The First Month
The countdown to a baby's birth actually begins about two weeks before
it is conceived, or the first day of the woman's last menstrual period. This is because
most women do not know when actual conception was, but most do know when their last period
began. Conception can only occur during ovulation, which happens about the middle of the
month between menstrual periods. The ripened egg, propelled by tiny finger-like projections,
travels to the fallopian tube, which is where it needs to be if it is to be fertilized. If
sexual intercourse happens during this time, the perfect time, the egg can be fertilized.
Out of the millions of microscopic sperm the man deposits into the woman, only one of
the tiny tadpole-like creatures is needed. Only one sperm in ten finds its way into the
cervix, one or two thousand make it into the fallopian tube (about an hour after the race began), and only a few hundred make it to the egg. All will try to break through the
membrane surrounding the egg and the first one to do so is the winner. After that one
sperm breaks through, the membrane toughens up so no others can come in, too.
The sperm, which has half of the DNA required to make a human being
(the egg has the other half), will eventually slough off its tail and fertilization is
complete. After that, the egg divides into two cells, then four, then
eight, and by the end of the process there will be billions - the newborn baby.
At this point the body must make a home for the little one. The egg,
which has become a ball of cells, moves down the fallopian tube until it reaches the
uterus. In a process called implantation, the egg attaches itself to the uterine lining.
The cells on the outside of the little ball of cells will become the placenta. The cells
inside will become the baby. A week after implantation the level of progesterone, a
hormone, dramatically increased in the woman's body. This is to tell the body there will
be no more menstruations, at least not until the baby is born. (Pregnancy tests detect
this hormone). After this the period is missed, the woman realizes something is amiss -
BINGO! she's pregnant.
The Second Month
The egg, or ball of cells, is now officially an embryo. It is only
one-tenth of an inch long and its cells are in three distinct layers. The outer layer forms
complex structures such as the brain and nerves and simple things such as hair and tooth
enamel. The middle layer will turn into bones, muscles, blood vessels, and the heart, as
well as part of the lungs. The inner layer forms the liver, intestines, urinary tract, and
the other part of the lungs. A tuck forms at each end of the embryo: one will be the head
and the other will be the one that wears the diapers.
Around the time the embryo is six weeks old, tiny bumps are forming that
will be the arms and legs and vital organs like the stomach and lungs find their
places. The two parts of the heart, which had developed separately, fuse then begin to
beat. Also during this time the umbilical cord is forming, which is attached to the uterus
at one end and the baby's navel at the other end. This is the lifeline that provides the
baby with nourishment.
By the end of the second month the embryo starts to look more human.
The eyes stem out from the brain and place themselves on the face and the baby's webbed
hands begin to separate to form fingers. With the eyes still on either side of the head and
not in front, though, the little tyke still looks like an alien from The X-Files,
The Third Month
Even though minute, immature, and not all fully functioning yet, all of
the major internal organs are present at the beginning of the third month, or at the end
of the first trimester. By the middle of the month testes have formed in boys and the
ovaries in girls. However, the external sex organs are still indistinct; it is still not
possible, even with the best ultrasound to determine the sex yet.
When the age of the embryo hits nine weeks, it is no longer considered an
embryo. In this landmark week, it is officially a fetus. The fetal umbilical cord is fully
formed at this point and contains two large blood vessels: one huge artery and one huge
vein. The cord is very stiff, tightly filled with blood: this is to avoid any kinks from
forming; such an event could be fatal to the little one.
At this stage of development, eyelids form over the eyes. After this
happens the eyes will remain closed during most of the remainder of gestation. Despite this,
after all is said and done, at the end of this month the fetus most definitely looks
The Fourth Month
The pregnancy really begins to show during this month. It is now very
difficult to hide it. This is the time period a lot of couples wait for to tell others the
wonderful news, because the chances of miscarriage at this point on are slim.
During this month fingernails begin to form on the newly-shaped
fingers, the gallbladder begins to make bile, and the baby makes its very own blood
with its own bone marrow. By the middle of this month the external sex organs become
distinctly male or female. All types of hair begin to form, including hair on the head,
eyelashes, eyebrows, and a fine downy hair that covers the entire body called lanugo. This
unique hair grows all over the body in swirly patterns and disappears shortly after
Four to six ounces of amniotic fluid surrounds the fetus at this point,
which allows for an amniocentesis to be taken. This fluid is mostly fetal urine and most
of it is removed when the baby swallows it. Yes, that does sound gross, that you drink
your own pee when you're a fetus, but don't worry, it doesn't do a bit of harm. The fluid is
completely replaced every day.
