Due to the fact that not all women remember exactly the date of sexual intercourse, at which the conception may have occurred, for the reference point the doctors take the first day of the last menstruation. The duration of gestation established during such calculations is usually called the obstetric term. Let's take a closer look at all possible terms for setting this parameter, and in particular we will find out: how many months, 30 weeks of pregnancy?
How can you calculate the duration of gestation on your own?
In addition to the above obstetric term, there is such a thing as an embryonic (real) term. It is he who most effectively reflects all the stages of fetal development.
When calculating it, the countdown begins immediately from the day of conception, i.e. from the day when the woman had sex. In order to calculate the gestation period in this way, it is necessary to take the number of days that have passed since that date from the current date.
However, midwives use the method directly, according to which the count is made at the last monthly period. In this case, the duration of each month is conditionally taken exactly 4 weeks. This is done so that there is no confusion, as well as to facilitate calculations. Thus, in order for a woman to find out for herself exactly how many months this is, 30 weeks' gestation is enough to divide by 4. As a result, this term corresponds to 7.5 months.
What should be taken into account in the calculations and why do errors occur?
First of all, it is necessary to say that some, especially young women, can not remember exactly the date of the first day before the onset of conception, monthly. Calling it approximately, they eventually receive an inaccurate period of their gestation.
However, this can be easily corrected by the use of ultrasound. That is why at the first planned such research, which is usually carried out in the interval of 10-14 weeks, the doctor can make an amendment, indicating the exact duration of pregnancy. Such calculations are possible due to measurements of individual parts of the torso of the future baby and comparison of their norm, which is established on the basis of observations conducted over many years.
Despite the high accuracy of this method of research, and with such calculations, errors are possible, but they are insignificant. Rundown in the period usually does not exceed 1-2 weeks. The explanation of this situation is the fact that everyone, even a small organism, is individual. That's why one grows a little faster than the other. Hence the difference in the definition of the term.
Why between the obstetric and embryonic period the breakdown in 2 weeks?
Calculate and give yourself an answer to us the question, 38 weeks of pregnancy - how many months it is, a woman can use the table. However, the result obtained may not coincide with the period that the doctor said at the first visit to him.
It all depends on how the mother herself was counting. In those cases, when she took the expected date of conception for the starting point, the difference in the time with obstetric can be 14 days.
The thing is that physicians in the establishment consider that time interval, which lasts from the beginning of menstruation to ovulation. On average, it is 2 weeks. That is why a difference arises in the calculations, and it should not be surprising if doctors call it as the main one.
Thus, as can be seen from the article, knowing the calculation algorithm, you can easily calculate how many months this is - 30 weeks of pregnancy, using a normal calendar.