Syphilis is a chronic infectious disease with a long incubation period that invades all organs of the body at the end of the incubation period, and has a variety of symptoms, the most obvious being skin ulcers. Syphilis infection in pregnant women may be due to the fact that the infection was already present before the pregnancy, but was not detected in time, or was not treated thoroughly after detection, resulting in detection during pregnancy. It may also be due to sexual intercourse, blood transmission or indirect infection during pregnancy. 1, sexual intercourse: sexual partners have syphilis, direct contact through sexual intercourse and be infected, is the most common way, is also the main way of syphilis transmission; 2, blood transmission: due to blood transfusion, skin and mucous membrane damage resulting in syphilis infection. If a pregnant woman has a wound on her body and comes into contact with the blood of other syphilis patients, resulting in the transmission of syphilis through the blood, she will be infected with syphilis; 3, indirect transmission: pregnant women may come into contact with the secretions of syphilis patients or contaminated household items, such as pregnant women in public toilets, sitting directly on the toilet seat, but the toilet seat was previously sat by syphilis patients, which may be attached to the syphilis, resulting in indirect transmission. Or share a bath towel or tub with a syphilis patient may be infected with syphilis, but this route is rare. If a pregnant woman is infected with syphilis, she should not be shy about seeking treatment, but must go to the hospital for active treatment. The doctor will treat the pregnant woman and the fetus according to their specific conditions to block and repel syphilis, which can effectively prevent the transmission of syphilis from the pregnant woman to the fetus.