Very early on in pregnancy, I estimated that my due date was probably June 22. This was based on when I believed ovulation to have occurred (September 28), so it was even more accurate than simply knowing the date of intercourse. Conception, after all, does not often happen on the day of intercourse (unless you have impeccable timing!). Conception occurs when you ovulate. That egg, it's precious. All the sperm are just lying in wait for it to be revealed.
(I don't think I would ever say that out loud to someone that I didn't know. I probably don't know you. This has now become slightly awkward.)
(...)
Anyway, so this is what I had figured out. When I had my surprise ultrasound at 5 weeks, guess what? She said that, by her measurements, my estimated date of ovulation and due date were right on. RIGHT ON. What I heard was: "you are a natural family planning genius."
So I was a bit dismayed that I could not convince the sonographer who did my 11-week ultrasound that I already knew my due date, and that her date was too early (she came back with June 18, based on her measurements). I explained to them about ovulation (I can't believe they didn't know, I can only assume they thought I didn't understand it well enough). I explained to them about the early transvaginal ultrasound (but I'm certain it was in my chart). I even explained to them that my husband is unusually tall, and all of our children so far have been unusually long at birth (my quack theory about why my due date keeps getting pushed up with each pregnancy). Alas, to no avail. It goes in my chart as June 18.
The reason I care about this so much is because I know that at 37 weeks, they are going to start asking me about induction. It's so predictable that it's almost funny, except not, because I've had one, and induction hurts. My children are not born before 40 weeks. They just aren't. And I have a stronger bargaining position if I simply refuse induction until my due date! Oh well. I'm sticking to my guns on this one, bargaining position be darned.