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State-specific birth rates for teenagers--United States, 1990-1996.

During the late 1980s, birth rates for teenagers in the United States increased sharply. Although rates have declined steadily since 1991 (1,2), age-, race-, ethnicity-, and state-specific rates have varied substantially. Despite recent declines, the U.S. birth rate for teenagers remains high compared with other industrialized countries. In 1996, an estimated 505,514 females aged <20 years gave birth; two thirds of births to teenagers are unintended (3). The adverse consequences of teenage childbearing include increased poverty for both mother and child. This report presents state-specific birth rates for females aged 15-19 years for 1991 and 1995 and compares race/ethnicity-specific birth rates for U.S. females aged <20 years for 1990-1996. These findings indicate that, during 1991-1995, birth rates among teenagers declined significantly in all but five states and the District of Columbia, and declines nationwide during 1991-1996 were especially large for teenagers aged 15-17 years and for black teenagers. Recent declines in abortions and abortion rates forteenagers, coupled with the trends described in this report for birth rates for teenagers, indicate that, since 1991, pregnancy rates for teenagers also have declined.

Adolescent↗

No difference in cycle pregnancy rate and in cumulative live-birth rate between women with surgically treated minimal to mild endometriosis and women with unexplained infertility after controlled ovarian hyperstimulation and intrauterine insemination.

OBJECTIVE: The association between infertility and minimal to mild endometriosis is controversial and poorly understood. The clinical pregnancy rate (PR) per cycle after controlled ovarian hyperstimulation (COH) with or without intrauterine insemination (IUI) is reportedly lower in women with surgically untreated minimal to mild endometriosis than in women with unexplained infertility. It is possible that prior laparoscopic removal of endometriosis has a positive effect on the clinical PR after COH and IUI. Therefore, we tested the hypothesis that after COH and IUI the PR per cycle and the cumulative live-birth rate (CLBR) are equal or higher in women with recently surgically treated minimal to mild endometriosis when compared with women with unexplained infertility. DESIGN: A retrospective, controlled cohort study. SETTING: Leuven University Fertility Centre, a tertiary academic referral center. PATIENT(S): One hundred seven women treated during 259 cycles with COH and IUI including patients with endometriosis (n = 58, 137 cycles) and unexplained infertility (n = 49, 122 cycles). All patients with endometriosis had minimal (n = 41, 100 cycles) or mild (n = 17, 37 cycles) disease that had been laparoscopically removed within 7 months before the onset of treatment with COH and IUI. INTERVENTION(S): Controlled ovarian hyperstimulation using clomiphene citrate (23 cycles) or gonadotrophins (236 cycles) in combination with IUI. MAIN OUTCOME MEASURE(S): Clinical PR per cycle and CLBR within four cycles of treatment with COH and IUI. RESULT(S): The clinical PR per cycle was comparable in women with minimal or mild endometriosis (21% or 18.9%, respectively) and in women with unexplained infertility (20.5%). The CLBR within four cycles of COH and IUI was also comparable in women with minimal endometriosis, mild endometriosis, and unexplained infertility (70.2%, 68.2 %, 66.5%, respectively). CONCLUSION(S): The data from our study suggest that COH and IUI shortly after laparoscopic excision of endometriosis is as effective as COH and IUI in patients with unexplained subfertility.

Adult↗

[Analysis of factors related to the recent decline in birth rate in Japan].

This study was undertaken in an attempt to determine whether regional differences exist for those factors which have affected the decline in the total fertility rate in Japan between 1970 and 1990. Age Stratified analysis of vital statistics of the 20 to 39-year-old female population for the 46 prefectures was performed, and evaluated in relation to urbanization. The parameters examined were birth rate, percentage of married women, rates of birth by married women, and percentage of the work force in the service industry. The results were as follows. 1. Characteristic changes were noted in birth rates for females between 25 and 29 years of age. The reasons are that average marriage age for females shifted from 20-24 to 25-29, causing the birth rates for females between the ages of 25 to 29 years to decline, while not uniformly, but with some regional differences among the 46 prefectures. 2. Urbanization has had a significant effect on the declining birth rate for females grouped by age. The advance of the urbanization process in each prefecture is directly related to the decline in the birth rates for females between 20 to 24 years and 25 to 29 years. The extent of urbanization in each prefecture is inversely related to the rate of birth by married women and the percentage of married women between age 20 to 24 and 25 to 29 in that prefecture. The trend toward delaying marriage and childbirth in the urbanized prefectures appeared to be a major factor leading to the decline in the total fertility rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

Seasonal differences in suicide birth rate in Alaska Natives compared to other populations.

