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At least 19 recordsLinked to original sources
PubMed2002

Delayed childbearing and its impact on population rate changes in lower birth weight, multiple birth, and preterm delivery.

OBJECTIVE: This study quantified the impact of delayed childbearing (maternal age greater-than-or-equal to 35 years) on population rate changes in low birth weight (LBW; < 2500 g), preterm delivery (< 37 weeks), multiple births, and small for gestational age (SGA; < 10th percentile) in Alberta, Canada, between 1990 (N = 42 930) and 1996 (N = 37 710). METHODS: Data were obtained from the provincial notification of a live or stillbirth. Analyses included relative risk estimates and chi(2) tests for trend. Potential confounding attributable to in vitro fertilization was investigated. RESULTS: The proportion of births to women greater-than-or-equal to 35 years of age was 8.4% in 1990 and 12.6% in 1996, a 51.2% increase. Among these women, LBW delivery increased 11%, and preterm delivery increased 14%. Delayed childbearing accounted for 78% of the change in LBW rate in the population and 36% of the change in preterm delivery rate in the population. Provincial multiple birth rates increased by 15% for twins and 14% for triplets. Delayed childbearing accounted for 15% of the twin increase and 69% of the triplet increase. When in vitro fertilization pregnancies were excluded, the change was 43% for preterm rates, 100% for LBW, 14% for twins, and 9% for triplets. Delayed childbearing did not contribute to changes in singleton SGA deliveries. CONCLUSIONS: The findings suggest that the recent increase in LBW and preterm delivery is partly related to the population phenomenon of delayed childbearing. Maternal age was not related to changes in SGA, suggesting that the age effect is through pregnancy complications that lead to preterm delivery and LBW. Prospective parents should be informed about the higher risk for neonatal morbidity associated with delayed childbearing. Health care providers should be aware of the impact of delayed childbearing on health care resources.

Adult↗
PubMed1984

What are the determinants of delayed childbearing and permanent childlessness in the United States?

This paper presents estimates of delayed childbearing and permanent childlessness in the United States and the determinants of those phenomena. The estimates are derived by fitting the Coale-McNeil marriage model to survey data on age at first birth and by letting the parameters of the model depend on covariates. Substantively, the results provide evidence that the low first birth fertility rates experienced in the 1970s were due to both delayed childbearing and to increasing levels of permanent childlessness. The results also indicate that (a) delayed childbearing is less prevalent among black women than among nonblack women; (b) education is an important determinant of delayed childbearing whose influence on this phenomenon seems to be increasing across cohorts; (c) education is positively associated with heterogeneity among women in their age at first birth; (d) the dispersion of age at first birth is increasing across cohorts; (e) race has an insignificant effect on childlessness; and (f) education is positively associated with childlessness, with the effect of education increasing and reaching strikingly high levels for the most recent cohorts.

Adolescent↗
PubMed1984

Long-term economic consequences for women of delayed childbearing and reduced family size.

Using data from the Panel Study of Income Dynamics, this study explored the association among delayed childbearing, completed family size and several measures of the economic well-being of women age 60 and older in 1976. By retirement age women who bore their first child at age 30 or older are significantly better off economically than either average-age childbearers or the childless. Economic well-being also appears to be related to family size among late childbearers . At retirement age the delayed childbearer with only one or two children appears better off than all other women. Thus, late childbearing and small family size appear associated with the highest standard of living for these women. This study also relates the experience of this early cohort of women to that of more recent birth cohorts.

Aged↗
PubMed1994

Delayed childbearing and pregnancy outcome.

This study is to analyze the effect of delayed childbearing on pregnancy outcome among nulliparous women. A hospital-based study was conducted with prospectively collected data from the computerized perinatal data base that includes information about all patients delivered in our Hospital. We studied 17,230 nulliparous women who were > or = 20 years of age with a singleton gestation delivered between 1987 and 1992. We assessed the rates of low birth weight (< 2500 g), preterm delivery (< 37 weeks), small for gestational age, perinatal death (> 500 g and 28 days of life), and selected complications of pregnancy and delivery (ante partum complications, meconium, labor abnormal fetal heart rate, cesarean section, breech presentation, Apgar score, umbilical cord-pH, and rates of neonatal admission). Compared with women aged 20-29 years, women aged > or = 35 years had no significantly higher odds ratio (OR) of low birth weight < 2500 g (OR = 1.3); preterm delivery < 37 weeks (OR = 1.2); small for gestational age (OR = 1.0); and perinatal death (OR = 1.7). In contrast, we found a significantly higher rates of specific antepartal complications (OR = 1.9); cesarean section (OR = 2.5); breech presentation (OR = 1.4); and higher rates of admission to the newborn intensive care unit (OR = 1.4); but excluding infants delivered before 37 weeks of gestation, we found no significantly higher odds ratio of neonatal admission (OR = 1.4). Delayed childbearing is associated with an increased risk of complications of pregnancy and delivery although neonatal outcomes were not appreciably different from those among infants of younger women.

