The fetus is most vulnerable during the first 12 weeks. During this period of time, all of the major organs and body systems are forming and can be damaged if the fetus is exposed to drugs, German measles, radiation, tobacco, and chemical and toxic substances. Even though the organs and body systems are fully formed by the end of 12 weeks, the fetus cannot survive independently. Women experience these changes differently. Some symptoms of pregnancy continue for several weeks or months, while others are only experienced for a short period of time.
Some women experience many symptoms, while other women experience only a few or none at all.
This is due to an increased amount of the hormones estrogen and progesterone. A supportive bra should be worn. Veins become more prominent on the surface of the breast. The uterus is growing and begins to press on the woman's bladder, causing the need for her to urinate more frequently. However, morning sickness does not necessarily occur just in the morning and rarely interferes with proper maternal and fetal nutrition.