3 Weeks Pregnant

Changes in Your Baby at 3 Weeks Pregnant

Three weeks pregnant is a time when the baby is growing rapidly but is too small to detect with the human eye. If you can picture the head of a needle, then you can imagine your pregnancy at week 3 and how large the baby is. Yet, it is growing so rapidly at this point if you monitor your baby week by week, you will find that it looks more like a blob, but this will change quickly in the coming weeks.

At 3 weeks pregnant many people wonder what their chances are of having twins. Generally, twins occur when your ovary or ovaries release more than one egg and are fertilized by two separate sperms to result in what we call fraternal or dizygotic twins. Fraternal twins are also referred to as non-identical twins.

Monozygotic twins, frequently referred to as identical twins, occur when a single egg is fertilized and divides into two babies. Identical twins will be the same gender and have like physical characteristics and chromosomal makeup.

To show you how truly remarkable the human body is and the endless possibilities, multiple combinations are possible. With triplets and quadruplets, three or more eggs can be fertilized to result in the combination. It is possible for one fertilized egg to split and another egg may be fertilized to form triplets.

If your family has a history of multiples you have a greater chance of conceiving multiples than someone who doesn’t share that history. However, just because that history exists doesn’t mean you will have twins. Generally, women who are “multiparous” meaning they have had more than one baby are more likely to have twins than a first time mom. With the reproductive technology today and assisted fertility it is becoming increasingly common for multiples to be born.

Most women will not realize at 3 weeks pregnant they’ve conceived and are pregnant. Even though you have not missed a period at this point your baby is growing inside you. At the moment your baby is an embryo consisting of nothing more than a ball of cells that is growing and expanding at an incredible rate. If you were to look through a magnifying glass at this point your baby would resemble nothing more than a group of cells with no human form. Your baby at 3 weeks of pregnancy is no bigger than the head of a needle, or about .006 inches long.

Fertilization is the biggest thing happening at this point. An egg will have to join with a sperm for a baby to be conceived. Hundreds of sperm surround the egg and one will have to penetrate the ovum for the sperm to commingle with the chromosomes of the female ovum. A combination of chromosomes from you and your partner are what basically make up a baby. Each of you contributes 23 chromosomes to the development of the baby. Then after three days of being fertilized, your egg will form a 9-cell embryo. The amniotic fluids will begin to collect around the ball of cells to comprise the embryo during pregnancy week 3 in a cavity that becomes the amniotic sac. This sac contains amniotic fluid to help cushion your baby throughout pregnancy. During the third week of pregnancy, a primitive circulation system made up of tunnels will connect this ball of cells to the uterine wall.

Changes in Your Body at 3 Weeks Pregnant

Pregnancy at 3 weeks is a time many women are anxious to uncover any physical changes in their body. The truth is most women will not realize any changes for a few more weeks. One clue that you are pregnant at this time may be implantation spotting without a normal menstrual flow. This bleeding actually can occur when the egg burrows into the uterine lining after about six days after fertilization.

It is vital that you begin taking care of yourself during the early weeks of pregnancy. You should begin eating healthy and adopting a wellness oriented lifestyle that would include an exercise program with your doctor’s approval. If you hadn’t exercised before you became pregnant, you can still adopt a lifestyle that is both healthy and active. If that is something you’ve already been doing, then you can usually make a few modifications ( low impact workouts ) and continue with your routine.

By 3 weeks pregnant most women are not aware of any significant physical changes. You may feel more tired and more bloating then normal. It is not until the pregnancy continues that your waistline will expand. Many women dread this inevitable change and the associated weight gain, while some women enjoy keeping a record of the 25 to 35 pounds normally gained during pregnancy (more if you are carrying multiples). Weight gain during pregnancy is natural and healthy as the weight is distributed among the placenta, uterus, amniotic fluid, fluid in the tissues, and the baby itself. Expect about 7 pounds maternal fat stores to be gained to help support breastfeeding. Take time to appreciate and embrace all of the remarkable changes that are and will occur in your body and remember that every pound you gain during pregnancy will help support your baby. During the time you are trying to get pregnant you are more than likely filled with excitement and anticipation. The bad news is that you won’t be able to test for pregnancy at three weeks pregnant for another 10 days or so because even the most sensitive tests usually cannot detect pregnancy until a few days before your period normally arrives.

Read next about your baby's growth, as well as the changes in your body at 4 weeks pregnant.