378: Utility of first trimester ultrasound in the setting of NIPT incorporation into practice: a retrospective pilot review

Abstract

Prior to the introduction of non-invasive prenatal testing (NIPT), first trimester (FT) risk assessment with nuchal translucency (NT) measurement and maternal serum analytes was routinely offered for aneuploidy screening. With the recent acceptance of NIPT as first-line screening for high risk individuals, the utility of FT ultrasound (US) has been called into question. Both ACOG and NIH propose that FT US can be offered to all patients, but it is not currently considered routine. We sought to identify the additional utility of FT US, even as the practice paradigm shift in screening moves toward routine use of NIPT. We performed a retrospective pilot review of all FT US that occurred in our referral center in a single month (October 2013). First trimester NT US at our prenatal diagnosis center routinely include anatomical surveys: the studies are performed both abdominally and vaginally as determined by operator preference. Results of FT US, second trimester targeted US, and NIPT were recorded. There were 134 FT US performed during the month of October 2013. Mean age was 34.5 years (range: 25-42). NIPT was performed in 76 (57%) of the patients, either prior to referral or at time of MFM US. Findings noted on US were: 8 fetal (5.9%), 12 gynecologic (8.9%), 5 placental (3.7%) findings. Of the fetal findings, 3 were isolated increased NT (range 3.6-5 mm), 2 were anatomical anomalies (acrania; micrognathia), and 1 anomaly associated with abnormal NT (enlarged bladder, NT 3.6 mm). Of the 8 fetal findings detected on FT US, 2 (25%) had negative or non-reportable NIPT. First trimester US provide valuable clinical information about fetal and maternal anatomy that cannot be detected on NIPT alone. Despite the convenience of NIPT, FT US should remain an important clinical tool in prenatal diagnosis.