I hate it when my pessimism is well founded. There was a single gestational sac. There was something, after much searching at different resolutions, that might have been a fetal pole. If it was a fetal pole it was not measuring right for 6w1d, it was about 3mm and it should have been 4. There was a sonographer who came out with the immortal line:
"Even in IVF pregnancies the pregnancy timing can be wrong, you might only be 5 weeks."
I thought I'd be kind and not ask her to explain to me precisely how that would work. Our embryos just hung around for a week not developing? That sounds healthy. They implanted a week late? How does that correspond with betas of 251 at 14dpo and 642 at 16dpo? Pretty good betas for an embryo which had only implanted on day 13.
We have another scan next week. My bloody connection is so slow today that I can't google effectively but my guess is that no clear fetal pole at 6w1d means it's blighted ovum and it's all over.
A few weeks ago I said I felt I was being made to go through every infertility hoop, one at a time. I guess this is the blighted ovum/miscarriage or D&C one. I expect the next pregnancy will be the 'see a heartbeat at 6w, embryo croaks subsequently' one.
I saw a chart that said that 85% of women of my age with my beta numbers go on to have a successful full term pregnancy. I guess this was my chance to fall on the wrong side of the statistics.