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PubMed1991

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↗
PubMedDate not supplied

Parental network structure and perceived support after birth of first child.

Changes in the content and structure of social relationships following the birth of the first child were studied with a nonprobability sample of primiparous couples. Differences between men and women were examined regarding changes in network structure, need for support, satisfaction with available support, access to support from network members, and stress and conflict in relationships with network members. In total, 108 subjects responded to investigator-developed tools during the third trimester of pregnancy, 92 subjects at 5 months postpartum, and 69 subjects at 8 months postpartum. More women than men perceived an increased need for support postpartum, but no differences in satisfaction with available support existed. For men, network size decreased, but the percentage of network members with preschool children, the percentage of members offering emotional support, and the boundary density with wives' networks all increased. Women reported decreased frequency of contact with coworkers, but increased frequency with friends, and, as did fathers, named more members with preschool children.

Conflict, Psychological↗
PubMed2006

Parity and risk of death from subarachnoid hemorrhage in women: evidence from a cohort in Taiwan.

The authors examined the relationship in women between age at first birth, parity, and subarachnoid hemorrhage mortality. They followed each woman from the time of her first birth and linked vital status with a mortality database. The risk was increased by 8% for each additional year of mother's age at first birth. The relative risk was 0.63 for women who had borne two children and 0.62 for women with three or more births.

Cohort Studies↗
PubMed1988

Perinatal mortality and mother's marital status at birth in subsequent siblings.

The effect of marital status on perinatal mortality is studied for births in Norway, 1967-1981, in terms of relative risk (RR) of unmarried vs. married mothers. The births were linked in units of sibships. At first birth, RR decreased from 1.86 in 1967-1971 to 1.32 in 1977-1981. At second birth the perinatal mortality varied greatly according to marital history with a RR of 2.03 when comparing sibships where mothers were unmarried at both pregnancies with mothers married at both pregnancies. Almost no excess risk was demonstrated for mothers that were married at second birth, but unmarried at first. These mothers appeared to have no excess risk even at the first birth in spite of being unmarried. The results suggest that marital status is still a risk factor to be considered, even in the Scandinavian countries where the marginal effect of marital status in recent years has been reported to be low. To an increasing extent, the high risk women, previously identified by marital status, are now hidden in a larger low risk group which apparently has more stable family relations, e.g. tending to be married at second birth.

Adult↗
PubMed1981

Socioeconomic differentials and trends in the timing of births.

This report contains an analysis of cumulative birth probabilities within first marriages in the United States. Trends and differentials in these probabilities, by race, Hispanic origin, education at first marriage, farm origin, religious preference, and timing of first birth are discussed. The probabilities are shown for specified birth order intervals and age at first marriage or previous birth.

Adolescent↗
PubMed2000

Are births underreported in rural China? Manipulation of statistical records in response to China's population policies.

Under the current family planning policy in China, the criterion for evaluating all parties involved in the birth planning system provides an incentive for everyone to see that the policy is met, either in reality through strict enforcement of family planning regulations, or statistically through manipulation of statistical records. We investigate underreporting of births in four rural counties of northern China, using data from a 1992 sample survey featuring a reproductive history. To clarify the mechanisms of underreporting, we focus on the ways in which reporting errors may affect the distribution of first births by time since marriage. The results of our investigation suggest that in three of the four counties, first-birth intervals are lengthened by underreporting of girl babies and by replacing them with second births reported as first births.

China↗
PubMed1982

The Pima infant feeding study: the role of sociodemographic factors in the trend in breast- and bottle-feeding.

In 1978, a retrospective study of the influence of sociodemographic factors on the trend in breast- and bottle-feeding was conducted among a sample of Pima Indian women 15 to 44 yr old residing on the Gila River Reservation. Based on interviews with 257 Pima Indian women about their infant feeding experiences, the proportion of women who breast-fed dropped significantly between 1949 and 1977. The decline in breast-feeding was evident among women aged 35 to 44 in 1978 across three socioeconomic strata, while women aged 30 to 34 experienced an increase in breast-feeding across two socioeconomic strata. Between 1949 and 1963, women of 50 to 100 and 100% Pima Indian descent breast-fed significantly less than those with other tribal affiliations; however, the influence of tribal descent was reduced thereafter. Bottle-feeding was more prevalent in the high birth orders over time. Among women with first births before 1963, those with small families bottle-fed more than those with large families across birth order. Conversely, among women with first births during or after 1963, those with large families bottle-fed more than those with small families across birth order.

