Low birth weight in pregnancies following induced abortion: no evidence for an association

Compared with women delivering a first pregnancy, those delivering a second pregnancy after aborting the first have similar rates of low (less than 2,500 g) birth weight newborns (relative risk (RR) G2A1/G1 = 0.86, 95% confidence interval (CI) = 0.49-1.51) and mean birth weight (delta = 16.3 g, p = 0.63). Abortion of the first pregnancy prevents the reduction in low birth weight and increase in mean birth weight in the second pregnancy which delivery of the first pregnancy normally bestows (RR G2P1/G2A1 = 0.48, 95% CI = 0.25-0.90; delta = 135.3 g, p less than 0.0001). Two prior induced abortions do not significantly increase risk for low birth weight (RR G3A2/G1 = 1.14, 95% CI = 0.37-3.56) or decrease mean birth weight (delta = 29.0 g), compared with women delivering their first pregnancy. The second of two deliveries has a reduced risk of low birth weight irrespective of whether both deliveries follow an aborted first pregnancy. Adjustment for confounding factors did not materially change these results. Low birth weight rates were higher after abortions performed in hospital compared with elsewhere (p = 0.03), but mean birth weight was not affected. Gestation at abortion, vacuum aspiration or dilatation and curettage, and abortion complications were unrelated to birth weight of subsequent pregnancies. Pregnancies conceived within six months of a prior abortion or delivery had lower birth weight than if the antecedent pregnancy ended more than six months previously.     

Previous abortion and the risk of low birth weight and preterm births

OBJECTIVE: To investigate the association between previous abortion and low birth weight (LBW) and preterm birth (PB). METHOD: The study examined live, singleton births using data from the United States Collaborative Perinatal Project. Logistic regression was used to control for obstetric and medical history, and lifestyle and demographic factors. RESULT: Compared with women with no history of abortion, women who had one, two and three or more previous abortions were 2.8 (95% CI 2.48 to 3.07), 4.6 (95% CI 3.94 to 5.46) and 9.5 (95% CI 7.72 to 11.67) times more likely to have LBW, respectively. The risk for PB was also 1.7 (95% CI 1.52 to 1.83), 2.0 (95% CI 1.73 to 2.37) and 3.0 (95% CI 2.47 to 3.70) times higher for women with a history of one, two and three or more previous abortions, respectively. CONCLUSION: Previous abortion is a significant risk factor for LBW and PB, and the risk increases with the increasing number of previous abortions. Practitioners should consider previous abortion as a risk factor for LBW and PB.     

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.     

Abortion and its effect on risk of preeclampsia and transient hypertension

We examined the effect of abortion type, number, and gestational age on the risk of preeclampsia and transient hypertension among women who received prenatal care from 13 obstetric practices in southern Connecticut between April 1988 and December 1991 (N = 2,739). Subjects were interviewed before 16 weeks' gestation regarding reproductive history and pregnancy-related risk factors. We estimated the risk of preeclampsia (N = 44) and transient hypertension (N = 172) among nulliparous women who had had one or more abortions, with nulliparous women with no abortion as the referent group. Similar effects were seen for one spontaneous or induced abortion, when analyzed separately. A single prior abortion was associated with a decreased risk of preeclampsia [odds ratio (OR) = 0.35; 95% exact confidence interval (CI) = 0.09-1.01]. One abortion had only a small association with risk of transient hypertension (OR = 1.09, 95% exact CI = 0.68-1.72); however, a history of two or more abortions was associated with a decreased risk (OR = 0.42, 95% exact CI = 0.16-0.94). Among nulliparous women with a history of one abortion, a decreased risk of both hypertensive disorders was observed among women whose aborted pregnancy ended at > or =3 months gestation. These findings suggest that a history of abortion in nulliparous women is a protective factor against the risk of preeclampsia in the subsequent pregnancy.     

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.     

Ectopic pregnancy and prior induced abortion.

