7-13-16 1st Trimter Ultrasound

© 2016           

By Keith S. Wexler, MBA, Maternal Fetal Medicine, Prenatal Diagnosis and Biotech Consultant, GENASSIST, Inc.

Paul Wexler, M.D., F.A.C.O.G., Medical Director, GENASSIST, Inc.

Clinical Professor, Department of OB/GYN, University of Colorado Health Sciences Center

Clinical Professor, Division of Genetics/Dept. of Pediatrics, Univ. of Colorado/The Children’s Hospital

Background: We get a call at least two to three times a week from a patient who is referred to us by her healthcare provider for a 1st Trimester Ultrasound and the patient states “If I have “Low Risk” Maternal Fetal DNA test result and I know the sex of my baby already, why do I need a 1st Trimester ultrasound”?

Dr. Wexler’s response to the patient is always “your healthcare wants us to perform a 1st Trimester fetal anatomical survey by ultrasound since the Maternal Fetal DNA test does not look or test for structural abnormalities in the pregnancy or fetus.

Although almost all babies are normal, we can occasionally find a problem which can alter the course for the pregnancy or the child.

The healthcare provider wants to combine the screening blood tests with ultrasound findings so that he/she can navigate the best course of how to manage your pregnancy”.


Since many of the healthcare providers that we work with never perform an ultrasound prior to offering Maternal Fetal DNA testing, the 1st Trimester ultrasound is often the first ultrasound that the patient has in pregnancy.

Over the past few years due to the nature of our referral practice we have seen the following ultrasound findings on patients with “Low Risk” Maternal Fetal DNA:

  • Abdomen – abdominal wall defects (gastroschisis)
  • Chorion-amnion separation (placental tear)
  • Central Nervous System – anencephaly, fluid on brain (hydrocephalus), open neural tube defect, bone abnormalities
  • Confirmation of dates or change in dates
  • Cystic hygroma
  • Fetal demise
  • Heart (fetal) – slow heart beat (bradycardia), irregular heart beat, rapid heart beat (tachycardia), enlarged heart, Fluid around heart
  • Hernia in diaphragm
  • Intrauterine growth restriction (IUGR)
  • Kidneys – excess fluid, horseshoe kidney, single kidney. Obstructed bladder
  • Limb abnormalities
  • Lungs – fluid around lungs
  • Multiple gestations
  • Ovarian abnormalities
  • 1Placental abnormalities – cysts/tumors (chorioadenoma)
  • Small for gestational age (SGA) versus off on dates
  • Umbilical cord – 2 vessel cord versus a three vessel cord
  • Uterine abnormalities (double uterus, fibroids – can lead to preterm labor)
  • Vanishing twin

1Placental abnormalities – cysts, benign tumors (chorioadenoma) can cause IUGR and increases the likelihood of excess fluid (polyhydramnios), placenta previa, chorion-amnion separation (bleeding)

The patient needs to understand that Maternal Fetal DNA is a wonderful screening tool, but when a healthcare provider is evaluating the health and well-being of the pregnancy and the fetus it is prudent to balance prenatal blood screening tests with ultrasound findings.

A follow-up question from the patient when an ultrasound finding on 1st Trimester ultrasound is found is “how will the ultrasound finding change my management or the outcome for my child?”

  • Medication can occasionally be administered to the mother and can treat the child by crossing the placenta
  • Maternal activity during the pregnancy may be modified
  • Ultrasound surveillance during pregnancy can help determine the optimum time for delivery and type of delivery (vaginal versus C-section).
  • The ultrasound findings may alter the timing and place of the delivery (home delivery versus hospital) to have appropriate expertise available
  • Rarely intrauterine procedure(s) may be recommended

In the end, everyone wants the happiest and healthiest babies that they can have!