Unintended pregnancy among American women

This research note presents new estimates of the proportion of American women of reproductive age who experience unintended pregnancies, unintended births and abortions. The data are based on tabulations from the 1982 National Survey of Family Growth (NSFG) and the Alan Guttmacher Institute's 1981-1982 national survey of abortion providers. Of 6.1 million women who became pregnant in 1982, 3.7 million gave birth, 1.6 million had abortions and 0.9 million experienced miscarriages. An estimated 37% of all births in the 5 years preceding the 1982 NSFG were unintended. Applying that proportion to 1982 births results in an estimate of 1.3 million unintended births. It can be assumed that all 1.6 million abortions were terminations of unintended pregnancies. Respondents in the 1982 NSFG reported that 40% of the births they had ever had were unintended. 33% of NSFG respondents said that they had had at least 1 unintended birth during their life. Abortions were seriously underreported in the NSFG, as they have been in most other surveys. Only 47% of the abortions that occurred during the period 1977-1981 were reported. The real proportion of women of reproductive age who have ever had an abortion appears to be 21%. 65% of all women aged 40-44 in 1982 had had at least 1 unintended pregnancy, and more than 1/3 of them had had at least 1 abortion. It is probably inappropriate to view these levels as representative of the proportions of today's young women who will ever experience an unintended pregnancy or abortion. Estimates of the proportion of women who will have had abortions by age 45 indicate that 18% of women will have had a 1st abortion by age 20; 41% will have had one by age 30; and 46%, by age 45.     

Spontaneous abortions and congenital malformations among women exposed to tetrachloroethylene in dry cleaning.

STUDY OBJECTIVE: The aim of the study was to determine whether exposure to tetrachloroethylene during the first trimester of pregnancy has harmful effects on pregnancy outcome. DESIGN: The study used record linkage identification of cases and case-control comparison. SETTING: The study involved dry cleaner and laundry workers throughout Finland who had become pregnant during the study period. Controls were age matched but otherwise unselected women giving birth to normal babies in the study period. SUBJECTS: Cases were defined as women who had been treated for spontaneous abortion or had delivered a malformed child. Out of 5700 workers nearly half had been pregnant during the study period. One pregnancy only was randomly selected for study per worker, and the final study population was 247 women with spontaneous abortions and 33 with malformed infants. Three age matched controls were selected for each abortion case and five for each malformation case. MEASUREMENTS AND MAIN RESULTS: Three women out of four had worked in early pregnancy. Exposure information was collected from 1108 women by mailed questionnaires, with a 77% response, and was partly confirmed by biological monitoring data. Exposure to tetrachloroethylene was found to be significantly associated with spontaneous abortions (odds ratio 3.6, p less than 0.05). CONCLUSION: The findings, together with other available data, indicate that exposure of pregnant women to tetrachloroethylene needs to be minimised.     

An epidemiological study of work with video screens and pregnancy outcome: II. A case-control study

A case-control study on work with video screen equipment during pregnancy has been made for three cohorts of women, identified with the aid of occupational codes in the census, linked to the Medical Birth Registry and a registry containing information on women hospitalized for spontaneous abortion. Five hundred and twenty-two cases were selected (women with spontaneous abortions or women who had infants that died, had severe malformations, or had a birth-weight below 1,500 g) and 1,032 controls (women who had infants without any of these characteristics) taken from the same age stratum as the cases. All pregnancies had occurred in 1980-81. Questionnaires were mailed to the women asking for information on their work situation, including questions about work with video screen equipment. Fifty-eight women were excluded for various reasons. Response rate was 93%--lower (89%) among women with spontaneous abortions than among women who gave birth (95%). As stress and smoking were associated with video screen work, the effect of video screen work was analyzed after stratification for stress and smoking--no statistically significant effect of video screen work was seen but odds ratios were above 1. Crude odds ratios for video screen work were significantly elevated and showed a dose-dependent effect. This finding is discussed from the point of view of biases in the study: selective non-responding, recall bias, geographical variability, and lack of information on women who had induced abortions. Using questionnaire data for exposure rates in the populations studied, an estimate of the effect greater than or equal to 10 hr weekly work with video screens on spontaneous abortion rate was made. The point estimate was 1.04 with a 95% confidence interval of 0.9-1.2. Analysis of 44 infants with birth defects whose mothers had worked more than 10 hr/week with video screen equipment compared to 30 infants with birth defects whose mothers had not used such equipment in early pregnancy showed no signs of specificity in the type of birth defect.     

