Fetus Age and Ultrasound Date Disagree

Cynthia Flynn's picture


Dear Midwife,

According to my LMP I am 8 weeks pregnant. I went in to see my doctor for the first time yesterday and he gave me a transvaginal ultrasound. According to the ultrasound, my baby is measuring 6 weeks.

I am really concerned because I am certain that I am 8 weeks pregnant, or close to it, because I took an ovulation predictor test and I tested positive for a pregnancy test a bit more than two weeks later.

I have an appointment to see my doctor again next week. Should I be concerned? The baby did show a heartbeat of 160 beats/minute, which helps me feel hopeful. However I am still very worried.


I would also be a bit concerned, except that 6-week babies do not usually have a strong heartbeat like yours does. I'm betting the baby was just at an odd angle and the measurement was a little off.

You might wait about 2-4 weeks and see if you can get another ultrasound to confirm the dating.

-- Cynthia, CNM. PhD.