The opening of one finger at six months of pregnancy may be caused by multiple births, multiple deliveries, cervical insufficiency, preterm miscarriage, etc. It is possible to keep the baby, but preterm labor is very likely. 1. Multiple births: If the pregnant woman has a history of multiple births, the cervical opening may have been relaxed, and the six-month-old fetus presses on the cervix, which will cause the opening to open up, and at this time, she should absolutely rest in bed. 2. Cervical insufficiency: pregnant women usually have a history of multiple miscarriages and abnormal cervical function, and should pay attention to cervical cerclage in order to preserve the fetus in another pregnancy. 3. Pre-eclampsia: If you are overworked, traumatized, or the fetus is abnormal, the uterus may open. When you are six months pregnant and find that the uterine opening is one finger open, you should go to the hospital in time to find out the cause, and under the guidance of the doctor, carry out the treatment of preserving the fetus. Don’t be overly anxious or nervous and trust your doctor’s guidance.