Pregnancy Calculator

The Pregnancy Calculator may predict a pregnancy timetable based on a due date, last period date, conception date, ultrasound date, or IVF transfer date.

Pregnancy Length and Expected Due Date

Pregnancy describes a woman’s status throughout the 9-month period when one or more children grow inside her. According to the World Health Organization, a typical pregnancy lasts between 37 and 42 weeks. Childbirth usually happens 38 weeks after conception or 40 weeks after the last menstrual cycle.

During the first OB-GYN appointment, the doctor offers an expected date of birth (dependent on a sonogram) or due date. A woman may also use the most recent menstrual cycle to predict the due date.

Although we can predict the due date, the actual duration of the pregnancy is determined by several variables, including age, prior pregnancy duration, and the mother’s weight at delivery. Natural variability in pregnancy lengths is still influenced by unknown factors.

According to research, less than 4% of deliveries occur on the exact due date, and 60% a week after the due date. Nearly 90% of the cases happen within two weeks of the due date.

Pregnancy Confirmation

You can confirm pregnancy using pregnancy tests or by observing a set of symptoms such as a missing menstrual cycle, elevated basal body temperature, exhaustion, nausea, and an increased rate of urine.

Pregnancy tests measure hormones that serve as biomarkers of pregnancy and include clinical blood or urine tests. They can detect pregnancy from six to eight days after fertilization.

Clinical blood tests are more accurate. They can determine the exact amount of the hCG hormone earlier and in smaller amounts. But they take longer to evaluate and are more expensive than home urine pregnancy tests.

A woman can also perform a clinical urine analysis. However, it is not always more accurate than a home pregnancy test and can be more expensive.

Determining the due date

There are several ways to determine your expected due date:

Human Chorionic Gonadotropin (hCG) levels

This hormone appears in the blood as early as two days after the implantation of the fertilized egg. The blood test allows you to know the level of hCG, but only a doctor can determine the term of pregnancy and expected delivery date by this indicator.

Ultrasound Scan

Usually, an ultrasound scan is done at 7–8 weeks of pregnancy to confirm the due date. During the ultrasound, doctors focus on the size of the fetus to determine its age.

Ovulation date

Add two weeks to the date of the last intercourse at the time of ovulation and count 40 weeks, or 280 days of pregnancy, from it. Ovulation usually occurs around 14 days after your period starts if your period is regular and has a 28-day cycle.

Last menstrual period date

This method determines your due date and the date of your upcoming delivery. It works for women who have regular menstrual cycles.

In most cases, women don’t know the exact date they conceived their baby, but they can tell you exactly when their last menstrual cycle started. This is the point from which pregnancy is usually counted. For most women, the most likely time of fertilization (ovulation) is in the middle of their monthly cycle, in other words, two weeks before their next menstrual cycle begins.

Based on this date, pregnancy lasts about 280 days, or 40 weeks, from the beginning of your last menstrual cycle. Thus, you can get your estimated due date by adding 280 days to the date you started bleeding in the last cycle.

This pregnancy calculation determines the fetus’s obstetric, gestational, or menstrual age. With this “calendar,” doctors and nurses will track fetal development.

Gestational age differs from fetal, ovulation, or fertile age, which is two weeks less than obstetric age and is counted from the actual date of conception.