How is your due date determined with an irregular cycle?

How with an obgyn determine your due date without knowing last menstrual cycle? I have a irregular cycle due to breastfeeding.


Early ultrasound gives a good guesstimate


Bloodwork, ultrasounds, sonograms, measurements… it’s all a giant math equation in their computers


They will determine the due date after the first sonogram

Measurements of the fetus during an ultrasound

I had a early ultrasound because of the same reason :sweat_smile: turns out I wasnt has far along as I thought. :woman_shrugging: that or baby was just measuring small…

I have irregular periods too and before I had my ultrasound they had guessed 18 weeks, which I knew was impossible. When she did the ultrasound the measurements of the baby determined that I was 8 weeks and 5 days. My first baby I didn’t know I was pregnant until 8 months along and by the time I went to the doctor I was already in labor and had him that same day, so they wanted to do an ultrasound as soon as possible. My last recorded period was in February.

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They determine the due date regardless of what last period date when they do the ultrasound

Bloodwork and ultrasound and possible conception date

The size of the baby, the size of the sac, or by the size of your placenta

Early ultrasound. I never had a period after my Mirena was removed (didn’t have one for 5 years when I had it in) so they went off of my 4-5 week ultrasound.

I received an ultrasound to determine my due date because I had an IUD when I got pregnant and had a weird cycle.

They had to give me an ultrasound because i think i had one while we were moving end of march/early april but couldn’t remember

Usually do a dating ultrasound to try to see gestational age.

Ultrasound, they will measure the fetus.

Determined mine by ultrasound at 7 weeks 4 days

Ultrasound. I hadn’t had a period in over a year when I got pregnant. We thought I was maybe 4 weeks ans ultrasound said I was actually 8.

They’ll go by an early ultrasound! With my son, I was irregular because I had just come off of birth control , they did an ultrasound to determine how far I was.

It’s silly determined with ultra sound size . That’s what happened to me . I skipped a month but based on ultrasound I was that far into pregnancy

I had 2 kids without a cycle between them. Dr did an u/s & determined that I was 18 weeks. He was the only 1 I had to be induced with so she might have over estimated.