Predictors of vaginal bleeding during the first two trimesters of pregnancy

This study evaluates maternal age, race, cigarette smoking, prior spontaneous abortion, prior induced abortion, and prior preterm birth in relation to vaginal bleeding during the first two trimesters of pregnancy. Information on vaginal bleeding and predictors came from the Pregnancy, Infection, and Nutrition Study, which enrolled 2806 pregnant women at 24-29 weeks' gestation during 1995-2000 in central North Carolina, USA. Generalised estimating equations were applied to take into account repeated episodes of vaginal bleeding during pregnancy. Women with advanced maternal age and passive smoking exposure were more likely to experience more intense vaginal bleeding during pregnancy, as were women with prior preterm birth. More intense bleeding was also more likely to be reported among women with multiple prior spontaneous abortions or multiple prior induced abortions, but not among women with a single prior spontaneous or induced abortion. The combination of prior spontaneous and induced abortion showed a dose-response association with the occurrence of vaginal bleeding during pregnancy.     

Abortion among young women and subsequent life outcomes

CONTEXT: Young women frequently cite concerns about the effects of unplanned pregnancies on future life course outcomes, including education, employment and relationships, as reasons for seeking abortion. There is relatively little evidence as to whether abortion leads to improved life course outcomes for young women who choose this option. METHODS: Data from 492 women participating in a 25-year longitudinal study of a New Zealand birth cohort were used in regression models that examined the relationship between pregnancy and abortion history prior to age 21 and selected social and economic outcomes at ages 21-25. RESULTS: Compared with young women who became pregnant before age 21 but did not seek an abortion, young women who had an abortion had significantly better outcomes on six out of 10 measures spanning education, income, welfare dependence and domestic violence. Adjustment for confounding factors indicated that most of these differences were explained by family, social and educational characteristics that were present prior to pregnancy. Nonetheless, even after adjustment for confounding factors, young women who had abortions had higher levels of subsequent educational achievement than those who became pregnant but did not have abortions. CONCLUSIONS: Abortion may mitigate some effects of early unplanned pregnancy. However, further study of its potential risks and benefits is needed so that women can make fully informed decisions as to whether to terminate unintended pregnancies.     

Estimating the probability of spontaneous abortion in the presence of induced abortion and vice versa.

An integrated approach to estimate the total number of pregnancies that begin in a population during one calendar year and the probability of spontaneous abortion is described. This includes an indirect estimate of the number of pregnancies that result in spontaneous abortions. The method simultaneously takes into account the proportion of induced abortions that are censored by spontaneous abortions and vice versa in order to estimate the true annual number of spontaneous and induced abortions for a population. It also estimates the proportion of pregnancies that women intended to allow to continue to a live birth. The proposed indirect approach derives adjustment factors to make indirect estimates by combining vital statistics information on gestational age at induced abortion (from the 12 States that report to the National Center for Health Statistics) with a life table of spontaneous abortion probabilities. The adjustment factors are applied to data on induced abortions from the Alan Guttmacher Institute Abortion Provider Survey and data on births from U.S. vital statistics. For the United States in 1980 the probability of a spontaneous abortion is 19 percent, given the presence of induced abortion. Once the effects of spontaneous abortion are discounted, women in 1980 intended to allow 73 percent of their pregnancies to proceed to a live birth. One medical benefit to a population practicing induced abortion is that induced abortions avert some spontaneous abortions, leading to a lower mean gestational duration at the time of spontaneous abortion.     

自然流产妇女血清MDA、SOD、VitE的测定及意义

目的:通过对自然流产妇女血清氧化应激指标———超氧化物歧化酶(SOD)、丙二醛(MDA)及维生素E(V itE)的测定,分析三个指标在自然流产发病机制中的意义。方法:用化学比色法对30例自然流产妇女及20例正常早孕组妇女血清中SOD、MDA及V it E进行测定。结果:与正常早孕妇女相比,自然流产妇女血清中MDA水平升高(P<0.05),SOD、V it E水平却下降(均P<0.05)。结论:上述三个指标对于预防及治疗自然流产有重要意义。     

Breast cancer in relation to the occurrence and time of induced and spontaneous abortion

