Development of the Baby
Your baby starts out as a fertilized egg, no bigger than the period at the end of this sentence. The baby will change and grow almost every single day and your body will change and grow too. It will take 280 days or 40 weeks before the baby is fully developed and is ready to live outside your uterus (womb). This is about 9 1/3 calendar months. Pregnancy is often divided into three periods called trimesters. Each is about 3 months long.
The First Trimester
During the first trimester, you may find it difficult to believe you are pregnant. You may experience few signs of pregnancy and gain only 3 to 4 pounds. Yet, the first 3 months of pregnancy are critical to your baby's health. During this time the baby will grow to 3 inches long and will have developed all of the major organs. Untreated illness or disease, radiation, or the use of tobacco, drugs, or alcohol during this time may harm your baby for life. Make sure you eat well, rest, and don't take any medication that has not been prescribed by your doctor. Tell any doctor, nurse, or dentist you visit that you are pregnant. Prenatal care, good nutrition, and adequate rest should be started immediately.
Your First Month. For the first 6 weeks, the baby is called an embryo. The heart, lungs, and brain are beginning to develop and the tiny heart will beat by the 25th day. The embryo is enclosed in a sac of fluid to protect it from bumps and pressure. The baby will grow in this sac until birth.
Your baby's umbilical cord is also developing. The cord is made up of blood vessels which carry nourishment from your body to feed the baby and carry away the baby's wastes.
During this time you may not notice a weight gain, but your breasts may be larger and may feel tender. You may also have some "morning sickness" or nausea.
Consumption of alcohol and smoking of cigarettes should be stopped as soon as you think you might be pregnant. Take only those drugs prescribed by a physician who knows you are pregnant.
You should schedule your first prenatal exam.
Your Second Month. During this month the embryo becomes a fetus, which means "young one." Arms with tiny hands and fingers and legs with the beginnings of knees, ankles, and toes are starting to form. Organs such as the stomach and liver have also begun to develop. The head now seems very large compared to the rest of the body because the brain is growing so fast. Tiny ears and the beginnings of hair are forming on the head. You still may not have a weight gain, but may tire more easily and need to urinate more frequently. Also, you still may be experiencing some nausea.
It is very important to eat the right foods, because you and your baby are changing and growing every day and you both need proper nourishment.
Your Third Month. Your baby is now about 3 inches long, weighs about 1 ounce, and signs of the baby's sex are beginning to appear. Finger and toe nails are developing. The mouth opens and closes and the baby is now starting to move the hands, legs, and head. At this point, though, you will not feel this movement.
You may have gained about 3 to 4 pounds and your clothes will begin to feel a little tight. You may also feel warmer than usual.
The Second Trimester
The second trimester begins with your 15th week of pregnancy. Many of the minor discomforts of the first trimester will disappear and you will begin to feel especially good. You can feel the baby move and you will start to look pregnant. Your baby starts to gain weight and is clearly a boy or a girl. Good nutrition will help you and your baby gain at the right rate. Your doctor will now begin listening to your abdomen for your baby's heartbeat with a special instrument called a fetoscope.
Your Fourth Month. Your baby, now weighing about 6 ounces, is growing very fast and is about 8 to 10 inches long by the end of this month. The umbilical cord continues to grow and thicken in order to carry enough blood and nourishment.
During the fourth month you will gain 3 to 4 pounds and start to "show." Maternity clothes and a maternity bra may now be more comfortable. You may start to feel a slight sensation of movement in your lower abdomen. This feeling is like "bubbles" or fluttering. When you first feel this movement, called "quickening," write down the date. This date will help the doctor determine when your baby is due.
Your Fifth Month. By the end of this month, your baby will weigh about 1 pound and be about 12 inches long. The doctor will now be able to hear the baby's heartbeat and you will begin to feel more definite movements. This month you may gain 3 or 4 pounds and begin to breathe deeper and more frequently. The area around your nipples may look darker and wider as your breasts prepare to make milk.
Your Sixth Month. You are now carrying a fully formed miniature baby except that the skin is wrinkled and red and there is practically no fat under the skin. The baby still needs to grow, being now only about 14 inches long and weighing only about 1 1/2 pounds. The baby cries and sucks on the thumb and you regularly feel the baby's movement.
You may gain 3 or 4 more pounds. You may experience some backache, but wearing low heeled shoes will give you a better sense of balance and comfort.
The Third Trimester
You have now completed 24 weeks of pregnancy. During these last 3 months, your baby will continue to grow and gain weight. As the baby grows larger, you may experience some discomfort from the pressure on your stomach or bladder. You will feel the baby's stronger and more frequent movements. Now is the time to start preparing yourself and your home for the baby's arrival.
Your Seventh Month. Your baby is now about 15 inches long and weighs about 2 to 2 1/2 pounds. The baby exercises by kicking and stretching, and changing position from side to side. You might even be able to see the movement when one of the tiny heels pokes you.
You may gain another 3 or 4 pounds this month, and may also notice some slight swelling in your ankles. A slight amount of swelling is normal. You may feel better if you lie down or prop your feet up during the day.
Your Eighth Month. Your baby has grown to about 16 inches long and weighs about 4 pounds. The eyes are open and the baby changes position in the uterus. This position is maintained until the baby is born. During this month, you may gain 3 to 5 pounds. Continue your daily activities, with rest periods, but stop doing any heavy lifting or work that causes strain.
Your Ninth Month. At 36 weeks your baby is about 19 inches long and weighs about 6 pounds. The baby's weight gain is about 1/2 pound per week. At 40 weeks, the baby is "full-term" and weighs from 6 to 9 pounds. Your baby settles further down into your pelvis and people will say that your baby has "dropped." You may feel more comfortable and your breathing will be easier, although you may need to urinate more frequently. You will be visiting your doctor every week until your baby is born.
During your pregnancy you should gain about 25 pounds, although the acceptable weight gain ranges from 20 to 30 pounds, depending upon the individual. You can expect to gain about 3 pounds during the first 3 months (first trimester), and about 3 to 4 pounds per month during the rest of the pregnancy. This weight gain enables your body to nourish the developing baby. As this chart shows, your baby is only part of the weight you gain.
Gaining an adequate amount of weight during pregnancy helps to insure an adequate birth weight for the baby. An infant whose birth weight is 7 to 8 pounds is generally much healthier than one whose weight is 5.5 lbs or less.
Because your baby's birth weight is affected by the amount of weight you gain, you should never try to lose weight during your pregnancy. Get advice from your doctor or nurse if you have questions about how much you should gain.
With proper eating and exercise most women return to their pregnancy weight within 3 to 6 months after delivery. If you breast feed your baby, you will usually lose weight more quickly.