First trimester (week 1 to 12)

During the first trimester, i.e., during the period of first twelve weeks, a pregnant woman will undergo the following changes in her body. The periods stops or becomes very light, she may feel nausea, queasiness, and vomiting quite often. The breasts of a pregnant woman swells and may be tender and the nipples along with the area around the nipples gets darker and broader. She undergoes frequent urination and extreme tiredness. She may become constipated and have heart burn very often. A severe headache occurring is also a common thing. She will also experience mood swings during the first trimester i.e., she feels angry, sad, or happy very often for no reason.