First Trimester
Nutrition
Foods with folate: asparagus, dark leafy greens, nuts, beans, whole grains, fortified cereal, broccoli, citrus fruits, peas, lentils, avocado, Brussels sprouts, seeds, cauliflower, corn, beets, celery, carrots, squash
Average total weight gain for the 1st trimester is 1-4 pounds.
At Four Weeks
Your baby’s brain and spinal cord have begun to form. The heart begins to form. Arm and leg buds appear. Your baby is now an embryo and one-twenty-fifth inch long.
At Eight Weeks
All major organs and external body structures have begun to form. Your baby’s heart beats with a regular rhythm. The arms and legs grow longer, and fingers and toes have begun to form. The sex organs begin to form. The eyes have moved forward on the face and eyelids have formed. The umbilical cord is clearly visible. At the end of eight weeks, your baby is a fetus and looks more like a human. Your baby is nearly 1 inch long and weighs less than one-eighth ounce.
At Twelve Weeks
The nerves and muscles begin to work together. Your baby can make a fist. The external sex organs show if your baby is a boy or girl. A woman who has an ultrasound in the second trimester or later might be able to find out the baby’s sex. Eyelids close to protect the developing eyes. They will not open again until the 28th week. Head growth has slowed, and your baby is much longer. Now, at about 3 inches long, your baby weighs almost an ounce.
Second Trimester
Nutrition
Foods with calcium: yogurt, milk, cheese, collard greens, kale, spinach, broccoli, edamame, oranges, salmon, tofu, almonds
Average total weight gain for the 2nd trimester is 12-15 pounds.
At Sixteen Weeks
Muscle tissue and bone continue to form, creating a more complete skeleton. Skin begins to form. You can nearly see through it. Meconium develops in your baby’s intestinal tract. This will be your baby’s first bowel movement. Your baby makes sucking motions with the mouth (sucking reflex). Your baby reaches a length of about 4 to 5 inches and weighs almost 3 ounces.
At Twenty Weeks
Your baby is more active. You might feel slight fluttering. Your baby is covered by fine, downy hair called lanugo and a waxy coating called vernix. This protects the forming skin underneath. Eyebrows, eyelashes, fingernails, and toenails have formed. Your baby can even scratch itself. Your baby can hear and swallow. Now halfway through your pregnancy, your baby is about 6 inches long and weighs about 9 ounces.
At Twenty Four Weeks
Bone marrow begins to make blood cells. Taste buds form on your baby’s tongue. Footprints and fingerprints have formed. Real hair begins to grow on your baby’s head. The lungs are formed, but do not work. The hand and startle reflex develop. Your baby sleeps and wakes regularly. Now at about 12 inches long, your baby weighs about 1 ½ pounds.
Third Trimester
Nutrition
Foods with iron: spinach, beef, lamb, other animal protein, kidney beans, red quinoa, sunflower seeds, fortified whole grains, fortified cereal, dark chocolate, tofu
Average total weight gain for the 2nd trimester is 12-16 pounds.
At Thirty Two Weeks
Your baby’s bones are fully formed, but still soft. Your baby’s kicks and jabs are forceful. The eyes can open and close and sense changes in light. Lungs are not fully formed, but practice “breathing” movements occur. Your baby’s body begins to store vital minerals, such as iron and calcium. Lanugo begins to fall off. Your baby is gaining weight quickly, about one-half pound a week. Now, your baby is about 15 to 17 inches long and weighs about 4 to 4 ½ pounds.
At Thirty Six Weeks
The protective waxy coating called vernix gets thicker. Body fat increases. Your baby is getting bigger and bigger and has less space to move around. Movements are less forceful, but you will feel stretches and wiggles. Your baby is about 16 to 19 inches long and weighs about 6 to 6 ½ pounds.