Induced abortion and risk of subsequent miscarriage

BACKGROUND: To evaluate the impact of surgically induced first-trimester abortion on the risk of miscarriage in a subsequent pregnancy. METHODS: The study is a pregnancy cohort study. It was conducted among 15 general hospitals or maternity and infant health institutes in Shanghai, China from November 1993 to March 1998. The abortion cohort consisted of pregnant women whose previous pregnancies were terminated by vacuum aspiration (98%). The reference cohort consisted of primigravidae. Subjects were recruited at 35-63 days of gestational age. A total of 2953 pregnant women were enrolled; 1502 in the abortion cohort, 1451 in the reference cohort. RESULTS: There were only 62 women lost to follow-up. The remaining 2891 women had 2732 live births, and 137 miscarriages. About 5.5% of pregnancies in the abortion cohort were miscarried and 4.0% in the reference cohort. Once potential confounders were controlled for by logistic regression, odds ratio (OR) of miscarriage between the abortion cohort and the reference cohort was 1.55 (95% CI: 1.08-2.23). The adjusted OR were 2.44 (95% CI: 1.16-5.15) among women who were recruited within 49 days of gestational age, and 1.72 (95% CI: 1.09-2.72) for the first-trimester miscarriage. CONCLUSIONS: Induced abortion by vacuum aspiration is associated with an increased risk of first-trimester miscarriage in the subsequent pregnancy.     

IUD use and subsequent tubal ectopic pregnancy.

As part of a case-control study of tubal ectopic pregnancy (TEP), we sought to evaluate the possible etiologic role of use of an intrauterine device (IUD) prior to conception. We interviewed 155 women who had a tubal ectopic pregnancy treated at one of five Seattle, Washington hospitals between 1975-79 regarding their reproductive, contraceptive, and medical histories; 456 women who delivered a baby in King County during the same period were identified from vital records and interviewed as controls. An elevated risk of TEP was detected among former users of the Dalkon Shield (adjusted OR = 2.5; 95% CI = 1.3-4.7). Women who had used other IUDs did not have an excess risk of TEP.     

Risk of ectopic pregnancy and previous induced abortion.

OBJECTIVES: This study investigated the role of prior history of induced abortion in subsequent ectopic pregnancies. METHODS: Data from two French case-control studies were used to examine the effect of induced abortion on ectopic pregnancy risk. Case patients (n = 570) were women admitted for ectopic pregnancy during the study period; controls (n = 1385) were women who delivered in the same center. RESULTS: The analysis among women with no previous ectopic pregnancy showed that, after control for the main ectopic pregnancy risk factors, prior induced abortion was associated with an increased risk of ectopic pregnancy (odds ratio [OR] = 1.5, 95% confidence interval [CI] = 1.0, 2.0); there was a significant trend between number of previous induced abortions and ectopic pregnancy risk (ORs = 1.4 for 1 previous induced abortion and 1.9 for 2 or more). CONCLUSIONS: This study suggests that induced abortion may be a risk factor for ectopic pregnancy for women with no previous ectopic pregnancy, particularly in the case of women who have had several induced abortions.     

Induced abortion and spontaneous fetal loss in subsequent pregnancies.

The effect of induced abortion on spontaneous pregnancy loss in subsequent pregnancies was studied based on 3,416 pairs of matched data in a follow-up investigation. Pregnancy outcome was examined also in relation to abortion procedure, gestation length at time of abortion, and number of previous abortions. In general there was no significant association between prior induced abortion and risks of pregnancy loss with the relative risks of 1.10, 0.88, and 0.81 for the first to third trimester respectively. A slight increase of first-trimester spontaneous loss was noted with the D&C/Suction procedure and early induced abortion (less than 9 weeks). The D&C procedure was associated with non-significant increase of second-trimester loss with the relative risk of 1.59.     

Induced abortion and congenital malformations in offspring of subsequent pregnancies.

