Thank you for an interesting question.
Determining the exact day is difficult and at best is just a guess,
but determining the week can generally be calculated.
Timing Intercourse For Conception by Lori Ramsey
"Is it really important to time intercourse in order to conceive a
baby? Well, the answer is a yes and no. If you consider all the women
throughout the ages who conceived and had no idea as to when
conception took place or wasn?t even trying - then the answer is no.
But the truth is, there is actually only a small window of opportunity
for conception to happen each cycle.
The truth is the time of ovulation is the only time in which an egg(s)
is released. The egg only lives from 12 to 24 hours. Sometimes -
though rare - another egg will be released from the other ovary within
24 hours of the first egg. Because of this small window of opportunity
- it is important to time intercourse to best achieve conception. It
is also important to chart your cycle - that way you will know exactly
when ovulation occurs and can benefit from having intercourse at the
On the other hand, sperm can live up to 72 hours and if there is good
quality cervical fluid they can live up to 5 days. So, for example, if
you ovulate on day 14 of your cycle - technically your egg(s) will
live for only 12 to 24 hours beyond day 14. Having intercourse on day
12 - day 15 would greatly increase your chances of conceiving.
However, if your cervical fluid is of good quality - you can have
intercourse on day 10 and possibly conceive. Remember this is based on
a woman ovulating on day 14 of her cycle. It?s important to know
exactly when ovulation should occur."
The following site has a calculator which can be very handy for
determining how the baby's gestational age in days and weeks.
Pregnancy Daily - Daily Pregnancy Calendar.
The Pregnancy Daily will tell you how pregnant you are in days and
weeks, how many days left until D-day, and also the baby's gestational
age in days and weeks! And every day there's something more. We have
over five hundred different entries to guide you through your
pregnancy, day-by-day, from preconception to post-dates.
Just enter the date of your LMP (the first day of your last normal
menstrual period before you got pregnant) or your due date, and we'll
calculate how far along you are to the exact day.
To use this calendar accurately, we must add or subtract days based
upon the length of your cycle. If you have a cycle that's longer or
shorter than 28 days, use your adjusted EDD when generating your daily
page. For more information about how these calculations are made, see
the article, When am I Due?.
Remember that every woman and every pregnancy is unique, and the
Pregnancy Daily contains only general information about pregnancy and
birth. The Pregnancy Daily should not be used as a substitute for care
you should receive from a qualified healthcare professional. If you
have questions or concerns about your health or the health of your
baby, please seek the advice of your healthcare provider.
Create your Pregnancy Daily page based on your: LMP (Last normal menstrual period)
Figure in your Month, Day and Year. Then click on MAKE MY DAY.
For example: If your LMP was April 6, 2004
That would be: Day Number 42 - 6 weeks
gestational age age: 28 days/4 weeks)
238 days remaining
Gestation is the period between conception and birth of a baby, during
which the fetus grows and develops inside the mother's uterus.
Gestational age is the time measured from the first day of the woman's
last menstrual cycle to the current date and is measured in weeks. A
pregnancy of normal gestation is approximately 40 weeks, with a normal
range of 38 to 42 weeks.
The following site is a cached page - please copy and paste the link
to access the page.
"You might be lucky enough to know the exact date of conception.
(Maybe it's the only time you've had sex this year!) For most women,
however, precise dates for ovulation and conception are hard to
calculate, which is why clinics and hospitals calculate the length of
your pregnancy based on the first day of your last menstrual period
(LMP). The first day of your LMP is considered the start of your
pregnancy, even though conception probably did not occur until some
For example, let's say that you realize you're pregnant in
mid-December. If the first day of your LMP was November 1st, and it's
now December 15th, then you are said to be six weeks pregnant - even
though conception probably took place in mid-November (most women
ovulate about two weeks after the first day of their LMP)."
What is the due date?
"Another important date to consider during the decision-making
process, is the estimated date of delivery (EDD). The average length
of pregnancy is 266 days from the date of conception, but many women
don't know exactly when they conceived. To calculate your EDD, count
280 days (40 weeks) from your LMP."