When are most babies born relative to due date

BabyCenter's Due Date Calculator

Use our pregnancy calculator by plugging in the date of your last period, the date you conceived if you know it, the timing of your IVF transfer, or your first ultrasound date.

The Due Date Calculator will do the rest!

How is my due date calculated?

There are several ways your due date is determined. If you happen to know the day you conceived, you can count 38 weeks from that day to find your due date.

Most common week to go into labor

(Human gestation takes about 38 weeks.)

But very few expectant moms know exactly when they conceived. Even if you only had sex once during your fertile period, you wouldn't conceive on that day unless you happen to be ovulating.

Sperm can live for up to five days inside your fallopian tubes.

Meaning it could be up to five days after you have sex that you release an egg (ovulate) and it gets fertilized by a waiting sperm. That's the day you conceive.

So without knowing the day of conception, how does anyone determine a due date?

First day of your last period

how accurate is your due date by ultrasound

how accurate is the due date