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The Second Trimester

Prenatal visits during the second trimester

During the second and third trimester prenatal visits, your health care provider may check the following, depending on your current medical condition and your baby’s health:

  • any current symptoms or discomforts
  • your weight
  • your blood pressure
  • urine test to detect albumin (a protein), which may indicate preeclampsia or toxemia, and sugar (glucose), which may indicate hyperglycemia
  • growth, size and development of the fetus
  • size of the uterus — after approximately 12 weeks of gestation, the uterus can be felt through the abdominal wall
  • height of the fundus (top of the uterus), starting at 20 weeks of gestation
  • fetal heartbeat

What to expect during the second trimester

The second trimester marks a turning point for mother and fetus. The mother usually begins to feel better and will start showing the pregnancy more. The fetus has now developed all its organs and systems and will now focus on growing in size and weight.

During the second trimester, the umbilical cord continues to thicken as it carries nourishment to the fetus. However, harmful substances also pass through the umbilical cord to the fetus, so care should be taken to avoid alcohol, tobacco and other known hazards.

During the second trimester, both the mother's body and the fetus continue to grow.

Fetal development during the second trimester

Now that all the major organs and systems have formed in the fetus, the following six months will be spent growing. The weight of the fetus will multiply more than seven times over the next few months, as the fetus becomes a baby that can survive outside of the uterus.

By the end of the second trimester, the fetus will be about 13 to 16 inches long and weigh about 2 to 3 pounds. Fetal development during the second trimester includes the following:

  • The fetus kicks and moves and can turn from side to side.
  • The eyes have been gradually moving to the front of the face, and the ears have moved from the neck to the sides of the head. The fetus can hear the mother's voice.
  • A creamy white substance (called vernix caseosa, or simply vernix) begins to appear on the fetus and helps to protect the thin fetal skin. Vernix is gradually absorbed by the skin, but some may be seen on babies even after birth.
  • The fetus is developing reflexes, such as swallowing and sucking.
  • The fetus can respond to certain stimuli.
  • The placenta is fully developed.
  • The brain will undergo its most important period of growth from the fifth month on.
  • Fingernails have grown on the tips of the fingers and toes, and the fingers and toes are fully separated.
  • The fetus goes through cycles of sleep and wakefulness.
  • Skin is wrinkly and red, covered with soft, downy hair (called lanugo).
  • Hair is growing on the head of the fetus.
  • Fat begins to form on the fetus.
  • Eyelids are beginning to open, and the eyebrows and eyelashes are visible.
  • Fingerprints and toeprints have formed.
  • The fetus is rapidly growing in size and weight.
  • The 20th week marks the halfway point of the pregnancy.

A fetus born at the end of 24 weeks may survive in a neonatal intensive care unit (NICU).

Changes in the mother's body

The second trimester is the most physically enjoyable for most women. Morning sickness usually abates by this time, and the extreme fatigue and breast tenderness usually subsides. These changes can be attributed to a decrease in levels of human chorionic gonadotropin (hCG) hormone and an adjustment to the levels of estrogen and progesterone hormones.

The following is a list of changes and symptoms that may occur during the second trimester:

  • Appetite may increase.
  • The mother may be able to feel the movement of the fetus for the first time by 20 weeks. This is a phenomenon called quickening.
  • The uterus has grown to the height of the belly button, making the pregnancy visible.
  • The skin on the belly may itch as it grows, and there may be pain down the sides of the mother’s body as the uterus stretches. The lower abdomen may ache as ligaments stretch to support the uterus.
  • The need to frequently urinate may decrease as the uterus grows out of the pelvic cavity, relieving pressure on the bladder.
  • A mother's nose may become congested, and she may experience nosebleeds. Her gums may become spongier and may bleed easily. Both of these things are due to the increase in hormones (estrogen and progesterone) that affect the mucous membranes in the nose and mouth.
  • Varicose veins and hemorrhoids may appear.
  • A woman may have a white-colored vaginal discharge called leukorrhea (a colored or bloody discharge may signal possible complications and should be examined immediately.)
  • The increasing weight gain may cause backaches.
  • Skin pigmentation may change on the face or abdomen due to the pregnancy hormones.
  • Heartburn, indigestion and constipation may continue.