4th Week of Pregnancy
How is pregnancy calculated?
There is always a lot of confusion when discussing the way in which pregnancy is calculated. Since most women do not know when they conceived, pregnancy is always determined from the first day of your last menstrual period (LMP). Given that this is the way pregnancy is calculated, your pregnancy will last around 40 weeks. For more information on how pregnancy is measured, please see our information on calculating your dates.
What changes are occurring in your body?
You may begin to exhibit some of the early pregnancy symptoms such as breast tenderness, headache, backache, or others. It is important to know that many of the early pregnancy symptoms are similar to those you may experience before your period. Other women may not have any symptoms of pregnancy except for a late or irregular period. If you have missed your period, then you could take a pregnancy test. This would be the earliest that a home pregnancy test can detect pregnancy.*
What is happening with your baby?
There are three layers to your baby- the ectoderm, mesoderm, and endoderm. These three layers will form the baby’s organs and tissues. The ectoderm will become the nervous system (which includes the brain), skin, hair, nails, mammary glands, sweat glands, and enamel for the teeth. The mesoderm will become the heart, circulatory system, skeleton, connective tissues, blood system, urogenital system, and the muscles. The endoderm will house the lungs and develops into the lining of the gastrointestinal tract, the liver, pancreas, and thyroid.
Arm and leg buds begin developing, but are not clearly distinguishable. The placenta has also begun to form and is producing some important hormones including hCG. There is movement of rudimentary blood through the main vessels.*
How big is your baby?
Babies are still very small at this point, and sizes vary from 0.014 inch to 0.04 inch in length.*
What should you plan for this week?
If your period is late or you have an irregular period, you would want to take a home pregnancy test. If the result is positive then you would want to schedule an appointment with a health care provider. Many health care providers wait to see you until you are 8 to 12 weeks pregnant.
If your test is negative and your period is late, then you should wait a week before testing again. Some women take 2 to 3 weeks after a missed period before producing a detectable level of the pregnancy hormone.
You also want to begin looking for a health care provider and decide where you will have your baby. Many doctors and midwives will allow you to arrange an appointment so that you can meet them and ask them questions before deciding if they will become your provider. For more informaiton on choosing your health care provider, see our information on your birthing choices.
Tips for making your pregnancy better:
If you have not begun an exercise routine, check with your healthcare provider to see what he/she recommends. Even if you already have a rountine, you might want to read about exercise during pregnancy. Take a look at our information on exercise guidelines during pregnancy, effects of exercise during pregnancy, top recommended exercises, and exercise warning signs.
You also want to be careful about the different medications you take during pregnancy. You should check with your health care provider before taking any over-the-counter or prescription medications.
Your prenatal vitamin should contain at least .4 mg of folic acid. Prenatal vitamins normally contain .8 mg to 1 mg of folic acid and also have a high iron content . These are important for both you and your baby.
Tips for mom’s partner:
Continue being open with your partner about your fears and excitement about her being pregnant. Talk about when you want to share the news with family and friends. Some couples like to share the news right away, while others prefer to wait until they have had their first prenatal appointment. Discuss the pros and cons of sharing the news now versus waiting.
If your partner has decided to interview several health care providers, try to go with her to as many of these appointments as possible.
* The information that the American Pregnancy Association provides is used as a general guide for healthy pregnancy development, although development may vary due to the mother’s health or a miscalculation of ovulation. Each woman and pregnancy is unique and may be experienced differently. Remember that babies develop at different rates, even before they are born. The purpose of this developmental information is to give you a general idea of how your baby is growing, and you must remember that your baby’s growth may vary from that which is outlined.