Adolescent↗
PubMed1998

Relative efficiencies of wither height and body weight increase from birth until first calving in Holstein cattle.

Female Holstein calves from the Purina Research Center herd averaged 74 cm of height at withers and 40 kg of body weight (BW) at birth. At first calving (24 mo of age), calves averaged 138 cm of height at withers, 611 kg at precalving BW, and 547 kg at postcalving BW. Fifty percent of the total height increase occurred from birth to 6 mo of age, 25% occurred during 7 to 12 mo of age, and 25% occurred during 13 to 24 mo of age. Twenty-five percent of the total BW increase occurred from birth to 6 mo of age, 25% occurred from 6 to 12 mo of age, and the remaining 50% occurred from 13 to 24 mo of age. The increase in BW for 2-mo intervals, expressed as a proportion of the BW of the previous 2-mo interval, declined most rapidly during the first 6 mo, intermediately during the second 6 mo, and more slowly and progressively during the final 12 mo. Feed cost per unit of BW gain was lowest during the first 6 mo and then increased at a decreasing rate over the final 18 mo. The proportion of BW to height linearly increased over the 24-mo period. The increase in wither height as a proportion of the wither height during the previous period was greatest during the first 6 mo, intermediate during the second 6 mo, and lowest in the final 12 mo. Feed cost per unit of height increase was lowest in the first 6 mo, intermediate during the second 6 mo, and highest with a rapid increase during the final 12 mo. The increases in relative BW and wither height are the most rapid and cost efficient during the first 6 mo of life.

Aging↗
PubMed1987

A prospective study of reproductive factors and breast cancer. I. Parity.

The relation between childbearing and breast cancer risk was investigated in a prospective study of 63,090 Norwegian women, among whom 1,565 breast cancer cases occurred in a follow-up from 1961 through 1980. The authors observed a strong and highly significant inverse association between the number of full-term pregnancies and the risk of breast cancer. The association was consistently found in all subgroups according to demographic variables and was obtained for all histologic subtypes except for cases classified as Paget's disease. The relation with parity could not be explained by confounding with age at first birth or other reproductive factors. The apparent protective effect of high parity was strongest in the groups with an early first birth, and no such effect could be established among women with their first birth at age 35 or later. The protective effect of multiparity was observed for cancers in all age groups. Uniparous women had, however, higher risk of developing breast cancer under age 60 than nulliparous women. Those who reported at least one abortion had somewhat lower risk than those who did not, but no trend according to the number of abortions was observed.

Abortion, Spontaneous↗
PubMed1991

Breast cancer mortality and the change in fertility risk factors at menopause: a prospective study of 800,000 married Norwegian women.

I examined breast cancer mortality in relation to fertility factors in a cohort of 800,814 married Norwegian women aged 25-74 years at the start of follow-up. Women aged 25-44 years with a first birth after the age of 35 years had a RR = 2.58 compared with women with a first birth before the age of 20 years. For women aged 45-74 years, the corresponding RR was 1.35. On the other hand, the rate differences between women with a late first birth (35+ years) and an early birth (less than 20 years) were similar for women of different ages. Small rate differences were found for premenopausal women between uniparous women and women with 6-7 children, but postmenopausal women with many children had lower rates of breast cancer mortality than uniparous women. For postmenopausal women the rate differences were stable over age categories. This study points toward a change in fertility risk factors at menopause.

Adult↗
PubMed2000

Pre-natal and peri-natal exposures and risk of testicular germ-cell cancer.