A case-control (n = 1427 and 3001, respectively) study in Connecticut found no relationship between delivery of an infant with congenital malformations and overall previous experience of induced abortion (odds ratio (o) = 0.9, 95% CL = 0.7, 1.1). Delivery of a congenitally malformed infant was also unrelated to: 1)abortion of penultimate pregnancy, 2) abortion of first pregnancy when index pregnancy is second, and 3) multiple previous abortions. Non-white women aged 25-29 who delivered a malformed child were significantly more likely to have aborted ( o = 2.6,95% CL = 1.2, 5.8, p less than 0.05). This may be due to more frequent histories of illegal and septic abortion, or to other characteristics of these women. Legal abortion performed under safe clinical conditions appears to impose no increased risk for subsequent delivery of a malformed infant.     

人工流产对再次妊娠分娩的影响分析

目的：人工流产对再次妊娠分娩的影响。方法：随机抽取2007年7月—2008年3月间拱墅区围产期保健手册共1286张,回顾性分析有、无人工流产史对孕产妇妊娠分娩的影响。结果：有人工流产史孕产妇孕早期出血、产后出血的发生率高于无人工流产史孕产妇（P〈0.05）,差异有统计学意义。结论：人工流产术可增加再次妊娠分娩时孕早期出血、产后出血的发生率。     

Mifepristone-induced abortion and vaginal bleeding in subsequent pregnancy

BackgroundThe aim of this study is to explore the effect of first-trimester mifepristone-induced abortion on vaginal bleeding in subsequent pregnancy.Study DesignThis observational cohort study was conducted during 1998–2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China. The study enrolled 4,931 women with one previous mifepristone-induced abortion, 4,925 women with no history of induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth.ResultsThe rates of vaginal bleeding in pregnant women with a history of medical abortion, no abortion, and surgical abortion were 16.5%, 13.9%, and 17.3%, respectively. The women with medical abortion had a higher risk (adjusted relative risk (aRR)=1.17, 95% confidence interval (CI): 1.07, 1.29) of vaginal bleeding compared with those with no abortion but similar risk to prior surgical abortion. When the correlation between medical abortion and vaginal bleeding was examined by period, increased risk was observed only in the early period (<16 gestational weeks) (aRR=1.25, 95% CI: 1.12, 1.39). The comparison between subgroups of medical abortion and no abortion showed that the observed risks increased particularly in those with abortion at gestational age ≤7 weeks (aRR=1.33, 95% CI: 1.18, 1.49), those followed by a postabortion curettage (aRR=1.58, 95% CI: 1.37, 1.84) or complications (aRR=1.99, 95% CI: 1.67, 2.37). There was no difference between women with medical abortion and women with surgical abortion in the occurrence of vaginal bleeding for either period.ConclusionsOne previous mifepristone-induced abortion increased the risk of vaginal bleeding in early gestation period of subsequent pregnancy compared with no abortion, especially if abortion occurred before 7 weeks of gestation and was followed by a curettage or complications.     

Mifepristone-induced abortion and vaginal bleeding in subsequent pregnancy

Background

The aim of this study is to explore the effect of first-trimester mifepristone-induced abortion on vaginal bleeding in subsequent pregnancy.

Study Design

This observational cohort study was conducted during 1998–2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China. The study enrolled 4,931 women with one previous mifepristone-induced abortion, 4,925 women with no history of induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth.

Results

The rates of vaginal bleeding in pregnant women with a history of medical abortion, no abortion, and surgical abortion were 16.5%, 13.9%, and 17.3%, respectively. The women with medical abortion had a higher risk (adjusted relative risk (aRR)=1.17, 95% confidence interval (CI): 1.07, 1.29) of vaginal bleeding compared with those with no abortion but similar risk to prior surgical abortion. When the correlation between medical abortion and vaginal bleeding was examined by period, increased risk was observed only in the early period (<16 gestational weeks) (aRR=1.25, 95% CI: 1.12, 1.39). The comparison between subgroups of medical abortion and no abortion showed that the observed risks increased particularly in those with abortion at gestational age ≤7 weeks (aRR=1.33, 95% CI: 1.18, 1.49), those followed by a postabortion curettage (aRR=1.58, 95% CI: 1.37, 1.84) or complications (aRR=1.99, 95% CI: 1.67, 2.37). There was no difference between women with medical abortion and women with surgical abortion in the occurrence of vaginal bleeding for either period.

Conclusions

One previous mifepristone-induced abortion increased the risk of vaginal bleeding in early gestation period of subsequent pregnancy compared with no abortion, especially if abortion occurred before 7 weeks of gestation and was followed by a curettage or complications.     

