Adverse perinatal outcomes among interracial couples in the United States

OBJECTIVE: We examined the association between parental race and stillbirth and adverse perinatal and infant outcomes. METHODS: We conducted a retrospective cohort analysis using the 1995-2001 linked birth and infant death files that are composed of live births and fetal and infant deaths in the United States. The study included singleton births delivered at 20 or more weeks of gestation with a fetus weighing 500 g or more (N = 21,005,786). Parental race was categorized as mother white-father white, mother white-father black, mother black-father white, and mother black-father black. Multivariable logistic regression analysis was performed to examine the association between parental race and risks of stillbirth (at > or = 20 weeks), small for gestational age (defined as birth weight < 5th and < 10th percentile for gestational age), and early neonatal (< 7 days), late neonatal (7-27 days), and postneonatal (28-364 days) mortality. All analyses were adjusted for the confounding effects of maternal age, education, trimester at which prenatal care began, parity, marital status, and smoking during pregnancy. RESULTS: Although risks varied across parental race categories, stillbirth was associated with a higher-than-expected risk for interracial couples: mother white-father black, relative risk (RR) 1.17 (95% confidence interval [CI] 1.10-1.26) and mother black-father white, RR 1.37 (95% CI 1.21-1.54) compared with mother white-father white parents. The RR for stillbirth was even higher among mother black-father black parents (RR 1.67, 95% CI 1.62-1.72). The overall patterns of association for small for gestational age births (< 5th and < 10th percentile) and early neonatal mortality were similar to those seen for stillbirth. CONCLUSION: There is an increased risk of adverse perinatal outcomes for interracial couples, including stillbirth, small for gestational age infants, and neonatal mortality. LEVEL OF EVIDENCE: II-2.     

Risk factors associated with preterm deliveries among racial groups in a national sample of married mothers.

Seven sociodemographic and behavioral factors that may explain the increased risk of preterm deliveries among black women were examined using data from a national sample of 5823 married mothers who responded to the 1980 National Natality Survey (NNS) Questionnaire. There was a twofold increase in the rate of preterm deliveries among black women. Additionally, there was a significant decrease (by 1 week) in the mean gestational age in black mothers (p less than 0.0001) compared with white mothers. The two groups were similar with respect to smoking and age; however, there were significant differences between the two groups with respect to other risk factors. Black women had a higher rate of heavy alcohol use, significantly fewer prenatal visits, prenatal care was started later during pregnancy (p less than 0.0001) and were less educated compared with white women. The odds ratio (OR) for race adjusted for the risk factors was 1.56 (95% confidence interval (CI) equals 1.21, 2.01). All other risk factors except education had adjusted ORs greater than 1. Those risk factors that were more strongly associated with the risk of preterm births included weight gain (OR, 2.10; 95%, 1.79, 2.47), number of prenatal visits (OR, 3.37; 95% CI, 2.87, 3.95) and smoking (OR, 1.34; 95% CI, 1.13, 1.59). We conclude that race is an independent risk factor for preterm deliveries. Additionally, it is shown here that the risk of preterm deliveries is attributable to health behaviors that are amendable to change.     

Epidemiology of fetal death in Latin America

BACKGROUND: To identify risk factors associated with fetal death, and to measure the rate and the risk of fetal death in a large cohort of Latin American women. METHODS: We analyzed 837,232 singleton births recorded in the Perinatal Information System Database of the Latin American Center for Perinatology and Human Development (CLAP) between 1985 and 1997. The risk factors analyzed included fetal factors and maternal sociodemographic, obstetric, and clinical characteristics. Adjusted relative risks were obtained, after adjustment for potential confounding factors, through multiple logistic regression models based on the method of generalized estimating equations. RESULTS: There were 14,713 fetal deaths (rate=17.6 per 1000 births). The fetal death risk increased exponentially as pregnancy advanced. Thirty-seven percent of all fetal deaths occurred at term, and 64% were antepartum. The main risk factors associated with fetal death were lack of antenatal care (adjusted relative risk [aRR]=4.26; 95% confidence interval, 3.84-4.71) and small for gestational age (aRR=3.26; 95% CI, 3.13-3.40). In addition, the risk of death during the intrapartum period was almost tenfold higher for fetuses in noncephalic presentations. Other risk factors associated with stillbirth were: third trimester bleeding, eclampsia, chronic hypertension, preeclampsia, syphilis, gestational diabetes mellitus, Rh isoimmunization, interpregnancy interval<6 months, parity > or =4, maternal age > or =35 years, illiteracy, premature rupture of membranes, body mass index > or =29.0, maternal anemia, previous abortion, and previous adverse perinatal outcomes. CONCLUSIONS: There are several preventable factors that should be dealt with in order to reduce the gap in fetal mortality between Latin America and developed countries.     

Racial differences in prenatal care of mothers delivering very low birth weight infants.