The present case-control study was undertaken to investigate the association between exposure to maternal hormones and risk of testicular germ-cell cancer by histologic subgroups. Cases were males, aged 16 to 59 years, diagnosed with testicular germ-cell cancer in Ontario between 1987 and 1989. Histologic review was performed on all eligible cases for the purpose of categorizing cases as seminoma or non-seminoma (the latter classified 2 ways, with and without tumors containing seminoma). Risk factor data were collected on 502 cases, 346 case mothers, 975 age-matched controls, and 522 control mothers. Exogenous hormone exposure was associated with elevated risk (OR = 4.9, 95% CI 1.7-13.9). Several additional risk factors were associated with risk of testicular cancer: bleeding and threatened miscarriage (OR = 0.6, 95% CI 0.3-1.0), maternal cigarette smoking (12+ cigarettes/day OR = 0.6, 95% CI 0. 4-1.0). pre-term birth (OR = 1.6, 95% CI 1.0-2.5), and treatment for undescended testicle (OR = 8.0, 95% CI 3.2-20.0). First births were associated with elevated risk (OR = 1.7, 95% CI 1.0-2.8) among mothers below the age of 24 years at conception. There was little evidence that risk factors differed by histologic subgroup. We found evidence that exposure to maternal hormones, particularly estrogens, is associated with testicular germ-cell cancer risk. Not only does exposure to elevated levels (exogenous hormone use, pre-term birth, and first births among young mothers) increase risk but also exposure to relatively lower levels (heavy cigarette consumption and, perhaps, bleeding and threatened miscarriage) may decrease cancer risk.

Abortion, Threatened↗
PubMed1996

The role of reproductive and menstrual factors in cancer of the breast before and after menopause.

The aim of the study was to elucidate the role of reproductive and menstrual factors in the aetiology of breast cancer, overall and by menopausal status. A cooperative case-control study was conducted between 1991 and 1994 in six different Italian areas (including three from the centre and the south). The study included 2569 histologically confirmed incident cases of breast cancer (median age 55 years, range 23-78 years) and 2588 control women (median age 56 years, range 20-79 years) admitted to the same hospitals for a variety of acute conditions unrelated to the hypotheses in study. A trend of increasing risk with increasing age at menopause (odds ratio (OR) for age at menopause > or = 53 versus < 45 years = 1.8; 95% confidence interval (CI) = 1.4-2.2). High parity reduced cancer risk (OR for > or = 4 versus 1 birth = 0.7; 95% CI = 0.5-0.9). Overall, nulliparous women showed a 20% lower risk than uniparous ones (OR = 0.8; 95% CI = 0.7-1.0). Late age at first birth (or pregnancy) had an independent adverse effect (OR for first birth at > or = 32 versus < 20 years = 1.7; 95% CI = 1.3-2.1) both before and after menopause. An approximately 2-fold elevation of breast cancer risk was evident up to 10 years after the last birth. No trend in risk was evident for induced abortions (OR = 1.2 for 1 and 1.1 for > or = 2 induced abortions versus 0). Other examined menstrual and reproductive characteristics did not seem important. Multiparity, early age at first birth and early age at menopause were therefore the most important determinants of breast cancer risk. The effects of the timing of births was significantly heterogeneous in pre- and postmenopausal women because of the transient adverse effect of such events, evident only in premenopausal women.

Adult↗
PubMed2005

Risk of low birth weight associated with advanced maternal age among four ethnic groups in the United States.

OBJECTIVES: To examine and compare the risk of low birth weight associated with delayed childbearing in four ethnic groups using nationally representative data in the United States. METHODS: We compared the risk of low (< 2.5 kg) birth weight among African Americans, Mexican Americans, Puerto Ricans, and non-Hispanic whites using birth data for the United States obtained from the National Center for Health Statistics. Comparisons were done separately for first births and births of second or higher order and in terms of odds ratios, risk differences and attributable fractions of very low (< 1.5 kg), middle low (1.5-2.5) and overall low birth weight. Statistical analysis included use of logistic regression models with likelihood ratio tests for interaction effects. RESULTS: African Americans and Puerto Ricans, and to a lesser extent Mexican Americans, had higher risk differences associated with advanced maternal age. For first births, the risk differences associated with advanced maternal age (> or = 35 years) in low birth weight were 5.3% (95% CI, 4.7-6.0), 4.3% (95% CI, 1.7-6.9), and 3.7% (95% CI, 2.8-4.5) for African Americans, Puerto Ricans, and Mexican Americans, respectively, as compared with 2.6% (95% CI, 2.4-2.7) for non-Hispanic whites. On the other hand, the odds ratios associated with advanced maternal age were more similar across the four ethnic groups. Differences were greater for all ethnic groups in the case of first births as compared with births of second or higher order. CONCLUSIONS: Advanced maternal age appears to be associated with for the most part similarly increased odds of low birth weight for African Americans, Mexican Americans, Puerto Ricans, and non-Hispanic whites. However, the age-related increments in the risk of low birth associated with advanced maternal age are greater for African Americans, Puerto Ricans and, to a lesser extent, Mexican Americans, as compared with non-Hispanic whites.

