Determinants of prenatal care use in Hawaii: implications for health promotion

This study examines the association between maternal sociodemographic characteristics and the receipt of different levels of prenatal care use (no care, inadequate, intermediate, adequate) in order to determine different patterns in the relationships between maternal characteristics and these distinct categories of prenatal care use. Using the 1979-1992 Hawaii live birth vital record file, single live births to Hawaii resident mothers of white, Hawaiian/part-Hawaiian, Filipino, or Japanese ethnicity, who did not indicate on the birth certificate that either parent was active duty military, were selected. Over one quarter of this study population did not initiate prenatal care in the first trimester. Given the high level of insurance coverage found in Hawaii, this finding is disconcerting, particularly in relation to the U.S. Year 2000 Objective of 90% initiation in the first trimester. Overall, the factors that predicted receipt of any prenatal care predicted more adequate use of prenatal care as well. Noteworthy exceptions were maternal age and ethnicity. Identifying these exceptions is important for the development of a more detailed understanding of risk factors related to use of prenatal care to better target program responses aimed at improving prenatal care use. In addition, these data suggest that removing financial barriers to access to care does not guarantee universal use of disease prevention and health promotion services.

Pregnancy outcomes of U.S.-born Puerto Ricans: the role of maternal nativity status

This study examines maternal sociodemographic characteristics, prenatal care use, and birth outcomes of U.S. resident Puerto Ricans by maternal nativity status in order to ascertain if Puerto Rican-born mothers exhibit better birth outcomes than U.S.-born Puerto Rican mothers, after controlling for maternal risk characteristics. All single live births to U.S. resident mothers indicating a Puerto Rican heritage or ethnicity on the infant's Certificate of Live Birth were selected for analysis from the 1983-1986 National Center for Health Statistics' Public Use U.S. Linked Live Birth and Infant Death File. Infants of Puerto Rican-born mothers had a significantly lower risk of low birthweight and small for gestational age infants than infants of U.S.-born Puerto Rican mothers, after controlling for available maternal risk factors. Nevertheless, infants of Puerto Rican-born mothers had a significantly higher risk of neonatal mortality, although they exhibited a significantly lower risk of postneonatal mortality. No significant maternal nativity status differences in very preterm, preterm, very low birthweight, and infant mortality were identified after controlling for the same maternal sociodemographic and prenatal care use variables. Infants of Puerto Rican-born mothers demonstrated higher birthweight-specific neonatal mortality rates but lower birthweight-specific postneonatal mortality rates for nearly every birthweight category. These findings emphasize the need for further investigation of the factors that may influence maternal nativity variations in intrauterine growth retardation, access to tertiary health care services, and postneonatal mortality.

Variations in pregnancy outcomes by race among 10-14-year-old mothers in the United States

This study used the 1983-86 U.S. Linked Live Birth-Infant Death Files to examine variations in pregnancy outcomes among 38,551 U.S. resident black and white adolescents ages 10 through 14. The birth rate was 4.29 per 1,000 for blacks, more than 7 times the rate for whites (.59 per 1,000). Black mothers had higher proportions of very low and low birth weight infants than did whites (very low birth weight: 3.7 versus 2.6; low birth weight: 15.0 versus 10.5). Neonatal and infant mortality rates were higher among very low birth weight and low birth weight white infants. Neonatal and infant mortality rates were similar for normal birth weight infants of both races, but were 3.7 to 7.4 times higher among black infants with birth weights more than 4,250 grams. Logistic regression indicated that black mothers were at higher risk for having infants who were low birth weight, very low birth weight, small for gestational age, preterm, and very preterm. There were no differences by race for neonatal, postneonatal, and infant mortality. While the risk for poor pregnancy outcomes is great among young adolescents, young black adolescents appear to be particularly vulnerable. Attempts to reduce unintended pregnancies in this group should receive highest priority.

