Abstract:Regarding the relationship between abortion and secondary infertility, most clinically observed obstetrics and gynecology department of Anyang Maternal and Child Health Hospital m Xishuang study lacks control, and one-sided observation inevitably leads to a biased view, and a case-control study method should be used to do prospective or retrospective analysis in order to draw fair and objective conclusions. Induced abortion does not increase the risk of secondary infertility, and complications from induced abortion have the potential to affect subsequent pregnancies. Fertility recovers quickly after abortion, and post-abortion services should be provided to avoid repeat unintended pregnancies and recurrent abortions. Currently, the number of abortions remains high. The proportion of repeat unplanned abortions among the abortion population is over 50%. At the same time, the number of people seeking medical care for infertility is increasing. Is there a correlation between abortion and secondary infertility? In addition, abortion methods have improved in recent years, including small suction tip surgery for early pregnancy, disposable non-metal suction tip surgery, painless surgery, and medication abortion. Does the mode of abortion change the effect of abortion on subsequent pregnancies? Therefore, it is necessary to reorganize our thinking and find the basis of evidence-based medicine to guide clinical practice. 1. the occurrence of infertility secondary to abortion is 5-2% in Beijing and Shanghai according to the population survey [1]. According to clinical observation, secondary infertility accounts for about 50% of the cases seen for infertility. Many clinical reports have collected tens to hundreds of cases of secondary infertility and found that a history of abortion accounts for about 60% to 80% of the patients with secondary infertility after abortion. This gives the impression that abortion is the main factor affecting secondary infertility, which is actually an illusion generated by one-sided observation. Abortion as a remedy for unwanted pregnancy is legal in China, and many women have received abortions before giving birth. According to the China Health Statistical Yearbook publicized, there are more than 7 million abortions since 2003 to date. The survey among pregnant women showed that those with a history of abortion accounted for 44.2% to 88.4%; the survey among women who had abortion showed that those with a history of abortion also reached 50% on. Therefore, to infer that abortion is the main factor of secondary infertility based only on the proportion of women with a history of abortion is a biased conclusion due to lack of control. Case-control studies can provide a fair and objective picture of the effect of abortion on subsequent pregnancies. A prospective study abroad included 433 aborted subjects as a case group and 1035 abortion-free subjects as a control group, and their pregnancy rate ratio (FRR) at follow-up was 0-94 (95% CI 0-83 to 1-07, P=0-37) [2]. Another retrospective study included 251 subjects with tubal infertility as a case group, and each 1 case was matched with 4 fertile women as controls, 2 hospital controls and 2 neighborhood controls to compare fertility history and abortion history. The results were OR=1・57 (95% CI 0・29 to 8・65) for the case group compared with hospital controls and OR=0・82 (95% CI 0・07 to 8・99) for the case group compared with neighborhood controls [3]. A recent French report comparing the history of abortion in postpartum women with infertile women with assisted reproduction also showed no significant difference in the history of abortion between these two populations [4]. A recent retrospective study in China included 229 infertile subjects with bilateral tubal obstruction as a case group, 251 infertile subjects with patent fallopian tubes and 226 pregnant subjects as a control group, and the incidence of history of abortion was 35-8%, 25-9% and 4-2%, respectively. The OR = 1・01 (95% CI 0・56 to 1・80) when compared with infertile controls; and OR = 1・06 (95% CI 0・62 to 1・81) when compared with pregnant controls [5]. These studies consistently suggest that there is no correlation between abortion and secondary infertility and that abortion does not increase the risk of secondary infertility. The occurrence of secondary infertility after abortion can be more visually demonstrated by prospective observation of subsequent pregnancies in women with abortion, and the results of all studies suggest that there is no significant increase in the occurrence of infertility after abortion. The survey data from 10 hospitals in Beijing showed that the incidence of secondary infertility after abortion was 1~38%. In recent years, there are two reports that the incidence of secondary infertility in women with abortion was 1.94%~3.88%, among which the surgical abortion was different from the medication abortion, with 20 cases of secondary infertility (4.8%) among 417 cases of negative pressure aspiration and 3 cases of secondary infertility (0.8%) among 382 cases of medication abortion, and the safety of medication abortion