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PubMed1988

[Fertility life tables].

"Three tables for measuring human fertility are presented. The first, the Parity-Fertility-Life-Table, includes the intensity of fertility only. The second table, the Marriage-Duration-Fertility-Life-Table, bases on the Parity-Fertility-Life-Table and measures the tempo of fertility altogether. The third table, the Birth-Interval-Fertility-Life-Table, completes the Marriage-Duration-Fertility-Life-Table in considering the point of time, at which the last parity is reached." The methods are illustrated using official data for the Federal Republic of Germany. (SUMMARY IN ENG)

Birth Intervals↗

PubMed1981

How long should a breast feed last?

Patterns of milk flow were studied in 50 mothers who were breast-feeding normal birth-weight babies on days 5-7 of the puerperium by progressive test weighing at 5-min intervals during two consecutive feeds. Compared with a regime in which mothers attempted to feed for 10 X 10 min on alternate breasts, a regime of 5 X 5 X 5 X 5 min increased the amount of milk taken in the first 10 min did not influence the final milk intake of the suckling-induced prolactin release. The wide variation of breast-feeding patterns between mothers was demonstrated in respect of the duration of the feed (mean 17.3 min; S.D. +/- 3.1; range 7-30 min), the initial rate of milk flow (mean 6 g/min; S.D. +/- 4.2, range 1-14 g/min) and the final milk intake (mean 70.9 g; S.D. +/- 20.5, range 42-125 g). The advice to breast-feed for 20 min was in appropriate for the majority of mothers because the nutritive feeding time was 15 min or less in 75% of the feeding episodes. The milk intake correlated with the initial rate of milk flow but not with the duration of the feed, the infant's birth weight, or the time since the last feed. It is suggested that the duration of a breast feed should be determined by the infant's response and not by an arbitrary time schedule.

Body Weight↗

PubMed1997

Environmental tobacco smoke and breastfeeding duration.

The effect of smoking on breastfeeding duration was investigated in a population-based birth cohort study of 1,098 Brazilian infants. There were few losses to follow-up (3.2%) in the first 6 months. Maternal smoking was strongly associated with breastfeeding duration, even after adjustment for confounding. Compared with nonsmokers, mothers smoking 20 or more cigarettes daily presented an odds ratio of 1.94 for breastfeeding for less than 6 months. Environmental tobacco smoke was also an independent risk factor. After adjustment for maternal smoking and other confounders, households where more than 10 cigarettes were smoked daily by persons other than the mother presented an odds ratio of 1.48 compared with those without smokers. These results remained unchanged after stratification for maternal smoking. This is the first report of a possible effect of environmental tobacco smoke on breastfeeding duration.

Adult↗

PubMed1996

[Birth intervals and birth of low weight infants in Benin].

Low birthweight is a public health problem in Benin but its etiology remains unclear. Studies in industrial countries suggest several risk factors including the interval between pregnancies or child spacing. The purpose of this cohort study was to assess the relationship between pregnancy interval and low birthweight in Benin. Data were collected from a total of 2,862 multiparous pregnant women randomly recruited in 1991 at the time of their first prenatal care visit to maternity units in Cotonou, Benin. Sociodemographic information and obstetrical history were obtained by interviewing the mother and reviewing delivery records. About 15% of the women recruited delivered low birthweight children. The relative risks of preterm birthweight and intrauterine growth retardation was calculated in function of three pregnancy intervals: less than 12 months, 12 to 23 months, and 24 to 34 months. It was 1.31 (1.00-1.75), 1.00 (0.70-1.02)) and 0.77 (0.60-0.87) respectively for preterm birthweight and 1.27 (1.03-1.64), 1.17 (0.79-1.39) and 0.79 5 (0.57-0.87) respectively for intrauterine growth retardation. Logistic regression analysis taking into account sociodemographic factors and previous obstetrical history did not show a significant correlation between pregnancy interval and preterm low birthweight or between pregnancy interval and intrauterine growth retardation. Maternal nutritional status, maternal age, number of previous births, and education level were correlated with low birthweight.

Adult↗

PubMed2004

Childhood overweight and parent- and teacher-reported behavior problems: evidence from a prospective study of kindergartners.

