During ovulation, which typically occurs 11-21 days after a woman's period ends, an egg is released from the ovaries. If sperm penetrate an egg in the fallopian tubes, conception occurs and the fertilized egg begins dividing as it travels down the fallopian tube. By 6-12 days after conception, the blastocyst implants in the uterine lining and the embryonic stage begins. Over the following weeks, all major organs develop as the embryo grows and differentiates into a fetus. By week 40, considered full term pregnancy, the fetus is ready for birth, weighing around 6.75-10 pounds.
3. Your menstrual period has just ended, and your body is
getting ready for ovulation. For most women, ovulation
takes place about 11 - 21 days from the first day of the last
period. During intercourse, several hundred million sperm
are released in the vagina. Sperm will travel through the
cervix and into the fallopian tube. If conception takes
place, the sperm penetrates an egg and creates a single
set of 46 chromosomes called a zygote, which is the basis
for a new human being. The fertilized egg spends a couple
days traveling through the fallopian tube toward the uterus,
dividing into cells ; it is called a morula. The morula
becomes a blastocyst and will eventually end up in the
uterus. Anywhere from day 6-12 after conception, the
blastocyst will imbed into the uterine lining and begin the
embryonic stage.
4. Week 3 - Gestational Age Week 4 & 5 - Gestational Age
(Fetal Age - Week 1): (Fetal Age - Weeks 2 & 3):
Arm and leg buds are visible,
The embryo is going through lots
but not clearly distinguishable.
of basic growth at this time, with
The heart is now beating at a
the beginning development of
steady rhythm. The placenta
the brain, spinal cord, heart, and
has begun to form and is
gastrointestinal tract.
producing some important
hormones including hCG.
There is movement of
rudimentary blood through the
main vessels. The early
structures that will become the
eyes and ears are forming. The
embryo is ¼ inch long by the
end of these weeks.
5. Week 7 - Gestational Age (Fetal
Week 6 - Gestational Age Age - Week 5):
(Fetal Age - Week 4):
At 7 weeks gestation, every
The formation of the essential organ has begun to
lungs, jaw, nose, and form in the embryo’s tiny
palate begin now. The body even though it still
hand and feet buds weighs less than an aspirin.
have webbed structures The hair and nipple follicles
that will become the are forming, and the eyelids
fingers and toes. The and tongue have begun
brain is continuing to formation. The elbows and
form into its complex toes are more visible as the
parts. A vaginal trunk begins to straighten
ultrasound could out.
possibly detect an
audible heartbeat at
this time. The embryo is
about a ½ inch in
length.
6. Week 8 - Gestational Age Weeks 9 thru 13 -
(Fetal Age - Week 6): Gestational Age (Fetal
The ears are continuing to Age - Weeks 7 thru 11):
form externally and The fetus has grown
internally. Everything that to about 3 inches in
is present in an adult length and weighs
human is now present in about an ounce. The
the small embryo. The genitalia have
bones are beginning to clearly formed into
form, and the muscles can male or female, but
contract. The facial still could not be
features continue to seen clearly on an
mature, and the eyelids are ultrasound. The
now more developed. The eyelids close and
embryo is at the end of the will not reopen until
embryonic period and the 28th week of
begins the fetal period. pregnancy. The
The embryo is about 1 fetus can make a
inch long and is the size of fist, and the buds
a bean. for baby teeth
appear. The head is
nearly half the size
of the entire fetus.
7.
8. Weeks 14 thru 16 -
Gestational Age (Fetal Weeks 17 thru 20 -
age - Weeks 12 thru 14): Gestational Age (Fetal
Age - Weeks 15 thru
The fetus’s skin is transparent
and a fine hair called lanugo
18):
The baby has reached a point
begins to form on the head. where movements are being
The fetus begins sucking and felt more often by the mom.
swallows bits of amniotic fluid. The eyebrows and eyelashes
Fingerprints which grow in, and tiny nails have
individualize each human begun to grow on the fingers
being have now developed on and toes. The skin of the
the tiny fingers of the fetus. fetus is going through many
Meconium is made in the changes and begins to
intestinal tract and will build produce vernix at the
up to be the baby's first bowel twentieth week. Vernix is a
movement. Flutters may be white pasty substance that
felt in the mom’s growing covers the fetus’s skin to
abdomen as the fetus begins protect it from amniotic fluid.
to move around more. Sweat A fetal heartbeat could be
glands have developed, and heard by a stethoscope now.
the liver and pancreas produce The fetus has reached a
fluid secretions. The fetus has length of 8 inches and
reached 6 inches in length and weighs about 12 ounces.
weighs about 4 ounces.
9. Weeks 21 thru 23 - Weeks 24 thru 26
Gestational Age (Fetal Age - Gestational Age
- Weeks 19 thru 21): (Fetal Age - Weeks
Lanugo now covers the 22 thru 24)-
fetus’s entire body. The Beginning the third
fetus is beginning to
Iftrimester: delivered
your baby was
have the look of a now, it could survive with
newborn infant as the the assistance of medical
skin becomes less technology. The fetus has
transparent while fat developed sleeping and
begins to develop. All the waking cycles and mom
will begin to notice when
components of the eyes each of these takes place.
are developed. The liver The fetus has a startle
and pancreas are working reflex, and the air sacs in
hard to develop the lungs have begun
formation. The brain will
completely. The fetus has
be developing rapidly over
reached about 10-11 the next few weeks. The
inches in length and nervous system has
weighs about 1 - 1 ¼ developed enough to
pounds. control some functions.
The fetus has reached
about 14 inches in length
and weighs about 2 ¼
pounds.
10.
11. Weeks 27 thru 32 -
Gestational Age (Fetal
Age - Weeks 25 thru
30): fetus really fills out
The
over these next few
weeks, storing fat on the
body, reaching about 15-
17 inches long and Weeks 33 thru 36 -
weighing about 4-4 ½ lbs.
Gestational Age
by the 32nd week. The
lungs are not fully mature (Fetal Age - Weeks
yet, but some rhythmic 31 thru 34):
This is about the time that
breathing movements are the fetus will descend into
occurring. The bones are the head down position
fully developed but are preparing for birth. The
still soft and pliable. The fetus is beginning to gain
fetus is storing its own weight more rapidly. The
calcium, iron and lanugo hair will disappear
phosphorus. The eyelids from the skin, and it is
open after being closed becoming less red and
since the end of the first wrinkled. The fetus is now
trimester. 16-19 inches and weighs
anywhere from 5 ¾ lbs to 6
¾ lbs.
12. Weeks 37 thru 40 - Gestational Age (Fetal Age
- Weeks 35 thru 38):
At 38 weeks the fetus is considered full term and
will be ready to make its appearance at any time.
Mom may notice a decline in fetal movement as the
fetus is now filling the uterus with little room to
move. The fingernails have grown long and will
need to be cut soon after birth. Small breast buds
are present on both sexes. The mother is supplying
the fetus with antibodies that will help protect
against disease. All organs are developed, with the
lungs maturing all the way until the day of delivery.
The fetus is about 19 - 21 inches in length and
weighs anywhere from 6 ¾ lbs to 10 lbs.