We compared the prior pregnancy histories of 85 multigravid women with an ectopic pregnancy and 498 multigravid delivery comparison subjects. We found a relationship between the number of prior induced abortions and the risk of ectopic pregnancy: the crude relative risk of ectopic pregnancy was 1.6 for women with one prior induced abortion and 4.0 for women with two or more prior induced abortions; however, use of multivariate techniques to control confounding factors reduced the relative risks to 1.3 (95 per cent confidence interval, 0.6-2.7) and 2.6 (95 per cent confidence interval, 0.9-7.4), respectively. The analysis suggests that induced abortion may be one of several risk factors for ectopic pregnancy, particularly for women who have had abortions plus pelvic inflammatory disease or multiple abortions.     

Delayed childbearing: no evidence for increased risk of low birth weight and preterm delivery

Prior studies of the effect of increased maternal age on reproductive outcome in primiparous women have often ignored the possible influence on this relation of more frequent histories of spontaneous abortion and infertility in older women. When these histories are taken into account, the present study of 1,382 white primiparous women who had live singleton deliveries at Yale-New Haven Hospital finds no evidence for an increased risk of low birth weight (relative risk (RR) = 1.06, 95% confidence interval (CI) = 0.38-2.94) or preterm delivery (RR = 1.07, 95% CI = 0.50-2.24) in women delivering at age 30 years or more compared with younger women. Mean birth weight (beta = -19 g, p = 0.57) and gestational age (beta = -0.16 weeks, p = 0.34) were also not significantly affected by older maternal primiparity. Women aged 35 years or more had twice the rate of preterm births compared with women under age 30, although this result was not statistically significant in this data set (RR = 2.07, 95% CI = 0.67-6.35). Other confounding variables were taken into account.     

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 in relation to breast cancer among parous women: a birth certificate registry study

We wished to assess the relation of induced abortion to the subsequent incidence of breast cancer among parous women, using a design that would prevent the possibility of differentially complete reporting of abortion history by women with breast cancer and controls. Our study was conducted within a cohort of women who gave birth to a child during 1984-1994 while residing in 13 counties of western Washington. Cases were women from the cohort diagnosed with breast cancer between 1984 and 1994. From the remaining cohort members, five controls were matched to each woman with breast cancer by year of index birth (ie, the last child born before breast cancer diagnosis) and by age at delivery. We categorized 463 cases and 2,201 controls according to history of induced abortion as recorded on the index birth certificate. The risk of breast cancer was not found to be associated with a prior induced abortion (estimated relative risk (RR) = 0.9, 95% confidence interval (CI) 0.7-1.2). These results suggest that an induced abortion, if followed at some later time by pregnancy and childbirth, does not increase a woman's risk of breast cancer.     

Cocaine use during pregnancy: perinatal outcomes

The relation between maternal cocaine use and perinatal outcomes was investigated among 17,466 non-Asian singleton deliveries in 1988 from the University of Illinois Perinatal Network data base in the metropolitan Chicago area. Elevated adjusted relative risks (RR) of low birth weight (RR = 2.8, 95% confidence interval (CI) 2.2-3.7), prematurity (RR = 2.4, 95% CI 1.9-3.1), abruptio placentae (RR = 4.5, 95% CI 2.4-8.5), and perinatal death (RR = 2.1, 95% CI 1.1-4.0) were observed for "any" cocaine users (n = 408) compared with women who did not use cocaine or any other drugs or alcohol (n = 17,058). There was an increased (although unstable) risk of intrapartum placenta previa not previously reported (RR = 2.3, 95% CI 1.0-5.1). The relative risk of small-for-gestational-age births for cocaine users who did not smoke (RR = 3.4, 95% CI 1.8-6.5) was greater than that for cocaine users who did (RR = 2.1, 95% CI 1.1-4.1). Irrespective of smoking status, cocaine use during pregnancy increased the risk of small-for-gestational-age births.     

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.     

