I’m pregnant and how far along I am doesn’t make sense. I had my first ultrasound today to find out my due date. They measured the baby and told me I’m 10 weeks & 3 days. I told them there was no way I could be that far along because I know the exact date that I had sex which was 8 weeks and 3 days ago.They kind of argued with me and told me there was NO WAY that the baby would be only 8 weeks because of the development. They also suggested that it could have been sperm “alive inside of me” for a while. I then explained to them that there was ZERO chances of that lol My boyfriend and I (together 8 years) went through a little drought so not even POSSIBLE. Anyway, has this happened to anyone else? Where you KNOW exactly the date you had sex and then had an ultrasound tell you you’re further along than that? These are facts and to have people argue that I’m wrong is MADDENING 
Please tell me I’m not the only one lol
Ultrasounds are accurate
When it comes to the size and gestation
They don’t go by when you have sex, rather when the start of your last cycle was.
The dates actually do line up, you are already considered 2 weeks around conception…that’s why you are 4 weeks at the date of your missed period.
It’s always 2. Weeks either way
Know many people this happened too especially early on. Some people get told info than at their next ultrasound the baby measures smaller than the first. Ultrasounds may be correct on measurements the baby could just be bigger.
The way gestation is calculated is based on your last period, 10 weeks sounds absolutely correct here… based on that considering your window to concieve (ovulation) is usually 12-14 days after your period which is 2 weeks. You may have gotten pregnant 8 weeks ago but youre baby is still 10 weeks gestational age, because of your last period. Thats what the measurments are based on, and its why delivering anytime after 38 weeks is fine because of the 2 week variation.
Your gestation starts from the day of your last period, not when you had sex, so your maths and the doctors is correct
Just use the calculator and see whose date is closer
I had the opposite. I had a cycle after conceiving which had my calculations off by 4 weeks. Ultrasound was accurate, and gave birth in line with their gestation measurements.
They do calculate from LMP (at least where I am) so could be that
The first 2 weeks or so of your “pregnancy” is actually before conception. The exact day of conception is difficult to determine because it does not necessarily fall on the day of coitus. Ovulation cannot be verified in natural conception. Thus, the fetus is approximately 8 weeks since conception but you are 10 weeks into pregnancy. It can be a bit confusing.
Pregnancy starts at the start of the end of last period. Dont ask why. I guess because ovulation is different and a wild guess at best
Labor nurse since 1988- everyone here is correct. 8 weeks and 3 days from s3x would be about 10 weeks and 3 days pregnant if you have a period every 28-30 days. Ultrasounds for dating in the first trimester are VERY accurate. Within a couple of days. It is when you move into the second and third trimester where they are not as accurate.
Maybe it’s developing quickly??
Happened to me too except they pushed me back 
I had this in reverse. I knew my conseption date just like you. However they told me my baby was too small to be as far along as I said I was. I stopped telling them they were wrong and just went with it. My daughter was born 6 weeks premature according them and by my calculations only 2 weeks premature. She did spend 2 weeks in the NICU before coming home because she was small.
Maybe you’re really healthy and the fetus is growing faster than usual.
I went into the doctor thinking I was 8 weeks almost 9 with a due date of April 30th and when the did the ultrasound I was measuring almost 13 weeks with a due date of April 2nd. I had a period which is why I was going with my date… needless to say he was born on his due date of April 2nd.
Yes it happened to me, turns out they had to delver me earlier than ther date because he was a very big baby
So pregnancy is counted day 1 from Last Menstrual Period dates
We usually ovulate around 2 weeks before our expected period.
So Day 1 would be your first day of your last period. Day ~14 is around the time you ovulated. Around day 28-35 we learn we are pregnant. So yes they are correct
Just go with the count. The baby will come when it is time. Just pray for good health for both of you.
You sure you ain’t stepping out… why do you need validation from the internet so bad.
Hi. I work in fertility. The date is from the last menstrual period so they are correct. However. This depends on the skill of the tech and or doctor. My best friend who’s a tech got my babies weight on the nose. My doctor. 1.5 lb difference and evicted her due to that. She was PERFECTLY FINE hanging out. Trust your gut when it’s time.
What she is saying is that they had sex 8 wks ago and she’s 10 wks along according to measurements. If the two weeks everyone is talking about is added that’s 12 wks.
Either you got pregnant earlier than you think/want or the baby is unusually big.
Either way you shouldn’t be stressing this because it is what it is and now you should focus on a healthy pregnancy.
If dad has any doubts he will get a paternity test.
You’re 2 weeks “pregnant” when you ovulate.
You give birth 40 weeks from the first day of your last period.
So you’re 10 weeks pregnant. But only 8 weeks from ovulation.
(Also, this is why we need better sex education in America)
What’s the big deal? It really cannot be that much of a difference maybe a week or two at the very most
They go by the growth of the baby. Dr’s don’t know when you had sex!! The baby could be measuring at 10 weeks and 3 days, although, you could only be 8 weeks and 3 days along!! They always had my due dates wrong, and I had a premie baby, which was my 1st!!
