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PubMed2001

Excess breast cancer risk and the role of parity, age at first childbirth and exposure to radiation in infancy.

Exposure to ionizing radiation is a known risk factor for breast cancer and the fertility pattern is a recognized modifier of breast cancer risk. The aim of this study was to elucidate the interaction between these 2 factors. This study is based on a Swedish cohort of 17 202 women who had been irradiated for skin haemangiomas in infancy between 1920 and 1965. The mean age at treatment was 6 months and the median breast dose was 0.05 Gy (range 0-35.8 Gy). Follow-up information on vital status, parity, age at first childbirth and breast cancer incidence was retrieved through record linkage with national population registers for the period 1958-1995. Analyses of excess relative risk (ERR) models were performed using Poisson regression methods. In this cohort, the fertility pattern differed from that in the Swedish population, with significantly fewer childbirths overall and before 25 years of age but more childbirth after that age. There were 307 breast cancers in the cohort and the standardized incidence ratio (SIR) was 1.22 (95% CI 1.09-1.36). A linear dose-response model with stratification for fertility pattern and menopausal status resulted in the best fit of the data. ERR/Gy was 0.33 (95% CI 0.17-0.53). In absolute terms this means an excess of 2.1 and 5.4 cases per Gy per 10(4) breast-years in the age groups 40-49 and 50-59 years respectively. The fertility pattern influenced the breast cancer risk in this irradiated population in a similar way to that observed in other studies. SIR at dose = 0 was highest, 2.31, among postmenopausal nulliparous women (95% CI 1.48-3.40, n = 62). SIR at dose = 0 was lowest in pre- or postmenopausal women with a first childbirth before 25 years of age; 0.89 (0.71-1.09) and 0.88 (0.58-1.25) respectively. Thus, in addition to the dose-effect response in the cohort, part of the breast cancer excess could be explained by a different fertility pattern. The estimates of ERR/Gy for the various categories of age at first childbirth, number of children, menopausal status and ovarian dose were very similar, contradicting any interaction effects on the scale of relative risk.

Adult↗

PubMed2003

[Reduced number of extrauterine pregnancies--increased fertility of women during the 1990s?].

BACKGROUND: The purpose of this study was to investigate trends in ectopic pregnancy in relation to fertility patterns in general. MATERIALS AND METHODS: All women hospitalised with ectopic pregnancy in Sør-Trøndelag county 1970-2002 were identified through hospital discharge registries (ICD-8, -9, -10). Medical records were reviewed in order to identify patients who were residents of the county and had ectopic pregnancy verified by histology. Incidence rates were analysed by age, previous ectopic pregnancy and previous infertility treatment. Cumulative incidence rates were analysed by birth cohort. Ectopic pregnancy related to the number of births (extrauterine ratio) was analysed by age and parity. RESULTS: The incidence of ectopic pregnancy (per 10 000 women-years) increased from 4.2 in 1970-74 to 15.1 in 1990-94, then declined to 6.5 in 2000-02. Women 25-34 years old had highest incidence rates throughout the whole study period and the sharpest decline after 1990-94. The proportion of women with previous ectopic pregnancy or previous infertility declined after 1990-94. Cumulative incidence rates by age 30 were lowest for the youngest cohorts. The extrauterine ratio increased by age throughout the whole period and decreased in all age and parity specific groups throughout the 1990s. INTERPRETATION: After the epidemic increase in ectopic pregnancy observed from 1970 to the end of the 1980s, the annual number of cases has declined sharply. The observations indicate better primary treatment for primary ectopic pregnancy and primary infertility and improved female fertility through the 1990s.

Adolescent↗

PubMed1978

Variation in mitochondrial translation products associated with male-sterile cytoplasms in maize.

Mitochondria were isolated under sterile conditions from maize lines with normal cytoplasm and with T, C, and S sources of cytoplasmic male sterility. Protein synthesis by these mitochondria was dependent upon the presence of ADP and an oxidizable substrate or an energy generating system and displayed characteristic sensitivity towards inhibitors of protein synthesis. Approximately 20 polypeptides were detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis of the [(35)S]methionine-labeled mitochondrial translation products. Mitochondria from the T and C cytoplasms were characterized by the synthesis of a single additional or variant polypeptide.These observations are discussed with reference to the possible mechanisms of male sterility and the susceptibility of plants with T cytoplasm to Helminthosporium maydis, race T. Our results also suggest a potentially rapid method of classifying sources of cytoplasmic male sterility that could be used in conjunction with existing methods, which depend on patterns of fertility restoration after an extended breeding program.