Seasonal differences in suicide birth rates among Alaska Natives and for populations at different latitudes (residents of the Yukon, Saskatchewan, Montana, Wyoming, and Pennsylvania) were investigated. Seasonal birth rates for the general population were similarly examined. Suicide birth rates showed small seasonal variations for Alaska Natives with summer births showing more suicides. However, at lower latitudes, suicide birth rates among other populations showed no seasonal differences. Hours of daily sunlight at the summer and winter solstice correlated with the proportion of suicide victims born during those seasons. Seasonal differences in birth rates of suicide victims correlated strongly with latitude and seasonal differences in daylight. General population birth rates did not show significant seasonal differences, and did not correlate with differences in latitude or sunlight length at the summer or winter solstice.

Alaska↗

Pregnancy, abortion, and birth rates among US adolescents--1980, 1985, and 1990.

OBJECTIVE: To analyze pregnancy, abortion, and birth rates among US adolescent girls in 1980, 1985, and 1990. DESIGN: Retrospective analysis of trends in data on pregnancies, abortions, and births. POPULATION: US adolescent girls aged 13 to 19 years. MAIN OUTCOME MEASURES: Pregnancy, abortion, and birth rates (with and without adjustment for sexual experience) among teenaged girls aged 15 to 19 years and girls under 15 years. RESULTS: Although pregnancy rates among all teenaged girls 15 to 19 years old remained fairly stable from 1980 to 1985, they increased by 9% during the last half of the decade, totaling 95.9 pregnancies per 1000 teenaged girls 15 to 19 years old by 1990. Because rates of sexual experience increased even faster, pregnancy rates among sexually experienced teens aged 15 to 19 actually declined between 1980 and 1990 by approximately 8%. Abortion rates among these teens remained stable during the 1980s, with 35.8 and 36.0 abortions per 1000 in 1980 and 1990, respectively. As with overall pregnancy rates, abortion rates among these sexually experienced teenaged girls declined during the 1980s. Between 1980 and 1985, birth rates among teenaged girls aged 15 to 19 years declined by 4%, but they increased by 18% during the latter half of the decade, totaling 59.9 births per 1000 in 1990. Among these sexually experienced teenagers, birth rates also declined between 1980 and 1985 and then increased over the next 5 years. In 1990, pregnancies and abortions among girls younger than 15 years accounted for only 3% of all adolescent pregnancies and abortions. However, the number of births among these younger adolescents increased by 15% over the decade. In that age group, trends in pregnancy, abortion and birth rates over the decade were similar to those for older teens. However, during the late 1980s, the abortion rate declined and the pregnancy rate remained stable, resulting in a 26% increase in the birth rate. CONCLUSIONS: Despite efforts to reduce adolescent pregnancy in the United States, pregnancy and birth rates for that group continue to be the highest among developed countries. Considering that 95% of adolescent pregnancies are unintended, increased efforts to prevent these pregnancies are warranted.

Abortion, Induced↗

Investigation of institutional differences in primary cesarean birth rates.

Differences in primary cesarean birth rates between a maternity center staffed by certified nurse-midwives (CNM) with physician backup on the premises and a university teaching hospital staffed by resident and attending physicians were studied. The study sample included 796 and 804 women, similar in demographics, who received their prenatal and intrapartum care in the respective sites in 1977 and 1978. Study results indicate a significantly lower rate of primary cesarean birth at the maternity center than at the university hospital that was independent of institutional differences in the indications for abdominal delivery. Although cesarean birth was related to contracted pelvis (at labor), fetal malpresentation, and placental bleeding at both institutions, it was significantly associated with preeclampsia, primiparity, fetal distress, and maternal age only at the university hospital. There were no noteworthy differences in pregnancy outcomes for women delivered vaginally or by cesarean, except for more newborns with low Apgar scores among primary cesarean births at the university hospital. A likely explanation for these findings is differing labor and delivery management styles between the providers of care at the two institutions.

Adolescent↗

Risks preceding increased primary cesarean birth rates.

