Well, no baby yet. Its coming soon – trust us, your body is preparing for its new addition.

This is the week that you will miss your first period, so be sure to mark this date. There’s no implantation yet, and the exact moment of conception is hard to pinpoint but this is your first medical week of pregnancy. This stage is known as fertilization.

Almost. Right now your baby is still in the making, as the sperm and egg are about to meet and become what scientists refer to as a blastocyst. This mass of cells will become both the embryo and the amniotic sac that your baby will live in for the next 9 months.

Your uterus will begin to thicken its lining in preparation of an impending pregnancy, and your ovaries are on high alert. This is occurs typically half way through your regular menstrual cycle, when your ovaries release a single egg (or two in the case of some twins) from its follicles. This egg you release every month during ovulation is leaving the ovaries and entering the fallopian tubes in search of its sperm.

Amniotic fluid is beginning to accumulate around this ball of cells, and it has implanted in the uterus. There is even a very primal system that handles circulation and nutrition – a task that will soon be taken over, typically within the next week or so, by the placenta.

Your little blastocyst is multiplying rapidly, and becoming an embryo that is going to implant in your uterus this week. Part of this group of cells is going to become the placenta, and the other part is going to begin to become your baby. Your body will begin to produce hCG (human chorionic gonadotropin) – the pregnancy hormone. This hormone tells your body to stop releasing other eggs and increases levels of the hormones estrogen and progesterone that keep your uterus from shedding its lining. You may notice your breasts feel very tender and look a bit swollen, and you feel exhausted for no reason. Maybe you’ve even noticed a bit of spotting, known as implantation bleeding. This is almost time to take a home pregnancy test. Don’t worry if it comes back negative; take another in a few days when the hCG levels may be higher.

Your baby is officially an embryo. This precious embryo is about the size of a poppy seed, beginning to be surrounded by its amniotic sac. This fluid protects the baby as she grows. There is also what is called the yolk sac forming – this important part of the sac is what delivers nutrients to your baby. This yolk will eventually be incorporated into the digestive track as the baby develops. There are several layers of the embryo, three in fact, that each will develop into particular parts of the baby’s body.

The ball of cells is now splitting into the placenta and the embryo. You will likely be experiencing the classic symptoms of pregnancy at this stage, including a heightened sense of smell, and increased nausea. While many women don’t begin to experience morning sickness (which is not limited to the AM hours) until the 6th week, some will find that they are ahead of the game and are feeling sick and even vomiting a bit. Be sure that you start a pre-natal vitamin, if you haven’t already. You need higher amounts of folic acid while you are pregnant, usually 600mcg a day, but check with your physician before you start any medical regiment.

Your baby has grown significantly this week, and is now about the size of a sesame seed, and resembles a tadpole. The circulatory system is starting to become prepared, and is starting to flicker inside your tiny baby. The heart is beginning to have tiny channels that will begin to pump blood.

Those three layers of the embryo are now more distinct, and can be identified. The outer most layer, the ectoderm, forms the baby’s hair, skin, eyes and nervous system. This layer will also produce tooth enamel and sweat glands. The baby’s brain, spinal cord and backbone will form from what is known as the neural tube, and this is found in this layer of the embryo. The middle layer, mesoderm, contains the heart and circulatory system. The heart will begin to beat and pump blood during this phase, and will help produce the muscles, bones, cartilage and tissues. The innermost layer will have the baby’s digestive track and lungs, and includes the intestines, liver and pancreas. This is the time where the placenta and umbilical cord are now firmly in place and working to provide the nutrition and sustenance your baby needs.

You may not notice any outward differences, but you will likely begin to need to urinate frequently and feel a bit nauseous. Your breasts may feel very sore and tender, and hurt to the touch. It’s important that you’ve contacted your physician to schedule your first prenatal exam, although you may not be seen until approximately 8 weeks. It’s also important that you avoid alcohol and eat healthy. Whatever you consume is also being consumed by your baby, so make sure its something you would want your baby to have too.