OBJECTIVES: To determine if there is a relationship between overweight and behavior problems among children as young as 5 years old by studying the association between overweight and behavioral health at entry into kindergarten and to determine whether overweight status is a risk factor for the onset of new behavior problems during the first 2 years in school. DESIGN: We use data from a nationally representative sample of kindergartners in the United States-the Early Childhood Longitudinal Study-Kindergarten class. Data on height, weight, and parent- and teacher-reported behavior problems were collected 3 times during their first 2 years in school for 9949 children. We use a multivariate regression analysis that controls for sociodemographic characteristics, parent-child interaction, birth weight, and mother's mental health. RESULTS: Among girls, but not boys, there is a significant association between overweight and teacher-reported externalizing behavior problems (odds ratio [OR], 1.81; 95% confidence interval [CI], 1.23-2.68), teacher-reported internalizing behavior problems (OR, 1.54; 95% CI, 1.09-2.17), and parent-reported internalizing behavior problems (OR, 1.49; 95% CI, 1.08-2.06) at the beginning of kindergarten. However, overweight status was not a risk factor for the onset of new behavior problems over time for either girls (teacher-reported externalizing behavior problems: OR, 0.58 [95% CI, 0.25-1.33]; teacher-reported internalizing behavior problems: OR, 1.34 [95% CI, 0.88-2.03]; and parent-reported internalizing behavior problems: OR, 1.29 [95% CI, 0.82-2.01]) or boys (teacher-reported externalizing behavior problems: OR, 1.02 [95% CI, 0.67-1.57]; teacher-reported internalizing behavior problems: OR, 1.02 [95% CI, 0.68-1.52]; and parent-reported internalizing behavior problems: OR, 1.42 [95% CI, 0.94-2.15]), whereas low family income and maternal depression were strong predictors of such problems. CONCLUSIONS: Childhood overweight is already associated with behavior problems when girls start school, but not boys. In contrast to common belief, overweight status does not predict the onset of new internalizing or externalizing behavior problems during the first 2 years of school.

Child↗

PubMed1996

Birth outcomes in pregnant women taking fluoxetine.

BACKGROUND: Although fluoxetine is the most frequently prescribed antidepressant drug in the United States, its safety in pregnant women has not been established. METHODS: From 1989 through 1995, we prospectively identified 228 pregnant women taking fluoxetine. We compared the outcomes of their pregnancies with those of 254 women identified in a similar manner who were not taking fluoxetine. RESULTS: The rate of spontaneous pregnancy loss did not differ significantly between the women treated with fluoxetine and the control women (10.5 percent and 9.1 percent, respectively), nor was the rate of major structural anomalies significantly different (5.5 percent vs. 4.0 percent). Among the 97 infants exposed to fluoxetine who were evaluated for minor anomalies, the incidence of three or more minor anomalies was significantly higher than among 153 similarly examined control infants (15.5 percent vs. 6.5 percent, P=0.03). As compared with the 101 infants exposed to fluoxetine only during the first and second trimesters, the 73 infants exposed during the third trimester had higher rates of premature delivery (relative risk, 4.8; 95 percent confidence interval, 1.1 to 20.8), admission to special-care nurseries (relative risk, 2.6; 95 percent confidence interval, 1.1 to 6.9), and poor neonatal adaptation, including respiratory difficulty, cyanosis on feeding, and jitteriness (relative risk, 8.7; 95 percent confidence interval, 2.9 to 26.6). Birth weight was also lower and birth length shorter in infants exposed fluoxetine late in gestation. CONCLUSION: Women who take fluoxetine during pregnancy do not have an increased risk of spontaneous pregnancy loss or major fetal anomalies, but women who take fluoxetine in the third trimester are at increased risk for perinatal complications.

Abnormalities, Drug-Induced↗

PubMed2004

Perinatal predictors of atopic dermatitis occurring in the first six months of life.

