How do the dates work ?

[Bexxy1992]

Hey everyone. I could really do with some help. I'm 1-2 weeks pregnant. Very early, I have had a very stressful few months with work etc. I don't even KNOW when my last period was it may have been recently or not. If I had sex on the 1st September , could I only be 1-2 weeks pregnant now ? Does that work our at all?

You're further along that you think. What was the date of your last period? The first day?

Do you mean 1-2 weeks pregnant on a clearblue test?

If you had sex on the 1st of September then stretching dates to the theoretical maximum you could have had a fertilised egg on the 6th of September and then implantation could have taken another few days so maybe the 10th of September. But you would still be about 4 weeks pregnant now. Which is actually 6 weeks pregnant because for the first two weeks of the 40 weeks you aren't actually pregnant.

Oh my God. I need to sleep. How did I miss that, you don't know the date of your last period. I think ovulation is around 10 days after the first day of your last period. So you could be about 7 weeks pregnant.

But the clear blue test says 1-2 weeks ? Shouldn't it say 5+ weeks ? Xx

Clear blue shows possible weeks from conception, pregnancy is dated from first day of last period, in 40 weeks of pregnancy they include the two weeks at the beginning where you are not actually pregnant, the lead up to ovulation. So if clear blue indicator says 1-2 weeks it means you are approx 3-4 weeks, but they can also be a little off with the weeks indicators dependent on when you take the test. Confusing I know, took me a few weeks to understand it all.

So did I most likely conceive on the 1st September or after this date :)?

Yes, if you go see your GP they may be able to offer an early scan as you have no idea with the dates.
If you conceived 6 weeks ago on the 1/09 you could be 6-8 weeks. If you've had sex since 1/09 it could be anything between 1-6 weeks.

If you got a 1-2 on a CB digi today you'd likely be 3-4 weeks pregnant. Did you have sex around 4 weeks ago?

Doctors date you from your LMP because most people know when their LMP is/was.

• Ovulation occurs 14 days after your LMP (on average)
• Implantation occurs 7-10 days after fertilization.

Once implantation occurs HCG starts to rise and you'll be able to tell you're pregnant by a HPT after a couple of days (depending on the sensitivity of the test/s).

Clearblue tests measure the amount of HCG in your urine and based on that level show how many weeks it's been since ovulation by using the average levels of HCG in pregnant women. This amount can vary from person to person and pregnancy to pregnancy. Multiples tend to have a higher level of HCG.

So in your particular instance with a clearblue that says 1-2 weeks, it's estimating ovulation having occurred 1-2 weeks ago (and thus if you had sex around that time then that's likely that's when you conceived), add 2 weeks and that's how far along the doc will say you are (3-4 weeks).

All that said, if you're trying to estimate who could be the father, bear in mind it's not a specific "day", it's a range of days. Sperm lives for 3-5 days (some studies say up to 7 days). The egg is good for around 24-36 hours. Implantation is a 7-10 day range. You never really know when you ovulate (test kits only measure LH levels which doesn't always mean you ovulated)... not to mention you could be someone with high HCG levels or low so the clearblue could be off a week or so either side. So really, you're looking at a possible window of around 2 weeks... until you get a dating scan which should narrow that down a bit.

Just so you know as well, the clearblue tests only show up to 3+ weeks and then stop and they're not the most sensitive so it might not be detecting all of the HCG in your system.

You need to make an appointment at your GP with your midwife. They will date your pregnancy from your LMP and then send you for a scan when you should (going by your LMP) be around 12 weeks pregnant. The scan will then give you the due date everyone will go by for the remainder of your pregnancy

Your pregnancy will be dated at your scan so even if you don't know when your last period was just give a rough date. I'm all over the place with periods since having my son and didn't know when my last was. Ended up going to my 12wk scan to find out I was 15wks and too late for screening (which doesn't matter as I wouldn't have done anything about the results anyway).

You wont be able to have a scan just to date your pregnancy though unless you go private. In early pregnancy you have to have bleeding or other issues for an early scan on NHS.