There is no guarantee that a mediastinum uterus is completely safe up to any number of weeks of pregnancy, and whether it is safe or not depends on the type of mediastinum i.e., the development of the fetus. Longitudinal uterus is caused by incomplete fusion of the paramedian tubes during embryonic development to form a septum in the uterine cavity, which can be categorized into complete longitudinal uterus and incomplete septate uterus. Complete longitudinal uterus is the longitudinal septum from the uterine fundus to the endocervical os, completely separating the uterine cavity into two parts. It is best to get pregnant after surgical treatment, such as laparoscopic surveillance hysteroscopic removal of the longitudinal septum, which may result in a favorable outcome of the pregnancy. Untreated pregnancies are prone to miscarriage, preterm labor, abnormal fetal position, and restricted fetal development. Incomplete longitudinal septum: the longitudinal septum does not run from the bottom of the uterine cavity to the endocervix, the length of the longitudinal septum can be long or short, if the length of the longitudinal septum is short and the fetus is not very big, then it basically has little effect on the development of the fetus, and the pregnancy can be carried to full term delivery. It is not possible to determine how many weeks of pregnancy are safe for a mediastinal uterus. The development of the fetus needs to be closely monitored throughout the entire pregnancy, and any abnormalities found should be dealt with in a timely manner. If ultrasound or hysteroscopy reveals a longitudinal uterus, it is recommended to perform a mediastinectomy first, and then get pregnant again to achieve a favorable pregnancy outcome.