OBJECTIVE: Previous studies of predictors of atopic dermatitis have had limited sample size, small numbers of variables, or retrospective data collection. The purpose of this prospective study was to investigate several perinatal predictors of atopic dermatitis occurring in the first 6 months of life. DESIGN: We report findings from 1005 mothers and their infants participating in Project Viva, a US cohort study of pregnant women and their offspring. The main outcome measure was maternal report of a provider's diagnosis of eczema or atopic dermatitis in the first 6 months of life. We used multiple logistic regression models to assess the associations between several simultaneous predictors and incidence of atopic dermatitis. RESULTS: Cumulative incidence of atopic dermatitis in the first 6 months of life was 17.1%. Compared with infants born to white mothers, the adjusted odds ratio (OR) for risk of atopic dermatitis among infants born to black mothers was 2.41 (95% confidence interval [CI]: 1.47, 3.94) and was 2.58 among infants born to Asian mothers (95% CI: 1.27, 5.24). Male infants had an OR of 1.76 (95% CI: 1.24, 2.51). Increased gestational age at birth was a predictor (OR: 1.14; 95% CI: 1.02, 1.27, for each 1-week increment), but birth weight for gestational age was not. Infants born to mothers with a history of eczema had an OR of 2.67 (95% CI: 1.74, 4.10); paternal history of eczema also was predictive, although maternal atopic history was more predictive than paternal history. Several other perinatal, social, feeding, and environmental variables were not related to risk of atopic dermatitis. CONCLUSIONS: Black and Asian race/ethnicity, male gender, higher gestational age at birth, and family history of atopy, particularly maternal history of eczema, were associated with increased risk of atopic dermatitis in the first 6 months of life. These findings suggest that genetic and pre- and perinatal influences are important in the early presentation of this condition.

Cohort Studies↗

PubMed2000

Increasing rates of cerebral palsy across the severity spectrum in north-east England 1964-1993. The North of England Collaborative Cerebral Palsy Survey.

OBJECTIVES: To report epidemiological trends in cerebral palsy including analyses by severity. DESIGN: Descriptive longitudinal study in north-east England. Every child with suspected cerebral palsy was examined by a developmental paediatrician to confirm the diagnosis. Severity of impact of disability was derived from a parent completed questionnaire already developed and validated for this purpose. SUBJECTS: All children with cerebral palsy, not associated with any known postneonatal insult, born 1964-1993 to mothers resident at the time of birth in the study area. MAIN OUTCOME MEASURES: Cerebral palsy rates by year, birth weight, and severity. Severity of 30% and above defines the more reliably ascertained cases; children who died before assessment at around 6 years of age are included in the most severe group (70% and above). RESULTS: 584 cases of cerebral palsy were ascertained, yielding a rate that rose from 1.68 per 1000 neonatal survivors during 1964-1968 to 2.45 during 1989-1993 (rise = 0.77; 95% confidence interval 0.2-1.3). For the more reliably ascertained cases there was a twofold increase in rate from 0.98 to 1.96 (rise = 0.98; 95% confidence interval 0.5-1.4). By birth weight, increases in rates were from 29.8 to 74.2 per 1000 neonatal survivors < 1500 g and from 3.9 to 11.5 for those 1500-2499 g. Newborns < 2500 g now contribute one half of all cases of cerebral palsy and just over half of the most severe cases, whereas in the first decade of this study they contributed one third of all cases and only one sixth of the most severe (chi(2) and chi(2) for trend p < 0.001). CONCLUSIONS: The rate of cerebral palsy has risen in spite of falling perinatal and neonatal mortality rates, a rise that is even more pronounced when the mildest and least reliably ascertained are excluded. The effect of modern care seems to be that many babies < 2500 g who would have died in the perinatal period now survive with severe cerebral palsy. A global measure of severity should be included in registers of cerebral palsy to determine a minimum threshold for international comparisons of rates, and to monitor changes in the distribution of severity.

Birth Weight↗

PubMed1999

Breast cancer and occupational exposures in women in Finland.

