How to work out conception/due date?

[lifebeginz]

After a positive pregnancy test yesterday I thought I was only 3 weeks pregnant because I thought I knew when baby was conceived.... over the long weekend 3 weeks ago😆. But I done 2 online due date calculators and they asked the first date of my last period and when I entered that one calculator came back with a result of 4 weeks and another one a result of 6 weeks pregnant so now I am really confused.

The only reason I checked is because my GP said wait until 6 weeks before I book the midwife so want to time that correctly

Apologies this is all very new to me 😬

If you know the exact date of the first day of your last period, then count from that day to now, that’s how many weeks/days pregnant you are.

Hi, congrats! Healthcare staff (certainly NHS) will work out dates based on the first day of your LMP so book with them based on that date, doesn’t matter if you know when you ovulated. All your appointments with them will be based on that measurement

Congratulations! It is confusing but technically the first couple of weeks of your pregnancy you aren’t even pregnant because it is counted from when your last period started.

the clearblue weeks calculator is based on conception, but the midwife will use the last period date.

it is weird that two online calculators have different dates if you know when your period was. Recommend using the one on the NHS website x

Thank you for your responses. So going by the first date of my last period I will be 5 weeks. I thought because this month is my first missed period and i had one in April and judging by when we last had intercourse I thought I knew conception date but clearly I don't have a clue ha! I don't know if everyone is as easily confused as me but this is very helpful so thank you :)

It's easy to be confused, as there are different definitions. When people talk about the how many week pregnant, this is normally based on gestational age, which is dated from 1st day of your last period. However the fetal age will likely be around 2 weeks younger than that. e.g if you are "6 weeks pregnant", the first two weeks of that you were'nt actually pregnant. So the fetal age is actually 4 weeks. Makes sense?

Ah ok - yes that makes sense and is super helpful, thank you. I was struggling to get my head around it :)

you're welcome. If you are trying to work out the conception date, then depending on if your cycles are regular, take 14 days off you cycle length and that will be around when you ovulated. Therefore sex would likely have been 1-5 days before or day after.

So 28 day cycle, around day 14 since start of last period. if your cycle is more like 33 days, work back rather than forwards. e.g around day 19.