After the relaxation of the family planning policy and the announcement of the possibility of having two children alone, many people are asking what they need to pay attention to when having a second child at an older age. There are four hurdles to overcome when having a second child at an older age: pregnancy is difficult, miscarriage is easy, birth defects are numerous, and the risk of hemorrhage is high. So, older friends who are planning to have a second child should be prepared to face bad news. The chance of pregnancy for women over the age of 35 starts to decline to about 10% per month, and the cumulative chance of conception for a year is about 75%. women over the age of 35 who want to get pregnant should consult a fertility specialist if they have not gotten pregnant after 6 months of active trying. women over the age of 40 have a dramatic decline in their ability to get pregnant. The monthly pregnancy rate is only about 5%, and even with in vitro fertilization (IVF), the pregnancy rate is only 10% per attempt, and the cumulative chance of conceiving in a year for women over 40 is about 40%-50%. This is due to the fact that the number of normal egg cells in the ovaries of women over 40 is greatly reduced. Therefore, women over the age of 40 who wish to conceive should seek help from a fertility specialist if they have not conceived after 3 months of trying. Getting pregnant over the age of 45 is a very difficult task, with less than a 1% chance of getting pregnant on your own. This is because virtually all remaining eggs are genetically abnormal and almost all successful pregnancies over 45 are the result of donor eggs. Miscarriage Prone In the population as a whole, the miscarriage rate is about 15% and increases gradually as age rises. At age 35, the miscarriage rate is 25%, at age 40 the rate is about 35%, and by age 45 the rate has reached 50-60%. The most important cause of miscarriage in older pregnancies is chromosomal abnormality of the embryo, so usually fertility preservation treatment is not meaningful. More birth defects As a woman ages, the quality of her eggs decreases and the probability of having problems with fertilized eggs increases significantly. At age 35, the risk of Down’s syndrome is 1/378 and the risk of all chromosomal abnormalities is 1/192; at age 40, the risk of Down’s syndrome is 1/106 and the risk of all chromosomal abnormalities is 1/66; at age 45, the risk of Down’s syndrome is 1/30 and the risk of all chromosomal abnormalities is 1/21. And that’s just the This is only the probability of chromosomal abnormalities and does not include the much higher incidence of fetal structural defects. Timely preconception screening is essential to reduce birth defects and improve population quality. To avoid the birth of children with chromosomal abnormalities such as Down syndrome, the traditional method requires prenatal serological screening and amniocentesis if the fetus has a high prevalence of the disease. This traditional screening technique is relatively inaccurate, and amniocentesis is associated with the risk of miscarriage, while prenatal genetic testing is accurate, safe, non-invasive, and does not require puncture, etc. It can detect potential chromosomal trisomy risk in the fetus by collecting only 5 ml of peripheral blood, and can also detect fetal chromosomal deletion/duplication syndrome. It can improve the screening rate for birth defects and thus prevent birth defects. High risk of hemorrhage In China, there is no official published rate of cesarean delivery. According to a WHO sample survey in three Chinese provinces and cities, the cesarean delivery rate is 46.2%, according to which the analysis is higher than 50% in large cities. Thus nearly half of the women who have second pregnancies have a history of cesarean delivery, and once the placenta of these people is implanted in the lower uterine incision, it is the so-called menacing placenta praevia. The thought of these time bombs makes obstetricians sleep poorly because of the high probability of postpartum hemorrhage from an aggressive placenta praevia, which can lead to hysterectomy in severe cases and maternal death in individual cases.