Adult↗
PubMed1991

Colorectal cancer in northeast Italy: reproductive, menstrual and female hormone-related factors.

The role of reproductive and menstrual factors and a few medical conditions linked to female hormones in the aetiology of colorectal cancer was investigated in a case-control study conducted in Pordenone province in northeastern Italy, on 89 women with colorectal cancer and 148 controls admitted to hospital for a wide spectrum of acute, non-digestive nor neoplastic disorders. After adjustment for age and social class, parous women, as compared to nulliparous ones, were significantly protected against colorectal cancer (odds ratio, OR = 0.4, [95% confidence interval, CI:0.2-0.8]) and the risk appeared to decrease with successive pregnancies up to five or more (0.2, [0.04-0.6]). Compared to women who had their first birth at age 24 or less, the OR for those who had it at 30 or older was 2.0, but the inverse trend in risk was not significant. However, among parous women only, age at first birth, but not parity, seemed to retain a certain influence. Late age at menopause seemed to decrease colorectal cancer risk (OR for menopause at age greater than or equal to 50 vs. less than 45 = 0.4, [0.2-1.0] chi 2(1) (trend) = 3.66). Conversely, age at last birth, number of abortions, years between marriage and first birth, age at menarche, pattern of menstrual cycle and occurrence of a few medical conditions potentially linked to female hormones were similarly reported by cases and controls. Due to the very limited number of oral contraceptive (OC) users (9 controls but only 1 case), and the lack of oestrogen replacement therapy users, the influence of exogenous female hormones on colorectal cancer could not be analysed meaningfully.

Age Factors↗
PubMed1996

The effect of malaria and malaria prevention in pregnancy on offspring birthweight, prematurity, and intrauterine growth retardation in rural Malawi.

While there is broad evidence for the adverse effects of Plasmodium falciparum infection in pregnancy, and the World Health Organization recommends preventive strategies, there is markedly reduced efficacy in sub-Saharan Africa of the most widely available, affordable and used antimalarial drug for chemoprophylaxis-chloroquine (CQ). During 1987-1990, we studied pregnant women in an area of high malaria endemicity in rural Malawi to compare the efficacy of CQ (the drug recommended by national policy) with mefloquine (MQ, a relatively new and highly effective antimalarial) in preventing low birth weight (LBW) due to prematurity and intrauterine growth retardation (IUGR). Among 1,766 women monitored during at least their last six weeks of pregnancy with observed ingestion of their regimen and facility delivery of a live born singleton, their babies had a mean +/- SD birth weight of 2,905 +/- 461 gm and 16.8% had LBW. In a multivariate analysis, factors significantly associated with LBW included: first birth (odds ratio [OR] = 4.27), female infant (OR = 2.92), maternal human immunodeficiency virus infection (OR = 2.66), low maternal weight (OR = 1.95), and placental blood P. falciparum infection (OR = 1.71). Factors significantly associated with IUGR-LBW included first birth, female infant, low maternal weight, and placental malaria. Factors significantly associated with preterm-LBW included maternal syphilis infection, umbilical cord blood malaria, first birth, low maternal weight, and female infant. Use of an effective antimalarial (MQ) was protective against LBW through its effect on reducing placental and umbilical cord blood malaria infection. The proportion of LBW babies born to women on MQ (12.5% [parity-adjusted for the population of delivering women]) was significantly lower than the proportion born to women on CQ (15.5%; P = 0.05). Effective prevention of malaria in pregnant women in malaria-endemic settings may reduce the likelihood of LBW by 5-14%, and may reduce the amount of preventable LBW by more than 30%. When evaluating antenatal care programs, health policy makers must consider providing an effective preventive drug (either MQ or other drugs identified in additional studies, e.g., sulfa-pyrimethamine compounds) as a means to prevent low birth weight and its consequences.

