Feeling dizzy or lightheaded during pregnancy is common, especially during the first trimester. Blood pressure tends to drop when you’re pregnant, and the blood vessels will dilate. Dizziness typically starts between the twelfth week of pregnancy and the beginning of the second trimester.
Additionally, feeling faint can be caused by low blood sugar levels. Morning sickness can make you not want to eat, leading to low blood sugar. Nausea can occur within days of conception so the dizziness can begin almost immediately after becoming pregnant. If you feel like the room is spinning, be sure to take care of yourself. See a doctor immediately to ensure that your blood sugar levels are okay and that you are not dehydrated.