Recent increases in cesarean birth rates are of concern to obstetricians and to the public. Previous studies often focused on indications for abdominal delivery, described in such broad categories as repeat cesarean, breech presentation, dystocia, and fetal distress, without detailed information concerning medical/obstetric risk factors. In this study of 2744 consecutively delivered mothers who received antenatal care, the problem was approached differently by evaluating approximately 100 pregnancy risk factors recorded in a computerized uniform perinatal record system before making a decision for delivery. Excluding repeat cesareans, relative risks for primary cesarean birth were calculated for each risk factor. For the large majority of patients, the need for primary cesarean birth could not be predicted before the onset of labor. Approximately 70% of primary cesareans could be accounted for on the basis of single pregnancy risks--antepartum problems, 11%; abnormal fetal presentation, 30%; abnormal labor, 14%, and fetal distress, 15%. This leaves 30% of primary cesareans without a single major preceding risk. Along with the facts that 80% of primary cesareans in this series were performed for normal-size infants and that dystocia appears to account for a 3.4-fold greater proportion of cesareans in the national experience than in the current study, this suggests that critical evaluation and study of obstetric management of dystocia may be most fruitful in responding to the question of rising cesarean birth rates.

Adolescent↗

The Green Bay cesarean section study. III. Falling cesarean birth rates without a formal curtailment program.

OBJECTIVES: We observed decreases in cesarean birth rates at two Green Bay hospitals after the 1990 publication of our first cesarean section study. The purpose of this study was to determine the causes of those decreases and to see whether any outcome changes occurred with lower rates. An additional objective was to determine the perceptions of the 10 physicians regarding the determinants of cesarean birth rates. STUDY DESIGN: We compared recent cesarean birth rates (1990 to 1992) to former rates (1986 to 1988) for 10 of the 11 physicians analyzed in our previous studies. Newborn outcomes were analyzed to determine whether variations occur in comparing low to high cesarean rate physician groups. RESULTS: The total, primary, and repeat cesarean birth rates declined from 13.3% to 10.2%, 8.6% to 6.8%, and 4.7% to 3.4%, respectively, between 1986 to 1988 and 1990 to 1992. Variations in cesarean rates occurred among physicians and groups of physicians. Higher cesarean rates did not result in better perinatal outcome. Literature reports, residency training, continuing medical education attendance, and liability risks were the major determinants of cesarean birth as perceived by the 10 physicians in the study. The least important determinant, rated fifteenth of 15, was the national cesarean birth rate.

Cesarean Section↗

Embryo morphology score on day 3 is predictive of implantation and live birth rates.

PURPOSE: To determine if embryo cleavage state or morphology on day 3 correlates with implantation or live birth rates. A retrospective cohort study of all fresh embryo transfers over 2 years. METHODS: Patients were grouped by the average cleavage state and morphology. Cleavage state groups were: <6, > or =6, <8, and > or =8 cells. Morphology groups by average grade were: group 1 (best) = 1, group 2 = >1< or =2, group 3 = >2< or =3, and group 4 (worst) = >3< or =4. RESULTS: The overall implantation rate for 158 cycles was 28.1% with a live birth rate of 37.3%. Morphologic state was highly predictive of both implantation rate and live birth rate. Implantation rates by group were 54.8% (group 1), 30.4% (group 2), 23.8% (group 3), and 11.1% (group 4). Likewise, live birth rates among groups were 61.5, 39, 20, and 21%, respectively. Cleavage state was not predictive of outcome. CONCLUSIONS: Embryo grade is highly predictive of implantation and live birth rate and can be used to determine the number of embryos to transfer. Cleavage state is not predictive of outcome.

Adult↗

Infertility treatment and multiple birth rates in Britain, 1938-94.

Trends in multiple birth rates are thought to have been substantially affected by subfertility treatments in the last 25 years, but there are few quantitative assessments of this. This paper examines trends in twin and higher multiple birth rates separately in Scotland, England and Wales and compares their course with corresponding multiple birth rates in the Oxford Record Linkage Study area, where the proportions following subfertility treatment are documented. National data on prescriptions for subfertility treatments reinforce the view that they have had a major effect on the trends, and currently perhaps 60% of triplet and higher order births and 15% of twins follow their use in Britain.

Birth Rate↗

Cystic fibrosis birth rates in Canada: a decreasing trend since the onset of genetic testing.

OBJECTIVE: To estimate cystic fibrosis (CF) birth rates in Canada from 1971 to 2000 and to assess the population impact of genetic testing in families with a history of CF, after identification of the CF transmembrane conductance regulator gene in 1989. STUDY DESIGN: Age-at-diagnosis data were obtained from the Canadian Cystic Fibrosis Foundation Patient Data Registry and Canadian births for the corresponding years from Canadian Vital Statistics. Estimates of the CF birth rate in each year were based on a nonparametric model that allows the birth rate to vary across the years and adjusts for censoring of currently undiagnosed patients. RESULTS: The overall CF birth rate from 1971-1987 was 1/2714 with no increasing or decreasing trend. Beginning in 1988, 1 year before identification of the CF transmembrane conductance regulator gene, estimated CF birth rates followed a linear decline to an estimated rate of 1/3608 in 2000. CF birth rates may have stabilized in the last few years, but further decline may occur with implementation of carrier screening in the general population. CONCLUSIONS: These results demonstrate the temporal association of genetic testing and declining CF birth rates in Canada. They may assist in decisions relating to the allocation of resources for prenatal and neonatal CF screening programs.