Journal Article↗

PubMedDate not supplied

The pattern of serum melatonin levels during ovarian stimulation for in vitro fertilization.

OBJECTIVE: To characterize the relationship between the pineal gland hormone, melatonin, and gonadal hormones. METHODS: We studied the pattern of serum melatonin at the time of ovarian stimulation for in vitro fertilization. Blood samples were obtained every morning, from 20 healthy women during the in vitro fertilization cycle. RESULTS: A progressive rise in serum estradiol and prolactin was noted in all IVF cycles, while serum melatonin levels remained unchanged throughout the cycles. In two of the subjects the circadian rhythm of serum melatonin was assessed at 4-hour intervals for 24 hours. In both subjects the melatonin rhythm was remarkably consistent in terms of phase, amplitude, and total melatonin secreted during the treatment cycles. CONCLUSIONS: These results indicate that endogenous estradiol, progesterone, and prolactin do not affect the levels or circadian phase of melatonin secretion in humans.

Adult↗

PubMedDate not supplied

Sperm motility analysis using multi-exposure photography (MEP): validity of the method with normal and abnormal patterns.

Spermatozoon motility is an important semen parameter that can be correlated with fertilizing capacity. It can be evaluated by subjective or objective methods such as the multiple exposure photography technique (MEP). This technique was: (1) validated in terms of accuracy and sensitivity, and (2) used to investigate the possibility of differentiating patient subgroups on the basis of sperm motility. The method was shown to be accurate. The within and between assay variation coefficients were less than 6% and 17% respectively. Maximal sensitivity required 100 spermatozoa, since coefficients of variation were high when counting smaller numbers. A significant difference between fertile, normozoospermic and asthenozoospermic groups on the basis of the population pattern was found in a retrospective study. Moreover, the asthenozoospermic group could be divided into three subgroups, depending on whether one, two, or three motility variables were altered.

Humans↗

PubMed1977

Statistical methods for detecting a moderate paternal age effect on incidence of disorder when a maternal one is present.

A statistical method is developed for detecting a moderate effect on the incidence of a disorder caused by advancing age of one parent when it is known that advancing age of the other parent is of great aetiological importance. The method is a conditional test procedure given the parental ages, therefore no assumptions about the parental age distributions have to be made. The method is applied on Danish material on Down's syndrome, for which a paternal age effect is demonstrated. Methods used in some well-known previous investigations have been discussed. Several of them, e.g. the classical one of Penrose (1933), could hardly detect any paternal age effect in Down's syndrome on the available data, because these methods are heavily affected by certain fertility patterns not recognized previously.

Denmark↗

PubMed1993

Fertility pattern of women in China: a parity progression analysis.

"Using the 1% sample data from China's fourth census and [the] period parity progression method...,this paper analyzes the reproductive age and parity patterns of Chinese women. In addition to the commonly used period parity progression and the total fertility rate obtained through the usage of this method, some other frequently ignored means of deducing and calculating statistical indexes are introduced here."

Age Factors↗

PubMedDate not supplied

Centrifugation on Percoll gradient enhances fluorescent lectin binding on human sperm: a flow cytometric analysis.

Centrifugation on a Percoll gradient is commonly used to enrich sperm preparations in mobile forms prior to in vitro fertilization attempts. It has been suggested that this method also induces the capacitation of sperm, a step preceding the acrosomal reaction allowing egg fertilization. The modifications of the acrosomal membrane involved in these physiological events likely include alterations of glycosylation patterns. This hypothesis was investigated by comparing the membrane binding of 15 fluorescein-conjugated lectins on 60 samples of sperm, before and after Percoll centrifugation. The numbers of labeled sperm and their mean fluorescence intensity, recorded in flow cytometry, significantly increased for 10 and 14 of the 15 lectins tested. Microscopic examination of the labeled sperm showed that the acrosome and equatorial plates were more often labeled after Percoll centrifugation, confirming the hypothesis that this method modifies the glycosylation pattern of structures important for egg fertilization.

