2. When Is Your Baby Due?
The beginning of a pregnancy is actually
figured from the beginning of your last menstrual period. For your
healthcare provider’s calculations, you’re pregnant 2 weeks before you
actually conceive! Pregnancy lasts about 280 days, or 40 weeks, from the
beginning of the last menstrual period. This can be confusing, so let’s
look at it more closely.
A due date is important in
pregnancy because it helps determine when to perform certain tests or
procedures. It also helps estimate the baby’s growth and may indicate
when you’re overdue—this will be really important to you as delivery
Your due date is only an estimate, not an
exact date. Only 1 out of 20 women actually delivers on her due date.
You may see your due date come and go and still not have your baby.
Think of your due date as a goal—a time to look forward to and to
Most women don’t know the exact date of
conception, but they usually know the beginning of their last period.
This is the point from which a pregnancy is dated. Figuring a due date
can be tricky because periods and menstrual histories can be uncertain.
Calculate your due date by counting 280
days from the first day of bleeding of your last period. Dating a
pregnancy this way gives the gestational age (menstrual age), which is
the way most healthcare providers keep track of time
during pregnancy. It’s different from ovulatory age (fertilization
age), which is 2 weeks shorter and dates from the actual date of
Some medical experts suggest instead of a
“due date,” women be given a “due week”—a 7-day window of time during
which delivery may occur. This time period would fall between the 39th and 40th
weeks. Because so few women (only 5%) deliver on their actual due date,
a 7-day period could help ease a mom-to-be’s anxiety about when her
baby will be born.
You may hear references to your stage of pregnancy by trimester. Trimesters divide pregnancy into three periods, each about 13 weeks long, to help group together developmental stages.
You may even hear about lunar months,
referring to a complete cycle of the moon, which is 28 days. Because
pregnancy is 280 days from the beginning of your period to your due
date, pregnancy lasts 10 lunar months.
Using a 40-week timetable, you actually
become pregnant during the third week. Details of your pregnancy are
discussed week by week beginning with Week 3. Your due date is the end
of the 40th week. Each weekly discussion includes the actual age of your growing baby. For example, in Week 8, you’ll see the following:
Definitions of Time
Gestational age (menstrual age)—Begins the first day of your last period, which is actually about 2 weeks before
you conceive. This is the age most healthcare providers use to discuss
your pregnancy. The average length of pregnancy is 40 weeks.
Ovulatory age (fertilization age)—Begins the day you conceive. The average length of pregnancy is 38 weeks or 266 days.
Trimester—Each trimester lasts about 13 weeks. There are three trimesters in a pregnancy.
Lunar months—A pregnancy lasts an average of 10 lunar months (28 days each).
EDC—Estimated date of confinement or due date.
Week 8 [gestational age]
Age of Fetus—6 Weeks [fertilization age]
This tells you how old your developing baby is at any point in your pregnancy.
No matter how you
count the time of your pregnancy, it’s going to last as long as it’s
going to last. But a miracle is happening—a living human being is
growing and developing inside you! Enjoy this wonderful time in your
Your Menstrual Cycle
Menstruation is the normal periodic
discharge of blood, mucus and cellular debris from the cavity of the
uterus. Two important cycles occur during the menstrual cycle—the
ovarian cycle and the endometrial cycle. The ovarian cycle provides an egg for fertilization. The endometrial cycle provides a suitable site for implantation of the fertilized egg inside your uterus.
Tip for Weeks
1 & 2
Over-the-counter pregnancy tests are reliable and can be positive (indicate pregnancy) as early as 10 days after conception.
There are about 2 million eggs in a
newborn girl at birth. This decreases to about 400,000 in girls just
before puberty. The maximum number of eggs is actually present before birth. When a female fetus is about 5 months old (4 months before birth), she has about 6.8 million eggs!
About 25% of women have lower-abdominal pain or discomfort on or about the day of ovulation, called mittelschmerz.
It may be caused by irritation from fluid or blood from the follicle
when it ruptures. The presence or absence of this symptom is not
considered proof ovulation did or did not occur.
3. Your Health Affects Your Pregnancy
Your health is one of the most important
factors in your pregnancy. Good health care is important to the
development and well-being of your baby. Healthy nutrition, proper
exercise, sufficient rest and taking care of yourself all affect your
Some Information May Scare You
information is not included to frighten you; it’s there to provide facts
about particular medical situations that may occur during pregnancy.
If a woman experiences a serious problem,
she and her partner will probably want to know as much about it as
possible. If a woman has a friend or knows someone who has problems
during pregnancy, reading about it might relieve her fears. We also hope
our discussions can help you start a dialogue with your doctor, if you
Nearly all pregnancies are uneventful,
and serious situations don’t arise. However, please know we have tried
to cover as many aspects of pregnancy as we possibly can so you’ll have
all the information at hand that you might need and want. Knowledge is
power, so having various facts available can help you feel more in
control of your own pregnancy. We hope reading information helps you
relax and have a great pregnancy experience.
If you find
serious discussions frighten you, don’t read them! Or if the information
doesn’t apply to your pregnancy, just skip over it. But realize
information is there if you want to know more about a particular