Determining Baby Due Date: 5 Different Ways

baby due date. a pregnant woman

Pregnancy is one of the most exciting and at the same time crucial periods in the life of every woman. Therefore, there is no surprise that every pregnant woman wants to know the baby due date as soon as possible. However, this question often causes numerous disagreements and disputes. Future mothers “torture” doctors with their questions, because they want to get prepared for such an important event, but doctors just shrug their shoulders, because they are not able to determine with high precision the date of birth of the long-awaited baby.

The estimated baby due date is calculated in several ways, each of which is indicative. That is, if, according to calculations, the baby should be born on January 1, then it is not a fact that this will happen with absolute accuracy on that very day. Very often there are deviations from the expected date in one direction or another. Childbirth can begin even 2 weeks earlier, or later. In the article we’ll discuss fairly simple but very effective ways to find out the likely date of birth of a child, which has been successfully used by many doctors in clinics for quite a long time.

Calculation On the Last Day of Menstruation

So, in order to independently calculate the gestational age and determine baby due date, it is necessary to recall the start date of the last menstruation. All calculations are based on it. From this date, you must subtract 3 months and add another 7 days to the result. The resulting number will be the estimated date of birth of your long-awaited baby.

baby due date. a calendar with baby shoes

For example, the date of the last menstruation is April 22. So, from this date you need to subtract 3 months. Subtract and get – January 22. We add 7 more days to this figure and get January 29th – this day will be the expected date of birth.

It is worth noting that this method of calculation is best suited for women with a regular menstrual cycle that lasts 28 days.

4 Alternative Ways to Calculate the Baby due Date

 A  Visit to the Gynecologist

To find out the term of birth, with fairly high accuracy, you can visit the gynecologist. The doctor will not prescribe any tests for this. He/she will simply measure the size of the uterus, which is increased in size in accordance with the age of the fetus. However, this method of calculating the date of birth of the baby is effective only in the first trimester of pregnancy. In the later stages (in the 2nd and 3rd trimester) for each woman, the increase in the size of the uterus occurs with different intensity, depending on the individual characteristics of the organism.


It is possible to calculate the date of birth by ovulation, which is the most favorable period in which conception most likely occurs. On such days, women usually experience increased sexual desire. In addition, secretions (cervical fluid) become more sticky and thick, the basal body temperature rises, the cervix is ​​lifted, and the mammary glands become denser and painful.

So, to find out when your baby will be born, according to ovulation, you need to add 280 days (the duration of pregnancy) to this day (ovulation). The resulting term will be the date of birth. If the period in which ovulation occurred is unknown, then calculate the middle of the last menstrual cycle, and add the rest to it.

baby due date

Similarly, you can perform calculations and the date of conception. However, you should know that this period does not always coincide with the day on which sexual intercourse took place. Fertilization of the egg, as a rule, occurs only on the third day.

 Hardware Calculation

Hardware calculation using ultrasonic waves can also be attributed to the most effective methods that allow you to determine the term of labor with an accuracy of 1-3 days. The most accurate calculations will be if the ultrasound is done during the period of 11-14 weeks of pregnancy.

 Baby Movements

The first movements of the baby can help determining the date of birth of your child, which usually occurs on the 20th week (for nulliparous) and on the 18th week – during the second and subsequent pregnancies. In ancient times, when there was no ultrasound, this was almost the only method of calculating the term of labor.

As soon as the expectant mother feels the first tangible pushes of her baby in her stomach, then from this point on, 20 weeks should be counted. The resulting date is likely to be the day of the birth of the child. If the birth is not the first, the movements are usually felt earlier – at week 18, therefore, it is necessary to add to this period not 20, but 22 weeks.

baby due date

The Effectiveness of Hardware Methods in Calculating the Baby Due Date

Examination of the fetus in the third trimester on the ultrasound machine allows you to accurately determine the date of pregnancy, and hence the expected date of birth. The fact is that only with the help of ultrasound diagnostics the doctor can observe the state of the placenta, the position of the baby’s head in relation to the entrance to the small pelvis, the opening level of the cervix, signs of fetus maturity, as well as many other important factors. All these parameters are crucial in determining the readiness of the future baby and his mother for childbirth.

Deviation from the Baby Due Date – Is It Normal?

As mentioned above, all calculations of the expected date of delivery are no more than an approximate guideline on which you should not rely. According to statistics, only 17% of women give birth on the appointed day, while the remaining 83% give birth either earlier or later. Thus, we can conclude that no specialist, no matter how clever and qualified he/she is, can predict with high accuracy the date of commencement of labor activity.

Normally, childbirth can occur in the range from 38 to 42 weeks of pregnancy. The birth of a child will not be neither premature nor late, but normal and physiological. Occasionally, for some reason, labor can start prematurely. This happens due to abnormalities in the development of the fetus, stressful situations, various pathological processes occurring in the mother’s body, hereditary factors, etc.

baby due date. a pregnant woman with a calendar

Often there is a prolongation of pregnancy due to the fact that in the first trimester there were some complications. In addition, maternal heredity should be taken into account. If your mother and grandmother gave birth much later than the expected due date, then most likely, the same expects you too. Therefore, it is very important to realize that the calculation of the term of childbirth is a very complex question, conditional and individual for each future mother.

How Do the Characteristics of the Menstrual Cycle Affect the Baby Due Date?

The duration of the woman’s menstrual cycle also affects the term of labor. For example, if it exceeds the standard twenty-eight days, then, most likely, the pregnancy will last more than forty weeks, and vice versa. However, in this case, the deviation in one direction or another is usually not more than 5 days. It is worth noting that in such calculations errors are often made, since very often the usual bleeding, which has already opened after fertilization of the egg, is taken for menstruation.

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