Your baby begins to form at the time of conception, starting off as embryonic cells that continue to grow throughout your pregnancy. Your body will also experience changes during your entire pregnancy. Depending upon your preference for prenatal care, your obstetrician or midwife will monitor fetal growth and development.
History
When you go to your first prenatal visit, you may hear your doctor refer to trimesters. Pregnancy consists of three trimesters, each lasting three months in length. Your doctor will give you an estimated due date, or EDD, of when your baby will arrive. Babies may be born a couple of weeks early or a couple of weeks late since your EDD is estimated based on your last menstrual period, according to KidsHealth.
Size
When your baby is conceived, she is very small--just a cluster of cells. In the second month of pregnancy your baby grows slightly larger--about 1 inch in length--and weighs less than 1 ounce. By the third month of pregnancy, which also marks the end of the first trimester, your baby weighs about 1 oz. and is about 3 inches long. In the fourth month, your baby will double in size and grow to about 6 inches long and weigh 5 oz. By the end of the second trimester, or the sixth month of pregnancy, your baby is about 12 inches and weighs about 1½ pounds. Within the last trimester of pregnancy, your baby will grow another approximate 7 to 8 inches in length, or 20 inches total, and when born, she can weigh 6 to 9 pounds. During the last month of pregnancy, she will gain about half a pound per week.
Physical Attributes
Each month of pregnancy will provide a new function or physical trait of the fetus. During the first month of pregnancy, as cells are rapidly growing, your baby will have a heartbeat by the fourth week. During the second month he will begin to develop genitals, and ankles, wrists, toes and fingers begin to take form. In the third month, all organs are developed but cannot fully function on their own. During the fourth month, external genitalia will begin to appear and his kidneys begin to function and produce urine. In the fifth month, he may begin to suck his thumb and wake and sleep regularly. By the sixth month, he can open his eyes, begins to grow hair and his fingers and toes can be seen. During the seventh month, he can detect changes of light, kick and stretch as well as respond to sound. In the eighth month, his bones begin to harden, he may hiccup and can taste sweet and sour with his newly formed taste buds. By the last month, he will develop a sleeping pattern and turn his head in a downward position to prepare for his arrival.
Significance
As you see your caregiver at each prenatal visit, he will take measurements of your abdomen and may occasionally order an ultrasound to ensure your baby is growing and developing properly. An ultrasound allows your caregiver to see the baby as she floats around in your womb. Your caregiver may also use a special piece of equipment called a Doppler to listen to your baby's heartbeat. It resembles a microphone, which the doctor will press against your abdomen so you can also hear the heartbeat.
Considerations
Speak with your caregiver about prenatal vitamins, signs or symptoms to watch for, what he expects as far as diet, nutrition and fetal growth, and how he handles labor and delivery situations. You may also want to ask your doctor if he has a trusted partner should you deliver while he is on vacation.