Discordance between LMP-based and clinically estimated gestational age: implications for research, programs, and policy

This study examines the comparability between the last menstrual period-based and clinically estimated gestational age as collected on certificates of live birth. It explores whether sociodemographic or delivery characteristics influence their agreement and contrasts health status and health care utilization indicators, such as preterm, small for gestational age, and adequacy of prenatal care percentages, produced by each gestational age measure. The 1989-91 South Carolina public use live birth files were used for this analysis. A total of 169,082 single births to resident mothers were selected for investigation. The clinically estimated gestational age distribution exhibited a higher mean and a tendency toward even number digit preference. The last menstrual period-based measure produced higher preterm and postterm percentages. More than 60 percent of the last menstrual period-based preterm births were classified as preterm by the clinical estimate. The sensitivity of the clinical estimate was 27 percent for postterm births. The overall concordance (the percentage of cases with the same value for both measures) was 47 percent, but it varied considerably by gestational age. Between 30 and 35 weeks, the clinical estimate exceeded the last menstrual period-based value by 2 weeks or more for more than 40 percent of the cases. Concordance also varied by race of mother, hospital delivery size, trimester prenatal care began, and birth weight. The last menstrual period-based and the clinically estimated gestational age distributions exhibited notable dissimilarities, produced marked differences in health status indicators, and varied in concordance by gestational age and by sociodemographic, prenatal care, and hospital characteristics. These systematic differences suggest that a transition from the traditionally used last menstrual period-based measure to the clinical estimate or a composite measure will not produce uniform results across geo-political areas and at-risk groups but will be appreciably influenced by population and health care characteristics.

Similarities and disparities in maternal risk and birth outcomes of white and Japanese-American mothers

This study compares the maternal sociodemographic and prenatal care characteristics and birth outcomes of US resident white and Japanese-American mothers, using data from the state of Hawaii. The specific focus is to determine to what extent these factors can explain variations in newborn maturity and mortality indicators. Single livebirths to resident, non-military dependent white and Japanese-American mothers were selected for analysis from the 1979-1990 linked livebirth-infant death files from Hawaii. Compared with white mothers, Japanese-American mothers were significantly more likely to be married, age 18 years and older, have higher educational attainment, and have adequate prenatal care utilisation. The majority of Japanese-American mothers were born in Hawaii, while the majority of white mothers were born on the US mainland. The mean birthweight of Japanese-American infants was 200 g lighter than that of white infants. Infant mortality rates (IMRs) for both groups were below the US Year 2000 Health Objective. After controlling for maternal sociodemographic and prenatal care factors with logistic regression, Japanese-American infants had significantly higher risks of low birthweight, preterm and very preterm birth and of being small-for-gestational age. These findings indicate that populations with preferential maternal sociodemographic and prenatal care risk indicators may still exhibit higher low birthweight percentages, but achieve comparatively low IMRs.

The role of prenatal care in preventing low birth weight

Prenatal care has long been endorsed as a means to identify mothers at risk of delivering a preterm or growth-retarded infant and to provide an array of available medical, nutritional, and educational interventions intended to reduce the determinants and incidence of low birth weight and other adverse pregnancy conditions and outcomes. Although the general notion that prenatal care is of value to both mother and child became widely accepted in this century, the empirical evidence supporting the association between prenatal care and reduced rates of low birth weight emerged slowly and has been equivocal. Much of the controversy over the effectiveness of prenatal care in preventing low birth weight stems from difficulties in defining what constitutes prenatal care and adequate prenatal care use. While the collective evidence regarding the efficacy of prenatal care to prevent low birth weight continues to be mixed, the literature indicates that the most likely known targets for prenatal interventions to prevent low birth weight rates are (1) psychosocial (aimed at smoking); (2) nutritional (aimed at low prepregnancy weight and inadequate weight gain); and (3) medical (aimed at general morbidity). System level approaches to impact the accessibility and the appropriateness of prenatal health care services to entire groups of women and population-wide health promotion, social service, and case management approaches may also offer potential benefits. However, data on the effectiveness of these services are lacking, and whether interventions focused on building cohesive, functional communities can do as much or more to improve low birth weight rates as individualized treatments has yet to be explored. The ultimate success of prenatal care in substantially reducing current low birth weight percentages in the United States may hinge on the development of a much broader and more unified conception of prenatal care than currently prevails. Recommendations for actions to maximize the impact of prenatal care on reducing low birth weight are proposed both for the public and for the biomedical, public health, and research communities.