Adolescent↗
PubMed1996

Update in preimplantation genetic diagnosis: successes, advances, and problems.

The field of preimplantation genetic diagnosis has undergone significant advances since the report of the first birth from this method in 1990. The first birth in the USA was reported in 1992, as was the first successful diagnosis and delivery of a baby free of a single gene defect disorder (cystic fibrosis and then Tay Sachs). Investigators have now reported approximately 40 births worldwide from preimplantation genetic diagnosis using the polymerase chain reaction and fluorescent in-situ hybridization methods to analyze single cells removed from early cleavage stage preimplantation embryos. The International Working Group on Preimplantation Genetics meets annually to discuss progress and pitfalls in this field. Although preimplantation genetic diagnosis offers hope to patients at risk of transmitting disease, there are many technical hazards of this experimental procedure. Technical difficulties must be overcome in order for preimplantation genetic diagnosis to become a standard clinical tool. This review will highlight some of the recent advances and problems in the field of preimplantation genetic diagnosis.

Age Factors↗
PubMed2003

Life-history parameters of a wild group of West African patas monkeys (Erythrocebus patas patas).

Based on long-term, although intermittent, observations (2 years 4 months of 14 years), we present data on birth seasonality, age at first birth, interbirth intervals, mortality rates, age at first emigration, and population change of a wild population of West African patas monkeys ( Etythrocebus patas patas) in northern Cameroon. Birth season was from the end of December until the middle of February, corresponding to the mid-dry season. In spite of large body size, the patas females had the earliest age at first birth (36.5 monthsold) and the shortest interbirth intervals (12 months) compared to the closely related wild forest guenons. Age at first emigration of the males was considered to occur between 2.5 and 4.5 years. The group size of the focal group drastically decreased between 1984 and 1987, and steadily increased until 1994, then decreased again in 1997. The neighboring group also showed a similar trend in group size. The population decreases were likely to be caused by drought over 3 years. Annual crude adult mortality rate was 4% during population increase periods (PIP) between 1987 and 1994. It rose to 22% during all the periods (AP), including drought over 3 years. Despite their smaller body size, the rate of the wild forest guenons ( Cercopithecus mitis) (4%) was the same and much lower than those of the patas during PIP and AP, respectively. The annual average juvenile mortality rate was 13% during PIP and it also rose to 37% during AP. That of wild forest guenons ( C. ascanius) (10-12%) was a little lower and much lower than those of the patas during PIP and AP, respectively. These findings were consistent with Charnov's theoretical model of mammalian life-history evolution in that patas with high adult and juvenile mortality showed early and frequent reproduction in spite of large body size. Charnov also considered high adult mortality as a selective force and high juvenile mortality as a density-dependent consequence of high fecundity. Our results support the former but not the latter research findings.

Age Factors↗
PubMedDate not supplied

Variations in fertility by marital status and marriage order.

Analysis of data from the June 1985 Current Population Survey reveals that although marriage continues to be an important setting for childbearing, the strength of this relationship varies considerably by the mother's race, education and age at first birth. The largest proportion of white births occurs during first marriages, with the next largest group made up of premarital births; that pattern is reversed for black births. The proportion of births occurring during second marriages is twice as high among whites as among blacks; however, intermarital childbearing is more common among blacks than among whites. For both races, the number and proportion of all births that occurred in second marriages increased between 1973-1974 and 1983-1984; in the latter period, women who were in their second marriage had about 300,000 births a year. About half of all nonmarital births in 1983-1984--370,000 births a year--were of birth order two or higher.

Adolescent↗