Week Ten

Your Baby's Development

By week 10, all of your baby's vital organs have been formed and are starting to work together.

As external changes such as the separation of fingers and toes and the disappearance of the tail takes place, internal developments are taking place too. Tooth buds form inside the mouth, and if you're having a boy, his testes will begin producing the male hormone testosterone.

Congenital abnormalities are unlikely to develop after week 10. This also marks the end of the embryonic period — in general, the embryo now has a distinctly human appearance and starting next week your baby will officially be considered a fetus.

Your Body

Your first prenatal visit, which often takes place around this time, is a milestone. At the doctor's office, you'll go through a series of tests and checks, including having your weight and blood pressure checked. You might also have an external abdominal examination to check the size and position of your baby and have your urine tested. During this first prenatal visit, your health care provider will thoroughly examine you, including an internal examination and a breast exam. Your health care provider will also ask you many questions about your medical history and any family health problems, to determine if your baby is at risk for genetic diseases. Another thing your provider will check? Your baby's heartbeat! Using a Doppler stethoscope, you should get to hear it for the first time.

As you leave your first appointment, your health care provider will probably send you for a blood test to find out whether you are immunized against varicella, measles, mumps, and rubella (German measles), as well as to determine your blood type and Rh factor.

Week Two

Your Baby's Development

This may sound strange, but you're still not pregnant! Fertilization of your egg by the sperm will only take place near the end of this week — read more about fertilization in the Your Body section below.

Although you'll have to wait to find out what color to paint the nursery, your baby's gender will be determined at the moment of fertilization. Out of the 46 chromosomes that make up a baby's genetic material, only two — one from the sperm and one from the egg — determine the baby's sex. These are known as the sex chromosomes. Every egg has an X sex chromosome; a sperm can have either an X or a Y sex chromosome. If the sperm that fertilizes your egg has an X chromosome, you'll have a girl; if it has a Y chromosome, your baby will be a boy.

Your Body

Your uterine lining, which will nourish the baby, is developing, and your body secretes follicle-stimulating hormone (FSH), which stimulates an egg to mature. At the end of this week, you will be at the midpoint of your menstrual cycle (if you have a regular 28-day cycle), and ovulation will occur (your ovary will release an egg into the fallopian tube).

This is when you're most likely to conceive. If you have sexual intercourse without protection around the time that you ovulate, you can become pregnant. After your partner ejaculates, millions of sperm travel through the vagina, and hundreds make it to the fallopian tube, where your egg is waiting. One sperm generally succeeds in penetrating the egg, and fertilization takes place. When that happens, you will be pregnant — although you will not be feeling any body changes just yet.