Centrifugation, Density Gradient↗

PubMed2002

Natural contraception using the Billings ovulation method.

OBJECTIVE: The Billings ovulation method (BOM) is a medical model of a natural procreation education method based on scientific observation of the changes in the cervical mucus. In this study we examined Turkish women's interest in accurate usage of cervical mucus changes in determining the ovulation time. METHOD: Fifteen regularly cycling women monitored their fertility patterns in 30 cycles using the BOM and urine luteinizing hormone (LH) kits. At the end ofeach cycle, the cervical mucus monitoring chart and LH kits were collected from the subjects and analyzed. RESULTS: The cervical mucus symptoms defined a potential fertile period of 10 days' average length, with the 'peak' mucus characteristic occurring at a mean of day 13.65 +/- 2.62 of the cycle. The duration ofthe LH surge, as observed in early morning urine samples, averaged 5 days, with the peak occurring at a mean of day 13.40 +/- 2.58 of the cycle. Data indicated that there was a strong correlation between LH in the urine and the peak in self-observed, cervical-vaginal mucus (p = 0.001). CONCLUSION: This study proved that women can distinguish patterns of ovulation and anovulation by self-detection of variations in cervical mucus characteristics, and that urinary LH levels strongly correlate with ovulation.

Adult↗

PubMed1988

Use-effectiveness of the ovulation method initiated during postpartum breastfeeding.

Between April 1981 to March 1984, 419 urban middle class postpartum women entered the Natural Family Planning (NFP) program of the Pontificia Universidad Catolica de Chile. This NFP program teaches the Ovulation Method (Billings). Only 1.9% of the women did not learn how to recognize the mucus pattern of fertility awareness. The sample of 378 women who were practicing the method to avoid a pregnancy completed 4,935 months of use of the OM. The cumulative life table unplanned pregnancy rate at the 12th postpartum month was 11.1 +/- 1.9 and the Pearl Rate was 12.1 per 100 woman-years. The Pearl Rate calculation of method-related failure was only 2.1 pregnancies per 100 woman-years. The breastfeeding group showed a significantly lower rate of unplanned pregnancies than the nonbreastfeeding group and there was no significant increase in unplanned pregnancy at the time of menstruation among previously amenorrheic women as compared to later intervals. The protection against unplanned pregnancy shown in this study should be viewed as the combination of two factors: breastfeeding and the Ovulation Method (OM) of NFP.

Adult↗

PubMed1999

Comparison of the expression of specific cell surface epitopes on in vitro fertilized and parthenogenetic bovine embryos.

Parthenogenetic embryos, which are produced by the spontaneous or artificial stimulation of the oocyte, partially develop in the complete absence of the male gamete but fail to produce live young in many mammalian species. The identification of developmentally regulated molecules on the cell surface of embryos has implicated their possible role in cell interactions during embryogenesis and differentiation. In this study the expression patterns of four stage-specific cell surface antigenic determinants (TEC-1, -2, -3, and -4) were investigated in both parthenogenetic and in vitro fertilized bovine embryos. When compared to embryos produced using in vitro fertilization methods the parthenogenotes, although appearing morphologically normal, differed markedly in their TEC epitope pattern of presentation. TEC-1, -2, -3, and -4 epitope presentation on in vitro fertilized embryos occurred during specific stages of preimplantation development. TEC-1 and -2 presentation was detected on oocytes and blastocysts only, TEC-3 on morulae and blastocysts, and TEC-4 on oocytes through to 8-cell embryos, with all subsequent stages negative. Parthenogenetic embryos did not show TEC-1, -2, or -3 epitope presentation whereas the TEC-4 epitope was present throughout the developmental period examined. Enzymatic cleavage of sialic acid residues on in vitro fertilized and parthenogenetic embryos resulted in presentation of the TEC epitopes during all the embryonic stages. Western blot analysis of the embryos showed the TEC epitopes to be present on all the embryonic stages examined. This study suggests the mechanisms responsible for control and presentation of each of the TEC epitopes may not be functioning the same in parthenogenetic embryos that undergo changed glycosylation or deglycosylation resulting in altered patterns of sialylation. The study also shows TEC epitope presentation may prove to be a useful indicator of parthenogenetically activated bovine embryos. J. Exp. Zool. 284:392-400, 1999.

