The effect of maternal smoking on birth weight in twin pregnancies

Information on 869 076 singletons and 17 566 twins, born during the period 1983-1991, was obtained from the Swedish Medical Birth Registry. Data on birth weight, gestational duration, vital status, and maternal smoking habits during pregnancy were analyzed in order to investigate whether twinning potentiates the effect of maternal smoking on birth weight and perinatal mortality. The individual birth weights were expressed as percentages of mean birth weight, where mean birth weights of singletons and twins were calculated separately. The birth weight reducing effect of maternal smoking was found to be of the same magnitude among twins and singletons weighing > 90% of mean birth weight. For infants weighing < 90% of mean birth weight, maternal smoking had a significantly stronger effect on birth weight among singletons than among twins. When gestational duration was taken into consideration, this difference was less pronounced. The effect of maternal smoking on gestational duration was stronger among singletons than twins. The smoking-related risk increase of perinatal death was of about the same magnitude among twins and singletons.     

Preterm and term births of small for gestational age infants: a population-based study of risk factors among nulliparous women

OBJECTIVE: To study risk factors for small for gestational age (SGA) infants by gestational age among nulliparous women and to estimate mortality rates among SGA and appropriate-for-gestational-age (AGA) infants by gestational age. DESIGN: A population-based study from the Swedish Medical Birth Register. Setting Sweden 1992 1993. POPULATION: Liveborn singleton infants to nulliparous women (n = 96,662). MAIN OUTCOME MEASURES: Crude and adjusted odds ratios of risk factors for SGA by gestational age. Rates of neonatal and postneonatal mortality. RESULTS: Older maternal age (> or = 30 years) was foremost associated with increased risks of very and moderately preterm SGA (> or = 32 weeks and 33-36 weeks, respectively), but also with term SGA (> or = 37 weeks). Risks of SGA increased with decreasing maternal height at all gestational ages. Smoking increased the risks of moderately preterm and term SGA. Short maternal education increased the risk of preterm SGA and low pre-pregnancy body mass index slightly increased the risk of term SGA. Pre-eclampsia and essential hypertension foremost increased the risk of very preterm SGA (OR = 40.5 and 32.4, respectively) and moderately preterm SGA (OR = 17.4 and 10.6, respectively), but also increased the risk of term SGA. Neonatal and postneonatal mortality rates of SGA infants were substantially influenced by gestational age, and mortality rates were consistently higher among preterm SGA infants compared with AGA infants. Conclusions: Risk factors for SGA and mortality rates among SGA infants vary by gestational age. A subdivision of risk factors by gestational age adds knowledge, particularly about risks of preterm SGA, where the highest rates of mortality were observed.     

Preterm delivery: effects of socioeconomic factors, psychological stress, smoking, alcohol, and caffeine

OBJECTIVE: To examine the relation between preterm birth and socioeconomic and psychological factors, smoking, and alcohol, and caffeine consumption. DESIGN: Prospective study of outcome of pregnancy. SETTING: District general hospital in inner London. PARTICIPANTS: 1860 consecutive white women booking for delivery; 1513 women studied after exclusion because of multiple pregnancy and diabetes, refusals, and loss to follow up. MEASUREMENTS: Gestational age was determined from ultrasound and maternal dates; preterm birth was defined as less than 37 completed weeks. Independent variables included smoking, alcohol and caffeine consumption, and a range of indicators of socioeconomic status and psychological stress. MAIN RESULTS: Unifactorial analyses showed that lower social class, less education, single marital status, low income, trouble with "nerves" and depression, help from professional agencies, and little contact with neighbours were all significantly associated with an increased risk of preterm birth. There were no apparent effects of smoking, alcohol, or caffeine on the length of gestation overall, although there was an association between smoking and delivery before 32 weeks. Cluster analysis indicated three subgroups of women delivering preterm: two predominantly of low social status and a third of older women with higher social status who did not smoke. Mean gestational age was highest in the third group. CONCLUSIONS: Adverse social circumstances are associated with preterm birth but smoking is not, apart from an association with very early births. This runs counter to findings for fetal growth (birth weight for gestational age) in this study, where a strong effect of smoking on fetal growth was observed but there was no evidence for any association with psychosocial factors.     

