If you try to use a pregnancy calendar to calculate the date of delivery that can be used for a few seconds, you can see that it is necessary to enter the start date of your last menstrual period, and sometimes, in addition to this - the length of yournormal menstrual cycle.How is the date of birth and a few are accurate as possible, which show a pregnancy calendar?
positive pregnancy test result causes a woman to think much about the future.What will be the sex of the child, and in general - what will this child?How to call it, if it's a boy, and how - if a girl?What to buy before the birth?Where to give birth?How to equip a children's room?Where will the child learn? ... However, many people are interested in a first, very important question - when the baby is born?To find out before the visit to the doctor, someone would pick up the calendar and start counting the forty weeks - and here lies the first snag.Not everyone knows by what date you need to count the weeks.
As pregnancy calendar
pregnancy calendar, which is now on the Internet hundreds - and they are in almost any language - determine the expected delivery date as well as doctors.
In normal intrauterine development of the person continues to 38 weeks from the day of conception.However, few expectant mothers know exactly when they conceive.Even if you know that in the period of maximum fertility (one or two days before ovulation Ovulation - How to determine as accurately as possible? , and the actual day of ovulation) have had sex only once, it does not necessarily mean that conception occurredit was then.Sperm may be in the fallopian tubes, and still quite viable and capable of fertilization for 4-6 days.In this case, they can fertilize the egg, as soon as it comes out of the ovary.
Like what way are calculated the date of birth if the day of conception is unknown?This is done by building on what is known for sure, for example - the date of the beginning of the last menstrual period.In women with normal menstrual cycle length menstrual cycle and its response Conception usually occurs about two weeks after that day, when the last menstrual period.That is why in the preparation of a calendar of pregnancy used the term at 40 weeks: 38 weeks plus two weeks between the start of menstruation and conception Conception, ovarian cycle, fertilization and genetics baby .Thus, pregnancy calendar, as well as the doctor at the first examination, determines the delivery date is only approximate.Pregnancy Calendar, which request not only the start date monthly, but the average length of the menstrual cycle, provide more accurate results, but they are often wrong.
Subsequent examination the doctor may adjust the delivery date previously calculated on the basis of ultrasound (US).If the ultrasound shows that the fetus is too small or large for their gestational age, the date will be shifted accordingly, backward or forward.
How accurately can calculate pregnancy calendar due date?
probability that a pregnancy calendar shows the wrong date of birth is quite high.However, even the doctors do not always correctly identify the delivery date - in the end, on the exact length of pregnancy is influenced by many factors.
Approximately 24% of deliveries begin at the fortieth week of pregnancy.Hence, the probability that the delivery will begin precisely at a given time, is about 3.4% (24% divided by 7 days a week).Very often the birth occur at 38-39 or 41-42 weeks of pregnancy.In relatively rare cases, women give birth at 37 weeks and before 43 weeks or later.Births before 37 weeks of pregnancy are more common than births after 43 weeks.Why
calculated due date is often wrong?Firstly, because not all women ovulate begins exactly fourteen days after the first day of the preceding month.Second, not every woman knows the average length of your menstrual cycle, and it needs to know in order to accurately calculate the time of childbirth.Finally, premature birth can start for a number of reasons, among them - overweight or underweight mother, alcohol or drug use during pregnancy, smoking and pre-eclampsia, diabetes, coagulation disorders, some infectious diseases, congenital malformations in the fetus, multiple pregnancy, and pregnancy was the result of artificial insemination or soon after the previous birth.Of course, all these factors can not be taken into account in advance, so, as mentioned above, a pregnancy calendar helps determine the date of birth only approximately.