Pregnancy calculation is based on the first day of your last menstrual period. With the pregnancy calculator tool, you can find out your pregnancy week without the need for a pregnancy calculation ruler. When you do your pregnancy calculation, it will automatically appear on which dates there are important doctor checks, the calculation of the week of gestation, and the calculation of the date of birth. The pregnancy calculator tool has been updated in 2022. Calculate how many weeks pregnant you are based on your last menstrual period now!
How to calculate pregnancy without a pregnancy Calculator
Most pregnancies last about 40 weeks (or 38 weeks after conception), so usually the best way to estimate your due date is to count 40 weeks, or 280 days, from the first day of your last menstrual period (LMP). This is how your doctor will estimate your due date (the date you will give birth) and this is a very accurate calculation. But remember: It’s normal to give birth a week or two before or after.
Pregnancy calculation using the date of conception
Calculating your due date based on the first day of your last menstrual period gives accurate results for women with regular menstrual cycles. However, if your cycle is irregular, the LMP method may not work right for you.
Since a reliable estimated due date is important, you and your doctor may use your date of conception instead of remembering that date. Add 266 days to calculate your estimated due date (date of birth).
Pregnancy calculation using the ultrasound Scan
Even if you can’t pinpoint the exact date you conceived, forget the day of your last menstrual period, or are unsure when ovulation occurred, other tips can help you and your doctor determine your due date at your first prenatal appointment:
An early ultrasound that can more accurately date the pregnancy. Some doctors routinely perform early ultrasounds, but most often only perform an early ultrasound if you have irregular periods, are 35 years of age or older, have a history of miscarriage or pregnancy complications, or if the due date cannot be determined based on your physical exam and LMP.
When the baby’s heartbeat is heard for the first time (around 7 or 8 weeks, though that varies) and when you feel the first fetal movement (average between 18 and 22 weeks, but can be earlier or later), pregnancy milestones, clues as to whether your due date for delivery is correct gives.
Your fundal height, which is the measurement from your pubic bone to the top of your uterus, should be checked by your doctor at each prenatal visit and will help confirm your due date.
The size of the uterus to note at your first internal pregnancy exam may also be a factor in determining your due date.