BACKGROUND: The etiology of breast cancer is not fully understood. Environmental and occupational exposures may contribute to breast cancer risk. METHODS: We linked 324 job titles from the 1970 census of 892,591 Finnish women with incidence of breast cancer (23,638 cases) during 1971-1995. We converted job titles to 31 chemical and two ergonomic agents through a measurement-based, period-specific, national job-exposure matrix. Poisson regression models were fit to the data, with adjustment for birth cohort, follow-up period, socioeconomic status, mean number of children, mean age at first delivery, and turnover rate. RESULTS: For premenopausal breast cancer, medium/high level of occupational exposure to ionizing radiation was associated with a standardized incidence ratio (SIR) of 1.3 (95% confidence interval (CI) 0.7-2.5; trend P = 0.03). For postmenopausal breast cancer, we found on SIR of 1.2 (1.1-1.3) for low level and 1.4 (1.1-1.8) for medium/high level of ionizing radiation (trend P = 0.001); and an SIR 1.3 (1.1-1.7) for medium/high levels of both asbestos and man-made vitreous fibers. Aromatic hydrocarbon solvents showed a significant trend for a modest excess of postmenopausal breast cancer. CONCLUSIONS: Our study indicates that occupational exposure to ionizing radiation may be associated with an increased risk of female breast cancer. High-quality studies on environmental and occupational etiology of breast cancer are needed for further elucidation of risk factors.

Adult↗

PubMed2006

Adaptive-filtering of trisomy 21: risk of Down syndrome depends on family size and age of previous child.

The neonatal incidence rate of Down syndrome (DS) is well-known to accelerate strongly with maternal age. This non-linearity renders mere accumulation of defects at recombination during prolonged first meiotic prophase implausible as an explanation for DS rate increase with maternal age, but might be anticipated from chromosomal drive (CD) for trisomy 21. Alternatively, as there is selection against genetically disadvantaged embryos, the screening system that eliminates embryos with trisomy 21 might decay with maternal age. In this paper, we provide the first evidence for relaxed filtering stringency (RFS) to represent an adaptive maternal response that could explain accelerating DS rates with maternal age. Using historical data, we show that the proportion of aberrant live births decrease with increased family size in older mothers, that inter-birth intervals are longer before affected neonates than before normal ones, and that primiparae exhibit elevated levels of DS incidence at higher age. These findings are predicted by adaptive RFS but cannot be explained by the currently available alternative non-adaptive hypotheses, including CD. The identification of the relaxation control mechanism and therapeutic restoration of a stringent screen may have considerable medical implications.

Adult↗

PubMed1995

Cervical competence as a continuum: a study of ultrasonographic cervical length and obstetric performance.

OBJECTIVE: Our purpose was to investigate the hypothesis that cervical competence is a continuum that is related to cervical length and is reflected by pregnancy history. STUDY DESIGN: A cross-sectional study was performed of cervical length measured by transvaginal ultrasonography in women with prior preterm delivery at < or = 26 weeks, 27 to 32 weeks, and 33 to 35 weeks compared with women with cervical incompetence and normal controls delivered at term. RESULTS: Transvaginal cervical length was measured during pregnancy in 32 subjects with cervical incompetence, 98 with previous preterm birth < or = 26 weeks, 98 with previous preterm birth at 27 to 32 weeks, 127 with previous preterm birth at 33 to 35 weeks, and 106 normal controls. The relationship between obstetric history and cervical length was evaluated by analysis of variance. The gestational age at the first preterm delivery was significantly correlated with cervical length in the current pregnancy at each gestational interval between 20 and 30 weeks in a continuous manner. CONCLUSION: Cervical competence is a continuous rather than categoric variable and is indicated indirectly by measurement of the length of the cervix.

Adult↗

PubMed2006

Stillbirth risk factors according to timing of exposure.