The authors evaluated whether an induced or spontaneous abortion during the first six months of gestation, particularly if it occurs before the first term pregnancy, increases the risk of breast cancer. Data from a case-control study of women under 70 years of age were used: 3,200 cases of breast cancer were compared with 4,844 controls with nonmalignant nongynecologic conditions. Among both nulliparous and parous women, the risk of breast cancer was not related to the number of induced or spontaneous abortions. After allowance for all identified potential confounding factors, the estimated relative risk for nulliparous women with an induced abortion relative to those who had never been pregnant was 1.3 (95% confidence interval (CI) 0.8-2.2), and for spontaneous abortion, the corresponding estimate was 0.9 (95% CI 0.5-1.5). Among parous women, the estimated relative risks were 1.2 (95% CI 0.9-1.6) for an induced abortion and 0.9 (95% CI 0.8-1.0) for a spontaneous abortion, relative to never having had an abortion of any type. The time of the abortion had little effect: The relative risk estimates were 0.9 (95% CI 0.5-1.4) for induced abortion before the first term birth, 1.4 (95% CI 1.0-1.9) for induced abortion first occurring after the first term birth, 0.9 (95% CI 0.7-1.2) for spontaneous abortion before the first term birth, and 0.9 (95% CI 0.7-1.0) for spontaneous abortion first occurring after the first term birth. Similar results were evident for women under age 40, among whom the frequency of induced abortion was relatively high. These data suggest that the risk of breast cancer is not materially affected by abortion, regardless of whether it occurs before or after the first term birth.     

Modelling prior reproductive history to improve prediction of risk for very preterm birth

Watson LF, Rayner J‐A, King J, Jolley D, Forster D, Lumley J. Modelling prior reproductive history to improve prediction of risk for very preterm birth. Paediatric and Perinatal Epidemiology 2010. In published studies of preterm birth, analyses have usually been centred on individual reproductive events and do not account for the joint distributions of these events. In particular, spontaneous and induced abortions have often been studied separately and have been variously reported as having no increased risk, increased risk or different risks for subsequent preterm birth. In order to address this inconsistency, we categorised women into mutually exclusive groups according to their reproductive history, and explored the range of risks associated with different reproductive histories and assessed similarities of risks between different pregnancy histories. The data were from a population‐based case–control study, conducted in Victoria, Australia. The study recruited women giving birth between April 2002 and April 2004 from 73 maternity hospitals. Detailed reproductive histories were collected by interview a few weeks after the birth. The cases were 603 women who had had a singleton birth between 20 and less than 32 weeks gestation (very preterm births including terminations of pregnancy) and the controls were 796 randomly selected women from the population who had had a singleton birth of at least 37 completed weeks gestation. All birth outcomes were included. Unconditional logistic regression was used to assess the association of very preterm birth with type and number of prior abortions, prior preterm births and sociodemographic factors. Using the complex combinations of prior pregnancy experiences of women (including nulligravidity), we showed that a history of prior childbirth (at term) with no preterm births gave the lowest risk of very preterm birth. With this group as the reference category, odds ratios of more than two were associated with all other prior reproductive histories. There was no evidence of difference in risk between types of abortion (i.e. spontaneous or induced) although the risk increased if a prior preterm birth had also occurred. There was an increasing risk of very preterm birth associated with increasing numbers of abortions. This method of data analysis reveals consistent and similar risks for very preterm birth following spontaneous or induced abortions. The findings point to the need to explore commonalities rather than differences in regard to the impact of abortion on subsequent births.     

Induced abortion: not an independent risk factor for pregnancy outcome, but a challenge for health counseling