The relationship of pretreatment serum hemoglobin level to the survival of epithelial ovarian carcinoma patients: a prospective review

OBJECTIVE: Our purpose was to examine the impact of gestational age and fetal growth restriction on fetal and neonatal mortality rates in the postterm pregnancy. STUDY DESIGN: All deliveries occurring in Sweden between Jan. 1, 1987, and Dec. 31, 1992, were evaluated for participation in this study. Data were derived from the National Swedish Medical Birth Registry. Pregnancies were selected for inclusion in the study on the basis of the following criteria: (1) singleton pregnancy, (2) reliable dates, (3) gestational age > or = 40 weeks, and (4) maternal age 15 to 44 years. Fetal growth restriction was defined as birth weight <2 SD below the mean for gestational age. A total of 181,524 pregnancies met the inclusion criteria and formed the study population. Fetal and neonatal mortalities at 40 weeks' gestation were used as reference levels. Logistic regression analysis was used to estimate the independent effects of gestational age and fetal growth restriction on fetal and neonatal mortality rates. RESULTS: A significant rise in the odds ratio for fetal death was detected from 41 weeks' gestation and on (odds ratios 1.5, 1.8, and 2.9 at 41, 42, and 43 weeks, respectively). Odds ratios for neonatal mortality did not demonstrate a significant gestational age dependency. Fetal growth restriction was associated with significantly higher odds ratios for both fetal and neonatal mortality rates at every gestational age examined (with odds ratios ranging from 7.1 to 10.0 for fetal death and from 3.4 to 9.4 for neonatal death). CONCLUSIONS: Postterm pregnancies have long been considered to be at high risk for adverse perinatal outcome. This study documents a small but significant increase in fetal mortality in accurately dated pregnancies that extend beyond 41 weeks of gestation. This study also demonstrates that fetal growth restriction is independently associated with increased perinatal mortality in these pregnancies.     

Objectively measured tobacco exposure during pregnancy: neonatal effects and relation to maternal smoking

OBJECTIVES: To measure quantitatively and objectively the maternal and fetal tobacco exposure during pregnancy and its neonatal effects. DESIGN: Tobacco exposure was assessed from maternal serum samples, obtained during the first half of pregnancy and from umbilical serum samples obtained at delivery, by measuring the concentration of nicotine metabolite, cotinine. Data on the respective pregnancies and neonates were collected from the Finnish Medical Birth Registry. SETTING: Finland. SUBJECTS: One thousand two hundred and thirty-seven pregnancies and newborns, representing all pregnancies resulting in a liveborn infant during one week in one country. MAIN OUTCOME MEASURES: Gestational age, birthweight and crown-heel length of newborns. RESULTS: Cotinine (> 6 micrograms/l) was detected in either maternal or umbilical serum in 300 pregnancies, and these mothers and newborns were classified as exposed. Important differences occurred between measured exposure and reported smoking behaviour. Of the exposed mothers, 38% were nonsmokers and 3.4% of the nonexposed mothers were smokers. Tobacco exposure was associated with shorter gestational age, reduced birthweight and shorter crown-heel length of the newborns. After correction for parity, gender, and gestational age, the exposed newborns were on average 188 g (95% confidence interval (CI) 123-253 g) lighter and 10 mm (95% CI 7-13 mm) shorter than the nonexposed newborns. One micrograms/ml of cotinine in maternal serum resulted in a mean decrease of 1.29 g (95% CI 0.55-2.02 g) in birthweight and in a mean decrease of 0.059 mm (95% CI 0.035-0.083 mm) in birth length. Maternal cotinine concentrations better explained the neonatal findings than the reported smoking habits. CONCLUSIONS: There is a quantitative dose and effect relation between tobacco exposure and a decrease in the gestational age at birth and size of the neonate. The smoking habit reported by mothers themselves is not an accurate measure of fetal tobacco exposure.     

