The goal of this atlas is to provide a quick resource that you can easily access on your computer or phone to help assess what is ‘normal’. Before moving on to diagnose what is ‘abnormal’, it is vital to be confident with what ‘normal’ fetal anatomy looks like during the second trimester scan.
While different countries may have different standards for timing of the 2nd trimester ultrasound. Biometry algorithms may likewise be dissimilar. But fetal anatomy is universal.
Aside from the brief summaries and ‘tips’, scroll down and you will find The ObG Project entries related to structures being reviewed, including current guidelines. Tap key words for helpful glossary terms.
Even in the best of hands, structural anomalies can be missed. It is always important to let a patient know that birth defects can occur in 3 to 4% of pregnancies and many, but not all abnormalities, can be detected on ultrasound. Sometimes the problem is simply too small to see, while some defects may not develop until later in the pregnancy.
If ever there is the slightest doubt as to whether an image is ‘normal’, consider referral to a center with expertise in fetal ultrasound to confirm whether there is a structural abnormality, and if so, to make a diagnosis quickly. You can find helpful resources, including where to find a maternal fetal medicine expert (US) and genetic services (US and Canada).
Sina Haeri MD, MHSA, FACOG for providing ‘Key Points’ and highlights.
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