Few of the symptoms which you may notice at four weeks are:
A spot of blood on your underwear can ring warning bells in your head and scare you. But remember, slight bleeding is common and nothing to worry about. Your embryo implanting into the uterine lining causes a bit of bleeding, which is normal. If you are bleeding like a regular period and observe clots, you must immediately see your gynecologist.
Another very common indication of pregnancy is morning sickness. This may be a misnomer, though, since morning sickness can strike at any time of the day. Again, blame the hormones for the queasiness. Not every woman experiences nausea, and different women experience them at different times.
Most women experience mild cramping during the early stages of pregnancy. Don't worry, cramping is a common tell-tale sign of pregnancy. You may also experience other PMS symptoms like mood swings. Learn to cope with them and inform your doctor if you feel concerned.
Feeling tired all the time? Needing to sleep more than normal? Blame it on the hormone progesterone. In addition, your body is trying to supply more blood to the developing embryo. As a result, your heart pumps faster. The hormones and the increased metabolism both contribute to you feeling tired all the time. Don’t worry. Use this extra time to pamper yourself and take the much-needed rest.
Has your favorite perfume turned into a not-so-favorite anymore? Are the slightest smells creating havoc in your nose? Sensitivity to smells is another widespread early pregnancy symptom and happens due to the hormone overdrive, especially hCG and estrogen. Some experts also believe that smell sensitivity is your body’s way of keeping safe from chemicals, toxins, and anything else that may not be safe for your pregnancy.
Baby’s Length: 0.25 cm.
Baby’s Weight: 0.1 gm
While you are still not sure whether you are pregnant or not, the fertilized egg or the blastocyst has found a safe home inside your uterus by travelling all the way from your fallopian tube. Following are the development of your baby.
The baby at week 4 is as tiny as a poppy seed and is called an Embryo. Once the cells have settled in comfortably in your uterus, they will split into two groups. Out of these, one half will go on to become your baby and the other half will form the placenta- the structure which will provide nutrients and oxygen to your baby. It also works to remove harmful waste from the baby.
The amniotic sac (known as water bag) also starts forming around the embryo. Along with it, the yolk sac is also formed. This yolk sac will later get absorbed into the baby’s digestive tract.
The embryo now has 3 different layers which will form the baby and its body parts. The outermost layer or ectoderm will form the baby’s nervous system, eyes, hair, and skin. Middle layer or mesoderm, will form the heart, blood vessels, bones, muscles, sex organs etc. And the innermost layer or the endoderm will form the baby’s stomach, intestines, liver, lungs etc.