Is it possible I'm farther along?

bbbieberrie

My first pregnancy I had implantation bleeding so my "period" was unreliable for calculating due date - and I'm worried this pregnancy (2nd) is too. Just had my first ultrasound and they measured at a week earlier than they had calculated based on my last period. But my ultrasound looks similar to ultrasounds that are farther along (about three weeks farther along at 16 weeks?) Instead of ultrasounds done at 13 weeks. I'm wondering how likely the possibility is that I had implantation bleeding again and I'm actually farther along and the baby is just measuring smaller? Probably just being paranoid though lol.

harpseal135

Dating ultrasounds are very accurate for estimated dur dates.  

coldlife2

bbbieberrie said:

My first pregnancy I had implantation bleeding so my "period" was unreliable for calculating due date - and I'm worried this pregnancy (2nd) is too. Just had my first ultrasound and they measured at a week earlier than they had calculated based on my last period. But my ultrasound looks similar to ultrasounds that are farther along (about three weeks farther along at 16 weeks?) Instead of ultrasounds done at 13 weeks. I'm wondering how likely the possibility is that I had implantation bleeding again and I'm actually farther along and the baby is just measuring smaller? Probably just being paranoid though lol.

Well, first off, implantation bleeding isn’t period-level bleeding. And implantation bleeding is a weird beast in that it doesn’t always happen, and maybe it wasn’t implantation bleeding anyway but rather spotting. So I wouldn’t think that would affect dating your pregnancy based on LMP. 

Secondly, dating ultrasounds are pretty accurate but can still be 5-7 days off. And thirdly, how long are your cycles? Because if they’re more or less than 28 days, that changes your due date as the standard due date calculation is based on a 28-day cycle.