Adult↗
PubMed2005

Is delayed childbearing changing gene frequencies in Western populations?

Experimental data and clinical observations suggest that delaying childbearing influences the biology of the mother-fetus relationship, with a negative effect on fetal development and predisposition to severe diseases such as type 1 diabetes. We reason that advanced maternal age may influence intrauterine selection, favoring genotypes that are more adapted to the intrauterine environment of less young women. In the present study we have investigated the relationship of maternal age to HP genotype and PGM1-Rh area (chromosome 1) that have been previously found to be associated with fertility and developmental parameters. HP phenotype was determined in 679 consecutive puerperae from the population of central Italy. PGM1 phenotype and Rh C phenotype were determined in 222 puerperae and 200 newborns. The HP 1,1 phenotype decreases and the HP 2,2 phenotype increases with maternal age. The proportion of phenotypes carrying both the Rh C and PGM1*1 alleles is much higher in puerperae older than 36 years than in puerperae of age 22 years. The frequency of the PGM1*1-Rh C haplotype increases and the frequency of the PGM1*2-Rh C haplotype decreases with maternal age. The changes in these genetic systems with advancing maternal age are similar in mothers and newborns. The delay of childbearing age, associated in Western countries with the fertility transition in addition to detrimental effects on intrauterine development and increased susceptibility to severe disorders, could bring about changes in the genetic composition of a population.

Adult↗
PubMed1990

Delayed childbearing and the outcome of pregnancy.

Whether women who delay childbearing are at increased risk for adverse outcomes of pregnancy is of concern because of the growing proportion of first births to older women. We assessed the effect of advancing maternal age on the outcome of pregnancy in first births in a hospital-based cohort study of 3917 private patients who were 20 years of age or older with a singleton gestation. There was a slight elevation in the risk of having a low-birth-weight infant among women who were 35 years of age or older (adjusted odds ratio, 1.3; 95 percent confidence interval, 0.9 to 1.9) as compared with the risk among women 20 to 29 years of age. However, there was no evidence that women between 30 and 34 or those 35 and older had an increased risk of having a preterm delivery or of having an infant who was small for gestational age, had a low Apgar score, or died in the perinatal period. In contrast, even after controlling for sociodemographic and medical risk factors, we found that women who were 35 or older were significantly more likely to have specific antepartum and intrapartum complications and those who were 30 or older were significantly more likely to have both cesarean sections and infants who were admitted to the newborn intensive care unit. This study suggests that although older primiparous women have higher rates of complications of pregnancy and delivery, their risk of a poor neonatal outcome is not appreciably increased.

Adult↗
PubMedDate not supplied

What do women know about the risks of delayed childbearing?

BACKGROUND: Women aged 35 and older account for an increasing proportion of births and are at increased risk of pregnancy complications and poor infant outcomes. The objectives of the study were: 1) to determine what women know about delayed childbearing, including pregnancy complications and outcomes associated with low birthweight (LBW, < 2500 grams), preterm delivery (< 37 weeks) and multiple birth, and 2) to assess the characteristics of women with limited knowledge of risks. METHODS: A computer-assisted telephone interview survey was conducted with 1,044 randomly selected women who delivered their first live-born infant, between July 2002 and September 2003, in two urban centres, Calgary and Edmonton, in Alberta, Canada. RESULTS: The proportion of women aware of specific childbearing risks associated with advanced maternal age were as follows: conception difficulties (85.3%), multiple birth (24.0%), caesarean section (18.8%), preterm delivery (21.8%), and LBW (11.2%). Knowledge of specific developmental and health-related risks of suboptimal infant outcomes ranged between 18.0% and 46.5%. Logistic regression revealed that limited knowledge of maternal age-related pregnancy risks were associated with unplanned pregnancy (OR, 1.48; 95% CI, 1.03-2.14), smoking (OR, 1.83; 95% CI, 1.29-2.60) and non-use of fertility treatment (OR, 2.15; 95% CI, 1.44-3.19). Characteristics associated with limited knowledge of the risks associated with suboptimal birth outcomes were: age 35-39 years (OR, 2.98; 95% CI, 1.35-6.58), less than post-graduate education (< or = high school OR, 2.14; 95% CI, 1.20-3.82), and not currently enrolled as a student (OR, 1.75; 95% CI, 1.02-3.00). CONCLUSIONS: Many women are generally unaware of the potential consequences of delayed childbearing. There are missed opportunities in preconception counselling and education, which should be addressed to allow for more informed decision-making about family planning.

