Any expectant parent can tell you, one of the most intriguing parts of
pregnancy is figuring out what stage of development your baby is at. Having
even the roughest knowledge that your unborn child is rapidly developing
from a small ball of cells into a full fledged human being is pretty awe
inspiring. Figuring out where exactly in that process your baby is in is a
little more complicated, but in general there are three separate and
distinct fetal development stages into which all pregnancies will fall.
These three stages are conception, embryonic development and fetal
The first stage of any pregnancy actually begins before you are even
pregnant. There are 40 weeks of pregnancy, with the first week being a
woman’s menstrual cycle. Once your body has completed your monthly period,
your uterus will begin developing a rich, blood perfused layer of cells that
is perfect for providing sustenance for a growing baby. In week two,
conception actually takes place, with a sperm fertilizing the egg. The
fertilized egg then makes its way down the fallopian tube, and into the
uterus, dividing and splitting into many cells all along the way. This is
the earliest stage of pregnancy, and is usually undetected by the pregnant
Once the fertilized egg finds its way to the uterus, it will implant itself
in the blood rich lining, and continue to divide and split itself. At this
stage, the pregnancy has entered the stage known as embryonic development.
Simply put, the fertilized egg is growing and changing, with the cells being
organized into those that will eventually become a fetus and those that will
be the placenta, which will nourish and sustain the unborn child. The
embryonic development stage of pregnancy lasts until approximately the
eleventh week of pregnancy, at which point, the baby is now called a fetus.
The final stage of pregnancy is fetal development. For the next 29 or so
weeks, your unborn child will be developing all of its organs and body
parts, in preparation for the big day when you will meet for the first time.
From the 29th through 40th weeks of pregnancy, the main focus is the
development of the lungs and the addition of weight. On average, a fetus
will gain an ounce a day from the 37th week until they are born.