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When you know you are
pregnant, the next thing you want to know is the due date. Nine months
may seem far away but it will come faster than you imagine. Your
health care provider may have already given you your due date or are
you are trying to figure it out for yourself?
It can be calculated in many different ways, from plain old pregnancy
calendar to high-tech electronics. The due dates predicted are usually
inaccurate. It usually happen two weeks before or after their actual
due dates
On an average, the length of a pregnancy is 40 weeks, The calculation
may look magical but it is quite simple and is based on a specific
dates of your last period and average gestation time.
Typically pregnancy due dates are calculated using the Last Menstrual
Period (LMP) method. This method used commonly by some obstetricians
uses the date of your last menstrual period to calculate when you are
most likely to deliver.
Ovulation typically occurs 14 days after menstruation and that the
average baby stays in the uterus for about 266 days. The LMP method is
based on that. Your health care provider will ask you for the date of
the first day of your last menstrual period. 14 days will then be
added on to this date in order to find the date of ovulation and
conception. 266 days will then be added to this date, in order to
calculate your expected pregnancy due date.
Naegle’s Rule: Naegle’s Rule is a fast and simple way to determine
when you are due. It is also based on the date of your last period and
typical gestation time. Naegle’s Rule requires that you find the date
of the first day of your last menstrual period. Count three months
back from this date and add seven days. This will give you the date on
which your baby will be due. Some health care practitioners use this
rule to determine due date.
There are other methods that can also be used to calculate due dates.
Basal Body Temperature (BBT) and Luteinizing Hormone (LH): If you have
been measuring your basal body temperature and luteinizing hormone,
you can calculate your due date. Women who are actively trying to get
pregnant often track their BBT and LH in order to determine their
exact date of ovulation. A rise in BBT and a surge in LH can help to
indicate precisely when you are ovulating. If you take this date of
ovulation and add 266 days, you will be able to calculate your due
date quite accurately.
Conception Date: It is quite easy to calculate the due date, if you
know the exact date on which you conceived. Simply add 266 days to
this date.
Ultrasound: An ultrasound test uses sound waves to create a picture of
your baby. During early pregnancy, your health care provider can use
the ultrasound to help determine the age of your baby and, therefore,
her expected due date.
Unfortunately, pregnancy due dates are very rarely accurate. It rarely
pinpoints the exact date but it gives you some idea of when baby will
arrive. Only some women actually give birth on their due date. That is
because their calculations are based on averages. It is assumed that
the average baby stays in the uterus for 40 weeks. But pregnancies can
last anywhere between 38 and 42 weeks.
Also they assume that ovulation and conception occur exactly 14 days
after the first day of your last menstrual period. But most women have
different menstrual cycle and also ovulation can occur at different
times. But by keeping track of your ovulation, you can increase the
accuracy of your due date calculation.
About 80 percent of babies are born within ten days of the due date. A
pregnancy that occurs during this time period--that is, between 38 and
42 weeks, is called full term.
Other 20 percent give birth outside those parameters. About eight to
ten percent give birth early, between the 20th and 36th week of
pregnancy. And about eight percent give birth later than the 42nd
week.
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