A record-linkage study on risk factors for cause-specific infant mortality

Infant death certificates were linked with birth certificates for infants born to residents of Tohoku, Tokai and Kyushu regions in 1989 (n = 409, 679, or about one-third of all births in Japan), to examine the effects of variables, as reported on birth certificates, on cause-specific infant mortality. "Certain conditions originating in the perinatal period" and "congenital anomalies" accounted for nearly 90 percent of neonatal deaths, while "congenital anomalies", "injuries and poisoning" and "sudden infant death" were responsible for about 65 percent of postneonatal deaths. Mortality rates for almost all causes of infant deaths, except injuries and poisonings, increased as birth weight decreased not only in the neonatal period but also in the postneonatal period. This suggests that low birth weight places some infants at higher risk of death, and conditions that lead to low birth weight independently contribute to the risk of infant death. Cox's proportional hazards linear model was used to assess the effects of variables on infant mortalities by causes of death. An extremely strong birth weight effect was noted for "certain conditions originating in the perinatal period" and "congenital anomalies". Being a male infant and late order of birth in multiparity were other risk factors for deaths from "congenital anomalies", while being a male infant, resident of Tohoku region and maternal stillbirth experience related to deaths from "certain conditions originating in the perinatal period". Elevated risks of sudden infant death syndrome (SIDS), of which mortality rate in Japan was considerably lower than those in most developed Western countries, i.e. 0.23 per 1,000 live births in 1989, were associated with low birth weight, being a male infant, low maternal age, late order of birth in multiparity and illegitimacy. Low maternal age, late order of birth in multiparity and illegitimacy, also, related significantly to increased risk of infant deaths for "injuries and poisoning". These results suggest the independent contributions of socioeconomic factors to infant mortality, especially postneonatal mortality, from SIDS, "injuries and poisonings".     

The effect of smoking cessation during pregnancy on preterm delivery and low birthweight

BACKGROUND: Evidence exists that maternal cigarette smoking is associated with preterm birth. Our purpose was to investigate the relation between maternal smoking cessation at different points during pregnancy and the preterm delivery rate and low birthweight. METHODS: Data from the 1988 National Health Interview Survey were analyzed. The study included women who gave birth to children within 6 years of the 1988 interview date (N = 4876). Preterm delivery and infant low birthweight were the main outcome measures. These measures were compared with maternal smoking status during pregnancy. Logistic regression models were computed to control for maternal age at the time of birth, parity, race, and total family income. RESULTS: Women who did not smoke cigarettes during pregnancy were less likely to give birth prematurely (5.9% vs 8.2%, P = .003) or give birth to a low-birthweight baby (5.5% vs 8.9%, P < .001) than women who smoked at some time during the year before giving birth. A significant association existed between maternal smoking status and both preterm delivery and low birthweight. Compared with those who smoked beyond the first trimester, those who quit smoking within the first trimester had reductions in the proportion of preterm deliveries (6.7% vs 9.1%) and low birthweight infants (7.9% vs 9.6%). CONCLUSIONS: Low birthweight and preterm delivery are reduced in women who stop smoking in the first trimester of pregnancy.     

Completeness of ascertainment of prenatal smoking using birth certificates and confidential questionnaires: variations by maternal attributes and infant birth weight. PRAMS Working Group. Pregnancy Risk Assessment Monitoring System

Birth certificate data frequently are used to monitor the prevalence of smoking during pregnancy. The authors used a two-sample capture-recapture method to estimate the completeness of ascertainment of prenatal smoking on birth certificates and on confidential questionnaires in six US states. Completeness of ascertainment was also examined according to maternal attributes and infant birth weight. The samples included white women who delivered a live infant between 1993 and 1995 in one of six states (Alabama, Alaska, Georgia, Maine, South Carolina, or West Virginia) and who responded to a questionnaire mailed to them 2-6 months postpartum as part of the Pregnancy Risk Assessment Monitoring System. State-specific sample sizes ranged from 2,647 to 4,795. The completeness of ascertainment ranged from 70.6% to 82.0% using birth certificates and from 86.2% to 90.3% using confidential questionnaires. In all six states, the birth certificates' completeness of ascertainment varied by maternal education and infant birth weight, and the questionnaires' completeness varied by maternal age. Both birth certificates and questionnaires underestimated the true extent of smoking during pregnancy among these white women. Differential reporting by birth weights recorded on birth certificates would result in an overestimated association between low birth weight and prenatal smoking.     

