reading pregnancy test

What’s It Like?

Although it’s only been four weeks since conception, your baby cells are multiplying rapidly. Right now, the embryo is the size of a poppy seed and consists of two layers the epiblast and the hypoblast, from which all of his or her organs and body parts will develop.

By the end of this week, you should be able to find out whether or not you are pregnant by taking a home pregnancy test. If positive, call your doctor’s office and schedule your first prenatal appointment. Most health practitioners won’t see you until you are eight weeks pregnant, unless you have symptoms that need further investigation, you have a medical condition, or have had problems with a pregnancy in the past.

Your Baby’s Growth

In the fourth week of pregnancy, the fertilized egg continues to grow, and the cells begin to organize by dividing themselves in order to form tissues and organs. This week marks the beginning of the embryonic period. From now until 10 weeks, all of your baby’s organs will begin to develop and some will even begin to function. At the end of the fourth week, the egg changes its shape, becoming flat like an embryonic disc. It then divides into three cell layers, the ectoderm (outside) and endoderm (inside) and the mesoderm (middle).

  • The ectoderm: the outer layer form’s your baby’s nervous system, tooth enamel, skin, anus.
  • The endoderm: the inner layer is the starting point for respiratory and gastrointestinal tract.
  • The mesoderm: the middle later forms your baby’s bodily tissues and structures like muscle, bone, and connective tissue.


About five days after conception, the embryo implants into the womb. Its cells begin to divide into two groups: those that form the placenta and those that form the baby. When the embryo is entirely embedded in the lining of the uterine cavity, the conception process is considered to be complete.


The placenta is also made up of two layers at this point. Its cells attach to the lining of your uterus, creating spaces for your blood to flow so that the developed placenta will be able to provide nutrients and oxygen to your growing baby. At the same time, the development of the amniotic cavity begins. On the 12th day after fertilization, your unborn baby, which now measures 0.007 inches (0.2 millimeters) in length, starts to feed from the placenta.

What Happens Inside Your Body?

In the fourth week of pregnancy, you may feel tired and experience mild nausea. Normally, it is the time of menstruation, but due to a hormone produced by the embryo, your menstrual cycle stops. Your breasts may feel enlarged and slightly painful, a sensation of fullness or pain in pelvis, increased vaginal discharge and urinate frequently. For some women, the abrupt hormonal changes cause sudden weight loss or weight gain. Others find they have mood swings.

Morning sickness is one of the earliest—and probably most problematic—signs of pregnancy. Studies estimate between 50-90 percent of women experience some form of the condition. Some women experience slight queasiness, nausea, vomiting while others experience nothing at all. All are perfectly normal. The nausea usually starts around 6 weeks of pregnancy, but it can begin as early as 4 weeks. It tends to get worse over the next month or so.

How Different Will You Look?

You are at the very beginning of your pregnancy, so it may be hard to spot any differences to your physical appearance. Some women find they have mild weight loss or gain (a few pounds) because of the hormonal changes. Your breasts might look slightly swollen and tight. However, these changes are probably no different to what you feel during your menstruation time.

How Can You Care For Both Of Your Loved Ones?

Now is about the time that you can have a firm answer on whether your partner has conceived. It can be a time of great anticipation, excitement or trepidation. Whatever the emotion, try to keep the lines of communication open and intimacy realized. If the test comes back positive, you may want to choose an obstetrician together. And if you want to get a head start, you can read ahead in Z Living’s week-by-week guide, or purchase or borrow books such as Dad’s Guide to Pregnancy For Dummies by Matthew M. F. Miller and Sharon Perkins or Be Prepared: A Practical Handbook for New Dads by Gary Greenberg and Jeannie Hayden.

Tips To Help You Go Through Your First Trimester

  • No booze, drugs or smoking: If you haven’t quit already, it is imperative to do so this week. The first trimester is crucial for the development and growth of your baby. During this period, you are most prone to miscarry or your baby prone to birth defects. Be good to yourself and your unborn child. (Related: Why You Shouldn’t Drink Wine When You’re Pregnant)
  • Think positively: Your raging hormones may make you prone to mood swings. Don’t worry this is perfectly normal — recent studies, however, have shown that up to 20 percent of women suffer from mood or anxiety disorders during the gestation and postpartum periods. However, if you are feeling anxious, you may want to try and calm yourself down. Yoga, meditation, breathing exercises or even just scheduled periods of relaxation are all important for your own health and that of your baby.
  • Drink water during exercise: It is perfectly safe and highly recommended to exercise during the first trimester of pregnancy, including running or jogging. However, you should avoid running in hot and humid weather. And you should make sure to drink plenty of water before and after any exercise. Overheating, especially in the first trimester, could be harmful to your baby.

Being 4 weeks pregnant can be a wonderful time in the pregnancy. You have just found out that you have conceived, but the physical changes, as yet, are pretty minor. You may have the beginnings of morning sickness, although most women only begin to develop it in the next few weeks. If you find yourself having abrupt mood changes, don’t worry, this too is perfectly natural and normal. Be good to yourself – good mental health is great for the well being of your baby.

For more interesting stories, visit our Health page. Read more about Pregnancy & Babycare here.