Help... when did I conceive?

[jessFREN122]

Hi, I am currently 10 weeks pregnant and the pregnancy was unplanned. I have polycystic ovaries syndrome(new diagnosis)  so have extremely irregular periods, often missing my period completely for the month. So last missed period gives me no indication as to when I fell pregnant. I am wondering if anyone can give advice as to which date they think is correct.
I had intercourse on December 16th and not again until the 2nd 4th 6th and 7th of January.

Today I am exactly 10weeks as dated by 2 different ultra sounds meaning my pregnancy started on the 22nd December.
I was being investigated for other conditions so was having multiple blood test and captured to exact day my hcg increased. On the 16th of Janurary my hcg was 2.8. On the 18th of January my hcg was 68.4 (two days apart).
I have read articles saying the first two weeks of your pregnancy you aren’t actually pregnant but is that only when you measure pregnancy from last missed period not ultra sound?
Also I have ready articles about timing of hcg production leaning towards the later dates being correct but hcg can be different for all pregnancies...

HELP!! Which dates add up?

[AnnieBrooke]

You're not pregnant by the guy from December 16. Is the cluster of dates from January all the same guy? If so, he is the daddy.

[jessFREN122]

Yes cluster of Jan dates are all the same guy. So the first week or so of the pregnancy my body was  just preparing and i wasn't actually pregnant?
thank you!

[AnnieBrooke]

Ultrasounds use the same method of counting out the pregnancy time period as do doctors, nurses, medical textbooks, and any other medical source, beginning the count on the "first day of last period." They will calculate a first day of last period (from the size of the embryo) to start the clock even if you didn't have a period at that time. Sounds like you conceived in the first week of January.

[jessFREN122]

That is really helpful, thank you!!!

[AnnieBrooke]

In response to your question (it crossed in the ether with my above comment), when a doctor talks about a 40-week pregnancy time period, he is not saying that pregnancy lasts 40 weeks from conception to full-term birth. Pregnancy lasts 38 weeks from conception to full-term birth. Medical people use the GA count of 40 weeks because in the old days before ultrasounds, the only possible way to even remotely guess when a woman's pregnancy began would be to ask her when the first day of her last period was. Ovulation is hidden and unknown, a period is a big, obvious signal. But the doc would know that a woman does not get pregnant on the first day of her last period. So the two weeks was added at the front end, to get from her last period to her presumed date of ovulation. This gives a 266-day actual pregnancy from conception to birth, a count of 280 days, or 40 weeks. All medical people use this count of the pregnancy time period, as do all medical machines.

[AnnieBrooke]

Anyway, by the count of 10 weeks today, you conceived around January 4, give or take a few days either direction. Not as early as December 16, even if the sperm had lasted in your body a few days. (In fact, if you had gotten pregnant from sex on December 16, they would have told you today that you were 12 weeks or more.)

[jessFREN122]

Thank you, that’s extremely helpful!!