I'm pregnant with my second so I've done this all before fairly recently and remember most of it. I went in for my nuchal translucency ultrasound this week and was 13w1d. The tech told us she couldn't get a good measurement because the baby was curled up. (And honestly it felt like she didn't know what she was doing compared to my first pregnancy) She took a measurement of the head instead to decide how far along I was. I told her my daughter and her dad (and his mom) all have big heads. Can I stand up and stretch to see if the baby will move into a different position? She said it wasn't necessary and then told me I'm actually 14w4d and they won't do the blood draw because I'm past the 13w6d window.