How to calculate the duration of pregnancy - the calculation of the gestational age
A woman, having learned from her doctor about her desired pregnancy, will necessarily want to find out the "age" of the future of the baby. There are several ways to determine the date of birth of the baby, both alone and with the help of specialists. How to correctly calculate the duration of pregnancy, and also how the real term differs from obstetrical, we try to tell in this article.
The obstetrical time that gynecologists put on the first admission of a future mother is noticeably different from the real one, but it is the most accurate parameter. It is believed that pregnancy occurs at the time of direct conception or fertilization of the maternal ovum. Usually this happens in the period closer to the middle of the menstrual cycle, so if a woman knows the day when the egg leaves the follicle and ovulation begins, then she can accurately calculate the gestation period.
Basal temperature( BT)
This is done daily, remaining in a horizontal position in the bed, to measure the temperature rectally. After menstruation, in the period of 10-14 days, it is most often not more than 37 degrees, and during ovulation and after it it can rise to 37.2-37.3 degrees. The day of conception does not always coincide with the time of sexual intercourse. The spermatozoon has the ability to survive from three to seven days in anticipation of the appearance of an ovum from the ovary. And the life span of the mother cell itself is limited to 24 hours. Therefore, if sexual intercourse occurred 5-7 days earlier than ovulation, then conception can occur 5-7 days later than coitus. Therefore, experts argue that this method of counting to determine the embryonic period is not entirely accurate. In addition, every woman, due to her individual characteristics: a certain menstrual cycle, the day of ovulation and the possibility of re-release of the ovum from the ovaries, will have a period of development of the fetus, which can not be determined 100%.
Obstetrical period
In obstetric practice, the date of the first day of the last month is used. The error of this method is only 7-14 days. The obstetric period is calculated in two ways: by the first day of the last monthly period, 10 average menstrual cycles( 28x10) or 280 days are added;in the second case, 3 months are subtracted from the same date and 7 days are added( Negele formula).In the ideal case, when the date of ovulation( 12-16 day of the menstrual cycle) is known, you can add 264 days.
Ultrasound examination
For many years, the ultrasound method is quite actively used in the diagnosis of fetal development. The most accurate term of gestation is obtained with the help of studies conducted at the earliest stage of pregnancy - for up to 8 weeks. The development of healthy embryos on these days is identical and it is possible to determine the length of gestation up to a day by the size of the fetus. In the future, children begin to show their individuality, in any healthy fetus may appear minor deviations( for example, the growth is slightly below the norm or the size of the head a little more).If this difference fits within a period of no more than 7-10 days, then doctors usually do not take this circumstance into account, but if it makes a period of two or more weeks, physicians diagnose an intrauterine delay in fetal development and recommend paying attention to the correct balanced diet, walks, healthy lifestyle, which will help to normalize the development of the embryo.
Inspection by gynecologist
Consultation of a gynecologist on the first day of delay about pregnancy is usually not necessary, since the doctor can not yet determine: the uterus is enlarged as a result of PMS or conception. The tangible growth of this female organ in connection with pregnancy begins only at the end of the first trimester. In the second or third week of the delay in menstruation( for a period of 5-6 weeks), the uterus reaches the size of a chicken egg, at 8 weeks - goose, at 10 - usually acquires the size of a female fist.
hCG and gestational age
How to calculate the duration of pregnancy with chorionic gonadotropin? The analysis of blood from the vein is ideally not used to determine the timing of an "interesting situation", but for the early diagnosis of possible complications. In the second week, an approximate table of hCG values in the blood of a pregnant woman contains a parameter from 25 to 150 mU / ml, and on the eighth - to 70 thousand mU / ml. Serious deviations from tabulated values indicate a serious pathology, such as a frozen or ectopic pregnancy.
The first movement of the fetus
The doctors say that for the first time in pregnant women the feeling of the baby's internal presence occurs exactly at 20 weeks of pregnancy, in the re-pregnant women in the 18-week period. This date is an important stage in the correct calculation of the gestational age. To notice the perturbation is easy, especially lying on the back.
Length of the uterus
Beginning with the second trimester of pregnancy, gynecologists measure the centimeter tape length of the uterus in the patient lying on the couch. At the future mother every week the uterus adds in size approximately on centimeter. In addition, there are special tables that can be found in the manuals on gynecology and obstetrics.
Heart tones
The fetal heart begins to beat already at the time of four and a half weeks( or 2-3 weeks after a woman's delay in menstruation).This is noticeable in early studies with an ultrasound machine. Through the midwifery stethoscope, the fetal heartbeat is audible much later, approximately after the date of the beginning of the waking of the future crumbs. Poor hearing can be triggered by the placenta, located closer to the front wall of the uterus or significant abdominal deposits of adipose tissue.
No matter how hard you try to correctly calculate the gestation period before the day, most likely, it is unlikely to succeed. This can only be done presumably. Your little one will appear in white light only according to the laws of Mother Nature when she is ready for it herself. Good luck in this difficult and noble cause!
Video
You can learn more about calculating the pregnancy period from the following video: