The first prenatal visit is the
most thorough. A healthcare provider asks the mother-to-be about her health history
and
does a physical exam. Certain tests and procedures are also done to check the initial
health of the mother and her unborn baby. The first prenatal visit may include:

• Personal health history. This may cover:

  • Past and current health
    conditions, like diabetes, high blood pressure (hypertension), anemia, and
    allergies

  • Current medicines
    (prescription and over-the-counter)

  • Past surgeries

• Maternal and paternal family health history. The
  healthcare provider will ask about illnesses such as diabetes or intellectual or
  developmental disabilities. He or she will also ask about genetic disorders, like
  sickle-cell disease or Tay-Sachs disease.

• Personal gynecological and obstetrical history. The
  healthcare provider will want to know about past pregnancies (stillbirths,
  miscarriage, deliveries, terminations) and menstrual history (length and duration
  of menstrual periods).

• Education. The healthcare provider will talk with the
  pregnant woman about the importance of eating a healthy diet, exercising
  regularly, and not using alcohol, illegal drugs, and tobacco. He or she will also
  cover any concerns about domestic violence.

• Pelvic exam. This exam may be done for 1 or all these
  reasons:

  • To note the size and
    position of the uterus

  • To determine the age of
    the fetus

  • To check the pelvic
    bone size and structure

  • To perform a Pap test
    (also called Pap smear) to find the presence of abnormal cells

• Lab tests. These may include:

  • Urine tests. These are done to screen for
    bacteria, sugar, and protein.

  • Blood tests. These are done to determine blood
    type. All pregnant women are tested for the Rh factor during the early weeks
    of pregnancy. A mother and fetus may have incompatible blood types. The most
    common is Rh incompatibility. Rh incompatibility happens when the mother’s
    blood is Rh-negative and the father’s blood is Rh-positive and the fetus’
    blood is Rh-positive. The mother may make antibodies against the Rh-positive
    fetus, which may lead to anemia in the fetus. Incompatibility problems are
    closely watched. Treatment is available to prevent the formation of Rh
    antibodies during pregnancy.

• Blood screening tests. These are done to find
  diseases, like rubella. This infectious disease is also called German measles.

• Genetic tests. These are done to find inherited
  diseases, like sickle-cell anemia and Tay-Sachs disease.

• Screening tests. These are done to find infectious
  diseases, like sexually transmitted infections (STIs).

The first prenatal visit is also a
good time for the mother-to-be to ask any questions or talk about any pregnancy
concerns.

A healthy first trimester is
crucial to the normal development of the fetus. The mother-to-be may not be showing
much
on the outside. But inside her body, all the major body organs and systems of the
fetus
are forming.

As the embryo implants itself into
the uterine wall, several developments take place:

• Amniotic sac. A sac filled with amniotic fluid
  surrounds the fetus throughout the pregnancy. The amniotic fluid is liquid made by
  the fetus and the amnion (the membrane that covers the fetal side of the placenta)
  that protects the fetus from injury. It also helps to regulate the temperature of
  the fetus.

• Placenta. The placenta is an organ shaped like a flat
  cake that only grows during pregnancy. It attaches to the uterine wall with tiny
  projections called villi. Fetal blood vessels grow from the umbilical cord into
  these villi, exchanging nourishment and waste products with the mother’s blood.
  The fetal blood vessels are separated from the mother’s blood supply by a thin
  membrane.

• Umbilical cord. The umbilical cord is a rope-like cord
  connecting the fetus to the placenta. The umbilical cord contains 2 arteries and a
  vein. These carry oxygen and nutrients to the fetus and waste products away from
  the fetus.

It is during this first trimester
that the fetus is most prone to damage from substances like alcohol, illegal drugs,
certain medicines, and illnesses, such as rubella.

During the first trimester, both
the mother’s body and the fetus are changing rapidly.

The most dramatic changes and
development happen during the first trimester. During the first 8 weeks, a fetus is
called an embryo. The embryo develops rapidly. By the end of the first trimester,
it
becomes a fetus that is fully formed. The fetus weighs about 1/2 to 1 ounce and
measures, on average, 3 to 4 inches in length.

