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Determination of the due date. Video
At the very beginning of pregnancy, the expectant mother wants to know when she can see the baby. The expected due date can be calculated in various ways, but none of the calculation methods can guarantee the birth of a baby on a specific day. This is due to the fact that pregnancy lasts an average of 40 weeks, but childbirth in the 38th to 42nd week is considered normal.
Determining the date of birth by date of conception
Calculating the date of birth by the day of conception is easy enough. On average, the menstrual cycle lasts 28–35 days, and ovulation (it is at this time that pregnancy is possible) occurs 14 days before the onset of menstruation. If the woman had unprotected sexual intercourse on the day of the release of the egg, the gestational age can be counted from this date, and accordingly, after making simple calculations, determine the baby’s birthday.
Ovulation can be determined by the basal temperature graph, mild aching or stabbing pains in the ovaries, an increase in the amount of vaginal discharge. More precisely, the day of egg maturation can be identified using ovulation tests or ultrasound.
With daily measurement of basal body temperature, you can notice that in the first half of the cycle it is normally 36,4-36,8 degrees, and after ovulation it rises by about 0,4 degrees
If the exact day of conception is unknown, assuming when ovulation occurred, it is easy to find out. It is necessary to subtract 14 days from the estimated start date of the next menstrual cycle. To determine the date of birth by the date of conception, 280 days should be added to the time of ovulation. This will be the estimated due date (PDD).
There are cases of late and early ovulation, therefore, if a woman has had several unprotected intercourses, it is better to calculate the date of birth not by the date of conception, but by the day of the beginning of the last menstruation.
Determining the due date by the day of the beginning of the last menstrual period
In medical practice, the date of birth is calculated from the day the last menstrual cycle began. To find out when the baby will be born, you need to subtract three months from the start date of the last menstruation and add seven days to the resulting date. It is also convenient to count from this date the obstetric gestational age, which is exactly forty weeks.
Due to the fact that the length of the menstrual cycle can vary greatly for different women, this method can give a significant error.
In addition, some pregnant women may confuse implantation bleeding with regular menstruation, which occurs 7-10 days after conception. If the pregnancy was unplanned, then confusion may arise when vaginal bleeding occurs associated with the threat of termination. If the menstrual cycle was irregular before pregnancy, it may also be difficult to calculate the due date.
Determination of the date of birth according to ultrasound and gynecological examination
The most accurate method for calculating the date of birth of a baby is an ultrasound scan in early pregnancy.
The diagnostic procedure is carried out up to 12 weeks of pregnancy, while you can find out the date of conception and childbirth by the size of the ovum (embryo)
Later in pregnancy, the date of birth is calculated based on the length of the fetus, the size of its head, abdomen and limbs. However, all babies develop differently in the womb, making the PDD even more inaccurate.
By the size of the uterus during a gynecological examination, it is also possible to establish the approximate date of birth of the child. The more experience the doctor has and the shorter the gestational age, the more accurately the gestational age can be determined.
Other ways to determine the DA
If the date of conception and the date of the last menstruation are unknown, and the pregnant woman visited the obstetrician-gynecologist’s office late, it is possible to calculate the approximate date of birth at the beginning of the first fetal movements. As a rule, primiparous women of average build begin to clearly feel the movements of the fetus by 20 weeks of pregnancy, so the baby should be born in approximately 20 weeks. Slender and multiparous pregnant women may feel wiggling at 16-18 obstetric weeks, fuller ones after 22.
If a woman felt the baby’s movements very early or, conversely, late, the date of birth determined by this method will be unreliable.
At a gestation period of more than 14 weeks, the grown uterus extends beyond the pubic articulation, so it can be felt through the abdomen. By 16 weeks, its bottom is in the middle between the pubic bone and the navel, and by 24 weeks – in the navel. The gestational age should correspond to the height of the uterine fundus, a deviation of 2-3 cm is possible.
How to find out the date of birth by the date of conception
Despite the large number of ways to calculate the date of birth, a very small percentage of women will be able to hug their baby for the first time on this very day. Childbirth that occurs between the 38th and 42nd weeks is not considered a pathology, and with multiple pregnancies, it can begin even earlier. In addition, the onset of premature birth is possible due to various abnormalities during pregnancy, such as polyhydramnios, isthmic-cervical insufficiency, late toxicosis, diabetes mellitus.
Also interesting to read: diet during pregnancy.