Baby measuring 6 weeks 2 days but only concieved 4 weeks 5 days ago?

[Moby9090]

had a private scan and the baby measures 6 weeks and 2 days but I could’ve only got pregnant at the earliest 4 weeks and 5 days ago. This now confuses my boyfriend and worries me! Is there an explanation for this? The sonographer did not want to seem to help… thanks :)

Are you calculating from the first day of your last period, or the day you believed you had sex and conceived?

Read up on how pregnancies are dated - they count from the first day of your last period, so the first two weeks of "pregnancy" are pre conception. The dates in your OP line up pretty perfectly.

As above, please have a look into pregnancy dating.

You need to add 2 weeks on to the date you conceived for gestation. So, if you are 6 weeks pregnant at a scan, it means baby was conceived 4 weeks ago. If you are 10 weeks, baby was conceived 8 weeks ago.

It's not exact at such an early stage though and not unusual to be a few days out either way so the midwife will count from the first day of your last period. The dating scan at 12 weeks will give you the most accurate dates.

i was told I’m 6 weeks 2 days pregnant by the first day of my last period , how they worked it out. But the baby is measuring 6 weeks and 2 days , just wondered how as I didn’t sleep with my boyfriend 6 weeks and 2 days ago. So we were both wondering how that’s possible . I know they add 2 weeks on and go by the first day of my last period but the sonographer more or less said the baby is measuring 6 weeks 2 days can’t be conceived 4 weeks ago. Baby would be invisible if was concieved 4 weeks ago, he was basically saying I’m lying and my boyfriend perhaps isn’t the dad and maybe we need a dna test :(

Yes the baby is measuring to the exact day of the first day of my last period (5th Nov) and I didn’t have sex until 13th November which was 4 weeks 5 days ago, so the sonographer when I asked, was not very clear with us and was more or less saying that’s a problem you 2 need to deal with not us. The baby is measuring 6 week 2 days so cannot be 4 weeks old feotus

The dating is right. You cancel bed 4 weeks or so ago, add on the two weeks from your last period and you get the 6 week date.

The measuring includes the 2 weeks. So the embryo will be 4w2d if they are saying 6w2d.

If you had sex 4w5 days ago, then that is correct. Sperm can live inside the body for up to 5 days. You probably ovulated 2-3 days after having sex.

At this early stage the dates are also not 100% as so tiny to measure. The 12 week scan is far more accurate that's why it's done at that stage.

Just Google, use some sense, and don't panic.

The baby is supposed to measure 6 weeks 2 days if your last period was 6 weeks and 2 days ago. That's spot on perfect and what you'd expect. You had sex 4 weeks ago, and the baby measures 2 weeks on top of that.
There isn't a problem here. Sounds like you got your wires crossed with the sonographer maybe?

Yes OP, the dates are correct.

You are measuring 6 weeks 2 days pregnant, which means conception was approx 4 weeks 2 days ago

Pregnancy is dated from the beginning of your monthly cycle, it's basically the life of the egg.

I'm not sure what part youre not getting.

You are sixish weeks pregnant. You are measuring as sixish weeks pregnant. This means actual conception was 4 weeksish ago.

All dates perfect. What's the problem?

OP did you sleep with someone else 6 weeks ago?

If not then you know this baby is your boyfriends and you know that the dates are correct and you know there is no issue here and even if your boyfriend did insist on a DNA test it would come back 100% his.

Thankyou & no I didn’t sleep with anybody else. The sonographer tried to insinuate I may have which is why he mentioned a dna test. Nice way for an early scan to go!

Really? That would be highly unusual.

By questioning the dates you probably confused the sonographer and made it sound like you were concerned about something... hence them saying we don't get involved in that and get a dna test if you need to.

You've clearly come across with some concern over dates which is what people do when there are multiple options. Just sounds like a miscommunication with them.

Yes I said just wondering about the baby measurements accuracy as i only had sex 4w 5 days ago and he said if you were 4 week 5 days there wouldn’t be anything to view on the scan. The baby measures 6 w 2 d & that’s between you 2 to sort out. Mentioned dna testing at 10 weeks etc

Your dates are correct,how can you not see that?

is what actually happened that the sonographer mentioned a DNA test when you kicked off about the measurements? So you were confused about the measurements (which are totally correct by the way) and then the sonographer said “If you’re doubtful about the paternity of the foetus, you could get a DNA test.” So it was actually YOU suggesting you had slept with someone else, because that’s the only way the baby could belong to someone other than your partner? Could that be how it went down?

The sonographer didn't know you don't know how pregnancy works, and you made it sound like you weren't sure your man is the father.

It's not the sonographer at fault here.

Sonographer explained how dating a foetus works. The intended parents to be didn’t understand, and continued to misunderstand coming out with different statements.

Sonographer does not have time for biology lessons and suggestions options for all eventualities.

OP if you’re 4 weeks pregnant is called 6 weeks.

If you’re 8 weeks, they’ll be telling you that you’re 10 weeks.

Always add + 2 weeks. Counts the baby dust 🧚🏻

I think a sonographer would understand how dating a pregnancy works so I really think you've misunderstood each other?
Any chance they mentioned chromosomal testing from 10 weeks, not DNA? They'd often mention things like NIPT for you to book back in for that privately..

Why were you having a scan so early?

It's probably worth you and your boyfriend watching a YouTube video on the fertility cycle and how dating of a pregnancy works?

We assume for the purposes of dating in the early stages that everyone has a 'typical' cycle - 28 days between periods.

Day 1 of your cycle is the first day your period starts - what you'll see referred to as LMP.

In this assumed cycle ovulation takes place around day 14 - two weeks after the start of your last period.

The egg released at ovulation typically only survives about 24 hours, so if it's not fertilised at this point then it's flushed out. Sperm can survive for up to 5 days so days 10-15 would be the days you can get pregnant (if you have a 'textbook' cycle).

If the egg is fertilised then it usually implants about 6-8 days later, it's only after this that it can be picked up on a test.

But.. it's hard to know exactly when ovulation happens and not all cycles follow the same pattern, ovulation testing is still fairly new - so we 'date' a pregnancy in the early stages counting from the first day of the last period. So it's correct, in the first two weeks you're not actually pregnant.

So if you're measuring 6 weeks, the conception would have typically happened 4 weeks earlier.

Presumably you know you didn't get pregnant 6 weeks ago as you'd have been on your period?

There are lots of good educational videos out there so definitely recommend you both watching one.

https://flo.health/pregnancy/week-by-week/gestational-age