Mifepristone-induced early abortion and outcome of subsequent wanted pregnancy

Follow-up information on subsequent pregnancies after mifepristone (RU486)-induced abortion is scarce. The authors examined whether one mifepristone-induced first-trimester abortion affects the outcome of a subsequent wanted pregnancy. In a study conducted in 1998-2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China, the authors enrolled 4,925 women with no history of induced abortion, 4,931 women with one previous mifepristone-induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth. The adjusted odds ratio for preterm delivery in women with one mifepristone abortion compared with women with no abortion was 0.77 (95% confidence interval: 0.61, 0.98). Although the mean birth weight of infants born to women with mifepristone abortion was 33 g (95% confidence interval: 17, 49) higher than that of infants born to women with no abortion, the frequencies of low birth weight and mean lengths of pregnancy were similar. There were no significant differences in risk of preterm delivery, frequency of low birth weight, or mean infant birth weight in the comparisons of women with previous mifepristone abortion and women with surgical abortion. This study suggests that one early abortion induced by mifepristone in nulliparous women has no adverse effects on the outcome of a subsequent pregnancy.     

Induced abortion and breast cancer risk

Results from case-control studies suggest that induced abortion may be associated with a small increase in risk of breast cancer. While risk estimates from cohort studies have generally not observed such an association, these studies have had limited information regarding abortion and possible confounding variables. Therefore, we conducted a study among a cohort of post-menopausal women from whom detailed information regarding pregnancy outcomes as well as risk factors for breast cancer had been collected. The study sample included 37,247 Iowa Women's Health Study participants, 55-64 years of age at baseline in 1986, who reported no history of breast, or other, cancer (except non-melanoma skin cancer), and for whom information regarding pregnancy outcomes (that is, live birth, stillbirth, spontaneous abortion, ectopic pregnancy or induced abortion) was available. We used linkage with records of the State Health Registry of Iowa, part of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, to estimate the incidence of breast cancer among cohort members through 1995. We calculated age-adjusted relative risks and 95% confidence intervals using Cox proportional hazards regression. Only 653 women (1.8%) reported an induced abortion. The age-adjusted relative risk of breast cancer among women with prior induced abortion compared with those without was 1.1 (95% CI = 0.8-1.6). Relative risks were higher among women whose age at first abortion was less than 20 or at least 30 years, for those whose abortion took place after their first birth or who never gave birth, and for those with early termination (0-2 months). These estimates varied from 1.3-1.7, but the confidence intervals around each were wide. Since most women in this cohort were beyond their reproductive years when abortion became legal in 1973, the low prevalence of induced abortion argues for a cautious interpretation.     

Induced abortion and low birthweight in the following pregnancy

BACKGROUND: To examine whether induced abortion increases the risk of low birthweight in subsequent singleton live births. METHODS: Cohort study using the Danish Medical Birth Registry (MBR), the Hospital Discharge Registry (HDR), and the Induced Abortion Registry (IAR). All women who had their first pregnancy during 1980-1982 were identified in the MBR, the HDR, and the IAR. We included all 15,727 women whose pregnancy was terminated by a first trimester induced abortion in the induced abortion cohort and 46,026 women whose pregnancy was not terminated by an induced abortion were selected for the control cohort. All subsequent pregnancies until 1994 were identified by register record linkage. RESULTS: Low birthweight (<2500 g) in singleton term live births occurred more frequently in women with one, two, three or more previous induced abortions, compared with women without any previous induced abortion of similar gravidity, 2.2% versus 1.5%, 2.4% versus 1.7%, and 1.8% versus 1.6%, respectively. Adjusting for maternal age and residence at time of pregnancy, interpregnancy interval, gender of newborn, number of previous spontaneous abortions and number of previous low birthweight infants (control cohort only), the odds ratios (OR) of low birthweight in singleton term live births in women with one, two or more previous first trimester induced abortions were 1.9 (95% CI: 1.6, 2.3), and 1.9 (95% CI: 1.3, 2.7), respectively, compared with the control cohort of similar gravidity. High risks were mainly seen in women with an interpregnancy interval of more than 6 months. CONCLUSIONS: The findings suggest a positive association between one or more first trimester induced abortions and the risk of low birthweight in subsequent singleton term live births when the interpregnancy interval is longer than 6 months. This result was unexpected and confounding cannot be ruled out.     

