Waiting for the first meeting with your baby is the most exciting period in the life of the future mother. Every week, or even a day, plays an important role in the process of growth and development of the child, moreover, the date of the coveted meeting tirelessly draws nearer. As practice shows, the most accurate way to calculate the PDR (the estimated date of delivery ) and determine the duration of pregnancy can be using the obstetric pregnancy calendar, or the table created on its basis.
Obstetrical pregnancy calendar - what's the point?
The obstetric method is widely used by doctors, because it is considered the most convenient and as close to reality as possible. Obstetric calendar for the reference point takes the first day of the last menstruation. That is, with a regular menstrual cycle lasting 28 days, the difference between the obstetric and embryonic period is two weeks. Because, according to the embryonic calendar, the gestation period is counted directly from the date of conception.
This is the clear advantage of the obstetric method, since not every woman remembers the date of a fateful sexual intercourse. In addition, there are no guarantees that fertilization occurred on this day, as, as is known, spermatozoa retain the ability to conceive within 3-4 days, and the egg cell - about a day. It should also be noted that not every woman can boast a regular 28-day cycle.
Actually, therefore, it is easier for physicians, and even for a woman, to start from the date of the last month and keep the midwife's pregnancy calendar by weeks, and also with it to calculate the PDR.
According to the midwifery method, the entire pregnancy period lasts 280 days or 40 weeks (more specifically, 9 months and 7 days). Accordingly, you can learn the approximate date of birth by simple calculations using two formulas:
- In the first variant, by the first day of the last month (PMDP), 9 months and seven days are added.
- The second formula proposes to take 3 months from the VDPM and add 7 days.
In antenatal clinics, use the maternity calendar as a table, based on Keller's formula (280 days are added to the PDPM).
Calendar of obstetrical weeks
Doctors, and many women, conduct an obstetric pregnancy calendar on a weekly basis to track the dynamics of growth and development of the embryo, as well as its compliance with the expected date. In addition, weight gain, changes in the roundness of the tummy, height of the uterine fundus, and many other parameters are taken into account.