Sudden infant death syndrome: risk factor profiles for distinct subgroups

The authors investigated risk profiles of sudden infant death syndrome (SIDS) as a function of age at death. A case-control study carried out in the Tyrol region of Austria enrolled 99 infants who died of SIDS between 1984 and 1994 and 136 randomly selected controls. Early and late SIDS (< 120 days of age vs. > or = 120 days) were defined according to the clear-cut bimodal age-at-death distribution. Inadequate antenatal care, low parental social and educational level, and the prone sleeping position were risk conditions that applied to both early and late SIDS. A marked seasonal variation (winter preponderance) was the most outstanding feature of late SIDS. A gestational age of < 37 weeks (odds ratio (OR) = 8.4, 95% confidence interval (CI) 2.6-26.0), repeated episodes of apnea (OR = 5.7, 95% CI 1.2-27.0), low birth weight (< 2,500 g) (OR = 3.4, 95% CI 1.1-11.0), a family history of sudden infant death (OR = 2.9, 95% CI 1.1-7.5), and maternal smoking during pregnancy (OR = 2.2, 95% CI 1.0-4.5) were associated with early SIDS. This study identified two distinct subgroups of SIDS infants characterized by different risk conditions and ages at death. These results underline a multiple-cause hypothesis for SIDS etiology which involves a genetic predisposition, immaturity in the first months of life, and environmental factors acting at various ages.     

1988 National Maternal and Infant Health Survey: methods and response characteristics

OBJECTIVES: The 1988 National Maternal and Infant Health Survey (NMIHS) was conducted by the National Center for Health Statistics to study factors related to poor pregnancy outcome, such as adequacy of prenatal care; inadequate and excessive weight gain during pregnancy; maternal smoking, drinking, and drug use; and pregnancy and delivery complications. METHODS: The NMIHS is a nationally representative sample of 11,000 women who had live births, 4,000 who had late fetal deaths, and 6,000 who had infant deaths in 1988. Questionnaires were mailed to mothers based on information from certificates of live birth, reports of fetal death, and certificates of infant death. Information supplied by the mother, prenatal care providers, and hospitals of delivery was linked with the vital records to expand knowledge of maternal and infant health in the United States. RESULTS: The response rates in all three components of the NMIHS differed according to the mothers' characteristics. Mothers were more likely to respond if they were 20-39 years of age, were white, were married, had fewer than four children, entered prenatal care early, had more prenatal visits, had more years of education, or resided in the Midwest Region. The percent of respondents was lower for teenage mothers, mothers of races other than white, and mothers with four or more children, little prenatal care, or fewer years of education. Mothers whose infants weighed less than 2,500 grams were less likely to respond in the live-birth and infant-death components than mothers whose infants weighed 2,500 grams or more. CONCLUSIONS: The NMIHS will provide an invaluable tool for researchers and practitioners seeking solutions to perinatal and obstetric problems.     

A prospective cohort study on the survival experience of under five children in rural western India

OBJECTIVE: To study the role of birth weight, nutrition, immunization and other medical as well as social factors in determining child survival. DESIGN: A prospective cohort study. SETTING: 45 villages in Shirur Development Block in Pune District in Maharashtra. METHODS: A cohort of 4129 children were followed from birth till 5 years of age. Weight and length/height of the child was measured at birth and at 3 monthly home visits. Information was also obtained on common childhood morbidities, immunization status and other bio-medical factors. Cause of death was ascertained by verbal autopsy. RESULTS: The neonatal, infant and underfive mortality was rates were estimated to be 37, 60 and 79 per 1000 live births, respectively. Diarrhea and ARI contributed to the major mortality burden. The Kaplan Meier Survival curve showed a sharp fall in the neonatal period, a less rapid decline in the post-neonatal period followed by a marginal fall in the post-infancy period till 5 years age. Girls had a better survival in the early neonatal period but the trend reversed in the late neonatal period. Normal birth weight children had better survival curves compared to low birth weight children. Survival improved with increasing birth order. Multivariate analysis revealed that birth weight, immunization status, and mother's and child's nutritional status influenced infant and under five mortality. CONCLUSION: Birth weight continues to exert its influence not only on survival/mortality in early life but even as late as 5 years of age. Strategies to improve child survival should include immunization and breastfeeding.     