Adult↗
PubMedDate not supplied

Delayed childbearing in Canada: trends and factors.

"Using period and cohort birth order statistics, an overview of the phenomenon of delayed childbearing in Canada is presented. Data employed in the period analysis were mainly from the years 1944 to 1985, while women born between the years 1935 and 1960 were the subjects of the cohort analysis. An examination of selected indices, namely, age-specific first-birth fertility rates, median ages of women at first-order birth and cumulative first-order birth rates shows that there is an overall trend for women to postpone the initiation of childbearing until late twenties or early thirties.... The results indicate that work experience, education, occupation and year of marriage are important variables influencing age at first birth and first-birth interval." (SUMMARY IN FRE AND ITA)

Age Factors↗
PubMed1990

Projected impact of the trend toward delayed childbearing on breast cancer incidence in the Saarland/FRG.

The potential impact of the trend toward delayed childbearing or nulliparity on future breast cancer incidence is quantitatively assessed for the Saarland/FRG. Distribution of age at first birth is estimated from vital statistics for seven five-year birth cohorts from 1936-40 to 1966-70. Estimates of the relative risks associated with age at first birth or nulliparity are based on median results of 23 controlled epidemiologic studies conducted in Europe and North America. Compared to the birth cohorts around 1940, a steady increase in incidence up to about +15% is projected for the younger cohorts indicating a substantial public health impact. Using data of the population based cancer registry of the Saarland, the cumulative incidence of breast cancer up to age 50 is calculated as 1.52% for the 1936-40 birth cohort and is projected to rise to 1.75% in the 1966-70 cohort. Similar changes in fertility patterns have been observed in other parts of the FRG. Given the continuing rise in mortality from breast cancer in the FRG this stresses the need for more effective screening procedures.

Adolescent↗
PubMed1987

Projected changes in breast cancer incidence due to the trend toward delayed childbearing.

Because there has been a recent trend toward delay of childbearing in the United States, women in the birth cohort of 1945-49 will have an estimated 5 per cent greater incidence of breast cancer, and those in the cohort of 1950-54 an estimated 9 per cent greater incidence compared with the cohort of 1935-39, which had the distribution of age at first birth most favorable for breast cancer risk.

Adult↗
PubMed2005

Reasons for delaying childbearing--a survey of women aged over 35 years seeking assisted reproductive technology.

BACKGROUND: Many women seeking assisted reproductive technology for their first planned pregnancy may be unaware of the impact of age on fertility. METHOD: An anonymous mailed survey to women aged over 35 years with no previous planned pregnancies, registered with Monash IVF between January 2002 and May 2003. RESULTS: One hundred and fifty-two out of 266 surveys were completed (57%). The most common reported reasons for delaying pregnancies were: not having a partner (50%), wanting financial security (32%) and a career (19%) before having a family, only recently becoming interested in having children (26%), and being unaware of the impact of age on fertility (18%). DISCUSSION: Some reported reasons for delaying childbearing were beyond personal control. Lack of awareness of the impact of age on fertility may have contributed to the delay in a proportion of the women surveyed.

Adult↗
PubMed1984

Delayed childbearing in Sweden.

Using data from the Swedish Medical Birth Registry, we examined whether reproductive history influenced pregnancy outcomes among women aged 30 to 39 years who gave birth to a first or second child in 1976 through 1980. They were classified group 1, primigravida; group 2, gravida 2, para O; and group 3, gravida 2, para 1. Compared with women aged 20 through 24 years with the same parity and gravidity, the relative risk (RR) of late fetal deaths was significantly greater among those aged 35 through 39 years (RR: group 1 = 1.76, group 2 = 2.22, and group 3 = 2.39). The risk of giving birth to newborns who were low birth weight and preterm, or low birth weight at term, or 2,500 g or greater but preterm was greater among women aged 30 through 39 years in groups 1 and 2--significantly so for group 1 aged 30 through 39 years v group 1 aged 20 through 24 years. Risk increased with maternal age, from 30 through 34 to 35 through 39 years. The increased risk with age and parity-gravidity has ramifications for the increasing rate of delayed childbearing in the United States and elsewhere.

Adult↗
PubMed1992

Delayed childbearing and risk of adverse perinatal outcome. A population-based study.