Birth Rate↗

The effect of war on marriage, divorce and birth rates.

The impact of war on marriage, divorce, and birth rates in the United States from 1933 to 1986 is explored. The author concludes that "the involvement of the nation in military activities was accompanied by a decrease in marriage and birth rates but not by any change in divorce rates. Mobilization of the armed forces and demobilization had no discernible impact on divorce, marriage or birth rates."

Americas↗

Declines in teenage birth rates, 1991-97: national and state patterns.

This report presents data on the numbers of teenage births and teenage birth rates for the United States for the period 1950-97 and State-specific birth rates for teenagers for 1991-96. After increasing sharply in the late 1980's, birth rates declined for American teenagers from 1991 through 1997. Rates fell overall by 16 percent for teenagers 15-17 years and by 11 percent for teenagers 18-19 years. Declines were reported for all race and ethnic origin groups, with the largest declines found for black teenagers, especially those aged 15-17 years. Particularly noteworthy has been the 21-percent decline in the rate of second births for teenagers who have had one child. Rates have fallen for first births as well, but the reductions are more modest, about 6 percent. Teenage mothers and their babies continue to be at greater risk of adverse health consequences compared with older mothers, including higher rates of preterm birth and low birthweight. While teenage birth rates vary considerably by State, rates fell in all States in the 1990's with nearly all declines statistically significant. Rates for black and non-Hispanic white teenagers dropped in most States from 1991 to 1996. Birth rate trends for Hispanic teenagers by State were not consistent. The proportion of second and higher order births among all teenage births declined substantially in most States. Data are from the National Center for Health Statistics' (NCHS) National Vital Statistics System.

Adolescent↗

The cesarean birth rate: influence of hospital teaching status.

Knowledge of how cesarean birth rates vary by hospital characteristics may aid in understanding and perhaps modifying some of the structural and process components of newborn delivery services to decrease the necessity of birth by cesarean procedure. To examine the influence of select hospital characteristics, data on hospital newborn deliveries in Illinois for 1986 among women 10-50 years of age inclusive (N = 130,249) were obtained from computerized hospital discharge abstract files. Characteristics of the hospitals were obtained from the annual American Hospital Association survey. Adjusting for mother's age at delivery; presence of pregnancy, labor, and delivery complications; expected primary payer; and size of hospital, women delivering in hospitals with teaching status were less likely (odds ratio = 0.76, p less than .001, 95 percent CL: 0.73, 0.79) to have a primary cesarean birth than women delivering in hospitals without this designation. A significantly lower cesarean birth rate in teaching hospitals was also observed in women of all age groups, in Medicaid and non-Medicaid women, and for most categories of delivery complications. These data suggest the need to identify the programmatic, technologic, and manpower functions associated with hospital teaching status that could decrease the likelihood of a primary cesarean delivery. The study also suggests that changes aimed at the manner of diagnosis, monitoring, and/or management of pregnancy/delivery complications may reduce the cesarean birth rate because of large differences in the primary cesarean birth rate found between teaching and other hospitals for most categories of newborn delivery complications.

Adolescent↗

Exposure of preimplantation embryos to platelet-activating factor increases birth rate.