Risk factors for low birth weight and intrauterine growth retardation in Santiago, Chile

An epidemiologic case-control study to ascertain the determinants of low birthweight was carried out in Santiago, Chile, from January to December 1989. The cases were defined as livebirths < 2500 g. The controls were livebirths > or = 2500 g of birthweight. All cases and a random sample (1:1) of controls were selected among 8,254 singleton births occurring at the El Salvador Hospital in the Eastern area of Santiago. These deliveries represented 50% of institutional deliveries in the area. Home deliveries (2%) and private hospital deliveries were not included in the study. Information was obtained from hospital medical records by six trained medical students. Some information could not be obtained from the hospital medical records. Thus the second step in data collection was the tracking of all the selected subjects to their referring neighborhood health centers. For the analysis, the data were divided into 3 case (outcome) categories: 453 subjects were the total case group. From these, 153 were the IUGR case group and 300 were the LBW preterm case group. The general control group consisted of 605 normal birthweight infants. 565 were the IUGR control group and 40 were the preterm control group. A total of 25 risk factors showed a significant crude odds ratio for at least one of the groups. In the multivariate logistic regression analysis eight variables: No. of pregnancies, previous adverse outcomes, previous LBW, pregnancy maternal weight, No. of visits, month of first prenatal care visit, maternal smoking and intrahepatic cholestasis of pregnancy, were significantly associated with LBW after adjustment by confounding. Eight risk factors: IUGR in previous pregnancies, Previous adverse outcome, Maternal smoking, intrahepatic cholestasis, maternal pregnancy weight, maternal height, month first prenatal visit, No. of visit, were significant to IUGR. Only two variables: pregnancy weight, divorced mother, were significantly associated with low birth weight in the preterm group. The most relevant risk factors were included in stepwise logistic regression models carried out for the outcome LBW for the general group, term group and preterm group, in order to adjust by confounding. Adjusted odds ratios were then obtained. Prenatal care related factors and maternal adverse obstetric factors were at higher significance for LBW in the general and IUGR groups. Only nutritional factors were related to LBW in preterm group. Women who delivered a LBW or IUGR infant were more likely to have fewer pregnancies, a history of previous LBW, lower prepregnancy weight and lower gestational weight gain. ICP was associated with an elevated risk of LBW that was independent of gestational age.     

Maternal serum human chorionic gonadotropin as a marker for the delivery of low-birth-weight infants in women with unexplained elevations in maternal serum alpha-fetoprotein

We wished to ascertain whether the measurement of maternal serum human chorionic gonadotropin (MShCG) in the serum of pregnant women with unexplained elevations of maternal serum alpha-fetoprotein (MSAFP) would more precisely define those women at risk of adverse pregnancy outcomes. MShCG was measured in samples of serum obtained from women in the second trimester of pregnancy who had elevated MSAFP, normal Level II ultrasounds, and normal fetal karyotypes. Based on the characteristics of a receiver-operator curve for MShCG and birth weight, patients were divided into two groups and pregnancy outcomes were compared. Pregnant women with an unexplained elevation in MSAFP, who also had an abnormal MShCG (< or = 0.5 MoM > or = 2.5) were at significantly greater risk of delivering a low-birth-weight infant compared to women with a normal MShCG (43% and 15%, respectively; P = 0.013). They were also more likely to deliver a preterm infant (48% and 11.9%), respectively; P = 0.001). In the prediction of low birth weight, an abnormal MShCG had a sensitivity of 50%, a specificity of 81%, and a positive predictive value of 43%; in the detection of preterm delivery the values were 59%, 88%, and 48%, respectively. These findings suggest that in pregnant women with a second trimester unexplained elevation in MSAFP, abnormal MShCG levels may identify a group of women at high risk of preterm delivery or delivery of a low-birth-weight infant.     