OBJECTIVE: To investigate the effect of advancing maternal age on pregnancy outcome among healthy nulliparous women, after adjustment for demographic characteristics, smoking, history of infertility, and other medical conditions. DESIGN: A population-based cohort study was conducted with prospectively collected data from the Swedish Medical Birth Register. PATIENTS: Nulliparous Nordic women (N = 173,715), aged 20 years and above, who delivered single births at Swedish hospitals from 1983 through 1987. OUTCOME MEASURES: Late fetal and early neonatal death rates; rates of very low birth weight (VLBW, less than 1500 g), moderately low birth weight (MLBW, 1500 through 2499 g), very preterm delivery (less than or equal to 32 weeks), moderately preterm delivery (33 through 36 weeks), and small-for-gestational-age (SGA) infants (less than -2 SDs). RESULTS: Compared with women aged 20 to 24 years, women aged 30 to 34 years had significantly higher adjusted odds ratios (ORs) of late fetal deaths (OR = 1.4); VLBW (OR = 1.2); MLBW (OR = 1.4); very preterm birth (OR = 1.2); and SGA infants (OR = 1.4). Among women aged 35 to 39 years, the adjusted OR was significantly higher for VLBW (OR = 1.9); MLBW (OR = 1.7); very preterm birth (OR = 1.7); moderately preterm birth (OR = 1.2); and SGA infants (OR = 1.7). Among women 40 years old and older, the adjusted OR was significantly higher for VLBW (OR = 1.8); MLBW (OR = 2.0); very preterm birth (OR = 1.9); moderately preterm birth (OR = 1.5); and SGA infants (OR = 1.4). CONCLUSIONS: Delayed childbearing is associated with an increased risk of poor pregnancy outcomes after adjustment for maternal complications and other risk factors.

Adult↗
PubMed1993

Do delayed childbearers face increased risks of adverse pregnancy outcomes after the first birth?

OBJECTIVE: To investigate whether the age-related risk of adverse pregnancy outcomes in the first birth persisted in the second birth, before and after adjusting for the influence of an adverse pregnancy outcome in the first birth and for other possible confounders. METHODS: Prospectively collected longitudinal data from the Swedish Medical Birth Registry (n = 210,735 women) were analyzed to contrast the effects of maternal age at the first birth on the risk of adverse pregnancy outcomes in the first and second successive births. RESULTS: Rates of adverse pregnancy outcomes were substantially higher in first than in second births. Compared with women aged 20-24, women aged 30-34 years had significantly higher odds ratios (ORs) of late fetal death (OR 1.4) and early neonatal death (OR 1.4) for the first but not for second births; women aged 35+ had a significantly higher OR of late fetal death (OR 2.2) for the first but not for second births. Women over 35 also had a significantly higher OR of early neonatal death for the first birth (OR 2.8) and less of an increase for second births (OR 1.8), a higher OR of low birth weight (LBW) for the first (OR 1.5) and second births (OR 1.6), and a higher OR of preterm birth for the first (OR 1.4) and second births (OR 1.7). Despite the strong tendency to repeat an adverse pregnancy outcome in second births, the age-related ORs did not change with adjustment for the previous pregnancy outcome. CONCLUSION: Women aged 30+ at their first births have increased risks of adverse pregnancy outcomes in first births. However, second births showed no age-related increase in late fetal death and a smaller increase in early neonatal death. Increased risks for LBW and preterm birth were similar for first and second births of delayed childbearers.

Adult↗
PubMed1997

Delayed childbearing by education level in the United States, 1969-1994.

OBJECTIVES: Advanced maternal age at first birth, but not at subsequent births, may have detrimental health implications for both mother and child, such as a poor birth outcome and an increased risk of maternal breast cancer. However, positive outcomes may also result such as an improvement in economic measures and offspring's performance on cognitive tests. Research has indicated that women increasingly are delaying their first births beyond the early twenties, but the recent trends in socioeconomic disparity in age at first birth, and the implications for public health, have not been well described. METHOD: This study used national birth certificate data for 1969-1994 to examine age at first birth by maternal education level. Current Population Survey data were also used to examine changes over time in age and educational distribution among women of childbearing age. RESULTS: Age at first birth increased during the time period. Median age at first birth increased from 21.3 to 24.4 between 1969 and 1994, and the proportion of first-time mothers who were age 30 or older increased from 4.1% to 21.2%. Age at first birth increased rapidly among women with 12 or more years of education; nearly half (45.5%) of college graduate women who had their first birth in 1994 were age 30 or older, compared with 10.2% in 1969. However, little change was observed among women with fewer than 12 years of education; among those with 9-11 years of education, only 2.5% of first births in 1994 occurred at age 30 or older. CONCLUSIONS: The trend toward postponed childbearing has occurred primarily among women with at least a high school education. Health services use, such as infertility treatment and cesarean section, may increase as a result of delayed childbearing among higher educated women. Future examinations of the association between maternal age at first birth and health outcomes may need to take greater account of socioeconomic differentials.

Adolescent↗