Brief Answer: You may get it repeated if needed. Detailed Answer: Hi XXXX Hope you are doing fine. TIFFA scan is usually done between 18-22 weeks. You may get it repeated if you wish to and there is no harm in doing so. It is as effective as earlier sonograms. The reason for doing the scan early is to detect any anomalies early enough to plan further management. You can proceed with your scheduled sonogram at 28 weeks as usual. You can also discuss with your consultant if you really need to go for another TIFFA scan. Please do not worry; any major anomalies would be easily detected even by less experienced sonographers. Since nothing abnormal had been reported, it was most likely to be a normal scan; slight markers or blips are normal even in normal babies. Hope your query has been clarified. Please feel free to contact if you need any more information. I will be happy to help. regards, Shanti.V.