The perinatal and infant health status of Native Hawaiians

Hawaii vital record data for 1979 through 1990 were analyzed to examine potentially differing relationships between maternal and infant risks and outcomes in native Hawaiian and White infants. Despite high rates of inadequate prenatal care and teenage and unmarried childbearing, the Hawaiian low-birth-weight rate was below the US average. Hawaiian infants experienced an elevated risk of mortality, particularly among those of normal birthweight during the postneonatal period. Public health initiatives to reduce infant mortality must go beyond preventing teenage pregnancy and low birthweight to address Hawaiian infants' unique pattern of risk factors and the social and economic environment in which such risks abound.

Prenatal care utilization in Minnesota. Patterns of concern, areas for improvement

We conducted an analysis of prenatal care utilization among Minnesota resident mothers for the years 1990 to 1991 to determine why this state ranks poorly in prenatal care use while its infant mortality rate is one of the lowest in the nation. We found that 6% of women began care in the first trimester yet did not receive an adequate number of visits. These women were more likely to deliver preterm, low birthweight infants than women who started care later. Fifteen percent of women had records missing important data, and these women also had higher rates of poor pregnancy outcomes. Our findings have implications for maternal outreach and follow-up efforts and suggest potential benefits from private and public health collaborations. In addition, efforts to improve the quality of data reporting should begin immediately.

Determinants of meconium-stained amniotic fluid in term pregnancies

This study examines ethnic variations in meconium-stained amniotic fluid in term pregnancies, taking into account the role of gestational age, maternal sociodemographic characteristics, and medical risk factors. The study population included black and white singleton live births (N = 14,419) between 37 and 42 weeks' gestation, delivered vaginally at the Medical University of South Carolina from 1982 through 1990. Chi-square and logistic regression analysis were used to examine the association between the independent variables and meconium-stained amniotic fluid (MSAF). An increased risk of MSAF was found for advancing gestational age, indicators of fetal stress, fewer than five prenatal care visits, and > 15 hours labor. After controlling for demographic and clinical characteristics, the risk of MSAF in black patients was approximately 1.5 times that of white patients. The higher proportion of MSAF in blacks could not be explained with obvious risk factors.

Hyaline membrane disease in black newborns: does fetal lung maturation occur earlier?

Debate has developed among several authors about possible accelerated maturation of black fetuses in comparison with whites. In Guadeloupe, French West Indies, where 85% of the population is of black African-American origin, it has been noted that the incidence of hyaline membrane disease (HMD) represents a significant drop beginning after the 32nd week of gestation. Over a 3-year period, 419 black low-birthweight singleton newborns were admitted in the University Hospital's Neonatal Department covering 70% of all births of the island. The incidence of HMD was 50% among very low birthweight (< 1500 g) and 8.3% among moderate low birthweight (> or = 1500 g; P < 0.001). The incidence of HMD was 48.8% among the very preterm (< 32 weeks) and 7.8% (26/331) among the moderate preterm (> or = 32 weeks; P < 0.001). These differences were similar for appropriate for gestational age and small for gestational age infants. Significant differences remained after controlling for several maternal risk factors. These results suggest that the 32nd week of gestation represents a significant drop in the risk for respiratory distress syndrome in black premature compared with that reported in literature on European infants (34th week) and therefore may implicate different obstetrical decisions in the management of critical pregnancies in this population.

