Commencement 24-hour interval of last period

Most pregnancies terminal effectually 40 weeks (or 38 weeks from formulation), so typically the best way to judge your due date is to count 40 weeks, or 280 days, from the offset 24-hour interval of your last menstrual menstruation (LMP). You could also subtract 3 months from the first day of your last menstruation and add seven days.

The first day of your LMP is how most health care providers gauge a baby's due date. But remember, it's only an estimated due date, not a deadline for your baby to arrive. Merely four percent of babies are born on their estimated due date.

Conception date

If you've been tracking ovulation symptoms or have been using ovulation examination strips, and so y'all may be able to utilize your conception appointment to calculate your pregnancy due date. Just add 266 days to become your estimated due date (or select "Formulation Engagement" from the carte du jour above, and let our Due Engagement Estimator do the math for yous).

IVF transfer date

If you conceived through in vitro fertilization (IVF), you tin can calculate your due date using your IVF transfer engagement. Most embryo transfers occur either three days or five days after egg retrieval and fertilization. If y'all had a day-three transfer, count 263 days from the transfer date to calculate your due engagement, and if y'all had a day-five transfer, count 261 days. (Or select "IVF" from the menu above.)

Ultrasound scan

Fifty-fifty if you tin't pinpoint when you conceived, forget the day of your last menstrual menstruum or aren't certain when ovulation occurred, other clues can aid you and your practitioner determine your due engagement at your first prenatal date, including:

  • An early ultrasound, which tin more accurately date the pregnancy. But be aware, however, that not all women get an early ultrasound. Some practitioners perform them routinely, only others only recommend one if your periods are irregular, you're 35 or older, you have a history of miscarriages or pregnancy complications, or the due date can't be determined based on your physical exam and LMP.

  • Pregnancy milestones such as the first fourth dimension the infant's heartbeat is heard (around week nine or ten, though information technology can vary) and when you lot first feel fetal motion (on average between 18 and 22 weeks, only it can be earlier or later), tin can give clues as to whether your due date is accurate.

  • Your fundal height, which is the measurement from your pubic bone to the height of your uterus, is checked past your practitioner at each prenatal visit and helps confirm your due date.

  • The size of your uterus, which will exist noted when your initial internal pregnancy test is performed, can likewise be a factor in pinpointing the EDD.

Tin can I programme my due date?

Whether y'all're trying to avoid being very significant in the eye of summer or are a teacher who wants to maximize time off with your fiddling i, you can try to time when you excogitate in order to "plan" your due date. But even if yous're one of the lucky ones who'southward able to get pregnant when she really wants to, just think that you probably won't be able to map out exactly when you'll give nativity to the day (or even the week or month!).

Still, yous tin try our Ovulation Calculator, which uses the engagement of your last menstrual period and your typical cycle length to observe the days you're nearly likely to be fertile and increase your chances of conceiving.

Can my due date change?

Yes, your due date can alter. While it's definitely not a reason to worry, your doctor may change your due engagement for a number of reasons as your pregnancy progresses.

It may be that you have irregular periods and your early ultrasound dating was off, or that your first ultrasound was in the second trimester.

It could also be because your fundal height is abnormal, or your levels of alpha-fetoprotein (AFP), a protein made by the baby, are outside the usual range. Talk to your practitioner if y'all accept whatever questions or concerns.