With the continuous development of modern medicine and science and technology, health care during pregnancy has developed rapidly in terms of theory, technology and methods, and the overall trend of neonatal and maternal mortality is decreasing. Mothers and fathers-to-be hope that they can have a healthy, beautiful and smart baby, so they are very concerned about the little changes during pregnancy, and therefore the demand for scientific knowledge about pregnancy is increasing. During this period, a fertilized egg cell differentiates and develops into a fetus with a head, torso, limbs, five senses and internal organs with a human shape. This is why early pregnancy is also called teratogenic sensitive period. 1, determine the pregnancy is intrauterine pregnancy: healthy women, especially women of childbearing age, have delayed menstruation after having sex, which is a signal of pregnancy, so we should pay enough attention to the diagnosis of early pregnancy, firstly, to determine the pregnancy, and secondly, to determine the intrauterine pregnancy, at this time, the examination is mainly early pregnancy ultrasound and blood human chorionic gonadotropin test. The first of these is the appearance of the intrauterine yolk sac at 5 weeks of gestation, and as the pregnancy progresses, the germ and fetal heart tube may appear one after another. 2. The main manifestations of this disease are menopause, abdominal pain, a small amount of vaginal bleeding, no intrauterine gestational sac visible on ultrasound, and blood chorionic gonadotropin levels slightly lower than normal pregnancy levels. Once ectopic pregnancy is diagnosed, it needs to be treated, and the treatment plan is based on the location and size of the ectopic pregnancy. (2) Miscarriage: There are many causes of miscarriage. Chromosomal abnormalities are the main cause of miscarriage in early stages, followed by systemic infectious diseases in the mother, luteal insufficiency, immune insufficiency, severe nutritional deficiencies, bad habits and environmental factors, and defects in the maternal uterus may cause miscarriage. Miscarriages are mainly classified as pre-eclampsia, refractory miscarriages, incomplete miscarriages and complete miscarriages. When an intrauterine pregnancy is confirmed, abdominal pain and vaginal bleeding are signs of preterm miscarriage, and it is necessary to go to the hospital and undergo relevant examinations to determine whether miscarriage can be preserved. Therefore, if abdominal pain or/and vaginal bleeding occurs during early pregnancy, it is necessary to be highly alert. However, if miscarriage occurs repeatedly then inquiry for the cause of miscarriage is needed. (3) Vomiting in pregnancy: Vomiting in early pregnancy varies in severity and often disappears naturally after 12 weeks. A few pregnant women have frequent nausea and vomiting and cannot eat, leading to dehydration, water-electrolyte disorders, and metabolic acidosis, and even liver and kidney function damage, most of which can be cured. If such symptoms appear in early pregnancy, you can consult a hospital and give rehydration treatment, most patients can be relieved. Pregnant women can eat foods with sour taste, such as prunes, mandarin oranges, vinegar, etc., to increase appetite and help digestion. Sometimes some vitamin b complex and vitamin c or calcium can also be taken to supplement their nutrition. Vitamin B6 may reduce pregnancy reactions. You can’t take “antiemetic” or “secret formula” to prevent adverse consequences. Once the ketonemia caused by severe pregnancy vomiting can lead to abnormal fetal development, the nutritional imbalance caused by vomiting can also affect the normal growth of the fetus. 3, early pregnancy precautions: early pregnancy, especially 3-8 weeks after conception gradually formed a variety of tissues and organs, this period is particularly susceptible to physical and chemical effects and induced malformations. After clinical observation, the heart of the embryo is most susceptible 21-40 days after fertilization, followed by the limbs and eyes, while the nervous system of the embryo is most susceptible to external substances for 20 days after fertilization until the delivery of the fetus. Therefore, it is necessary to supplement folic acid in early pregnancy to prevent the fetus from developing neural tube malformation. There are many factors leading to fetal malformations: (1) fever: some scholars have studied that body temperature tasting more than 1℃ above normal temperature for more than 24 hours is teratogenic and may lead to fetal brain, resulting in pediatric spasms and mental retardation, etc. In addition, high temperature activities such as sauna and Finnish bath need to be avoided during early pregnancy. (2) Intrauterine infections: the most common ones are toxoplasma, rubella virus, cytomegalovirus, herpes simplex virus, etc. As more and more families are keeping pets, although they can bring us happiness, the toxoplasma growing on pets may cause infection in pregnant women, which may lead to fetal malformation, etc. Therefore, it is better to board the pets before and during pregnancy to avoid contact. (3) Tobacco, alcohol and X-rays: Pregnant women who smoke or passively smoke can cause low birth weight babies, and it has been reported that nicotine in tobacco can lead to an increase in the chance of miscarriage and a decrease in the survival rate of newborns. The fetal malformation caused by drinking alcohol during pregnancy is called alcoholism syndrome, X-rays can cause fetal malformation, which is a well-known thing, fetal cells are very sensitive to X-rays, due to the “ionizing effect” and “biological effect” of X-rays, resulting in fetal cell chromosome Due to the “ionizing effect” and “biological effect” of X-rays, the fetal cell chromosome aberration causes fetal malformation, death, leukemia, etc. Therefore, before and during pregnancy, try to stay away from places with X-rays. 5, the application of drugs: the use of drugs during pregnancy may cause harm to the embryo and fetus, especially in the early stages of pregnancy, the harm is even greater, so in the early stages must be clear indications for the use of drugs, when it is necessary to use drugs, according to the needs of the pregnant woman’s condition, the use of effective and safer drugs for the fetus.