The first week of development, in the process of pregnancy, is conception, which is from ovulation to implantation. During this phase, there are many changes occurring in the female body. They are regulated mostly by the reproductive hormones. The beginning of the story lies in the menstrual cycle. Many primary follicles begin to grow during the ovarian cycle. Out of them, only one reaches full maturity and only one oocyte is produced at ovulation. During ovulation, some women feel slight pain and also experience a slight increase in their body temperature. This oocyte is pushed into the fallopian tube. It takes three to four days for an oocyte to reach the uterine lumen.
The egg is ready for fertilization for 12 to 24 hours after the ovulation. If fertilization does not occur, the corpus luteum shrinks and degenerates. The uterine wall and the unfertilized egg along with some blood are shed out by the body as the menstrual discharge. If the sperm comes in contact with the egg, it penetrates and fertilizes the egg to form an embryo. This usually takes place in one of the fallopian tubes.
In a few days, the embryo is found to be in the blastocyst stage, which marks the beginning of the implantation process. In this process, the embryo attaches itself to the wall or the lining of the uterus. Implantation bleeding, a brown discharge, is observed in some females. The placenta starts to develop and the human chorionic gonadotropic hormone is released. Increased levels of this hormone in the urine are used for the detection of pregnancy by the home pregnancy kit.
Estrogen and progesterone are the two main hormones produce during ovulation. Estrogen thickens the uterine lining and increases the blood flow to the uterus and progesterone stimulates various secretions, which nourish the fertilized egg. The human body, with the help of hormones, tries its best to create a suitable environment for the development of the embryo so as to make the unborn baby's journey a comfortable one.