EDD 16 days later than first estimated (acc to menstrual cycle)

hi,

I'm not sure where to put this thread. I'm pregnant but not as far gone as originally calculated according to the date of my last menstrual cycle.

Today I went in for my 19 week scan to have a look at the baby (and hopefully get an idea of the baby's gender - we're too impatient this time).

It turns out that baby is too young to reveal it's sex. 16 days younger infact. Woh, so I am now 16 weeks+5 days pregnant, and have suddenly lost 2 weeks :wall:

The due date (Nov 9) was calculated according to the date of the first day of my last period (Feb 2). The midwife explained that it is more accurate to calculate according to the date of ovulation, although not everyone knows this (we had a rough idea as I was using an ovulation kit but didn't note the date).... I remember the hormone levels rose (ie I was ovulating within 24-48 hours) a little after the kit predicted, going by the "average"... but it definately wasn't 16 days afterwards.

Do that mean I theoretically ovulate at the end of my cycle?

I can't get my head around this. I think I need to lie down. :o

I'm no expert but ovulation is usually mid cycle. The average cycle is 28 days which means you'd ovulate at day 14 so 16 days sounds about right to me.

Hi Tanyaya, congratulations on your pregnancy :) My cycles average 34 days & I tend to O around cd17-19. With DD2 even using my O date to EDD Bub was still measuring a week behind what I suspected at the 9wk u/s. The only thing I could think of was I had O'd late and then implanted later than average. Does that help/make sense?

Have you had a scan before this one? That would be more accurate to compare the difference in dates.

By memory at 19weeks if you get an EDD from that the area for effort is said to be + or - 3weeks. So although you may indeed be 19weeks (or 17weeks since conception) the baby can be growing at a different rate so be smaller or larger then the average 19week baby. It makes sense when you think we are not all going to have an average 3.3-3.4kg baby. The bigger babies ted to measure a week plus ahead and the smaller ones less.

With my 2nd my 18week scan showed I was 21+ weeks. The EDD was 30th April although my 8week scan had given me an EDD of the 15th of May. She arrived at 36weeks weighing almost 8lb but clearly early (due to vernix, poor muscle tone and too tired to feed).

hi ladies

thanks for all your replies and for shedding light on the situation - after a night's sleep, I feel much more energetic today and less like the wind has been taken out of my sails.

The EDD given at the 12 week scan was November 9, which is what I had mentally prepared for (I know, I need to give up this illusion of control, especially given that the baby comes when baby is ready). So when I yesterday heard that the baby didn't look so big (but was in proportion, so the lady doing the ultrasound wasn't "worried") and was measuring at 16w5d, then I was just flabbergasted.

Having said that, I was apparently having a contraction and had a very full bladder (as requested) which could have cramped up baby and given unrepresentative measurements.

We have been invited back to do another ultrasound in 2 weeks, with the woman who did our 1st scan at 12 weeks. So we will be comparing apples with apples so to speak.

Thanks again, and have a great day :-)

my cycle had returned relatively recently (it was my 5th menstruation before I got pregnant), and the average length was 27 days (however the first one was 34 days). I wasn't ovulating around days 14-16 (according to the ovulation kit), it was slightly later..... and according to the person doing the scanning, 16 days later (ie day 30) LOL

however i am no expert on cycles either... but know enough to think that ovulating on day 30 of a 28 day cycle doesn't make sense.

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I'm no expert but ovulation is usually mid cycle. The average cycle is 28 days which means you'd ovulate at day 14 so 16 days sounds about right to me.

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