PURPOSE: Low birth weight (LBW), preterm births, abnormal placentation, and miscarriages have been associated with prior induced abortions. An incidence-related effect has been suggested. The objective of this study is to assess the effects of prior induced abortions on obstetric risk factors and pregnancy outcome in conditions of free high-standard maternity care used by almost the entire pregnant population in Finland. METHODS: We analyzed a population-based database including 26,976 singleton pregnancies from 1989 to 2001, of which 2364 were among women with one prior induced abortion and 355 women had had at least two prior induced abortions. Data included maternal risk factors, pregnancy characteristics, and obstetric outcome measures and were based on results of a self-administered questionnaire at 20 weeks of pregnancy and clinical records. Odds ratios (ORs) concerning pregnancy outcomes were calculated in multiple logistic regression analysis. RESULTS: Induced abortions were associated with several known pregnancy risk factors; specifically, maternal age older than 35 years, unemployment, unmarried status, low educational level, smoking, alcohol consumption, overweight condition, and chronic illnesses. Preterm birth (OR, 1.19; 95% confidence interval, 1.01-1.41) in women with one prior abortion (7.3% versus 6.2%) and LBW (OR, 1.54; 95% confidence interval, 1.02-2.32) in women with two or more prior abortions (7.0% versus 4.7%) appeared to be more common, but after logistic regression analysis, we found no evidence of adverse pregnancy outcomes. CONCLUSIONS: Induced abortion is not an independent risk factor for adverse obstetric outcome. Marked health behavioral pregnancy risks are associated with prior induced abortions. Health counseling of these women is a challenge, but this objective has not yet been achieved.     

Obesity increases the risk of spontaneous abortion during infertility treatment

OBJECTIVE: This study examines the relationship between body mass and the risk of spontaneous abortion in a large cohort of patients who received infertility treatment. RESEARCH METHODS AND PROCEDURES: This is a retrospective study using data on pregnancies (n = 2349) achieved after treatment in a tertiary medical center from 1987 to 1999. One pregnancy per subject was included, and the subjects were stratified into five body mass groups based on body mass index (BMI): underweight, <18.5 kg/m(2); normal, 18.5 to 24.9 kg/m(2); overweight, 25 to 29.9 kg/m(2); obese, 30 to 34.9 kg/m(2); and very obese, > or =35 kg/m(2). Logistical regression analysis was used. RESULTS: The overall incidence of spontaneous abortion was 20% (476 of 2349). The effect of BMI on the risk of spontaneous abortion was significant after adjusting for several independent risk factors. Compared with the reference group (BMI 18.5 to 24.9 kg/m(2)), underweight women had a similar risk of spontaneous abortion, whereas there was progressive increase of risk in overweight, obese, and very obese groups (p < 0.05, p < 0.01, and p < 0.001, respectively). DISCUSSION: Of all known risk factors for spontaneous abortion, the control of obesity has great significance because it is noninvasive, potentially modifiable, possibly amenable to low cost, and self-manageable by patients. This study established a positive relationship between BMI and the risk of spontaneous abortion in women who became pregnant after assisted reproductive technology treatment.     

Characteristics of women with recurrent spontaneous abortions and women with favorable reproductive histories.

Women with a history of recurrent spontaneous abortions (repeaters) are compared with women who have had live births and no spontaneous abortions (multiparae) and women who have had live births and only one spontaneous abortion (sporadics) to identify characteristics of the women and their abortuses that might predict subsequent fetal loss. A number of risk factors for recurrent spontaneous abortion have been identified: the loss of a chromosomally normal conception, loss after the first trimester of pregnancy, a delay in conceiving prior to the study pregnancy, a diagnosis of cervical incompetence, and a history of very low birthweight deliveries. The odds ratios associated with being a repeater vary from 1.4 to 5.6 depending on the number of characteristics present.     

Observation: contraceptive method use following an abortion

Researchers comparing 1st and repeat abortion patients directly, have found that the latter were using methods that are only slightly or no more effective than those used by 1st-abortion patients at the time they became pregnant. It is here argued that such direct comparisons are not appropriate because repeat patients are not typical of all women who have ever had an abortion. Most women who use effective methods consistently after a 1st abortion, will never appear in the repeat abortion statistics. Therefore, in terms of contraceptive use, repeat abortion patients overrepresent women who use no method or the least effective method. This point is illustrated using 1981-82 data collected by the Minnesota Department of Health on virtually all the state's residents obtaining abortions in the state during a 2-year period. A total of 22,070 women obtained 1st abortions and 8734 women repeat abortions. The data is collected by method used and shows the monthly contraceptive failure rate per woman, the number of users per failure, the estimated % distribution of women at risk of a 1st abortion, the acutal distribution of those obtaining a 1st abortion, and the estimated distribution of women at risk of a repeat abortion. Comparisons of these statistics show that of the women exposed to the risk of abortion, those acutally obtaining one are disproportionately using no cotraceptives (70%) or the least effective method. The pill and sterilization were the methods used most commonly by the group exposed to the risk of a repeat abortion. By contrast, at the time of the 1st abortion, only 5% of women had been using the pill and less than 1% had depended on sterilization. Only 9% of women at risk of a repeat abortion used no method, compared with 70% before the 1st abortion. Thus although women who have an abortion tend to be relatively poor contraceptive users, after the abortion, they use methods at least as effective as those used by women at risk of a 1st abortion. The data suggest a marked improvement in contraceptive practice subsequent to a 1st abortion. While a number of factors may contribute to this improvement, it is probable that the abortion experience and the contraceptive services offered at the time of the abortion play an important role in improving contraceptive practice.     