Growth this month is rapid; the fetus, 5 inches long at this point, is
just big enough to cradle in the palm of your hand.
The Fifth Month
It's Quickening time! That's right:
quickening refers to the first time the mother feels the baby move inside of her.
At this point all doubt about what is happening in there is quelched. If all goes well, this
baby's coming! The muscles and limbs, which are much stronger this month than the last, give
the baby the ability to move around to explore this little world it's in, as well as push
and kick at things. If the baby's thumb gets close enough to its face, it grabs
it and begins sucking on it. This instinct is for when, after birth, it is ready to
Lots of important stuff goes on in the brain
during the fifth month. The number of nerve cells in the front of the brain, the thinking
section, grows rapidly. The sounds of the mother's stomach rumbling or blood in her vessels
gushing are constant noises for the little one that can both sooth and annoy it.
Inside the intestines the baby's first stool, called meconium, forms.
And, believe it or not, if the baby is a girl she begins to develop her own eggs,
which, decades later, will possibly begin this life cycle again. The skin of the baby gets
covered up by a fatty, yellowish substance called vernix, which is produced by the same
annoying glands that will give it pimples when it is an adolescent. The lanugo will hold
the vernix in place, which protects the baby's skin from constant exposure to the amniotic
fluid. By the end of this month most babies are about 7 inches long and will weigh 10 to 12
The Sixth Month
It is during this month that bones harden, growth and weight gain are
rapid, and others can feel the baby move. It's getting crowded in there for the baby at this
point and when it pushes out you can usually tell if it is a hand or a foot trying to break
free of the womb. Also, its hearing becomes good enough to where loud noises outside of the
mother's body can startle it.
The only other significant thing this month is, even though the baby will
not need to use them until the moment of birth, the lungs become fully-formed and ready to
The Seventh Month
Things get even more cramped this month as the baby continues to grow. It
goes into the typical fetal position with its legs bent into its chest. The baby is very
active during this month; indeed, as the mother lies in bed at night, she might actually see
her whole stomach change shape as her baby shifts its position.
During this month the eyelids, which formed in the second month, begin to
open, awakening the baby's sense of sight! Now it can see as well as it can hear. The
brain is also rapidly growing, becoming folded and wrinkled; each section is assigned its
duty, like controlling speech or recording memories. If the baby is a boy, the
testicles, which had formed in the abdomen, will begin to move down to the scrotum.
At the end of this month, the baby will weight about 3 pounds and is
roughly 11 inches long.
The Eighth Month
The baby needs some cardboard boxes at this point, because it's preparing
to pack up and move out! And if it is born during this month, it has a pretty good shot at
The baby gets lots of antibodies from the mother's immune system this
month to protect it from a plethora of diseases that could infect it after birth. But this
is only a temporary immunity which goes away after birth. However, the length of this
immunity can be extended by breastfeeding. Also, even though it cannot breathe on its own
yet, it will hiccup.
It is important at this point to dispel an old wives' tale that
purports that babies born in the eighth month are more likely to survive than babies born in
the ninth month. This is absolutely not true. So don't believe it, no matter
how much your mother insists it is. The closer to the due date the little one is born, the
The Ninth Month
"Let me outta here!"
Growth finally begins to slow as the baby is ready to get out. The
lanugo is almost all gone and most of the vernix has been shed as well. The lanugo
remains in grooves like the back of the knees and groin. The baby moves into a position he
or she will take during delivery. This is commonly where the head is down, facing the
mother's back. When the head slips down into the mother's pelvis - an event called
lightening - the mother will notice that she can breathe a lot easier. But the bad news is
after this happens it becomes much more difficult to sit or walk.
As if that isn't enough, movement increases exponentially: the baby is
kicking so much you'd think he was trying out for a soccer team! But don't worry, it'll be
out soon. Even though what exactly triggers labor is still a mystery, it will eventually
One suspect trigger of labor, though, seems to be stretching of the
uterus. Another theory is that the levels of progesterone, the hormone that has supported
the pregnancy all this time, declines, which allows the womb to finally serve its nine-month
guest an eviction notice.
When that beautiful little baby boy or girl enters the world, on
average it will eight anywhere from 6 to 9 pounds and measure from 17 to 22 inches. Birth is
quite traumatic: lights are much brighter and sounds are so much louder! Also, it's so cold
out here! And somebody gives it a good smack so it starts breathing on its own.
Well, actually, I don't think doctors do this anymore.
Source: "As Your Baby Grows: From Conception to Birth" published by American Baby, 2003