Adverse reproductive outcomes among female veterinarians

Because female veterinarians are exposed to several known reproductive hazards, the authors conducted a reproductive survey of all female graduates of a US veterinary school (n = 537) and law school (comparison group, n = 794). Analysis was confined to pregnancies completed after the second year of professional school and from 1966 to 1986. Based on one randomly chosen eligible pregnancy per woman (veterinarians, n = 176; lawyers, n = 229), spontaneous abortion rates, adjusted for elective abortions, were 13.3% for the veterinarians and 15.1% for the lawyers; these did not differ significantly. A Cox life table regression model controlling for age, smoking, alcohol use, and prior spontaneous abortion also showed no significant difference in spontaneous abortion rates between the two populations. Using all pregnancies, veterinarians who reported performing five or more radiographic examinations per week had a marginally elevated risk of spontaneous abortion, but the statistical significance disappeared when analysis was limited to one random pregnancy per woman. For one random eligible birth per woman, the mean birth weight did not differ significantly between the veterinarians and lawyers, even after controlling for possible confounders in regression analyses. A higher rate of reportable birth defects was observed among the veterinarians than among the lawyers (relative risk = 4.2, 95% confidence interval 1.2-15.1), but this unexpected result must be considered hypothesis-generating. The authors did not find an overall increased risk for spontaneous abortion or low birth weight infants among veterinarians compared with lawyers, but veterinarians who reported performing five or more radiographic examinations per week may have been at increased risk for spontaneous abortion.     

人类免疫缺陷病毒感染孕产妇所产婴儿死亡的影响因素分析

目的 了解我国获得性免疫缺陷综合征(AIDS)高流行地区人类免疫缺陷病毒(HIV)感染孕产妇所产婴儿死亡的影响因素.方法 结合2004年建立的HIV感染孕产妇及所产婴儿随访研究队列,于2008年8-11月对我国4省7县区2004年1月至2007年11月HIV感染孕产妇所产婴儿的死亡状况及其影响因素进行调查.实际收集了498对HIV感染孕产妇及所产婴儿的相关信息.采用单因素和多因素Cox比例风险模型对HIV感染孕产妇所产婴儿死亡的影响因素进行分析.结果 498名婴儿,总观察人年数为406.22人年,死亡45例,死亡密度为110.78/1000人年.单因素分析结果显示,母亲孕产期处于AIDS前期或发病期(RR=1.971,95%CI值:1.143～3.396)、孕产妇生存状况(RR=3.062,95%CI值:1.097～8.550)、经产妇(RR=0.517,95%CI值:0.278～0.961)、自然分娩(RR=0.561,95%CI值:0.345～0.910)、早产(RR=5.302,95%CI值:2.944～9.547)、低出生体重(RR=4.920,95%CI值:2.691～8.994)、母子预防性服用抗逆转录病毒药物(RR=0.227,95%CI值:0.121～0.428)及婴儿感染HIV(RR=5.870,95%CI值:3.232～10.660)等因素影响HIV感染孕产妇所产婴儿的死亡.进一步的多因素分析显示,处于AIDS前期或发病期的孕产妇较处于AIDS潜伏期者所产婴儿死亡危险增加(RR=6.99,95%CI值:1.92～25.64);孕产期CD4~+T淋巴细胞计数低于200个/μl的孕产妇,所产婴儿发生死亡的危险增加(RR=2.05,95%CI值:1.01～4.15);母子未预防性服用抗逆转录病毒药物增加婴儿死亡的危险(RR=6.17,95%CI值:1.62～23.26);早产婴儿死亡危险是足月产婴儿的2.87倍(95%CI值:1.12～7.35);HIV感染婴儿死亡危险是非HIV感染婴儿的9.87倍(95%CI值:3.81～25.62).结论 提高HIV感染孕产妇自身免疫力,降低HIV母婴传播率及HIV感染孕产妇所产婴儿早产、低出生体重的发生率有助于降低婴儿死亡率.     