Animals↗

PubMed2001

Births: final data for 1999.

OBJECTIVES: This report presents 1999 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal characteristics (medical risk factors, weight gain, tobacco and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS: Descriptive tabulations of data reported on the birth certificates of the 3.96 million births that occurred in 1999 are presented. RESULTS: Overall birth and fertility rates changed less than 1 percent in 1999. Teenage birth rates fell 2 to 6 percent. The rate for women aged 20-24 years declined slightly, while rates for women in their late twenties and their thirties rose 2 to 3 percent each. The number of births to unmarried women, the birth rate, and the percent of births that were to unmarried women each rose 1 percent or less. Smoking by pregnant women overall dropped again, but rose among women aged 18-24 years. Improvements in prenatal care utilization continued. The cesarean delivery rate increased for the third year after declining for 7 consecutive years. The proportion of multiple births continued to rise; however, higher order multiple births (e.g., triplets, quadruplets) declined for the first time in over a decade, following increases of 13 percent per year during 1990-98. The percent low birthweight remained at 7.6 percent, while preterm births rose to 11.8 percent. These trends are in large part the result of increases in multiple births.

Adolescent↗

PubMed1999

Births: final data for 1997.

OBJECTIVES: This report presents 1997 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal lifestyle and health characteristics (medical risk factors, weight gain, and tobacco and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant health characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown including teenage birth rates and total fertility rates, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS: Descriptive tabulations of data reported on the birth certificates of the 3.9 million births that occurred in 1997 are presented. RESULTS: Birth and fertility rates declined very slightly in 1997. Birth rates for teenagers fell 3 to 5 percent. Rates for women in their twenties changed very little, whereas rates for women in their thirties rose 2 percent. The number of births and the birth rate for unmarried women each declined slightly in 1997 while the percent of births that were to unmarried women was unchanged. Smoking by pregnant women overall dropped again in 1997, but continued to increase among teenagers. Improvements in prenatal care utilization continued. The cesarean delivery rate increased slightly after declining for 7 consecutive years. The proportion of multiple birth continued to rise; higher order multiple births (e.g., triplets, quadruplets) rose by 14 percent in 1997, following a 20 percent rise from 1995 to 1996. Key measures of birth outcome--the percents of low birthweight and preterm births--increased, with particularly large increases in the preterm rate. These changes are in large part the result of increases in multiple births.

Adolescent↗

PubMed2000

Births: final data for 1998.

OBJECTIVES: This report presents 1998 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal lifestyle and health characteristics (medical risk factors, weight gain, and tobacco and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant health characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown including teenage birth rates and total fertility rates, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS: Descriptive tabulations of data reported on the birth certificates of the 3.94 million births that occurred in 1998 are presented. RESULTS: Birth and fertility rates increased in 1998 by about 1 percent, the first increase since 1990. Birth rates for teenagers fell 2-5 percent. Rates for women in their twenties increased 1-2 percent each, whereas rates for women in their thirties rose 2-4 percent. All measures of childbearing by unmarried women increased in 1998; the number of births rose 3 percent, the birth rate increased about 1 percent while the percent of births that were to unmarried women rose to 32.8 percent. Smoking by pregnant women overall dropped again in 1998, but continued to increase among teenagers. Improvements in prenatal care utilization continued. The cesarean delivery rate increased for the second year after declining for 7 consecutive years. The proportion of multiple births continued to rise; higher order multiple births (e.g., triplets, quadruplets) rose by 13 percent in 1998, following a 14 percent rise from 1996 to 1997. Key measures of birth outcome--the percents of low birthweight and preterm births--increased. These changes are in large part the result of increases in multiple births.

Adolescent↗

PubMed1998

Report of final natality statistics, 1996.

