Pre-eclampsia miscarriage on birth control for half a month and then suddenly have a little blood, may be caused by germ cell dysplasia, cervical opening laxity, luteal insufficiency and other reasons, can be taken to spontaneous abortion, cervical cerclage, progesterone treatment and so on. 1. Germ cell dysplasia: Pre-eclampsia during pregnancy may be caused by maternal or paternal germ cell dysplasia. If there is a little bleeding after half a month of fertility preservation to check for embryonic deformities and dysplasia of germ cells, there is no need to continue fertility preservation, and it is better to let nature take its course and abort the baby. 2. cervical relaxation: early pregnancy women have cervical relaxation can also cause preeclampsia, half a month after the birth control may suddenly have bleeding, early pregnancy, pay attention to bed rest, reduce don’t walk around, elevate the hips to the birth control, 14 to 22 weeks of pregnancy to do the cervical cerclage surgery, after the surgery to give magnesium sulfate and other drugs to inhibit contractions, to improve the success rate of the birth control. 3. luteal insufficiency: the luteal insufficiency in the body after pregnancy, the body secretes insufficient progesterone will cause preeclampsia, the body progesterone has not returned to normal, may be half a month after the birth control and a little bit of bleeding, it is recommended to continue to take medication to protect the fetus under the guidance of the doctor, oral progesterone capsules or intramuscular injection of progesterone. After the preeclampsia and a little bleeding, it is recommended to deal with under the guidance of the doctor.