Whether the pregnancy is in the first half of the month or the second half of the month can be determined by menstrual projection, ultrasound examination and other methods. 1. Menstrual projection: If the menstruation is relatively accurate, it is possible to project the pregnancy through the menstruation is the first half of the month or the second half of the month, for example, the cycle is 28 days, counting from the first day of the last menstruation before the pregnancy, before and after the 14th day of the ovulation, then the pregnancy is in the period of ovulation. 2. Ultrasound: The use of ultrasound to determine the time of pregnancy is more accurate, by observing the size of the gestational sac to determine the time of pregnancy. There is no big difference between the first half of pregnancy and the second half of pregnancy, pregnant women do not need to worry too much, do a good job of maintenance measures, if the body has uncomfortable phenomenon recommended timely medical care.