OBJECTIVES: To determine whether there are any racial differences in the prenatal care of mothers delivering very low birth weight infants (VLBW). STUDY DESIGN: Retrospective cohort study of infants cared for at a single regional level III neonatal intensive care unit over a 9-year period, July 1993-June 2002, N = 1234. The main outcome variables investigated included antenatal administration of steroids, delivery by cesarean section, and use of tocolytic medications. Both univariate and multivariate analyses were performed. RESULTS: After controlling for potential confounding variables, white mothers delivering VLBWs had an increased odds of cesarean delivery (odds ratio 1.5, 95% confidence intervals (CI) 1.1-2.0), receiving antenatal steroids (1.3, CI 1.01-1.8), and tocolysis (1.4, CI 1.1-2.0) compared to black mothers. The models controlled for gestational age, multiple gestation, premature labor, clinical chorioamnionitis, maternal age, income, year of birth, and presentation. CONCLUSIONS: In our population of VLBWs, white mothers are more likely to receive antenatal steroids, tocolytic medications, and deliver by cesarean section when compared to black mothers. From our data we cannot determine the reasons behind these racial differences in care of mothers delivering VLBWs.     

Heterogeneity of perinatal outcomes in the preterm delivery syndrome

OBJECTIVE: Our aim was to document the differential neonatal morbidity and intrapartum and neonatal mortality of subgroups of preterm delivery. METHODS: This analysis included 38,319 singleton pregnancies, of which 3,304 (8.6%) were preterm deliveries (less than 37 completed weeks) enrolled in the World Health Organization randomized trial of a new antenatal care model. We classified them as preterm deliveries after spontaneous initiation of labor, either with or without maternal obstetric and medical complications; preterm deliveries after prelabor spontaneous rupture of amniotic membranes (PROM), either with or without obstetric and medical complications; and medically indicated preterm deliveries with maternal obstetric and medical complications. Severe neonatal morbidity and neonatal mortality were the primary outcomes. RESULTS: Fifty-six percent of all preterm deliveries were spontaneous, without maternal complications. Small for gestational age was increased only among the medically indicated preterm delivery group (22.3%). Very early preterm delivery (less than 32 weeks of gestation) was highest among PROM with complications (37%). For intrapartum fetal death and neonatal death, after adjusting by gestational age and other confounding variables, we found that the obstetric and medical complications preceding preterm delivery predicted the different risk levels. Conversely, for severe neonatal morbidity the clinical presentation, ie, PROM or medically indicated, predicted the increased risk. CONCLUSION: There are differential neonatal outcomes among preterm deliveries according to clinical presentation, pregnancy complications, gestational age at delivery, and its association with small for gestational age. This syndromic nature of the condition should be considered if preterm delivery is to be fully understood and thus reduced.     

Impact of race and ethnicity on the outcome of preterm infants below 32 weeks gestation.

OBJECTIVES: To determine the impact of race/ethnicity on mortality and morbidity such as intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), bronchopulmonary dysplasia (BPD) and bacteriologically confirmed sepsis, assisted ventilation, surfactant administration, intrauterine growth retardation (IUGR), and patent ductus arteriosus (PDA) among very prematurely delivered infants. STUDY DESIGN: Retrospective study of a cohort of 1006 preterm neonates with gestational age ranging from 22 to 32 weeks discharged from the Neonatal Intensive Care Unit (NICU) between 1998 and 2001. Subgroup analysis according to gestational age (GA) (22 to 24, 25 to 28, and 29 to 32 weeks) and plurality (singleton and multiple) was performed using the chi(2) test and an analysis of variance. RESULTS: Of the 1006 infants, 54.3% were white, 21.7% black, 13.7% Hispanic, and 10.3% were classified as Other. Multiple births among white infants were approximately twice that in (42.4%) black infants (22.1%), and was also significantly higher than in the Hispanic (28.3%) and other race/ethnic groups (25.2%). Overall, a higher proportion of black infants were born with a GA 相似文献   

Racial and ethnic differences in preterm birth: A complex,multifactorial problem

Preterm birth remains the leading cause of morbidity and mortality among nonanomalous neonates, and is a major public health problem. Non-Hispanic black women have a 2-fold greater risk for preterm birth compared with non-Hispanic white race. The reasons for this disparity are poorly understood and cannot be explained solely by sociodemographic factors. Underlying factors including a complex interaction between maternal, paternal, and fetal genetics, epigenetics, the microbiome, and these sociodemographic risk factors likely underlies the differences between racial groups, but these relationships are currently poorly understood. This article reviews the epidemiology of disparities in preterm birth rates and adverse pregnancy outcomes and discuss possible explanations for the racial and ethnic differences, while examining potential solutions to this major public health problem.     