It’s an estimate at that stage. Wait til later on in the pregnancy; all that really matters is the measurements and baby’s health 
The ultrasound are correct it goes on your last period not the day you had sex as your ovulation could of been off and correct sperms can live 7days
Back in 1977 when they didn’t have all the technology they have today, my OB told me that I was due August 26th. We calculated from the date of my last period plus the antique ultrasound I had (LOL) and they also did blood work. All three agreed. When August 26 came and went and no baby, they had me coming back weekly. Each week he would say “If you make it to your next appointment, we will induce labor” and each visit, they didn’t. When September 15 came along, they sent me for another ultrasound that said I was overdue. So they scheduled an “emergency” c-section. Not much of an emergency because it was scheduled for several days later. So around September 20, I checked into the hospital and I was all ready to have a baby and THEY SENT ME HOME!!! They said that my blood pressure was too high to do surgery! So they put me on blood pressure meds. Not to mention that my ankles were swollen up like balloons and I could barely see five feet in front of me because I had spots in my line of sight. Now, I was only 19 and didn’t know much about pregnancy , so I didn’t question anything. I was miserable. On September 23, my water broke. It was green! I was terrified. No labor pains. We went to the hospital where upon examination, they said she was coming “HAND first”, not head first! They tried to move her hand but no go. So off to the ER I went to give birth to a 10 pound baby girl by C-section. I was knocked out cold, and only saw her for about three seconds upon waking up. They took her right away to the NICU. She was jaundiced and very hairy! 21 1/2 inches long! That was when I found out that I had toxemia! It took a week of bed rest for me (in the hospital) and UV light therapy for her, to get us ready to go home. I missed the baby/mother bonding moments. I didn’t hold her until she was three days old. We were in the hospital for seven days. She turned out to be okay, but recovery for me was really long. This kind of stuff doesn’t happen much anymore (I hope) but babies come when they want to, technology or not!
Ultrasound can be off by 2 weeks that’s why a doctor can not induce labor unless medical reason before 39weeks
Your baby may be developing faster. You know the date of conception. Just be prepared for an early delivery.
It goes off last period, not off ovulation
Changed my 1st baby’s due date 3 different times and i knew exactly when was conceived lol cause his size and he was born right on time like labor at midnight on his 3rd and final due date lol almost 9 lbs
Yes. Frustrating. But the opposite ? My US said I was 8 1/2 weeks. But I feel I was further along. Granted not by much but I believe it’s at least a week off. Idk… my first ever pregnancy so what do I know I guess. Lol
Mine changed 3 times. First due date was July 14, second due date July 6. I had her June 20th 8lbs 3oz
Yip! They said was due nov 22 and the next scan they said due dec 19th so they were over 3 weeks off.
Oh honey thats NOT THE DAY YOU CONCIEVED. OR THE DAY YOU OVULATED. just the medical date of calculating pregnancy. Count two weeks back from the date you CONCIEVED and that’s the date they gave you!!!
I didn’t have this but was told my daughter was big they were estimating around 9-10lbs ! She weighed 8 lbs. I was given the option to evict her before due date. I opted out of that and let her hang out until she was ready as my body does its thing when it’s time. She came 2 weeks before due date.
Ive had the opposite, where i knew i was further…knew when i conceived and they still set my due date 2 weeks further than they should’ve. My water broke on my own calculated due date and dr said oh hes a little early… sir no he’s not
Go with your instinct and take control of yourself and your health. You are in control. Good luck and best wishes.
Go with ultrasound estimate. Before 15 weeks, it’s extremely accurate.
Yes, I fell pregnant on the 2nd of January, they said it was a Christmas concieval. We hadn’t had sex since november
EDD is done from your last period. If you do it from the date that you conceived, it works out the same. I had this with my first, I knew the date that I conceived but the baby was two weeks older than I knew it could possibly be. Like I said because it’s worked out from your last period that’s why it does it but it really doesn’t matter x
I think it’s based on period tbh coz I conceived mid February however it’s all backdated to my last period
OK so the day you conceive you’re technically abour 2 weeks pregnant already as they go from last period not day if sex. Bless you can’t believe no ones explained this to you
Usually goes by period Date. But I know my exact period Date and measuring a week behind which they said was because everyone ovulates at different times, so who knows. How long before the conception was your period? Could possibly be why?
It’s really not that deep gurl 
they go off the date of your last period because that’s when your cycle actually starts. A mere 2 weeks isn’t that big of a deal so early on in pregnancy. I wouldn’t be wasting your time or energy trying to argue your point. Just relax woman 
Pregnancy starts two weeks before you conceive, they back date to your last cycle, they add two weeks, even though you’re eight weeks medically you’re ten.
The only way it would be a big deal is if you cheated. Then the timeline would be off for it to be your boyfriends. I went and got my ultrasound having all the dates where conception happened thinking I was farther along and they told me I was eleven weeks vs fifteen. Me and my guy looked at each other like wtf. But the baby is still measuring on target with that information so we are just going with it.
Well pregnancy is measured from your last menstrual cycle not by when you had sex.
Time of pregnancy starts at the day of your last period. So your doctor and scan are actually pretty spot on asuming you ovulated withing tbe average time period of a womans cycle… This is wild that woman don’t know this.
Happened to me. I knew the last 2 dates at could’ve happened. Me and dad broke up after. I found out 3 momths later but I also had a period for 2 of those.
The Dr argued I wouldn’t be more than a few wks.
Try about 4 months.
Keep in mind, ultrasound dates are “guesstimates”. Plan according to both dates, just in case.
Sounds like you may be having a big baby. I had this happen with my first son. It corrected later as the pregnancy went on. My due date was Feb 14 and he was born Feb 24. “Overdue”. He was 9lbs 4 oz 
. Things happen. It’ll work out
Drs are right, it’s based off of your last period.
So for one the babies measurements don’t go by conception date they go by the first day of your last period. So that would make perfect since being your usually fertile about 2 weeks after start of period. Also all babies grow different. Those things aren’t totally accurate
It goes by the first date of your last period