Do Pregnancy Calculators Work?

One of the first questions women ask when they learn they’re pregnant is, “When am I due?” Knowing your estimated due date allows you to plan for a healthy pregnancy and to be prepared for the baby’s arrival. Pregnancy calculators can be effective tools in approximating your due date, but it’s important to understand that any calculator you use will only be able to offer an estimate, and that the odds of delivering on that exact date are slim.

How Do Pregnancy Calculators Work?

Whether you use an online pregnancy calculator, or you had your due date projected by a doctor or midwife, there are typically two methods used for calculating your due date. The first option is to estimate the due date based on the date of your last menstrual period. The second option is to base the estimation on the date of conception.

To calculate your due date based on your menstrual cycle, count 40 weeks from the date of your last period. To calculate your due date based on the date of conception, count out 38 weeks from the exact or approximate date you think you conceived.

How Accurate are Pregnancy Calculators?

According to BabyCenter, only about one in 20 women deliver on their due dates. It’s important to understand that a pregnancy calculator based on your conception date will offer a good approximation of the baby’s arrival. However, most women don’t know their exact conception date, making it difficult to calculate an exact due date. It is also possible that conception did not occur the same day you were sexually active, as your egg may have been fertilized a day or two later by sperm that was waiting in the fallopian tube.

For this reason, most health care experts recommend calculating your due date based on the date of your last menstrual period. Even using the menstrual period method, you’re still only left with an estimated due date. A doctor or midwife may alter your due date during your pregnancy based on the results of an ultrasound test that will indicate impacting factors, such as the size of the baby. To be best prepared for the baby’s arrival, use a pregnancy calculator as a guide, but know that you may ultimately deliver any time within one or two weeks before or after your calculated due date.

Pregnancy Support Services

Avail NYC offers a variety of pregnancy support services and referrals to help women and couples facing an unplanned pregnancy remain healthy and prepared. Contact us today to learn more about how we can help you to make an informed and confident decision.

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Avail NYC exists to be a safe haven for women and men facing an unexpected pregnancy or seeking support after an abortion. We are not a medical provider.