The first week of pregnancy involves the early development of the zygote, the cluster of cells that eventually grow into a fetus, but many women remain unaware of their pregnancy until a missed menstrual cycle. Your body hormones start to change, but it could take a few weeks before you feel much different. Nonetheless, a few symptoms of pregnancy might happen in the first week of pregnancy.
Fertilization
The very first stage of pregnancy happens when a man's sperm fertilizes the egg in a woman's uterus. This creates a fusion of cells that start multiplying rapidly. At this stage you'll generally have no way of knowing if you're pregnant unless you take a pregnancy test. Hormonal changes do occur soon after fertilization, but most women don't experience any radical body changes right away. Doctors even count the first week of pregnancy from your first missed period when calculating the delivery due date.
Symptoms
The first week of being pregnant might trigger symptoms even if you're unaware of your pregnancy. For example, your breasts might feel tender or tingly. "Morning sickness," a general term for sickness in pregnancy, might hit you at any time of the day and make you feel nauseated or tired. Some women feel early fatigue as the body diverts blood to the womb and fetus. In the first week or two, your heart rate might increase by up to 15 beats per minute, according to the Netwellness website.
Risks
The majority of miscarriages happen in the first trimester, but up to 50 percent of all fertilized eggs are lost without a woman even realizing she's pregnant, according to MedlinePlus. Depending on behavior, this lack of being aware of pregnancy in the first week can increase the chances of miscarriage. For example, a woman might smoke or drink heavily before she finds out she's pregnant. Drinking alcohol in the first weeks of pregnancy increases the risk of miscarriage and developmental problems in the fetus.
Considerations
Doctors recommend taking folic acid supplements during the course of your pregnancy, but it's unlikely that you'll be taking folic acid in your first week of pregnancy unless you already are taking the vitamin while trying to conceive. As soon as you find out that you're pregnant, add a 400 mg folic acid supplement to your daily diet, according to Kidshealth.org. A multivitamin with the right folic acid dose is sufficient. Folic acid helps reduce the chances of your child developing spina bifida,
References
- Netwellness; Pregnancy -- First Trimester; Thomas A deHoop, M.D., et al.; March 2006
- Bupa; Stages of Pregnancy; April 2010
- MedlinePlus; Miscarriage; November 2010
- "American Journal of Preventative Medicine"; Alcohol Use Prior to Pregnancy Recognition; R.L Floyd; August 1999
- Kidshealth.org: Pregnancy Calendar Week One -- Your Baby's Development
