My Due Date?

Ok here is my story. The first day of my last period was June 16th 2007. Well I found out i was pregnant on July 20th. So when I found out I went online and did one of those due date calculator things. It gave me a due date of March 22, 2008. So then once I go to the doctors and get my first ultrasound, the doctors give me a due date of April 1st. When I went to get my anatomy scan at 18 weeks, the ultrasound tech gave me a due date of March 27th. I could understand the difference between the April 1st and March 27th since thats only like 5 days. but why would 40 weeks from my last pregnancy,march 22nd, and my due date from the doctors, april 1st, be off my like two weeks? just curious.

My Due Date?
If you used your last period to estimate your due date on a calculator then it is easy for that estimate to be off. When using your last period, those calculators assume that you ovulated 14 days after the first day of your LMP (last menstrual period). Some women do ovulate on the 14th day, but it can vary widely from only a few days to months if the period is really irregular. The only way to be sure of a due date is to know what day you ovulated by tracking your basal body tempurature (BBT). Look it up at babycenter or pregnancy.org or something. The ultrasound can give you a better estimate of exact fetal age, but it's better to have done very early as that is when the fetus changes most. At 18 weeks a fetus just looks like a small baby and the tech is estimating based on size.
Reply:some doctors take it at the beginning from ur last period


and well once u have a scan the baby's size confirms the real due date for example


i had my last period in 12th November07 and i thought i would be due around 19th August07 i was close but my son actually due date was 20th August because of when i conceived


i would go with the ultra tech due date and keep that one in mind
Reply:Your calculations are probably a little off. A lot of times docs will go by ultra sounds to determine a due date, not just date of last period. Congrats!
Reply:The first ultrasound is probably more reliable than counting from the last period. If your ovulation was a bit later than normal, that could already have caused such a difference.


- But anyway, only 10% of all babies ever come on the due-date.





Congrats and good luck!
Reply:It is very common to be off by 2 weeks. Due dates (as I'm sure you already understand) are just estimates. That's why you're not considered "overdue" until 42 weeks and not premature at 38 weeks.
Reply:when doctors measure you and do ultrasounds, they aren't completely accurate. it gives them an idea of where you are in your pregnancy. Sometimes, they assume you got pregnant earlier than you thought.


if you have a regular period, i would use your last menstrual period date and count forward from that. Also, ask the doctor "what is my due date??"


Throughout my pregnancy, I have measured bigger compared to my last menstrual period due date, but the most accurate is from the last menstruation. Especially, if you have a normal period. If you don't, then that's another story.
Reply:You could have implanted late. When the sprem meets the egg it travels down and then implants into the uterine wall. This time can be short or longer. I would go by the first ultrasound that you had and assume your due date is 4/1. Mine babies were all born closer to the due date I got from early ultrasounds than any other duedates.
Reply:MY doctors gave me a due date of November 17th, I came up with the 7th on my own with a calculator.. My daughter was born on the 7th... But the baby comes when they want. I bet any time in that two weeks!
Reply:The doctor and the ultrasound tech are estimating the delivery date by the measure of the baby. I wouldn't get too wrapped up in the date. Most women do not deliver on their date anyway. The average baby is delivered at 41 weeks according to a recent Harvard study-- not 40 weeks, as previously believed. Going by the traditional 40 weeks from last period method, March 22nd would be your correct EDD. However, if your doctor is saying April 1st-- go with that one. That means you will be given more time to have the baby without pressure of going to the hospital to be induced--- which trust me, you do not want.
Reply:you may have ovulated later than you figured. really though, a due date is just a prediction- and the baby will come when it is good and ready! you are almost done! enjoy your last few weeks!!!
Reply:its gonna come out when its ready anyway...so it dont matter. It might come out tomorrow...it might come out still born...
Reply:The size of the fetus could be throwing everything off. If he/she is too big doctors assume you are farther along and if to small you will be later due date. However be prepared to not give birth on the due date... my son was due on the 28th and gave birth on the 12th. Congrats for the new baby!
Reply:they are calculating that by messuring the baby..the first one is always the most acurate..becuase babies grow at different speeds..or everyones kid would weigh the same at birth...i had 3 different dates too but they told me to go by the 1st one..my last ultrasound was 2 weeks off basically she explained to me my baby is the size of one due 2 weeks before my due date..but the average baby is anywhere from 6-8 lbs..mine were above that always..its just an estimated messurement..go by the first one!
Reply:maybe you ovulated later , i think I'm 8 weeks but ultrasound shoes 7 weeks
Reply:the u/s one is most accurate. go with that one. not surprising that the other two were within a week on either side of it... they were more guesstimates rahter than based on how developed the baby is.