Ovulation without period? Gestational sac measurements?

[koyama83]

I had my lmp on Aug 17, 2016 and my gestation sac was only about 4mm last Friday, which would have meant that I was only 4 weeks 4 days. My hcg was around 400. I don't think that my cycles are average and I'm not sure when I ovulate but according to an ovulation calendar that I set up based on my lmp I conceived, or was fertile Sept 24-27 and was supposed to have a period Sept 14-18 but had no period.
According to the measurements of the gestational sac I would have gotten pregnant around the time I was supposidly on my period...can the measurements be off? I think that a sac can be 4-6mm at 4 weeks? I am confused because I never got a period the month that I got pregnant.

[lucie27]

I had a scan at  7 weeks and six days and all of it measured 15mm and in my fist pregnancy I had a scan at 5 weeeks 6 days and it measured 5mm. As your breastfeeding you could have ovulated at any point. I would just go with the edd they gave you and go by how many weeks the scan showed you to be at.

[koyama83]

Thanks. I'm pretty irritated because I had a scan in er to r/o  ectopic pregnancy for severe pain. The gestational sac was only 4mm but the radiologist dated it at 5weeks 1day and 4-6mm would be a 4 week gestational sac. The report didn't say if there was a yolk sac or anything so I'm guessing there was no yolk and my hcg was only 406, which statistically would put me at less than 4 weeks...but at less than 4 weeks the sac would not be visible and I have no idea when I ovulated because I'm breastfeeding my baby and I haven't had a period since August.... I'm not sure about the sizes and yolk and all of that either. I am so frustrated. My appointment is next month.

[pinkpixie86]

When I had my first scan to date we realised that my last period was an implantation bleed,I had conceived the week before.As our first scan was 7 weeks it was pretty accurate.

[zorbie1]

If you have irregular periods you could have ovulated anytime really. Early ultrasounds are really the better indicator they are unlikely to be more than a few days off in most cases.

[koyama83]

Nobody knows anything about this?

[koyama83]

Bump