A normal pregnancy takes an average of 40 weeks / 9 months. However, the doctor reports the pregnancy period on a weekly basis based on the last menstrual date. Because the date you learn that you are pregnant is not the date your pregnancy started. The important thing is the process where fertilization begins. Detailed pregnancy week calculation is also made according to this logic. In what week of birth does it happen and questions such as when do I give birth are frequently asked. Although pregnancy is said to last 40 weeks, 38-42 of your birth. It is also normal to occur between weeks. Pregnancies that end after 38 weeks are called preterm birth. Generally, the terms related to the duration of pregnancy are as follows:
- Pregnancy Week (Menstrual Week): It starts on the first day of the last menstrual period, which takes place 2 weeks before conception. This week is the week that most doctors use to assess pregnancy. The average pregnancy time is 40 weeks.
- Ovulation Week (Fertilization Week): The day when you become pregnant begins. Its average duration is 38 weeks.
- Trimester: Each trimester lasts 13 weeks. There are 3 trimesters in one pregnancy.
- Calendar Month: A pregnancy lasts an average of 10 calendar months. It is equivalent to 280 days by calculating each month from 28 days.
How to Calculate Pregnancy Week?
As mentioned above, many women do not know exactly the date they got pregnant. Therefore, the gestational week confuses. In fact, the first day of the last menstrual period is considered the beginning of pregnancy. Therefore, pregnancy calculation is made according to the last menstrual date. In other words, when the last period is deducted from the current date and the result is divided by 7, the pregnancy week is found.
How to Calculate Birth?
The question of when to give birth is among the curious. There are 2 different methods for calculating the date of birth. One is to count 280 days, starting from the first day of the last menstrual period. The result is considered a probable date of birth. Another process is to go 3 months back from the menstrual date and add 7 days to the found date. For example, if the last menstrual date is July 1, the estimated birth date will be April 7, as a result of calculating.
How to Calculate Pregnancy Week in Menstrual Irregularity?
The method of pregnancy calculation according to the last menstrual period for women with regular periods gives good results. Since a normal pregnancy will last between 38-42 weeks, delivery also takes place within 2 weeks before or after the calculated date. However, if the menstrual cycle is irregular, this method may not work. Since a reliable birth date prediction is important, it is necessary to talk to the doctor about this. A number of data (other than the last menstrual date) can be helpful in this prediction. The first clue is the measure of the uterus. This measure is measured and noted at the first doctor’s control. It is expected that pregnancy will be compatible with the stage in which it is estimated. The second tip is early ultrasound control. Some doctors routinely perform ultrasound examinations, others only to women whose periods are irregular, previously miscarried, had a complicated pregnancy, whose predicted date of birth is unpredictable according to SAT and physical examination. Accordingly, data can be obtained for pregnancy calculation. In the following days, there will be developments that will reveal the estimated date of birth more precisely. The developments that will clarify the estimated date of birth are:
- The first hearing of the fetus’s heartbeat (can be heard with Doppler at 9th to 12th week)
- Feeling the first life move (16th to 22nd week)
- The height of the fundus, that is, the upper part of the uterus (For example, it reaches the level of the navel around the 20th week)
All these clues are helpful, but none of them provide a precise date. Only the baby determines when it will be born.
What Other Data can the Pregnancy Week Calculation be Done?
Some special conditions, such as menstrual irregularities, can create problems in creating a pregnancy calendar. In such cases, since the fertilization date is not clearly determined, a different pregnancy and estimated date of birth calculation formula should be applied. The first of these is in vitro fertilization and other treatment methods. In these applications, since fertilization is performed in laboratory environments, pregnancy calculation according to the menstrual day may give wrong results. Therefore, in vitro pregnancy calculation can be done by embryo transfer date, blastocyst transfer date and egg collection process date.
Apart from this, pregnancy calculation can also be made according to the date of the relationship. However, this is not a reliable method since it is not known whether fertilization occurred immediately during the last relationship.