OBJECTIVES: This report presents 1996 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal lifestyle and health characteristics (medical risk factors, weight gain, tobacco and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant health characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown including teenage birth rates and total fertility rates, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS: Descriptive tabulations of data reported on the birth certificates of the 3.9 million births that occurred in 1996 are presented. RESULTS: Birth and fertility rates declined very slightly in 1996. Birth rates for teenagers fell 3 to 8 percent. Rates for women in their twenties increased slightly in 1996, the first increase since 1990, while rates for women in their thirties rose 2 to 3 percent. The number and percent of births to unmarried women increased slightly in 1996 while the birth rate for unmarried women declined modestly. Smoking by pregnant women overall dropped again in 1996, but increased among teenagers. Improvements in prenatal care utilization continued. The cesarean delivery rate declined. The proportion of multiple births continued to rise; higher order multiple births (e.g., triplets, quadruplets) rose by 19 percent. Key measures of birth outcome--the percents of low birthweight and preterm births--increased slightly, in large part the result of increases in multiple births.

Adolescent↗

PubMed1985

Sustained release systems for ethinylestrogens.

The immunoreactive serum concentration of ethinylestradiol (EE) was measured by a specific radioimmunoassay after a single intramuscular administration of a combined preparation of Norethindrone (NET) and Mestranol (ME). The mean peak serum value for the 6 women studied was 278.5 pm/m1/m2 of body surface area (BSA), and was reached 11.17 days after dosing, with a half-life of absorption (T1/2 abs) of 9.37 days. In 5 out of 6 subjects EE was detectable in the circulaton for 21 days after injection. The mean serum concentration time curve was calculated in 2720.67 pg/day/m1/m2. The shape of the 1-21 day concentration-time curve shows a sustained release pattern, suitable for a long acting fertility regulation method.

Biology↗

PubMed2002

Births: final data for 2000.

OBJECTIVES: This report presents 2000 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal characteristics (medical risk factors, weight gain, tobacco and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS: Descriptive tabulations of data reported on the birth certificates of the 4.059 million births that occurred in 2000 are presented. RESULTS: The number of births rose 3 percent in 2000; birth and fertility rates rose 1 to 2 percent. The total fertility rate was above "replacement" for the first time in almost 30 years. Teenage birth rates continued to fall while birth rates for women aged 20-24 years rose slightly, and rates for women in their late twenties and thirties rose 3 to 5 percent. Births to women in their forties and early fifties were also up for 2000. The number of births to unmarried women, the birth rate, and the percent of births that were to unmarried women rose 1 to 3 percent, but birth rates for unmarried teenagers declined. Smoking by pregnant women was down again. The cesarean delivery rate rose 4 percent to 22.9, the fourth consecutive increase; the primary cesarean rate was up and the rate of vaginal births after a previous cesarean was down. The number and rate of twin births continued to rise, but the triplet/+ birth rate declined for the second year in a row. For the first year in almost a decade the preterm birth rate declined (to 11.6 percent); the low birthweight rate, however, was unchanged at 7.6 percent.

Adolescent↗

PubMed1998

The World Health Organization Multinational Study of Breast-feeding and Lactational Amenorrhea. I. Description of infant feeding patterns and of the return of menses. World Health Organization Task Force on Methods for the Natural Regulation of Fertility.

OBJECTIVE: To detect differences between populations in both infant feeding practices and the duration of lactational amenorrhea, if they exist. DESIGN: Prospective, nonexperimental, longitudinal follow-up study. SETTING: Five developing and two developed countries. PATIENT(S): Four thousand one hundred eighteen breast-feeding mothers and their infants. INTERVENTION(S): Breast-feeding women collected ongoing information about infant feeding and family planning practices, plus the return of menses. Fortnightly follow-up occurred in the women's homes. MAIN OUTCOME MEASURE(S): Breast-feeding frequency by day (and by night); 24-hour breast-feeding duration, percent of all infant feedings that were milk/milk-based (and solid/semisolid foods); time until the end of full breast-feeding; time until regular supplementation; and time until the end of lactational amenorrhea. RESULT(S): Differences between the centers in the duration of amenorrhea were substantial, ranging from a median of 4 months in New Delhi (India) to 9 months in Chengdu (China). Women in developed countries (but also women in Chengdu) were more likely to delay supplementation (for up to 5 months), whereas women in Santiago (Chile), Guatemala City (Guatemala), and Sagamu (Nigeria) started supplements much earlier, sometimes as early as 1 week after birth. CONCLUSION(S): Both breast-feeding behavior and the duration of lactational amenorrhea vary markedly across settings, indicating that breast-feeding promotion and family planning advice should be site- and culture-specific.

Adult↗