Relation of the content of prenatal care to the risk of low birth weight. Maternal reports of health behavior advice and initial prenatal care procedures

OBJECTIVE

Numerous studies have found a relationship between the quantity of prenatal care received and birth outcomes. Few studies have had the opportunity to examine the content of prenatal care. This study examined the relationship between two components of the content of prenatal care: maternal reports of health behavior advice received and initial prenatal care procedures performed during the first two visits and low birth weight in a national sample of women. Advice and initial procedures were categorized based on the recommendations of the US Public Health Service Expert Panel on the Content of Prenatal Care.

DESIGN

Interview survey of a nationally representative sample of women who had live births in 1988.

PARTICIPANTS

A total of 9394 women, with data from the National Maternal and Infant Health Survey.

MAIN OUTCOME MEASURE

Low birth weight (< 2500 g) as reported on the birth certificate.

RESULTS

After controlling for other sociodemographic, utilization, medical, and behavioral factors, women who reported not receiving all the types of advice recommended by the Expert Panel on the Content of Prenatal Care were more likely to have a low-birth-weight infant compared with women who reported receiving the optimal level of advice (odds ratio = 1.38; 95% confidence interval, 1.18 to 1.60). There were no differences between women who reported receiving all the recommended initial prenatal care procedures and those who reported not receiving all recommended prenatal care (odds ratio = 1.00; 95% confidence interval, 0.87 to 1.14).

CONCLUSION

These data suggest that women who report receiving sufficient health behavior advice as part of their prenatal care are at lower risk of delivering a low-birth-weight infant.

Screening for cerebral palsy in preterm infants: delay criteria for motor milestone attainment

We evaluated the efficacy of various delay criteria (12.5%, 25%, 37.5%, 5%, 50% delay) for motor milestone attainment to screen a sample of 173 high-risk preterm infants with gestational age < 32 weeks who had been sequentially followed for 18 to 24 months. Sensitivities were best with 12.5% and 25% delays, but specificities and positive predictive values were relatively lower. Since societal resources for evaluation and treatment of cerebral palsy are limited, the excellent specificities (81% to 95%) and positive predictive values (48% to 85%) with 50% delay are more important than the somewhat lower sensitivities, especially since milestones involve a multistep screening process. Screening preterm infants by obtaining a history of motor milestone attainment with each child care visit, correcting for degree of prematurity, and using a 50% delay criteria is a practical, inexpensive method of identifying infants at highest risk of cerebral palsy.

Comparing mothers' reports on the content of prenatal care received with recommended national guidelines for care

The Public Health Service's Expert Panel on the Content of Prenatal Care Report in 1989 provided detailed guidelines for the components of each prenatal visit. However, the extent to which women were receiving the recommended care when the guidelines were being formulated has yet to be determined. The 1988 National Maternal and Infant Health Survey results permit an examination of the proportion of women who reported receiving some of the recommended procedures. Women were asked if they received six of the recommended procedures (blood pressure measurement, urine test, blood test, weight and height taken, pelvic examination, and pregnancy history) in the first two visits, and whether they received seven types of advice or counseling (nutrition; vitamin use; smoking, alcohol, and drug use cessation; breastfeeding; and maternal weight gain) any time during their pregnancy. Only 56 percent of the respondents said they received all of the recommended procedures in the first two visits, and only 32 percent of the respondents said they received advice in all of the areas. Logistic regression analysis indicated that women receiving their care from private offices were significantly less likely to receive all the procedures and advice than women at publicly funded sites of care. This study suggests that recommendations of the Public Health Service's expert panel were not being met.

Racial disparities in reported prenatal care advice from health care providers

OBJECTIVES

The relationship between certain maternal behaviors and adverse pregnancy outcomes has been well documented. One method to alter these behaviors is through the advice of women's health care providers. Advice from providers may be particularly important in minority populations, who have higher rates of infant mortality and prematurity. This study examines racial disparities according to women's self-report of advice received from health care providers during pregnancy in four areas: tobacco use, alcohol consumption, drug use, and breast-feeding.

