Chapter 7: Learning a pregnant woman’s health history
How pregnant is she now? When is the baby due?
Find out how many months pregnant the woman is at the time of her first checkup.
This will also tell you the date that she will probably give birth (the due date).
There are 3 ways to figure out how pregnant the woman is now and her due date:
• Use the date of her last monthly bleeding.
• Measure the size of her womb.
• Have the woman get an ultrasound at a medical center.
Note: It is normal and safe for the baby to be born as much as 3 weeks
earlier or 2 weeks later than the due date.
Using the last monthly bleeding to predict the due date
If a woman bleeds regularly every 4 weeks, her pregnancy will start about 2 weeks
after the first day of her last monthly bleeding. To find out if you can use this
method to estimate her due date, you must first ask the mother 3 questions:
1. Has your monthly bleeding been mostly regular, once every 4 weeks
(once every month)?
2. Was your last monthly bleeding normal for you (not unusually light
3. Do you remember the date of the first day of your last monthly bleeding?
If the woman answers “no” to any of these 3 questions, you cannot be certain
this method will give you a correct due date.
If she answers “yes” to all 3 questions, you can figure out the due date and
how pregnant the woman is at this visit.
Remember that a pregnancy lasts about 40 weeks or 280 days. This is about
9 calendar months or 10 lunar months from the last monthly bleeding.
Using a calendar
To figure out the due date,
add 9 months and 7 days to
started May 6th.
the day that her last monthly
(You could also subtract
3 months and then add
7 days to get the same date.)
For a helpful tool to
If I add 9 months, that
comes to February 10th.
Then I add 7 days,
which tells me her baby
should be born around
estimate the due date using the
last monthly bleeding, see page 527.
A Book for Midwives (2010)