How to use our
Due Date Calculator
How do we calculate...
your due date?
An expected date of delivery can be between 37 weeks to 42 weeks, and starts from the first day of your last period, so we use your menstrual cycle to work out an estimated due date with our pregnancy calculator.
At around 10 to 14 weeks of pregnancy you’ll be invited for your first ultrasound which is called a dating scan, during the scan the doctor will measure your baby and give you a more accurate date based on your baby’s size. Sometimes your due date may be different from the one you’ve been given based on your cycle, this isn’t always an accurate prediction as babies can come in all different shapes and sizes!
Starting your pregnancy journey…
If you have taken a pregnancy test and you think you might be pregnant, it’s important to speak to your doctor as soon as possible. Your doctor will give you a pregancy blood test to check for pregnancy.
Your doctor will then talk you through your next steps. They’ll go through your medical history and be able to advise on everything from your diet to any vitamins you may need.
More about pregnancy
You can calculate this through a pregnancy due date calculator. Most doctors calculate your baby’s estimated due date by looking at the first day of your last menstrual period (LMP). In Oman on average most pregnancies last around 40 weeks or 38 weeks from conception.
If your period comes regularly and your average cycle lasts 28 days and if your ovulation usually happens on day 14 of your cycle, your conception probably happened two weeks after your last menstrual period (LMP).
The most common way to calculate your pregnancy due date is by counting 40 weeks, or 280 days, from the first day of your last menstrual period (LMP). You can also minus 3 months from the first day of your last period and add seven days.
However, this is only an estimated pregnancy due date and may vary on multiple factors. Only 4 percent of babies are actually born on their estimated due date.
Your doctor may perform an early ultrasound, which can accurately date the pregnancy. Your first ultrasound will be taken between 7 and 8 weeks of pregnancy, and you will also find out if you are having one baby, twins or even more.
Another way to find out your due date is when the baby’s first heartbeat is heard (around week 9 or 10 weeks, though it can vary) as well as another pregnancy milestone, like when you first feel fetal movement. On average this can be between 18 and 22 weeks of pregnancy, but it can vary. Additionally, the size of your uterus can be a factor that pinpoints your estimated due date. The measurement of your uterus will be checked during your initial internal pregnancy exam.
For IVF patients, the first ultrasound is scheduled at around 4 to 5 weeks after an embryo transfer and this makes it about the sixth or seventh week of pregnancy. However, an ultrasound would be performed earlier if an ectopic pregnancy is suspected. In such cases an ultrasound would take place about three and a half weeks after an embryo transfer.
Other reasons could be that your funal height is abnormal, or your levels of alpha-fetoprotein (AFP), a protein made by the baby, are outside the usual range. Speak to your doctor if you have any questions or concerns always.