METHODS

Health care providers' advice to 8310 White non-Hispanic and Black women was obtained from the National Maternal and Infant Health Survey.

RESULTS

After controlling for sociodemographic, utilization, and medical factors, Black women were more likely to report not receiving advice from their prenatal care providers about smoking cessation and alcohol use. The difference between Blacks and Whites also approached significance for breast-feeding. No overall difference was noted in advice regarding cessation of drug use, although there was a significant interaction between race and marital status.

CONCLUSIONS

These data suggest that Black women may be at greater risk for not receiving information that could reduce their chances of having an adverse pregnancy outcome.

Multiethnic variations in the pregnancy outcomes of military dependents

OBJECTIVES

We examined the pregnancy outcomes of three ethnic groups: African-American Blacks, non-Hispanic Whites, and Filipinos. In an attempt to reduce ethnic dissimilarities in parental employment and access to health care, this investigation compared the single-live-birth outcomes of married, adult women who resided in the state of Hawaii and who indicated that their spouse was on active-duty status in the US military.

METHODS

The data for this study were obtained from the 1979-1989 Hawaii vital-record file that provides linked live birth-infant death information. Multiple logistic regression was used to calculate odds ratios for the independent effects of maternal factors on low birthweight and neonatal mortality.

RESULTS

Significant differences in maternal age, maternal education, paternal education, parity, hospital of delivery, and use of prenatal care were observed among the ethnic groups. The results of a logistic regression analysis of low birthweight indicated significantly higher risks for Filipinos and Blacks compared with Whites. For very low birthweight, only an increased risk for Blacks was observed. No ethnic differences in neonatal mortality were found.

CONCLUSIONS

This investigation revealed more comparable infant mortality experiences among the ethnic groups in spite of persistent birthweight differences.

Paternity patterns and risk of preeclampsia in the last pregnancy in multiparae

Few authors have published investigations regarding a possible association between preeclampsia and changing paternity. This study employs an epidemiological approach to explore the relationship between severe preeclampsia and changes in paternity patterns among multigravidae in a Caribbean community (Guadeloupe, French West Indies). Multiparae who were diagnosed with preeclampsia or eclampsia with fetal complications (transfer of their infants in the Neonatal Department) and controls were examined (134 mothers' interviews). Information concerning paternity for the index and previous pregnancies was collected from three groups: women with pregnancy-induced hypertension (PIH); women with chronic hypertension (CH); and a control group consisting of women without hypertension during pregnancy. In 21/34 (61.7%) of PIH mothers, the father of the current pregnancy was different than that of the former, compared to 4/40 (10%) among CH and 10/60 (16.6%) in the controls (P < 0.0001). Moreover, considering three and four consecutive pregnancies, there was a significant trend (P < 0.005 and P < 0.02) for an increase in PIH with having a different father in each successive pregnancy. Patterns of changing paternity were significantly correlated with pregnancy-induced hypertension in multiparae but not with chronic hypertension and controls.

Hyaline membrane disease: the role of ethnicity and maternal risk characteristics

OBJECTIVE

Our objective was to explore the association between maternal ethnicity and maternal antepartum complications of pregnancy, maternal sociodemographic factors, and newborn characteristics with the incidence of hyaline membrane disease.

STUDY DESIGN

By using a retrospective cohort analysis the incidence of hyaline membrane disease was determined for 2295 preterm infants. The study population consisted of all live, inborn infants delivered vaginally from 1982 to 1987. Statistical differences were assessed by use of chi 2 and Student's t tests. A logistic regression procedure determined the relationship of ethnicity and hyaline membrane disease after the study was controlled for all other significant population differences.

RESULTS

The differences between black and white populations in marital status, were statistically significant years of education, prolonged rupture of membranes, anemia, and chronic hypertension were statistically significant. Infants of black mothers were diagnosed with hyaline membrane disease less often than infants of white mothers (overall and at each gestational age interval). After the study was controlled for population differences, infants of black mothers were still found to experience hyaline membrane disease less often.