PROBLEM: Platelet-activating factor (PAF) plays a significant role in fertility. Preimplantation stage embryos produce PAF (ePAF) which is required for development. PAF's mechanism of action is receptor-mediated and its presence has been reported in the developing mouse and human embryo. Exposure of preimplantation stage mouse embryos results in higher implantation rates. However, the effect of such treatment on live-birth rates and birth weights has not been reported. Therefore, the objective the study was to determine the effect of exposing preimplantation mouse embryos to PAF on subsequent birth rate and weight. DESIGN: Two-cell stage preimplantation stage mouse embryos exposed to PAF (10(-7) M) for 15 min prior to intraoviductal transfer. METHODS: Preimplantation stage embryos were recovered from eCG/hCG primed BDF1 female mice. Embryos were exposed to synthetic PAF (10(-7) M) for 15 min. PAF-treated embryos were transferred to the oviducts of pseudopregnant female CD-1 female mice. Superovulated and cultured BDF1 embryos not treated with PAF served as in vitro controls and naturally ovulated embryos with no collection/culture served as in vivo controls. Embryos were permitted to develop to term (18-21 days). The number of pups born per litter and litter weights subsequently were recorded. RESULTS: A total of 160 BDF1 mouse embryos were collected, treated, and transferred (20 per CD-1 recipient) as described. There was a significant (P < 0.05) increase in the number of pups born to the PAF treatment group (56/80; 70%) as compared to the control group (44/80; 55%). There was also a significant difference (P < 0.05) in litter birth weights between the PAF (1.31 g/litter) and controls groups (1.25 g/litter). There was a significant difference (P < 0.05) in birth weights between the PAF treatment group and the in vivo group (1.51 g/litter). There was a significant difference in birth weights between the in vitro-control and in vivo groups (1.51 g/litter). There were no observational malformaties to pups born in any group. CONCLUSIONS: Brief exposure of preimplantation stage embryos to PAF will result in a significant increase of delivery rates (pups/litter) as well as birth weights. However, the increase of birth weight was significantly below that found naturally. Additional studies are warranted to elucidate the mechanism of PAF's action in the preimplantation stage embryo and subsequent uterine development.

Animals↗

Pregnancy and birth rates after oocyte donation.

OBJECTIVE: To determine accumulated conception and live birth rates in ovum donation. DESIGN: Retrospective study from a computer database. Pregnancies with one gestational sac observed by ultrasound have been included as conceptional cycles and pregnancies that resulted in one live child were recorded for the analysis of the live birth rates. Life table analysis was applied. SETTING: Oocyte donation program at the Instituto Valenciano de Infertilidad. PATIENT(S): Three hundred ninety-seven recipients undergoing a total of 627 ETs were analyzed. INTERVENTION(S): Ovarian stimulation and ovum pick-up in donors. Uterine ET in recipients after appropriate exogenous steroid replacement. MAIN OUTCOME MEASUREMENT(S): Accumulated and estimated (95% confidence intervals [CI]) conception and live birth rates in the oocyte donation program as well as considering age and cause of infertility of the recipients. RESULT(S): Pregnancy rate after one cycle was 53.4% (CI 50.9% to 55.9%), with a delivery rate of 42.6% (CI 40.1% to 45.1%). Accumulated pregnancy rate increased up to 94.8% (CI 90.6% to 99.0%) after four transfers. Similarly, live birth rates reached 88.7% (CI 88.1% to 89.3%) after four attempts of ET by ovum donation. Cycle fecundity rates were maintained at approximately 50% after each attempt. Implantation rate was 18.3% (430/2,340 replaced embryos). Age and cause of entering the program did not influence the overall results of ovum donation. CONCLUSION(S): Oocyte donation is a successful treatment modality for infertile couples that offers even higher success rates than natural conception. No difference in cumulative pregnancy rate was observed regardless of recipient age, indication for oocyte donation, or number of cycles attempted.

Adult↗

The relationship of sperm counts to birth rates: a population based study.

PURPOSE: We determined if a statistical relationship exists between changes in sperm counts and birth rates by comparing data from a single geographic location for a 24-year period. MATERIALS AND METHODS: We retrospectively analyzed data from 660 men who banked 1,972 semen samples before vasectomy in Minnesota from 1971 to 1994. Using general linear models, annual variations in sperm count were determined after adjusting for age, duration of abstinence and seasonal (monthly) effects. Adjusted annual mean sperm count was then correlated with regional birth rate data obtained from The National Center for Health Statistics. RESULTS: Multiple regression analysis revealed a significant linear increase in mean annual sperm count at an estimated rate of 1.03 x 10(6) sperm per ml. per year (b = 0.14, t = 5.641, p < 0.0001). There was no effect of age (t = -0.814, p = 0.4156) but there were significant effects of abstinence (b = 0.14, t = 8.808, p < 0.0001) and month of sperm banking (b = 0.025, t = 5.00, p < 0.0001) on sperm counts. Using analysis of covariance there was a significant, nonlinear (year-to-year) fluctuation in mean sperm counts (F = 8.63, p < 0.001). For the study period mean birth rates in Minnesota (live births per 1,000 population) fluctuated yearly from 13.8 in 1973 to 16.7 in 1981. There was a strong correlation between adjusted mean yearly sperm count and annual birth rates (r = 0.63, p = 0.001). CONCLUSIONS: We found a statistically significant correlation between yearly variations in mean sperm counts and birth rates. Our data suggest that variations in male reproductive function may affect population based birth rates and, therefore, may be more important than previously understood.

Adult↗