Induced abortion in a rural area of Bangladesh

Mortality rates from indigenous abortion practices have not been described previously. From September 1982 to August 1983, traditional birth attendants, under medical supervision, collected data on all identifiable pregnant women and pregnancy outcomes in a geographically defined population in rural Bangladesh. Of 9,906 pregnancies, 9,317 ended in live birth, 412 in induced abortion, and 177 in spontaneous abortion. All abortions were induced by indigenous health practitioners. The abortion-to-live-birth ratio was 44.2 per 1,000. Ten women died after induced abortion, yielding a death-to-case rate of 2.4 percent. The death-to-case rate was highest for women 35 and older and women of parity five and higher. The authors conclude that improved distribution of safe, acceptable means of fertility regulation may save many mothers' lives.     

Abortion and fertility control in Korea

Findings are presented from a detailed study that used data from the 1974 Korean National Fertility survey to evaluate the impact of abortion on fertility and to investigate the interrelationships of abortion, contraceptive use, and contraceptive effectiveness in Korea. The relative effectiveness of contraception is low, the best being 76% effectiveness for women aged 30-34 in urban areas. Among women using contraception after abortion, the effectiveness is even lower. After the 1st abortion, 85% of the women aged 25-29 become pregnant with 2-5 years. 74% of women who use contraception after abortion become pregnant in this time compared to 92% of women who do not. Contraception when added to abortion achieves intervals that are twice as long as those for abortion alone. By using contraception, the interval from abortion to pregnancy is lengthened on average by 10.3 months for women aged 25-29, 11.5 months for those aged 30-34, and 9.3 months for those aged 35-39. The average number of abortions needed to avert a live birth in Korea is lower than the figure of 3.3 Potter estimated for societies with prolonged lactation. When contraception is not used, at least 1 abortion is needed each year to avert 1 live birth. With contraceptive use, the number of abortions needed to avert 1 live birth is between 0.55 and 0.62. The number of abortions needed in this case is greatly reduced when contraception is practiced more effectively. Comparing the actual level of contraceptive effectiveness in Korea in 1974 with a possible 95% effectiveness shows that this latter high level would have the same effect on fertility with approximately 6 fewer abortions throughout a woman's reproductive life. The actual reduction in numbers would be 5.8 in the 25-29 age group, 5.9 in the 30-34 age group, and 8.2 in the 35-39 age group. This reduction in the number of abortions necessary with 95% effective contraception as compared with actual contraceptive use, suggests considerable potential for reducing the need for additional abortions with improved contraception. The current situation has improved since 1974, due to the success of the sterilization program.     

自然流产妇女弓形虫感染的调查研究

目的　探讨自然流产妇女与弓形虫 (Tox)感染的相关性。方法　采用酶联免疫吸附试验(EL ISA)对自然流产的 4 76例孕妇外周血进行了弓形虫循环抗原 (CAg)和特异性抗体 (Tox- Ig M,Tox- Ig G)的检测 ,并和正常妊娠妇女作比较 ;应用聚合酶链反应 (PCR)技术对经 EL ISA测定为阳性的 1 4例孕妇流产物进行 Tox- DNA检测。结果　流产组 CAg,Tox- Ig M,Tox- Ig G等阳性率分别为 5 .2 5 % ,6 .30 % ,1 1 .76 % ,其中 CAg及 Tox- Ig M阳性率与正常孕妇相比 ,差异有非常显著性 (P<0 .0 1 ) ;1 4例流产物中 Tox- DNA阳性 8例 ,阳性率为 5 7.1 4 %。结论　 Tox可通过胎盘传给胎儿 ,引起流产 ;孕妇急性感染与自然流产有相关性 ,CAg,Tox- Ig M,CAg+Tox- Ig M阳性率与发生流产次数呈正相关     

