Delayed due date is not always a female baby; the sex of the fetus is determined by the sex chromosomes. In addition, the delayed due date of pregnant women may be caused by the imbalance of the ratio of estrogen and progesterone in the body and the weakening of spontaneous contraction of the uterine myometrium. Delayed due date has no relationship with the sex of the fetus, which is determined by the sex chromosome carried by the father. If the father’s X sex chromosome combines with the mother’s X sex chromosome to form a fertilized egg, the sex of the fetus formed at this time is generally female. If the mother’s X sex chromosome combines with the father’s Y sex chromosome to form a fertilized egg, the sex of the fetus is usually male. The delay in the expected date of labor is mostly considered to be caused by the imbalance of the ratio of estrogen and progesterone in the pregnant woman’s body, weakening of spontaneous contractions of the uterine myometrium, overweight of the pregnant woman, heredity, too many fetuses, and malposition of the fetus. Generally can not be delayed to determine the sex of the fetus, it is recommended that women with a delayed due date of more than 1 week, you need to go to the hospital in time to wait for delivery, the doctor will choose the appropriate measures according to the situation of the pregnant woman to deal with.