PURPOSE: The purpose of the present study is to identify risk factors for stillbirth and explore hypotheses about the cause of stillbirth based on the time in gestation when exposures occur. METHODS: Relationships between lifestyle factors, pregnancy conditions, medication use, and occupation on risk for stillbirth were examined within a population-based case-control study. Women who had a stillbirth and a random sample of women who had a live birth between 1999 and 2001 were identified through perinatal databases in Nova Scotia and Eastern Ontario, Canada. Exposure data were collected for each month of pregnancy and analyzed within trimesters. Case-control data were converted to case-cohort data, and hazard ratios (HRs) and 95% confidence intervals (CIs) were determined from Cox proportional hazards models. RESULTS: This study included 105 stillbirth cases and 389 live-birth controls. Fertility treatment in the present pregnancy was associated with increased risk for stillbirth (adjusted HR, 4.0; 95% CI, 1.4-11.6). Smoking during the first trimester also was associated with increased risk for stillbirth (adjusted HR, 2.4; 95% CI, 1.2-4.9). Other risk factors included antiemetic use during the first trimester, second-trimester antibiotic use, low family income, and age older than 35 years. CONCLUSIONS: Risk factors identified in this study concur with findings of previous studies and support the importance of early pregnancy exposures on stillbirth risk.

Adult↗

PubMed1999

Outcome of pregnancies occurring within 1 year of hydatidiform mole.

OBJECTIVE: To determine the outcome of subsequent pregnancies in patients with partial or complete molar pregnancy who conceive before completing the recommended hCG follow-up of at least 6 months. METHODS: Retrospective record review of patients with partial or complete mole who conceived before the standard gonadotropin follow-up of 6 months was completed during 1980-1998. RESULTS: Sixty-seven patients with molar pregnancy who conceived before completion of hCG follow-up were identified. Thirty-five (52.2%) patients had a prior partial mole, and 32 (47.8%) had a prior complete mole. The mean interval from first achieving undetectable hCG level to new pregnancy was 3.1 and 3.4 months in patients with partial and complete mole, respectively. Eleven patients underwent elective termination, and 12 were lost to follow-up. Of the remaining 44 patients, 33 (75.0%) had live births, 10 had spontaneous abortions, and one had an ectopic pregnancy. A viable pregnancy outcome was achieved in 20 (83.3%) of 24 patients with partial mole and 13 (65.0%) of 20 patients with complete mole. None of the patients developed any evidence of postmolar persistent gestational trophoblastic tumor. None of the live births had any detectable fetal anomalies. CONCLUSION: The risk of persistent tumor is low and reproductive outcome is favorable once undetectable hCG levels are achieved. Pregnancies occurring before the completion of recommended hCG follow-up may be allowed to continue under careful surveillance.

Adolescent↗

PubMed2000

Factors predicting peri- and neonatal outcome in diabetic pregnancy.

A population-based birth cohort including 296 consecutive type 1 diabetic births in a geographically defined catchment area was used to evaluate factors predicting poor perinatal and neonatal outcome. Though perinatal mortality has decreased (17.1/1000 births at 28 or more weeks of gestation), the neonatal morbidity rate still remains high despite improved maternal metabolic control and developed antepartum surveillance. Poor glycemic control during the first weeks of pregnancy was the most important risk factor (relative risk (RR) 2.91; 95% confidence interval (CI) 1.29-6.55) predicting adverse neonatal events such as long (>10 days) stay in the neonatal unit, malformation or perinatal death. The risk was further increased in cases of severe diabetes (White class F-R; RR 2.75; 95% CI 1.59-4.76) and primiparity (RR 1.64; 95% CI 1.02-2.65). By evaluating these risk factors at the first antenatal visit, a subgroup with a particular need of counselling and intensive feto-maternal monitoring can be identified.

Adult↗

PubMed1996

Population-based recurrence risk of sudden infant death syndrome compared with other infant and fetal deaths.