may be relatively higher [6-7]. In recent years, humanized services have been promoted to reduce the pain of women undergoing abortion, painless abortion has been widely carried out, and disposable non-metallic suction tubes have been put into use. Painless abortion has no significant impact on the procedure itself, and there is no significant increase in surgical complications. The disposable non-metal suction tube reduces the cleaning and disinfection of the instruments, reduces the mechanical stimulation of the uterus, which is conducive to surgical safety and has no significant impact on the surgical operation process. The causes of female infertility include endocrine, tubal, uterine and pelvic problems, systemic or local immune problems and other factors. Many clinical observations analyze the composition of the causes of secondary infertility and compare it with the primary infertility, the results mostly show that the primary infertility is dominated by endocrine factors and the secondary infertility is dominated by tubal obstruction factors. Infertility is caused by multiple factors. To analyze the causes of primary and secondary infertility, in addition to the disease factors mentioned above, the influence of behavioral factors such as age, living environment, nutrition, and lifestyle should be emphasized. As time passes, many factors such as changes in physical and living conditions and reproductive tract infections may affect the re-pregnancy as age increases. Of course, secondary infertility after abortion also requires consideration of surgery-related factors. As mentioned earlier, the fact that abortion is not associated with secondary infertility does not mean that we do not need to worry about abortion. This conclusion is premised on the premise that abortion is safe. If the abortion is unsafe and complications occur, it can lead to secondary infertility. There are historical studies that prove that illegal abortions lead to an increased risk of secondary infertility. There were 2 case-control studies in Greece at the same study site in the same region, 15 years apart. The first study was conducted in the early 1970s when abortion was illegal and concluded that abortion significantly increased the risk of secondary infertility with RR=3・4 (95% CI 1・38 to 8・37); the second study 15 years later, conducted after abortion was legalized, found a risk of secondary infertility with R=2・1 (95% CI 1・1 to 4・0) [8]. The main recent complications of abortion are incomplete abortion, bleeding, infection, and cervical canal or uterine adhesions, and it is mainly the latter two that may lead to secondary infertility. The incidence of complications of abortion in China is very low, much lower than that reported abroad, which is in line with the clinical reality that clinicians in China have much more practical experience than those abroad. Infections such as endometritis, adnexitis and pelvic inflammatory disease secondary to abortion, which affect the function of the fallopian tubes, are the more common factors. Many clinical reports analyze cases of secondary infertility in outpatient clinics, and since they are not multicenter studies, the number of reported cases varies widely among families and the results vary widely. For example, the results of hysterosalpingography show tubal obstruction ranging from 32% to 68%, but they consistently reflect that tubal obstruction ranks first among the causes of secondary infertility. The factors associated with it were investigated, such as the number of repeated abortions, grade of surgical institution, post-abortion infection, uterine injury, incomplete abortion, and bleeding for more than 2 weeks after abortion. The proportion of tubal obstruction increased with the number of abortions. Those with a history of one abortion had about 22% tubal obstruction; those with a history of three abortions had about 44%; those with a history of five or more abortions had about 75%. In patients with secondary infertility, tubal obstruction can reach 70% in those with a history of post-abortion infection and more than 40% in those with incomplete abortion and post-abortion bleeding for more than 2 weeks [9-10]. Cervical or uterine adhesions after abortion are less common. Data from our family planning clinic show that its incidence was 0-4% in the 1990s and 0-6% from 2001 to 2007 [11]. In contrast, in the infertility clinic, uterine adhesions are also an important cause of secondary infertility in subjects with a history of abortion, accounting for about 13-6% [9]. The main factors associated with this are surgical operation problems and repeated abortions. Excessive suction with negative pressure; entering and leaving the cervical uterine cavity with negative pressure; excessive aspiration and scraping of the uterus for fear of incomplete abortion tissue residue; repeated abortions, especially recent abortions, are all high-risk factors for abortion, and the endometrium may be damaged to the basal layer after several aspirations. Therefore, the operation technique of the procedure is very important. The problem of residual ossification of embryonic tissue is mostly reported as a case study with residual fragmented bone or residual ossification of tissue after forceps scraping resulting in secondary infertility. Individual clinical observations in large samples have reported up to 0-6% of women with a history of abortion with secondary infertility [9]. 