So I'm 17 weeks and 2 days, I went to my Drs appt Friday, he did an ultrasound and said everything looked great. After leaving his office, I got a call from his nurse saying I need to do blood work for spinal testing. My concern is that the dr didn't mention this to me at all and I thought that he was going to check everything at my 20 week appointment for the anatomy check. Has anyone had this blood work at 17 to 18 weeks?