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Risk factors for adenocarcinoma of the cervix: a case-control study.

To assess risk factors for cervical adenocarcinoma data were collected in a case-control study of 39 cases and 409 controls conducted in the greater Milan area. Questions were asked about personal characteristics and habits, gynaecologic and obstetric data, history of lifetime use of oral contraceptives and other female hormones, and general indicators of sexual habits (age at first intercourse and total number of sexual partners). The relative risk of cervical adenocarcinoma increased with number of births and abortions, early age at first birth and early age at first intercourse. These estimates did not materially change after adjustment for the potential reciprocal confounding effect. Further, there was a positive association with overweight, but an apparent association with lower education was not significant. No relationship emerged with oral contraceptive use. Thus, despite the similarities with the epidemiology of squamous cell cancer, reproductive patterns and other factors related to the risk of endometrial cancer (i.e., overweight) seem to play an important role in the risk of adenocarcinoma of cervix uteri.

Abortion, Spontaneous

Risk of late first and second trimester miscarriage after induced abortion.

A cohort of 3110 women anticipating delivery were interviewed after their first prenatal visit at private obstetric practices and HMOs in Connecticut. In all 19.57% reported a prior induced abortion. The research participants were followed to determine whether the pregnancy was miscarried or delivered. In all, 2.19% miscarried in the late first or second trimester. The association of a prior induced abortion on risk for late miscarriage was analyzed by pregnancy history. Women who aborted their first pregnancy had no increased risk (RR = 0.56, 95% CI = 0.16, 1.92) of miscarriage compared with women pregnant for the first time, or compared with women experiencing their second pregnancy after delivering the first (RR = 0.69, 95% CI = 0.18, 2.60). No evidence was found for an increased risk of multiple induced abortion on subsequent miscarriage.

Abortion, Induced

Preference for male children and contraceptive use in Taiwan.

Taiwan has an active family-planning program. Yet the preference for sons is deeply ingrained in the Chinese culture and may discourage women from limiting their family size if they feel they have too few sons. In this study, research problems concerned the relationships between women's stated preferences for the sex of their children, their perceptions of their in-laws' preferences for the number and sex of their children, and their use of birth control and choice of birth control methods. It was found that few women verbalized a preference for the sex of children, but the number of boys already in the family was related to the reliability of contraceptive method used later and to the willingness to consider abortion if pregnancy occurred. The desired number and occurrence of additional children related to women's perceptions of their in-laws' preferences for boys. The perception of in-laws' preferences for girls either related negatively or was not significant.

Adult

Determinants of fertility in Guatemala.

The 1978 Contraceptive Prevalence Survey for Guatemala provides an opportunity to examine fertility levels and a number of determinants of fertility for three broad segments of the country: the Department of Guatemala and, in the remainder of the country, the Ladino and Indian populations. While Ladinos had a much higher rate of contraceptive use than did Indians, the two groups had similar birth rates. The lack of difference in fertility appears to be due to the pattern of prolonged breastfeeding among Indians and perhaps to differences in the rate of conception due to nutrition, coital frequency, or other factors.

Adult

Determinants of fertility decline in China, 1981: analysis of intermediate variables.

This study examines the proximate determinants of fertility in China by making use of the data collected by the One-per-Thousand Sample Fertility Survey of 1982. The results indicate that the most important inhibitor of potential fertility is deliberate control. Its contribution to fertility change has been far greater than all other proximate determinants. The marital structure of the population is also an important factor, while lactational infecundability and induced abortion are relatively unimportant. Comparative results by using data from the In-depth Fertility Survey conducted in Shanghai Municipality, Hebei and Shaanxi Provinces in April 1985 agree well in the ranking of the four intermediate factors. The findings point to successful family planning program and government population policies, which propelled the fertility transition to a substantial degree. Further research needs and policy implications of the results of the study are discussed.

Adolescent

Multiple pregnancies among adolescents: incidence and correlates.

The study of adolescent fertility traditionally has focused on understanding and predicting the occurrence of an initial adolescent pregnancy. The complex problem of multiple pregnancies among teenagers is explored. Current knowledge regarding the incidence and correlates of repeated pregnancy is summarized and reviewed. Intervention strategies and directions for further research are suggested.

Adolescent

Early abortion and breast cancer risk among women under age 40.

