Conception and Calculating Due Date for the First Three Weeks of Pregnancy

You will not know that you are pregnant in the first three weeks of pregnancy. In all actuality, you are not even pregnant in week one and week two. The first two weeks are used for calculating your baby's due date. Those weeks only become pregnancy weeks after you conceive during pregnancy week three.

Pregnancy Week 1

During the first week of pregnancy the woman is technically not pregnant. Healthcare providers base a pregnancy on the first day of the last menstrual cycle that the woman experiences. That first day becomes the start of your first week of pregnancy even though you have not conceived yet, and your due date is forty weeks from this date.

The gestational age of the baby is determined by this date. Your official due date is forty weeks from the first day of your last menstrual cycle. If you are unsure about this date, your doctor may suggest an ultrasound to determine the baby's development in order to give you an accurate due date.

Pregnancy Week 2

Week two is another pregnancy bonus week. Your body is gearing up for ovulation and implantation of a fertilized egg. Ovulation occurs about fourteen days before your next menstrual period begins. It is impossible to precisely predict when your next period is going occur so the rule of thumb for trying to conceive is around two weeks after the start of your last period. Since most women are on a twenty-eight day cycle, conception should occur fourteen days after the start of your last period which would be fourteen days before the start of your next period.

The time to put aside all of your habits is when you are trying to conceive. You won't know your exact conception day so you will have to prepare yourself before you know you are pregnant. If you smoke you should get a plan in place to help you quit. Also, avoid any alcohol consumption.

You should also start taking prenatal vitamins if you are trying to conceive. Folic acid it essential for your baby's early development because it helps to prevent neural tube defects, or more popularly known as, spina bifida. Do not take any medications or drugs that are not approved for pregnant mothers.

Pregnancy Week 3

This is the week of conception. The sperm and the egg meet in the fallopian tube where the egg is fertilized. Your baby is now called a zygote. The zygote immediately starts to divide into two cells, then four, and then eight. This division keeps going until the embryonic structures start to develop. The journey through the fallopian tube to the uterus takes three to four days. By the end of the third week, your baby is implanted in your uterus and is now called an embryo.

You probably do not even know you are pregnant yet because your next menstrual period is still a week away. If you are really in tune with your body you may actually start to feel pregnant and even have some of the early pregnancy symptoms. When I was pregnant with my second child, I knew it by the end of my third week of pregnancy. I took an early home pregnancy test and was ecstatic to see a faint, positive result.

Some pregnant women experience something called implantation bleeding around this time. Implantation bleeding is minor spotting from when the baby attaches itself to the uterine wall. Women who have light periods may think that this is their menstrual period which can confuse the correct conception date and due date.

You are already three weeks pregnant by the time of conception. Most women do not find out they are pregnant until week four or later.

Click here to find more information on your pregnancy and baby's development.

Sources:

Fit Pregnancy (2009). Pregnancy Calendar. Retrieved: April 8, 9, 2009. Web Site: fitpregnancy.com/calendar/40251887.html

Myers-Gorrie, Trula, Slone-McKinney, Emily, & Smith-Murray, Sharon (1998). Foundations of Maternal-Newborn Nursing (2^nd ed.). Philadelphia, PA: W. B. Saunders Company.

What to Expect (2009). Weekly Pregnancy Calendar. Retrieved:April 8, 9, 2009. Web Site: whattoexpect.com/pregnancy/week-by-week/landing.aspx