Delayed childbearing--are there any risks?

OBJECTIVE: To determine whether women delivering their first child at age 35 years or older are at increased risk of adverse (non-genetic) pregnancy outcomes. DESIGN AND SETTING: A cross-sectional analytic study of singleton deliveries in Northern Sydney Area Health Service (NSAHS) hospitals. PARTICIPANTS: All women aged > or = 20 years delivering their first child between 1 January 1990 and 31 December 1991. MAIN OUTCOME MEASURES: Obstetric complications and procedures, type of delivery and neonatal outcomes. RESULTS: Compared with women aged 20-29 years, women delivering their first child at > or = 35 years were at increased risk of pre-existing maternal hypertension (adjusted odds ratio [OR], 3.5; 95% confidence interval [CI], 1.7-7.0), antepartum haemorrhage (adjusted OR, 2.4; 95% CI, 1.6-3.7), preterm delivery (33-36 weeks) (adjusted OR, 2.0; 95% CI, 1.5-2.8) and breech presentation (adjusted OR, 1.8; 95% CI, 1.3-2.4). Women aged > or = 35 years were also substantially more likely to have an operative delivery, induced labour and/or epidural anaesthesia. Neither these women nor their infants were at increased risk of pregnancy-induced hypertension, gestational diabetes, threatened premature labour, postpartum haemorrhage, very preterm delivery (< or = 32 weeks), perinatal death, low Apgar scores or the need for neonatal resuscitation. CONCLUSIONS: Women who delay the birth of their first child face some increased risks, but these risks, for the most part, are manageable in the context of modern obstetric care.     

Target position variability throughout prostate radiotherapy

OBJECTIVE: It was our objective to evaluate the association between early maternal weight gain (before 20 weeks), midpregnancy weight gain (20-28 weeks), and late pregnancy weight gain (28 weeks to birth) with fetal growth and birth weight in twins. STUDY DESIGN: This historic cohort study was based on 1564 births of live twins >/=28 weeks' gestation from Baltimore, Maryland, Miami, Florida, Charleston, South Carolina, and Ann Arbor, Michigan. RESULTS: Early fetal growth was affected only by smoking and chorionicity. Factors in models of both mid and late fetal growth included maternal age, pregravid weight, parity, rates of early pregnancy and midpregnancy maternal weight gain, smoking, and pre-eclampsia. Increased midpregnancy fetal growth was associated with early maternal weight gain (10.91 g/wk per pound per week) and midpregnancy maternal weight gain (15.89 g/wk per pound per week). Increased late fetal growth was associated with early maternal weight gain (16.86 g/wk per pound per week) and midpregnancy maternal weight gain (23.88 g/wk per pound per week). Increased birth weight was associated with early (283.02 g per pound per week), mid (163.58 g per pound per week), and late (69.76 g per pound per week) maternal weight gains. CONCLUSIONS: These findings confirm the importance of early maternal weight gain in twin fetal growth and birth weight.     

The unreamed AO femoral intramedullary nail, advantages and disadvantages of a new modular interlocking system. A prospective study of 67 cases

The aim of this study was to investigate associations between sudden infant death syndrome (SIDS) and social factors in the Nordic countries. A case-control study was conducted in Denmark, Norway and Sweden: The Nordic Epidemiological SIDS Study. Parents of 244 SIDS infants and 869 control infants matched on gender, age at death and place of birth filled in questionnaires. The dataset was analysed by conditional logistic regression. In univariate analysis, the following sociodemographic factors were associated with an increased risk of SIDS: low maternal age [odds ratio (OR) 7.8; 2.8-21.5], high birth order (OR 4.4; 2.5-7.5), single motherhood (OR 2.9; 1.7-5.0), low maternal education (OR 4.5; 2.8-7.1), low paternal education (OR 3.0; 1.9-4.7), maternal unemployment (OR 2.4; 1.8-3.4) and paternal unemployment (OR 4.0; 2.7-5.9). In a multivariate analysis where maternal smoking was also included, only paternal unemployment, young maternal age and high birth order remained significantly associated with SIDS. Housing conditions were not associated with SIDS. However, the risk of SIDS was high if the family had lived in their present home for only a few years (OR 2.3; 1.3-4.1). Sociodemographic differences remain a major concern in SIDS in a low-incidence situation and even in an affluent population with adequate health services.     