Relations of gestational length and timing and type of incomplete pregnancy to ovarian cancer risk

While the protective nature of parity with respect to ovarian cancer has been well documented, whether a history of incomplete pregnancy affects ovarian cancer risk is uncertain. Data collected from 739 epithelial ovarian cancer cases and 1,313 community controls in the Delaware Valley from 1994 to 1998 were used to evaluate the relation between gestational length and timing of first induced or spontaneous abortion and ovarian cancer risk. Incomplete pregnancy was not associated with ovarian cancer among nulliparous women or among ever-pregnant women either before or after adjustment for relevant confounders (for nulliparous women, odds ratio (OR) = 1.12, 95% confidence interval (CI): 0.66, 1.89; for ever-pregnant women, OR = 0.95, 95% CI: 0.76, 1.18). Among unigravid women, one full-term pregnancy was more protective than an incomplete pregnancy (adjusted OR = 0.29, 95% CI: 0.15, 0.57). These results were independent of the type of pregnancy loss. Among ever-pregnant women, a spontaneous abortion before a first birth provided significant protection (adjusted OR = 0.47, 95% CI: 0.30, 0.75), while no significant effect was found for an induced abortion prior to a first birth (adjusted OR = 0.80, 95% CI: 0.44, 1.47). These data do not support an independent association between incomplete pregnancies, either spontaneous or induced, and ovarian cancer risk.     

Risk factors for neonatal seizures: a population-based study, Harris County, Texas, 1992-1994.

Risk factors for neonatal seizures were evaluated in 116,048 infants born between 1992 and 1994 to residents of Harris County, Texas; 207 of these infants were diagnosed with clinical neonatal seizures. Information was obtained from the infant's birth certificate to assess the relation between seizures and birth weight, gender, ethnicity, place of birth, mother's age, method of delivery, parity, and multiple births. These factors were evaluated by univariate and multivariate analysis using logistic regression. For preterm infants, a birth weight of <1,500 g was the strongest risk factor (relative risk (RR) = 9.1, 95% confidence interval (CI): 4.7, 17.5), followed by birth in a private/university hospital (RR = 2.8, 95% CI: 1.5, 5.0) and male gender (RR = 1.8, 95% CI: 1.0, 3.4). For term infants, significant risk factors included birth by cesarean section (RR = 2.2, 95% CI: 1.5, 3.2), small birth weight for gestational age (RR = 1.9, 95% CI: 1.2, 2.9), birth in a private/university hospital (RR = 1.8, 95% CI: 1.1, 3.0), and maternal age of 18-24 compared with 25-29 years (RR = 1.6, 95% CI: 1.1, 2.3). Birth by assisted vaginal delivery and primiparity were marginally significant for term infants. Birth weight is a significant risk factor for neonatal seizures. The role of perinatal complications warrants further evaluation.     

Induced abortion and the risk of subsequent ectopic pregnancy.

This study assessed the effect of legal induced abortion on ectopic pregnancy risk by using a comparison group of reproductive-age women who were at risk of becoming pregnant during the same time period the women with ectopic pregnancy conceived. Cases were members of Group Health Cooperative of Puget Sound who were hospitalized for ectopic pregnancy from October 1981 through September 1986 (N = 211). Controls were randomly selected members matched to cases on age and county of residence (N = 457). All subjects in this analysis had had one or more prior pregnancies. Eighty-eight cases (41.7 per cent) and 177 controls (38.7 per cent) had a history of one or more induced abortions. The relative risk of ectopic pregnancy associated with one abortion was 0.9 (95 per cent confidence interval 0.6, 1.3), adjusted for age, county, reference date, religion, gravidity, age at first pregnancy, lifetime number of sexual partners, and miscarriage history. Among women with two or more prior pregnancies, the risk associated with two or more abortions was 1.2 (0.6, 2.4). Controlling for pelvic inflammatory disease and use of intrauterine devices did not alter these risks. We conclude that legal abortion as performed in the US since 1970 has little or no influence on a woman's risk of ectopic pregnancy in subsequent pregnancies.     

