What is prenatal development?
Pregnancy is an exciting
time. As you prepare for the arrival of your baby, you may decorate the
nursery, think of baby names, and start preparing your finances for a new
addition. Your body will change over the next nine months, and as your due date
nears, you’ll want to keep close track of your baby’s growth and development.
starts at conception and ends with the birth of your baby. It takes about 40
weeks or nine months to create a new life, and your pregnancy is broken into
three, 12-week trimesters. Each trimester brings about new changes and
The first trimester
Most women ovulate once a
month, about two weeks after their last menstrual cycle. Ovulation is the
release of an egg. If you have sexual relations before, during, or within 24
hours of ovulation, sperm can travel from the vagina into your fallopian tubes
and fertilize the egg. Sperm can live in the body for up to five days, so your
chances of conceiving are higher if you have intercourse in the days leading up
The first trimester is the
first 12 weeks of your pregnancy. This is also the embryonic stage, which
continues through the 10th week of your first trimester. Your baby is called an
embryo at this stage. Since you're early in the pregnancy, you may experience
early pregnancy symptoms, such as:
It’s during the embryonic
stage that embryo cells begin to multiply and form your baby’s body.
The embryo’s gastrointestinal
tract, spinal cord, heart, and brain are the first organs to develop. This
starts about one week after conception.
The placenta also develops
in the embryonic stage and it plays a vital role in pregnancy because it
carries nutrients, oxygen, and water to your baby. This development takes place
about two or three weeks after conception.
Your baby’s body also
begins to form. This includes development of:
- the nasal
- hair follicles
- taste buds
continue up to week 10, which is the end of the embryonic stage. Your baby’s
sex organs will have formed by the end of this stage, although it's too early
to determine the baby’s sex on an ultrasound.
The second trimester
Your second trimester of
pregnancy begins at week 13. At the end of the embryonic stage, your baby is
about 3 inches long and weighs about 1 ounce. Once the embryonic stage ends,
your baby enters the fetal stage.
Around weeks 12 through 14, the
fetus begins sucking and swallowing, as well as moving inside the womb,
although it may be too early to feel these movements. The fetus will grow to
about 6 inches during these two weeks.
As your baby’s muscles develop
and grow, you'll begin to notice movement around weeks 15 through 18. It’s also
around this time that your baby’s skin develops a white substance called
vernix, which protects the skin from amniotic fluid. Your baby will begin
making facial movements inside the womb, and you may catch a glimpse of the
fetus appearing to smile or squint on a 3-D ultrasound.
The fetus’s middle ear
typically develops at week 20, and with this development your baby can hear
your heartbeat and voice.
During the final weeks of your
second trimester, fat starts to develop on your baby’s skin, and its major
organs — such as the liver and pancreas — become stronger. At the end of 24
weeks, the fetus is about 10 to 11 inches long and weighs about 1 pound.
The third trimester
You’ve finally reached the last
12 weeks of your pregnancy and you're nearing the finish line! By your sixth
month your body experiences a lot of changes, such as weight gain, heartburn,
and you may have trouble sleeping. But while you may be uncomfortable at times,
you're elated and amazed by your baby’s progress and development.
Your final trimester begins 25
weeks after conception. All of your baby’s organs have developed, and movement
inside the womb increases over the next couple of months. Sometimes, it may
feel as if you're being punched and kicked in the stomach. But that's just your
baby exploring its surroundings.
The baby’s lungs are not fully
developed in the early stages of the third trimester, but it may weigh about 4
pounds and be able to recognize changes in sound. The baby is surrounded by
darkness, but it can detect bright lights from outside the womb. The lungs
fully develop after 28 weeks or seven months.
Between weeks 31 and 34 weeks
after conception, your baby begins preparing for birth and gradually moves into
a head-down position. Since you're nearing the home stretch, the fetus will
grow rapidly over the final weeks and you may notice less movement. Don't panic
if your baby doesn’t move as often. Since the fetus is getting bigger every
day, it doesn’t have as much room in the womb to move around. But if you have
concerns, don't hesitate to contact your doctor.
The final weeks of the third
trimester — and your pregnancy — begin 35 to 38 weeks after conception, which
is 37 to 40 weeks since your last period. You’re considered full-term 36 weeks
after conception (or 38 weeks after your last period). Your baby’s organs are
developed, the fetus is fully matured, and you can deliver at any day. At this
stage of prenatal development, your fetus is about 19 to 20 inches long and
weighs between 6 and 10 pounds.
You’re close to delivering the
baby when labor contractions intensify and occur every five minutes.
Labor and delivery
Your doctor estimates your due
date in the pregnancy based on the date of your last menstrual cycle.
Understand, however, that only 5 percent
of babies arrive on their due dates.
Don't be alarmed if your baby
doesn’t arrive by your due date. It’s common. You also shouldn’t panic if the
baby arrives early. Your chances for a healthy pregnancy and delivery increase
the longer the baby stays in the womb. However, you may find it comforting to
know that a baby born as early as the beginning of the third trimester can
survive without the help of medical technology.