Risk of spontaneous abortion in Italy, 1978-1995, and the effect of maternal age, gravidity, marital status, and education

This paper describes the trend in the risk of spontaneous abortion in Italy from 1974 to 1995. There was a dramatic decline in the risk after the law that legalized induced abortion was passed in 1978, which implies that probably many induced abortions performed before 1978 were registered as spontaneous abortions. Data for 1991 have been extracted from the Italian national registers of births and abortions and analyzed to investigate the effects of maternal age, gravidity, marital status, and education on the risk of spontaneous abortion. In comparison with women under age 20 years, the risk is found to be increased for women aged 35-39 (odds ratio = 1.45) and women over age 40 (odds ratio = 3.10). The odds ratio is almost 2 for women who have been pregnant two or more times previously. Unmarried women have an increased risk (odds ratio = 1.33), but no important effect of education was observed. There is an important interaction between maternal age and gravidity. The risk of spontaneous abortion is excessively high for young women with high gravidity. It is hypothesized that this could be due to the effect of short intervals between pregnancies.     

Environmental tobacco smoke and risk of spontaneous abortion

BACKGROUND: Studies of exposure to environmental tobacco smoke (ETS) and risk of spontaneous abortion are limited to a few studies of self-reported exposure, and the results have been inconsistent. The aim of this study was to investigate risk of early spontaneous abortion related to ETS and active smoking as defined by plasma cotinine levels. METHODS: We conducted a population-based case-control study in Uppsala County, Sweden, between January 1996 and December 1998. Cases were 463 women with spontaneous abortion at 6 to 12 completed weeks of gestation, and controls were 864 pregnant women matched to cases according to the week of gestation. Exposure status was defined by plasma cotinine concentrations: nonexposed, <0.1 ng/mL; ETS-exposed, 0.1-15 ng/mL; and exposed to active smoking, >15 ng/mL. Multivariable analysis was used to estimate the relative risk of spontaneous abortion associated with exposure to ETS and active smoking. RESULTS: Nineteen percent of controls and 24% of cases were classified as having been exposed to ETS. Compared with nonexposed women, risk of spontaneous abortion was increased among both ETS-exposed women (adjusted odds ratio = 1.67; 95% confidence interval = 1.17-2.38) and active smokers (2.11; 1.36-3.27). We could not show a differential effect of exposure to ETS or active smoking between normal and abnormal fetal karyotype abortions. CONCLUSIONS: Nonsmoking pregnant women exposed to ETS may be at increased risk of spontaneous abortion. Given the high prevalence of ETS exposure, the public health consequences of passive smoking regarding early fetal loss may be substantial.     

Pregnancy in mixed connective tissue disease

The authors carried out a retrospective study of the pregnancy of 31 women suffering from mixed connective tissue disease (MCTD). They summed up the number of growing children, stillborns, and spontaneous abortion in the period before and after commencement of the disease process. Their results point to a rather marked occurrence of spontaneous abortion even in the period before the actual disease process. In the majority of patients there were observable clinical signs which, retrospectively, was an autoimmune disease process, but now known as the appearance of MCTD. In the period following the disease only a smaller percentage of patients became pregnant, not on account of their age or previous spontaneous abortions, but rather because of their symptoms. They investigated those clinical abnormalities which could be reasons for the adverse conditions for fetal development in MCTD.     

巨细胞病毒感染与自然流产的关系

目的:探讨人巨细胞病毒(HCMV)感染与自然流产的关系。方法:采用荧光定量PCR(FQ-PCR)对41例自然流产妇女(病例组)的流产组织进行HCMV DNA检测,以及采用免疫组化(IHC)检测HCMV感染阳性者流产组织局部细胞因子(IL-2、IL-10、TNF-α)的变化,并与30例正常孕妇(对照组)进行比较。结果:病例组HCMV DNA的阳性检出率为41.46%,对照组的阳性检出率为13.33%,两组HCMVDNA的阳性率经统计学检验具有显著性差异(P<0.01),HCMV阳性病例组IL-10较对照组升高(P<0.05),IL-2有所降低(P<0.05),TNF-α无显著差异。结论:HCMV感染与自然流产有关,HCMV感染会引起孕妇免疫功能进一步抑制,促进了胎儿宫内感染并可能最终导致流产。