# How to calculate pregnancy period?

Many mothers are curious when they are pregnant in the early stages of pregnancy, and then calculate their pregnancy cycle. Calculate the pregnancy cycle and understand the baby’s due date, which can help pregnant moms and physicians accurately track the growth of the fetus.

This article will introduce the calculation method of pregnancy cycle, pregnancy cycle, and related knowledge of pregnancy cycle to help Mommy understand how to calculate the pregnancy cycle and easily estimate the due date!

## How to calculate pregnancy period?

Starting from the first day of the last menstruation, most of the pregnant mummy will experience 280 days or 40 weeks. Therefore, Mommy can use the first day of the previous menstrual period as the calculation benchmark, and calculate 280 days or 40 weeks in the future, which will be the due date of pregnant mummy!

The Negeram method is a simpler calculation method, allowing pregnant mommy to easily estimate the due date. The calculation method of the pregnancy cycle is also based on the first day of the last menstruation, plus one year, subtracted for three months, and the last seven days will be the due date of the mummy. The simpler formula is “minus 3 plus 7”. For example, the first day of the last menstruation was June 12, and it will be 6-3 = 3; 12 + 7 = 19. The due date will be March 19 next year.

Pregnant moms can also refer to the figure below to find the last day of the previous menstruation (black number). As long as the date (blue number) is compared with the date (blue number), you can quickly know the due date. It is more convenient than the formula calculation or the pregnancy cycle calculator!

▲ Find the first day of the last menstrual period, and directly to the next date, that is, Mommy’s due date!
Picture source: Calculation due date | Johns Hopkins University

The calculation of the pregnancy cycle is so important! Fetal development tracking and checkup date arrangement, all look at the pregnancy cycle
At each stage of the fetus, the fetus has its own development goals. For example, in the early stages of pregnancy, the fetal bones and muscles develop rapidly, and the limbs are gradually developing; in the middle of pregnancy, the fetal facial features are fully developed and the fetal movement is more obvious. Organs can operate normally. Calculating the pregnancy cycle can help us track the growth of the fetus. If there are abnormalities or do not achieve long targets, we can find it early.

On the other hand, in the early stages of pregnancy, calculating the pregnancy cycle can also help pregnant moms arrange for delivery time, such as the best time for fetal ultrasound scanning and high -level ultrasound examination. Therefore, mastering the pregnancy cycle can not only continue to track the development of the fetus, but also help track their own health.

I don’t know what to do last time? How to calculate the pregnancy cycle irregularly?

If you don’t remember the last menstrual date, you can’t calculate the pregnancy cycle and due period, and pregnant moms don’t have to worry too much. If you know which week’s menstruation is coming, the doctor can still estimate the due date of Mommy; if you do n’t remember when the last menstruation is at all, the physician will judge Mummy ’s pregnancy cycle through ultrasound examination.

If the pregnant mother’s original menstrual cycle is irregular, it is impossible to apply the calculation method of the Graer’s law. After all, the premise of the Nile’s law is “28 days of menstrual cycle, ovulation and fertilization on the 14th day.” Therefore, when the menstrual cycle is irregular, we recommend that the fetal growth status is confirmed by ultrasound examination, and we can accurately estimate the due date.

Common problems with the pregnancy cycle!

Pregnant moms are more or less doubtful in the pregnancy cycle. The following common pregnancy periods are compiled, so that mommy can fully understand the pregnancy cycle and stay with the baby with peace of mind.

### Q1: Is the due date calculated by the pregnancy cycle accurate?

Regardless of whether it is in the Nurie’s rule or the estimation of the pregnancy cycle calculator, the due date will still be different due to factors such as daily life and actual growth of the fetus. It is recommended that it is still based on the professional judgment of the physician. The real delivery date will fall within two weeks before and after the due date.

### Q2: How to judge the pregnancy cycle of ultrasound inspection to estimate the due date?

Abdominal ultrasound examination can help doctors measure the length of the head and hip (CRL), that is, the length of the baby’s head to the buttocks, which can make the doctor judge the pregnancy cycle and estimate the due date. Usually the due date of the ultrasound examination is usually different from the calculation, and the ultrasonic examination is high in the early stages of pregnancy. The doctor will also use this result to adjust the due date of the pregnant mummy.