To investigate the recurrence of sudden infant death syndrome (SIDS) among siblings, the authors analyzed data for all 352,475 mothers whose first and second single births were reported to the Medical Birth Registry of Norway during 1967-1988. Recurrence of stillbirths from the 16th week of gestation onward and infant deaths other than SIDS were also studied. Relative risk of recurrence for SIDS was 5.8 (95% confidence interval (CI) 2.1-13.2); for asphyxia- and immaturity-related infant deaths, 12.5 (9.2-17.4); for congenital malformations, 7.2 (4.7-11.0); and for other causes of infant death, 8.0 (2.0-22.1). Deaths due to infections did not recur. Similar categories of infant deaths had higher overall relative risk, 9.1, compared with 1.6 for dissimilar categories. Previous early stillbirth (16-27 weeks) had a high recurrence (relative risk (RR) = 21.8, 95% CI 17.5-26.9), while late stillbirth (> or = 28 weeks) had lower recurrence (RR = 4.6, 95% CI 3.7-5.8). Previous SIDS was associated with an increased risk of all other types of loss. In contrast, previous late stillbirth and previous asphyxia- and immaturity-related infant deaths were associated with a reduced risk of subsequent SIDS (RR = 0.31, 95% CI 0.08-0.84, and RR = 0.23, 95% CI 0.01-1.13, respectively). In conclusion, as with other infant and fetal deaths, SIDS deaths showed strong sibship aggregation consistent with a genetic susceptibility in subsets of SIDS that may interact with environmental factors. The authors also suggest common pregnancy-specific risk factors for late stillbirths, asphyxia- and immaturity-related infant deaths, and SIDS.

Cause of Death↗

PubMed1978

Growth fraction and cycle duration of hepatocytes in the three-week-old rat.

The proliferation of hepatocytes in the liver of 3-week-old rats has been investigated by autoradiographic methods. This investigation is a continuation of earlier work on the same topic (Schultze & Maurer, 1972; 1973). 21 days after birth, 102 rats received a single injection of 3H-TdR. The percentage of labelled mitoses was then determined 1 hr later and at various times throughout the interval up to 12 days after application of 3H-TdR. In agreement with earlier work, a first peak of labelled mitoses was found 7 hr after 3H-TdR injection. The area under the peak indicates an S phase duration of 8 hr. In addition a second very broad peak of labelled mitoses was found between 2 and 12 days after pulse labelling. The analysis of the results leads to the conclusion that the hepatocytes of the 3-week-old rat have a growth fraction close to 1 and a doubling time of 6-7 days. This is at variance with earlier results of Post, Huang & Hoffman (1963) and Grisham (1969) who had derived a value of 21.5 hr for the duration of the cell cycle and a value of only 0.1-0.2 for the growth fraction of the hepatocytes.

Animals↗

PubMed1976

Plasma concentrations of testosterone in the developing ram in different social environments.

Plasma testosterone profiles were determined by taking frequent blood samples at intervals from birth to 21 months of age from rams reared in isolation, in an all-male group and in a mixed-sex group. The testosterone pattern was not modified by these different social environments. The ability of the ram to copulate when first exposed to an oestrous ewe, apparently a maturational process, was also independent of social rearing. At birth plasma testosterone levels were detectable but low, they were higher at 10 and 16 weeks of age and showed a marked rise by 26 weeks, coincident with the time of puberty. Depressive effects of season on testosterone profiles occurred during the 2nd year of life but not the 1st year.

Age Factors↗

PubMed1994

First-trimester anesthesia exposure and the risk of central nervous system defects: a population-based case-control study.

OBJECTIVES: Although up to 2% of women undergo surgery during pregnancy, teratogenic effects of general anesthesia have not been adequately studied. Recently, an association between first-trimester operations and central nervous system defects has been described. This issue was explored in a population-based case-control study. METHODS: Case patients included live-born and stillborn infants with central nervous system defects born to residents of metropolitan Atlanta, Ga, between 1968 and 1980. Control patients included normal babies frequency matched to case patients by race, birth hospital, and period of birth. Conditional logistic regression analysis was used to adjust for potential confounding factors. RESULTS: Of 694 mothers of infants with central nervous system defects, 12 reported first-trimester anesthesia exposure; 34 of 2984 control mothers reported such exposure (odds ratio [OR] = 1.7, 95% confidence interval [CI] = 0.8, 3.3). A striking association was observed between reported anesthesia exposure and hydrocephalus with another major defect (OR = 9.6, 95% CI = 3.8, 24.6). The strongest association was that of anesthesia exposure with hydrocephalus and eye defects (OR = 39.6, 95% CI = 7.5, 209.2). CONCLUSIONS: An increased risk of hydrocephalus with other defects was found among offspring of mothers with reported first-trimester anesthesia. Further studies are needed to explore the possible teratogenic effects of general anesthesia.

Abnormalities, Drug-Induced↗