Induced abortion after the 12th week of pregnancy. I.]

Of the 303 abortions performed in the second trimester in the Wilhelmia Gasthuis in Amsterdam between 1967 and 1977, 150 were performed by hypertonic saline solution instillation, 83 by hysterotomy, and 70 by prostaglandin administration. The instillation of saline solution is an acceptable method for inducing abortion in the second trimester. Blood loss exceeded 500 ml in 8.7% of the cases, transfusions were necessary in 4%. 26% of the patients required mechanical cervical dilatation. 14% developed temperatures above 38 degrees C. 3 cases of light hemolysis were observed; these occurred only among the first 13 patients. The saline solution instillation method showed a failure rate of 5.8% among the 150 patients. 24 patients were administered less than 150 ml of the 20% saline solution, while 125 were administered more than 150 ml. The interval between instillation and abortion was markedly shorter among the patients who were administered more than 150 ml. In 64.8% of a group of 71 patients, the fetal heartbeat stopped within 2 hours after instillation.     

Induced abortion after the 12th week of pregnancy. II.]

70 patients, 16-42 years of age, underwent abortion induced by prostaglandin administration. 21 patients underwent extraamnial PGF2 alpha instillation; 250 mcg was administered the first hour and 750 mcg every hour afterward. Complete abortion occurred in 25% of the cases and incomplete abortion in 57%. The average total dosage was ca 14800 mcg with an average induction-abortion interval of ca 26 hours. 48 of the patients received 250 mcg i.m. injections of 15(s)-15-methylprostaglandin F2 alpha every 2 hours. The rate of complete abortions was 48% and of incomplete abortions was 48%. The average total dosage was 3022 mcg for nulliparae and 2480 mcg for multiparae. The average induction-abortion interval was ca 18 hours for nulliparae and ca 14-1/2 hours for multiparae. Most patients experienced severe gastrointestinal side effects. 1 patient underwent intraamniotic PGF2 alpha instillation, but experienced such severe pain and side effects that the procedure was not used again.     

先兆流产及异位妊娠血清血管内皮生长因子水平的改变

目的探讨血清血管内皮生长因子(VEGF)水平在先兆流产及异位妊娠患者血清中的改变及其意义。方法采用双抗体夹心酶联免疫吸附技术(SandwichELISA),检测先兆流产及异位妊娠患者和正常宫内妊娠者血清VEGF水平,并将其与血清β绒毛膜促性腺激素(βHCG)及孕酮(P)进行相关性比较。结果与正常妊娠(89.0±31)pg/ml比较,先兆流产及异位妊娠患者VEGF水平(分别为143±59pg/ml和357±147pg/ml)均明显升高,三者间差别均有极显著意义(P<0.001),相关性分析发现,VEGF与βHCG负相关(r=-0.379,P<0.001),与P负相关(r=-0.290,P<0.005)。结论VEGF与异常妊娠的发生有显著关系,血清VEGF水平的异常可以作为早期预测先兆流产及异位妊娠的参考指标。     

人工流产术对妇女再次妊娠及新生儿的影响

目的:探讨人工流产术对再次妊娠孕妇及新生儿的影响。方法:2007年6月~2007年12月对有生育史的妇女770人进行问卷调查。结果:9.9%的妇女有过人工流产史,城市妇女的人流比例明显高于农村妇女,中学学历的妇女人流比例高于小学和大学及以上的妇女;有人工流产史的妇女,再次妊娠时产后出血、胎盘粘连及新生儿窒息的发生比例明显高于无人工流产史的妇女。结论:人工流产术对妇女再次妊娠及新生儿都有一定影响,应积极做好计划生育宣传工作,尽可能做到首次妊娠分娩。     

A comparison of women with induced abortion, spontaneous abortion and ectopic pregnancy in Ghana

Background

Despite having one of the most liberal abortion laws in sub-Saharan Africa, complications from induced abortion are the second leading cause of maternal mortality in Ghana.

Study Design

The sample is composed of patients with pregnancy termination complications in Ghana between June and July 2008. The majority of patients report having had a spontaneous abortion (75%; n=439), while 17% (n=100) and 8% (n=46) report having had an induced abortion or an ectopic pregnancy, respectively. Factors associated with women in each of the three groups were explored using multinomial logistic regression.