Just as each child grows and
matures at different rates and at different times, so does that same child as it begins
its life in the womb. The chart below provides benchmarks for most normal pregnancies.
But each fetus develops differently.

By the end of 4 weeks	All major systems and organs begin to form. The embryo looks like a tadpole. The neural tube, which becomes the brain and spinal cord, the digestive system, and the heart and circulatory system begin to form. The beginnings of the eyes and ears are developing. Tiny limb buds appear, which will develop into arms and legs. The heart is beating.
By the end of 8 weeks	All major body systems continue to develop and function, including the circulatory, nervous, digestive, and urinary systems. The embryo is taking on a human shape. But the head is larger in proportion to the rest of the body. The mouth is developing tooth buds, which will become baby teeth. The eyes, nose, mouth, and ears are becoming more distinct. The arms and legs can be easily seen. The fingers and toes are still webbed but can be clearly distinguished. The main organs continue to develop. You can hear the baby’s heartbeat using an instrument called a Doppler. The bones begin to develop, and the nose and jaws are rapidly developing. The embryo is in constant motion but cannot be felt by the mother.
From embryo to fetus	After 8 weeks, the embryo is now referred to as a fetus, which means offspring. Although the fetus is only 1 to 1 1/2 inches long at this point, all major organs and systems have been formed.
During weeks 9 to 12	The external genital organs are developed. Fingernails and toenails appear. Eyelids are formed. The fetus starts to move more. The arms and legs are fully formed. The voice box (larynx) begins to form in the trachea. The fetus is most vulnerable during the first 12 weeks. During this time, all the major organs and body systems are forming. They can be damaged if the fetus is exposed to drugs, rubella, radiation, tobacco, and chemical and toxic substances. Even though the organs and body systems are fully formed by the end of 12 weeks, the fetus cannot survive independently.

During pregnancy, many changes are
also happening in the body of the mother-to-be. Women experience these changes
differently. Some symptoms of pregnancy continue for several weeks or months. Others
are
only experienced for a short time. Some women have many symptoms. Other women have
only
a few or none at all. Here is a list of changes and symptoms that may happen during
the
first trimester:

• The mammary glands enlarge,
  causing the breasts to swell and become tender in preparation for breastfeeding.
  This is due to an increased amount of the hormones estrogen and progesterone. A
  supportive bra should be worn.

• A woman’s areolas (the
  pigmented areas around each breast’s nipple) will enlarge and darken. They may
  become covered with small, white bumps. These are called Montgomery tubercles
  (enlarged sweat glands).

• Veins become more noticeable
  on the surface of the breasts.

• The uterus is growing and
  begins to press on the woman’s bladder. She may need to urinate more often.

• Partly due to surges in
  hormones, a pregnant woman may have mood swings much like premenstrual syndrome
  (PMS). Women with PMS may have mood swings, irritability, and other physical
  symptoms that happen shortly before each menstrual period.

• Increased levels of hormones
  to sustain the pregnancy may cause “morning sickness.” This is feelings of nausea
  and sometimes vomiting. Morning sickness does not necessarily happen just in the
  morning. And it rarely interferes with proper nutrition for the mother and her
  fetus.

• Constipation may happen as
  the growing uterus presses on the rectum and intestines.

• The muscular contractions in
  the intestines, which help to move food through the digestive tract, are slowed
  due to high levels of progesterone. This may, in turn, cause heartburn,
  indigestion, constipation, and gas.

• Clothes may feel tighter
  around the breasts and waist as the size of the stomach increases for the growing
  fetus.

• A woman may be extremely
  tired due to the physical and emotional demands of pregnancy.

• Cardiac volume increases
  by about 40% to 50% from the start to the end of the pregnancy. It causes an
  increased cardiac output. An increased cardiac output may cause an increased pulse
  rate during pregnancy. The increase in blood volume is needed for extra blood flow
  to the uterus.