CONCLUSION

These data suggest that hyaline membrane disease occurs less frequently, is less severe, and is accompanied by fewer related complications in black preterm infants.

Geographic patterns of low birth weight in Hawaii

This study examines areal variations in low birth weight, using the census tract as the unit of analysis. Reports from the 1980 U.S. census were used to develop summary indicators of environmental and socio-economic conditions, including poverty, employment, education and crowding, for 155 census tracts in the state of Hawaii. Maternal socio-demographic, prenatal care utilization, and medical risk indicators and low birth weight percentages for resident, single live births were extracted from the Hawaii 1979-1987 vital record live birth files and aggregated by census tract. Multiple regression analysis was used to develop a model that predicted 61% of the variation among census tracts in the percentage of low birth weight. Patterns of low birth weight were primarily associated with ethnic patterns of maternal residence and single marital status. There was no association between inadequate prenatal care and low birth weight at the census tract level.

Birth outcomes of Korean women in Hawaii

Since the end of the Korean War, immigration of Koreans to the United States has increased rapidly. In 1990, 11.6 percent of all Asians in the United States were of Korean ethnicity, and it is projected that Koreans will outnumber all other Asian groups, except Filipinos, in the United States by the year 2030. Despite the growing size of this population, very little is known about their health status. This study, using 1979-89 Hawaii vital record data, investigates the relationship between maternal sociodemographic characteristics, prenatal care utilization factors, and birth outcomes among Koreans as compared with Caucasians. The ethnic term "Caucasian" is used in Hawaii's vital records and is synonymous with non-Hispanic whites. Korean mothers were more likely to be older and have lower educational attainment, and less likely to be adolescent, single, or to have received adequate prenatal care than Caucasian mothers. More than 80 percent of the Korean mothers were foreign born. Significantly higher risks for very preterm delivery (less than 33 weeks) and very low birth weight births were observed for Koreans as compared with Caucasians. Nativity had no effect on birth outcome in this population. The results of this study suggest that prevention of preterm birth is an important focus for improving pregnancy outcomes in this growing ethnic group.

Ethnic variation in postnatal assessments of gestational age: a reappraisal

While the possibility of an ethnic bias in postnatal assessments of gestational age has been suggested by several investigators, others have reported that postnatal assessments do not provide biased estimates in non-White ethnic groups. In the light of this ongoing controversy, this study examines the validity of the Ballard postnatal assessment of gestational age by ethnicity, using a relatively large hospital data base that allows for the inspection of ethnic variations in the agreement between the Ballard assessment and last menstrual period (LMP). The results indicate that there is a greater over-estimation of the LMP interval by the Ballard method in Blacks compared with Whites and suggest that systematic differences exist by ethnicity of mother in the agreement between the Ballard postnatal assessment and the LMP interval. After taking maternal characteristics and pregnancy complications into account, for a given gestational age interval, Blacks have on average a greater level of maturity as measured by Ballard. One interpretation of these findings is that postnatal assessments may provide biased over-estimates of the LMP gestational age interval in certain ethnic groups. An alternative interpretation of these data is that the gestational age interval based on LMP is not a valid indicator of fetal maturity, readiness for birth and infant risk status across all ethnic groups.

Validity of postnatal assessments of gestational age in low birthweight infants from a Caribbean community

The Dubowitz assessment of gestational maturity was compared with the best obstetric estimate of gestational age based on date of last menstrual period (LMP) or ultrasonography performed early in the pregnancy or both. This study involved 384 low birthweight infants admitted to the neonatal tertiary center in Guadeloupe, French West Indies, during the period 1986 through 1988. The Dubowitz assessment exceeded the best obstetric estimation by an average of nearly 5 days. This overestimation by the Dubowitz method was observed at every gestational age and was greatest at gestational ages of less than 35 weeks. The physical characteristics of the postnatal assessment were in closer agreement with the best obstetric estimate than the neurological characteristics. These findings concur with other investigations that indicate that the Dubowitz postnatal assessment of gestational age overestimates the gestational age interval from date of LMP in low birthweight and preterm infants.

