Women do not know the exact date of conception so in general, it is determined from the first day of the last menstrual period.
On your week four of pregnancy, this is usually the time when you suspect you're pregnant because of a missed period and the presence of early signs and symptoms.
During this time, you may start to notice early pregnancy symptoms such as breast tenderness, regular headaches, backache and cramping.
Most women are not aware that they are already conceiving because the symptoms are very similar to having a period.
They usually find out late or they wait until they miss one or two periods.
Some women on the other hand may not have any symptoms of pregnancy except for a missed period.
You may also experience fatigue on your week four of pregnancy.
By this time, your body should start pumping out progesterone, this is needed to grow a healthy baby.
The placenta will begin to form.
The placenta is the one that supplies nutrients to the baby.
On your week four of pregnancy, the three layers (ectoderm, mesoderm and endoderm) will begin to form the baby's organs and tissues.
The first layer-ectoderm will become the nervous system and this includes the brain, skin, hair, nails, mammary glands, sweat glands and the teeth's enamel.
The mesoderm will become the heart, skeleton, connective tissues, blood system, urogenital system, muscles and the circulatory system.
The third layer-endoderm will develop into the lining of the gastrointestinal tract, liver, pancreas and thyroid.
It will also house the lungs.
Your baby is still very tiny and it measures about 0.
078 inches in length.
As early as now, start looking for a health care provider.
You can ask a relative or a friend for some recommendations.