3. post-abortion fertility status For most women, an abortion procedure without recent complications has no effect on a woman’s subsequent fertility. However, there may be some impact on subsequent pregnancy outcomes, such as spontaneous abortion, placenta praevia, and placental adhesions. Ovulation resumes after abortion in about 2 to 3 weeks, as early as from the 11th postoperative day, and 67% of the 1st menstrual cycle after abortion is ovulated. The average time to return to menstruation after abortion was 33-8 d. Menstruation resumed within 30 d in 78% of cases. If abortion is thought to cause secondary infertility and contraception is not used promptly after abortion, it is not uncommon to have a second pregnancy after abortion without resumption of menstruation. 2-3% of women have been reported to have another pregnancy before menstruation due to lack of contraception [12]. It has also been reported that those with a history of abortion are more likely to have an unintended pregnancy with OR=1・91 (95% CI1・09~3・34) [13]. The rapid recovery of fertility after abortion and inadequate post-abortion services have led to the problem of repeat abortions. Currently, multiple repeat abortions have become the number one factor for high-risk procedures. The proportion of repeat abortions among the abortion population is similar in major cities: 55-2% in Beijing, 44-1% in Shanghai, 56-4% in Zhengzhou, and 24-3% in Shenyang. Moreover, the interval between repeat abortions was short, with 35-97% of repeat abortions occurring within six months [14]. The survey of unmarried population showed that the rate of repeat abortion within 1 year was 23-5%, and the average time was (6-32±3-63) months. A recent survey of the occurrence of repeat unintended pregnancies after abortion in our hospital showed the same trend, with 54-3% of abortion subjects having repeat unintended pregnancies, of which 55-6% had one abortion in the past, 27-8% had two, and 16-7% had three or more. In general, abortion does not increase the risk of secondary infertility, but repeated abortion is a high-risk procedure with a high complication rate, and once complications occur, it may affect subsequent pregnancies and may eventually lead to secondary infertility. 4, to avoid complications of abortion to avoid complications of abortion, the first is to avoid abortion, especially to avoid repeated abortions, must start at the source, in-depth and careful education and informed choice of contraceptive methods to avoid unintended pregnancy. The second is to improve the level of safe abortion. Strictly follow the technical specifications of abortion, grasp the quality management of the surgical process, and deal with the operational details in each work procedure. Treat each abortion woman seriously, prepare well before the operation, complete all preoperative examinations, assess the preoperative physical condition, exclude hidden problems that may lead to complications, treat reproductive tract infections, etc.; operate steadily, accurately and gently, dilate the cervix gradually, and control the pressure by negative pressure attraction to avoid damage to the cervix and uterine cavity; observe and follow up after the operation to properly deal with bleeding and infection in a timely manner to reduce the operation The third is the health care after abortion. The third is post-abortion health education and post-abortion services. Postpartum services include health guidance and contraceptive guidance to promote physical recovery after abortion and avoid repeated unintended pregnancies. The significance of this work is to do a good job in the aftermath of the abortion and the “aftercare” work, educate women to protect their fertility, use the correct contraceptive methods, not to have an unwanted pregnancy when they do not want to have children, and to have a pregnancy when they want to have children as they wish. In our recent survey of repeat abortion patients, we found that failure to choose a reliable contraceptive method, failure to use contraceptive methods consistently and correctly, and lack of awareness of the dangers of abortion are important causes of unintended pregnancies among repeat abortion patients. The two most used contraceptive methods were condom and safe period, accounting for 84-9% and 53-8%, respectively, but the proportion of women who used condom incorrectly resulting in unintended pregnancy reached 41-8%. Individuals believed that abortion would cause infertility and thus did not use contraceptive methods after abortion resulting in unintended pregnancy. 78-3% of the respondents wanted post-abortion contraceptive guidance services, and they thought the best time was after the procedure (58-6%), the best way was individual counseling (51-7%), and the best person was a doctor or nurse 49-4%).