Tobacco smoke exposure and pregnancy outcome among working women. A prospective study at prenatal care centers in Orebro County, Sweden

Among 4,687 women undergoing prenatal care in Orebro County, Sweden, from October 1980 to June 1983, 678 nonsmokers reported passive exposure to tobacco smoke. Of these women, 267 had been passively exposed at work, and the risk ratio (RR) for intrauterine death (spontaneous abortion or stillbirth) among these pregnancies was increased to 1.53 (95% confidence interval (CI) 0.98-2.38) compared with pregnancies of unexposed working women. This could not be explained by age, previous spontaneous abortion, educational level, planning of pregnancy, or alcohol use. The effect was confined to first-trimester fetal loss (adjusted RR = 2.16, 95% CI 1.23-3.81), while active smoking was associated with intrauterine death after the first trimester. Passive exposure in the workplace was weakly associated with preterm birth (less than 37 weeks) but not with low birth weight (less than 2,500 g) among full-term livebirths. Active smoking clearly increased the risk of both of these outcomes. However, passive exposure in the home only did not seem to affect pregnancy outcome. The lack of quantitative exposure data points to the need for more research before passive exposure to tobacco smoke can be regarded as an established hazard to fetal development and survival.     

Enigma of maternal race and infant birth weight: a population-based study of US-born Black and Caribbean-born Black women

The authors used 1985-1990 Illinois' vital records to determine the low birth weight components of infants delivered to US-born Black women, Caribbean-born Black women, and US-born White women. The moderately low birth weight rate (1,500-2,499 g) was 10% for infants with US-born Black mothers (n = 67,357) and 6% for infants with Caribbean-born mothers (n = 2,265) compared with 4% for infants with US-born White mothers (n = 34,124); the relative risk equaled 2.7 (95% confidence interval (CI): 2.5, 2.8) and 1.7 (95% CI: 1.4, 2.0), respectively. The very low birth weight rate (<1,500 g) was 2.6% for infants delivered to US-born Black women and 2.4% for infants to Caribbean-born women compared with 0.7% for infants to US-born White women; the relative risk equaled 3.6 (95% CI: 3.1, 4.1) and 3.3 (95% CI: 2.5, 4.4), respectively. Among the lowest risk mothers, the relative risk of moderately low birth weight for infants with US-born Black mothers and Caribbean-born mothers (compared with US-born White mothers) was 2.7 (95% CI: 2.1, 3.4) and 1.2 (95% CI: 0.4, 3.1), respectively; the relative risk of very low birth weight for infants with US-born Black mothers and Caribbean-born mothers was 6.7 (95% CI: 3.8, 12) and 4.2 (95% CI: 1.0, 18), respectively. The authors conclude that Caribbean-born women and US-born Black women have disparate moderate rates but equivalent very low birth weight rates.     

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.     

Pregnancy complications and subsequent maternal cerebrovascular events: a retrospective cohort study of 119,668 births

Low birth weight infants are at increased risk of cerebrovascular disease in adulthood. This has been attributed to physiologic programming following inadequate intrauterine nutrition. The authors sought to determine whether mothers who deliver low birth weight infants or who suffer related pregnancy complications are also at increased risk. They used routine data to identify all first singleton livebirths in Scotland (1981-1985) and found that 342 of the 119,668 mothers suffered cerebrovascular events over 14-19 years' follow-up. Compared with women who delivered babies of > or = 3,500 g, women who delivered low birth weight (<2,500 g) infants were at increased risk of cerebrovascular disease (adjusted hazards ratio (HR) = 2.51, 95% confidence interval (CI): 1.71, 3.70) with a consistent trend across birth weight categories. The lowest birth weight quintile (adjusted HR = 1.29, 95% CI: 1.01, 1.65), preterm delivery (adjusted HR = 1.91, 95% CI: 1.35, 2.70), and previous spontaneous abortion (adjusted HR = 1.49, 95% CI: 1.09, 2.03) were all predictive of subsequent maternal cerebrovascular events. The effects were additive. Women who experienced all three complications had a sevenfold risk (adjusted HR = 7.03, 95% CI: 2.24, 22.06). The association with low birth weight in mothers, as well as offspring, is unlikely to be explained by intrauterine programming and suggests that cerebrovascular disease and low birth weight may share common genetic or lifestyle risk factors.