# Just when is a trans-vaginal ultrasound medically necessary? **URL:** \ **Category:** Factual Questions\ **Created:** [February 25, 2012, 5:59am UTC](https://boards.straightdope.com/t/just-when-is-a-trans-vaginal-ultrasound-medically-necessary/613926 "2012-02-25T05:59:45Z")\ **Posts on this page:** 2\ **Page:** 2
**Author:** ![MandaJo](https://avatars.discourse-cdn.com/v4/letter/m/ac91a4/32.png) [@MandaJo](https://boards.straightdope.com/u/MandaJo)\ **Post date:** [February 26, 2012, 12:44pm UTC](https://boards.straightdope.com/t/just-when-is-a-trans-vaginal-ultrasound-medically-necessary/613926/21 "2012-02-26T12:44:07Z")
> [@Edward\_The\_Head](#): > > Do you have a good cite for this, because if this is the case then my ex lied to me as they told us something that was a week to 10 days before I know we were together. It’s what my ultrasound tech told me. I am sure there are outliers, of course, but very early ultrasounds are pretty good. ---
**Author:** ![BetsQ](https://avatars.discourse-cdn.com/v4/letter/b/fbc32d/32.png) [@BetsQ](https://boards.straightdope.com/u/BetsQ)\ **Post date:** [February 26, 2012, 7:25pm UTC](https://boards.straightdope.com/t/just-when-is-a-trans-vaginal-ultrasound-medically-necessary/613926/22 "2012-02-26T19:25:00Z")
Ive had them for dating a pregnancy, investigating miscarriages or potential miscarriages, and for tracking down a wayward IUD. Like MandaJo says, they’re not that big a deal, but that doesn’t mean they should ever be mandated. Edward, here’s an article that addresses the accuracy of ultrasounds for early pregnancy dating: [New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study - PubMed](http://www.ncbi.nlm.nih.gov/m/pubmed/18348183/) [Previous page](https://boards.straightdope.com/t/just-when-is-a-trans-vaginal-ultrasound-medically-necessary/613926.md?page=1)