In New York State, incidence of cancer and fetal death are reportable health events mandated by state law. These data enabled a population-based record linkage study of the effect of early pregnancy termination on breast cancer risk to be conducted. In upstate New York 1451 cases under age 40 were reported to the Cancer Registry during 1976-1980. Cases were matched with 1451 population controls by year of birth and by residence using zip codes. All names including those changed by marriage were matched with the reports of fetal deaths occurring between 1971 and 1980. Matched pairs analyses revealed an excess of early pregnancy terminations among cases in all categories. Odds ratios (OR) were significantly elevated among those with an induced abortion (OR = 1.9) and a spontaneous abortion (OR = 1.5). Elevated risks were also noted for consecutive abortion events without intervening livebirths.

Abortion, Incomplete

Changes in fertility and the acceptability of pregnancies in northern Finland during the last 20 years.

The acceptability of pregnancies was studied in two birth cohorts in Northern Finland which represent 96% of all births in the region in 1966 (12,068 births) and 99% (9362 births) in 1985-1986. The numbers of women of fertile age in the area during these years were 148,000 and 158,000, so that fertility may be said to have fallen from 81 to 59 per 1000. The pregnancy was wanted in 63.0% of cases and unwanted in 12.2% in 1966, the rest being classified as accepted later. The corresponding figures in 1985-1986 were 91.8% and 1.0%. The latter figures changed very little when maternal age, parity and social class were standardized to the 1966 levels. Acceptability was connected with age, in that the age groups in which childbearing was most frequent, 20-25 years in 1966 and 26-30 years in 1985-1986, had the highest incidence of desired pregnancies. In spite of the fact that there were 1.4 times as many births per woman aged 15-49 years in the former cohort, more wanted children were born to the age group 25-34 years in the latter cohort. The percentage of wanted pregnancies also varied with the woman's parity, social class and marital status. The children in the 1966 cohort were followed until the age of 14 and the incidences of cerebral palsy (CP) and mental retardation (IQ less than 71) were 3.2 times higher among the unwanted children than among the wanted ones.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Legal

Risk factors for epithelial ovarian tumours of borderline malignancy.

A case-control study was conducted on 91 cases with histologically-confirmed borderline ovarian tumours and 237 control subjects in hospital for acute non-gynaecological, hormonal or neoplastic disease. Women reporting three or more births, compared to nulliparae, had a relative risk (RR) estimate of 0.6, but this finding was not statistically significant (95% confidence interval (CI): 0.2-1.4). The risk of borderline tumours increased, although not significantly, with later age at first birth: compared to women reporting first birth at age 24 or before, the RRs were 1.3 and 1.7 in those reporting respectively their first birth at age 25-29 and 30 years or more. No significant relationship emerged between borderline ovarian cancer and age at menarche, menopausal status and lifelong menstrual pattern. Cases tended to report a later age at menopause than controls, but the trend in risk was not statistically significant. Nine cases (9.9%) and 68 controls (24.9%) reported oral contraceptive use: compared with never users the multivariate RR for ever users was 0.3, and the risk dropped with duration of use to 0.2 in users for two years or more (chi 2 (1) trend = 12.70, p less than 0.001). This study provides epidemiological evidence of a pathogenetic continuum between borderline and invasive ovarian tumours.

Adult

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.

Abortion, Induced

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.

Abortion, Induced

Risk factors for spontaneous abortion and its recurrence.

Pregnancy histories of women interviewed as normal population controls during 1974-1981 in four case-control studies in the US and Canada were examined to identify risk factors for the occurrence of miscarriage. In total, 2,068 ever-gravid women aged 20-79 years at interview (mean age, 50.3 years) described 6,282 pregnancies, including 805 miscarriages. The roles of previous pregnancy history, age at pregnancy, and other factors were evaluated using relative risk binomial regression methods (similar to logistic regression). Risk of miscarriage during a given pregnancy was found to increase directly with the number of previous miscarriages (the risk was closely approximated by (1 + number of prior miscarriages)1.01), but appeared to be unrelated to the order of miscarriages within all previous pregnancies. Maternal age was also highly related to risk after controlling for gravidity and previous miscarriages, with doubled risk (compared with age 20 years) seen for pregnancies in women older than age 40 years. Risk of miscarriage did not appear to be associated with years since previous pregnancy, height, weight or obesity, use of oral contraceptives within one year before pregnancy, or duration of oral contraceptive use. A slight increase in risk was seen for women who had ever regularly smoked cigarettes (relative risk = 1.14, 95 per cent confidence limits = 1.00, 1.30). Thus, the levels of risk of miscarriage found in this analysis are similar to those of previous studies, and the analytic methods suggest how age, obstetric history, and other factors can be simultaneously examined for associations with such risk.

Abortion, Spontaneous