Validity of postnatal assessments of gestational age: a comparison of the method of Ballard et al. and early ultrasonography

This study investigates the accuracy of the postnatal gestational age assessment method of Ballard et al. to predict very preterm, preterm, term, postterm, and small-for-gestational-age infants, with gestational age by early ultrasonography used as the gold standard. Sensitivity, specificity, and predictive value were examined for each gestational age category, with 4193 single live births occurring during the period from 1982 through 1989 with an ultrasonographic examination done by 20 weeks' gestation and a postnatal assessment at 28 to 44 weeks. These data indicate that the postnatal assessment overestimated the gestational age of preterm births, resulting in an underestimation of very preterm and preterm percentages. Nearly three fourths of the postterm births by ultrasonography were misclassified by the method of Ballard et al. because of underestimation of postterm gestational ages. These data indicate that, for research purposes, appreciable misclassification of preterm, postterm, and small-for-gestational-age infants will occur if gestational age is determined by the technique of Ballard et al.

Using gross motor milestones to identify very preterm infants at risk for cerebral palsy

The authors evaluated the efficacy of 10 gross motor milestones to screen for cerebral palsy in 173 high-risk, very preterm infants (less than or equal to 32 weeks gestation) followed for 18 to 24 months. Correcting for preterm birth and using population norms led to a better improvement in specificity and positive predictive values; race-specific norms did not contribute significantly. Incorporating a history of milestone attainment into the routine during sequential office visits will help health-care providers to monitor the development of high-risk infants.

Area-level predictors of use of prenatal care in diverse populations

Patterns and predictors of the use of prenatal care in Hawaii were examined by census tract, taking into account summary measures of socioeconomic status, environmental conditions, and aggregated indicators of pregnancy-related risk characteristics of mothers. The objectives of the study were to identify those census tracts with high levels of inadequate use of prenatal care services; to develop a model, based on census tract characteristics, to explain observed geographic variations in the use of prenatal care services; and to identify for further investigation specific localities with unanticipated patterns of use. Data were drawn from 1980 census reports and vital statistics live birth files for the period 1979-87. Regression analysis was used to develop a model that was able to predict 61 percent of the census tract variation in the percentages of inadequate use of prenatal care services. Increased proportions of mothers of Japanese and other Asian-descent and of adults with more than high school education were associated with low levels of inadequate use of prenatal care services. Increased proportions of high parity-for-age risk and Samoan mothers were associated with higher levels of inadequate use. Census tract maps of actual and predicted percentages and studentized residual values were used to identify areas with high and low rates of inadequate use of prenatal care services. The area-level methods used are believed applicable to health care planning in other areas with ethnically or socioculturally diverse populations.

Seasonal variation in adolescent conceptions, induced abortions, and late initiation of prenatal care

The monthly distribution of conceptions among adolescents and the proportion of adolescent pregnancies that are voluntarily terminated by induced abortion by month of conception are the objects of this study. Additionally, seasonal variations in the timing of initiation of prenatal care services by adolescents are investigated. Vital records files of single live births, fetal deaths, and induced terminations of pregnancy to residents in the State of South Carolina, 1979-86, were aggregated to estimate conceptions. There was a significant difference between adolescents and adults in the monthly distribution of conceptions. The peak month of adolescent conceptions coincided with the end of the school year. Pregnancies of adolescents occurring at this time further demonstrated later access of prenatal care services than conceptions occurring at other times of the year, most notably during the school term. These findings suggest that there is considerable opportunity for improving the availability of reproductive health care services for adolescents. The results specifically suggest the potential benefit of increasing adolescent pregnancy prevention efforts prior to high-risk events and increasing the availability of and access to health care and counseling services to adolescents during the school recess months of the summer.