Racial disparity in pregnancy outcomes: analysis of black and white teenage pregnancies

The pregnancies of black women are complicated by adverse outcomes such as prematurity and low birth weight at twice the rate of complications in pregnancies of white women. Although the cause of this racial disparity is unknown, it is most likely multifactorial. The disparity in outcomes has been found in many studies despite implementation of controls for the factors of age, socioeconomic status, and access to health care. We hypothesized that the increased incidence of adverse outcomes may be strongly affected by adequacy of prenatal care. We investigated the effects of comprehensive prenatal care delivered at the University of North Carolina-Chapel Hill Teenage Obstetric Clinic. The gestational age at the onset of prenatal care and the mean number of prenatal visits were the same for black and white teenagers. Among 183 teenagers we found no significant difference between black and white pregnancies for the outcomes of premature labor, premature delivery, fetal death, neonatal mortality, or hypertensive diseases. The mean gestational age at delivery was 38.3 weeks and 39.1 weeks for black and white women, respectively. The mean birth weight was 3126 gm and 3272 gm for black and white women, respectively. There was a trend (p < 0.09) toward more low birth weight infants in white women: 7% for black infants and 12% for white infants. We believe that comprehensive prenatal care significantly lessens the racial disparity in pregnancy outcomes between black and white adolescent women.     

Does passive smoking in early pregnancy increase the risk of small-for-gestational-age infants?

OBJECTIVES: This study tested the hypothesis that women who deliver small-for-gestational-age infants are more often exposed to passive smoking at home or at work. METHODS: Among a 1-year cohort of nulliparous women in the city of Malm?, Sweden 872 (87.7%) women completed a questionnaire during their first prenatal visit. The study was carried out among women whose pregnancies resulted in a singleton live birth (n = 826), 6.7% of infants were classified as small for their gestational age. RESULTS: Passive smoking in early pregnancy was shown to double a woman's risk of delivering a small-for-gestational-age infant, independent of potential confounding factors such as age, height, weight, nationality, educational level, and the mother's own active smoking (odds ratio [OR] = 2.7). A stratified analysis indicated interactional effects of maternal smoking and passive smoking on relative small-for-gestational-age risk. CONCLUSIONS: Based on an attributable risk estimate, a considerable reduction in the incidence of small-for-gestational-age births could be reached if pregnant women were not exposed to passive smoking.     

Idiopathic normal pressure hydrocephalus: analysis of factors related to cerebrospinal fluid dynamics determining functional prognosis

OBJECTIVE: To examine the effect of maternal smoking on the relationship between maternal hemoglobin levels and pregnancy outcome. DESIGN: A prospective study of healthy parous women from early pregnancy and of their infants. SETTING: Three Scandinavian university hospitals covering all deliveries from well defined geographical areas. SUBJECTS: Smoking (669) and non-smoking (368) mothers, para 1 and 2 and with > or = 37 weeks of gestational length. MAIN OUTCOME MEASURES: Birth weight and placental weight. Ponderal Index and Placental Index as measures of possible discordant fetal and placental growth. RESULTS: In non-smoking mothers the hemoglobin levels in the three trimesters had no relation to birth weight. In smoking mothers a significantly lower birth weight was seen with a high hemoglobin level in the third trimester, but hemoglobin levels in early or mid-pregnancy had no association to birth weight. Smoking mothers also had a significantly greater fall in hemoglobin concentration from first to second and third trimester as compared to non-smokers although ferritin levels were similar in smokers and non-smokers, implying similar iron stores. The ratio of placental weight to the weight of the newborn was significantly higher in smokers, but no association was found to different hemoglobin levels. CONCLUSIONS: Fetal growth impairment associated with maternal smoking is even more pronounced in smoking mothers with high hemoglobin levels in late pregnancy. Smoking mothers were also found to have disproportional fetal/placental growth with relatively high placental weights. In non-smoking mothers hemoglobin levels had no relation to birthweight.