Xiao Li and Xiao Song just entered the marriage hall, preferred to take the pill way of contraception. However, birth control pills are not foolproof, Xiao Song menstruation late for half a month, urine pregnancy test is written “positive”! The couple is torn between taking the pill and getting pregnant, can they still have a child? Why can I still get pregnant after taking the pill? Currently commonly used contraceptives are short-acting contraceptives, long-acting contraceptives and emergency contraceptives, the composition of which is mostly estrogen and progesterone compound preparation, or low-dose or strong progesterone, the principle of contraception is because it can inhibit ovulation, or change the quality of the cervical mucus, impede the penetration of sperm, thus preventing fertilization or inhibit the endometrium to proliferate and make its secretion is not good, not conducive to the fertilization of the egg to bed. However, the success rate of any contraceptive measure is not 100%. A common cause of contraceptive failure is not taking the medication as prescribed. Firstly, omission of short-acting contraceptive pills or having unprotected sex again after taking emergency contraceptive pills are the main reasons for the failure of oral contraceptive pills. Secondly, the failure of contraceptive pills is also caused by improper storage of the pills when the pills are not effective, gastrointestinal reasons for the absorption of obstacles, or some drugs taken at the same time interfere with the effectiveness of contraceptive pills, which is also a cause of contraceptive failure. Can pregnancy after contraceptive failure lead to fetal abnormalities? During pregnancy, drugs can have adverse effects on the embryo by passing directly through the placental barrier. The hormonal components of contraceptive pills usually use synthetic hormones rather than natural hormones. Synthetic sex hormones may have certain effects on the fetus, such as feminization of male fetuses or masculinization of female fetuses, malformations of the reproductive tract in female fetuses, and testicular hypoplasia in male fetuses. Contraceptives can also indirectly affect embryonic development by affecting maternal endocrine and metabolism, such as the occurrence of spontaneous abortion. The effects of drugs on embryos are closely related to gestational age. Pre-implantation period, that is, 2 weeks after fertilization of the fertilized egg, because at this time the fertilized egg and maternal tissues have not yet direct contact, but also in the fallopian tube or the uterine cavity in the secretion fluid, so this period of drug use on the embryo is not much effect. Clinically, this period is also referred to as the “all or nothing” period, that is, the use of drugs in this period, such as drug toxicity is very large, the fertilized egg can not be attached to the bed, it is impossible to continue to develop into an embryo; such as the drug does not affect the fertilized egg attached to the bed, then the drug does not have a significant impact on the embryo. However, after the late-stage embryonic sacs have been laid, that is, two weeks after fertilization, as the embryo has already established contact with the mother through the chorionic villi and the placenta, at this time the pregnant woman uses the drug, the drug may interfere with the normal differentiation of the embryo or fetal tissues and organs. Whether or not you can have a child after the pill has failed depends on whether or not you are taking the pill during the “all or nothing” period. What tests are needed to continue the pregnancy? If you choose to continue the pregnancy, you should strengthen your monitoring during pregnancy to detect congenital defects as early as possible and prevent the birth of children with congenital defects through screening. Specifically: 1, in early pregnancy, it is recommended to take blood test Ⅰ Down’s syndrome screening at 7 to 13 weeks of pregnancy, and NT at the end of 11 to 13 weeks of pregnancy, in order to assess the risk of chromosomal abnormalities; 2, due to a history of adverse drug exposure, it is recommended that amniocentesis be performed at 18 to 24 weeks of pregnancy to take amniotic fluid to perform fetal cell culture, fetal chromosome karyotyping, to find out whether there is any chromosomal abnormality; 3, in the 20-24 weeks of pregnancy need to do prenatal diagnostic ultrasound; 3, in the 20-24 weeks of pregnancy need to be done to find out whether there is any chromosomal abnormality. At 20 to 24 weeks of pregnancy, prenatal diagnostic ultrasound is needed to observe the fetal structure and find out whether there is any developmental abnormality. Induced abortion does not cause much harm to women’s bodies, therefore, on the question of whether pregnancy must be terminated when contraception fails, both husband and wife must go to a regular hospital for consultation, and refer to the reasonable advice of experienced doctors according to the specific situation, in order to minimize the risk.