difficult to understand for an untrained observer.