Results

When compared to women with spontaneous abortions, women with induced abortions were younger, poorer, more likely to report no religious affiliation, less likely to be married, more likely to report making the household decisions and more likely to fail to disclose this pregnancy to their partners. Within the induced abortion subsample, failure to disclose the most recent pregnancy was associated with already having children and autonomous household decision making.

Conclusion

Identifying the individual and relationship characteristics of induced abortion patients is the first step toward targeted policies and programs aimed at reducing unsafe abortion in Ghana.     

Increased risk of ectopic pregnancy with maternal cigarette smoking.

As part of a case-control study of ectopic pregnancy, we evaluated the potential etiologic role of cigarette smoking. Maternal cigarette smoking at the time of conception was associated with an increased risk of ectopic pregnancy with a dose-response relationship (adjusted odds ratios: 1.30 to 2.49). On the other hand, partner's smoking was not associated with ectopic pregnancy. The study provides a supplementary argument towards a causal effect of smoking in the development of ectopic pregnancy.     

Induced abortion and the chromosomal characteristics of subsequent miscarriages (spontaneous abortions)

Data from a case-control study of miscarriages (spontaneous abortions) were used to test whether single and multiple induced abortions are associated with miscarriage in subsequent euploid (chromosomally normal) pregnancies. Cases and controls were identified in three New York City hospitals between April 1974 and November 1982. It was hypothesized that, if induced abortion increased the risk of subsequent miscarriage, an association would be observed with euploid but not aneuploid (chromosomally abnormal) miscarriage. The frequencies of single and multiple induced abortions among euploid cases and aneuploid cases were compared with those among controls. Among both private and public patients, the proportion of women reporting a single induced abortion was similar in euploid cases and in aneuploid cases compared to controls. Among public patients only, the proportions reporting multiple induced abortions were also similar in euploid cases and in aneuploid cases compared to controls (odds ratios = 0.9 and 1.0, respectively). In contrast, among private patients, the proportion reporting multiple induced abortions was raised among euploid cases (odds ratio = 2.2, 95% confidence interval = 1.3-3.7), although not among aneuploid cases. This association was strongest when the first induced abortion was carried out before 1973, at a young age, or with a procedure other than suction curettage. In public patients, the associations with miscarriage did not vary with characteristics of the first induced abortion, but multiple induced abortion histories when the first two induced abortions occurred before 1973 were in excess among euploid cases compared to controls. These results suggest that, for both private and public patients, neither single nor multiple induced abortions as now performed are likely to increase the risk of miscarriage in subsequent pregnancies. They also suggest a mechanical origin for some miscarriages.     

流产经历对再次妊娠时分娩结局的影响

目的分析流产经历对女性再次妊娠时分娩结局的影响。方法基于天津市妇幼卫生信息系统建立的母婴健康队列研究,收集2009年1月-2010年12月在天津市内六区和滨海新区建档并分娩的36 647对母婴的相关信息。结果共有11 551名(31.52%)孕妇有流产经历,其中1次流产经历8 528名(23.27%),2次及以上流产经历3 023名(8.25%)。相对于没有流产经历的女性,流产次数越多,分娩时剖宫产率越高,婴儿巨大儿、大于胎龄儿、死胎/死产/7 d内死亡的比例越高,小于胎龄儿、过期产的比例越低(Ptrend0.05)。调整孕妇年龄、受教育年限、是否吸烟、是否有过生育史、孕早期首次产检时体重指数(BMI)、孕24~28周时血压、孕24~28周时妊娠期糖尿病筛查值(GCT)、胎龄及新生儿性别后,Logistic回归分析显示,相对于无流产经历的女性,有流产经历的女性剖宫产[OR(95%置信区间)=1.23(1.17~1.29)]、巨大儿[OR(95%置信区间)=1.22(1.13~1.31)]、大于胎龄儿[OR(95%置信区间)=1.21(1.14~1.29)]风险增高,小于胎龄儿[OR(95%置信区间)=0.82(0.6~-0.98)]风险降低。结论有流产经历的女性再次妊娠时选择剖宫产的可能性增加,巨大儿、大于胎龄儿的风险增高,而小于胎龄儿的风险降低。