Timing of planned cesarean delivery by racial group

OBJECTIVE: To estimate the incidence of newborn respiratory distress syndrome (RDS) and transient tachypnea of the newborn (TTN) in relation to gestational age and planned cesarean delivery in white, South Asian, and black women. METHODS: Included in this study were 442,596 white, South Asian, and black women who delivered single live infants at 28 of weeks gestation onwards between 1988 and 2000. Using multiple logistic regression, the gestation-specific patterns of RDS for all deliveries and RDS plus TTN for deliveries by planned cesarean delivery were analyzed by racial group. The predictors of RDS from 37 weeks of gestation onwards were determined. RESULTS: More South Asians (28.2%, 95% confidence interval [CI] 27.8-28.6) and blacks (24.6%, 95% CI 24.0-25.1) delivered spontaneously before 39 weeks than whites (16.9%, 95% CI 16.8-17.1). Respiratory distress syndrome patterns by gestation differed significantly (P<.001). Compared with whites, the gestation-specific crude RDS rate was lower in South Asians up until 40 weeks and after adjusting for confounders; South Asians were most protected against RDS (odds ratio [OR] 0.6, 95% CI 0.5-0.9). The gestation-specific patterns of RDS plus TTN after planned cesarean delivery also differed significantly (P<.001) between racial groups. The lowest rate of TTN plus RDS was at 40 weeks for whites, but in South Asians and blacks, it was lowest at 38 weeks. CONCLUSION: The gestation-specific patterns of RDS differed significantly by racial group from 32 weeks of gestation onwards. Preterm black infants had a lower rate of RDS when compared with whites; also, South Asians had the lowest rate of transient tachypnea until 38 weeks and the lowest rate of RDS until 40 weeks of gestation. The advantages of waiting until 39 weeks to perform planned cesarean delivery for white women are not seen in South Asians or blacks.     

The relationship between cesarean delivery and gestational age among US singleton births

The increasing trend of delivering at earlier gestational ages has raised concerns of the impact on maternal and infant health. The delicate balance of the risks and benefits associated with continuing a pregnancy versus delivering early remains challenging. Among singleton live births in the United States, the proportion of preterm births increased from 9.7% to 10.7% between 1996 and 2004. The increase in singleton preterm births occurred primarily among those delivered by cesarean section, with the largest percentage increase in late preterm births. For all maternal racial/ethnic groups, singleton cesarean section rates increased for each gestational age group. Singleton cesarean section rates for non-Hispanic black women increased at a faster pace among all preterm gestational age groups compared with non-Hispanic white and Hispanic women. Further research is needed to understand the underlying reasons for the increase in cesarean section deliveries resulting in preterm birth.     

Racial variation in the frequency of intrapartum hemorrhage

OBJECTIVE: To evaluate racial variation in the frequency of intrapartum hemorrhage. METHODS: Using information from birth certificates of live singleton births in North Carolina from 1990 to 1997 (n = 807,759), we evaluated the frequency of intrapartum hemorrhage and its association with maternal race. Logistic regression models were used to evaluate the risk of any intrapartum hemorrhage, placental abruption, placenta previa, and unspecified hemorrhage in each racial group, adjusted for other risk factors. RESULTS: Black women had the highest rates of any hemorrhage (1.52% black, 1.47% white, 1.33% other race, P =.006) and placental abruption (0.79% black, 0.68% white, 0.56% other race, P =.001) but had lower rates of unspecified hemorrhage (0.37% black, 0.42% white, 0.42% other race, P =.001). Race was not associated with placenta previa. Maternal race remained associated with intrapartum hemorrhage after multivariable analysis, but the direction of the association was reversed. Black women were less likely to have any intrapartum hemorrhage (odds ratio [OR] 0.80, 95% confidence interval [CI] 0.77, 0.85), placental abruption (OR 0.76, 95% CI 0.70, 0.82), placenta previa (OR 0.89, 95% CI 0.81, 0.98), or other unspecified hemorrhage (OR 0.84, 95% CI 0.76, 0.92) compared with white women. Women of other minority races were at lower risk for placental abruption (OR 0.76, 95% CI 0.67, 0.87) but were comparable to white women for risk of placenta previa (OR 1.06, 95% CI 0.91, 1.24) and other unspecified hemorrhage (OR 1.02, 95% CI 0.88, 1.19). CONCLUSION: Although black women had higher rates of intrapartum hemorrhage than whites, the increased frequency was attributable to differences in clinical presentation and other risk factors.     

Risk factors for perineal injury during delivery

OBJECTIVE: We sought to identify risk factors for anal sphincter injury during vaginal delivery. STUDY DESIGN: This was a retrospective, case-control study. We reviewed 2078 records of vaginal deliveries within a 2-year period from May 1, 1999, through April 30, 2001. Cases (n = 91) during the study period were defined as parturients who had documentation of greater than a second-degree perineal injury. Control subjects (n = 176), who were identified with the use of a blinded protocol, included women who were delivered vaginally with less than or equal to a second-degree perineal injury. For each patient, we reviewed medical and obstetrics records for the following characteristics: maternal age, race, weight, gestational age, parity, tobacco use, duration of first and second stages of labor, use of oxytocin, use of forceps or vacuum, infant birth weight, epidural use, and episiotomy use. RESULTS: Of the 2078 deliveries that were reviewed, we discovered 91 cases (4.4%) of documented anal sphincter injury. The mean maternal age of our sample was 24.9 +/- 5.9 years). Nearly two thirds (63.2%) were white; 26.7% were black, and 10.1% were of other racial backgrounds. Forceps were used in 51.6% of deliveries that resulted in tears (cases), compared to 8.6% of deliveries without significant tears (control subjects, P <.05). Using cases and control subjects with complete data (cases, 82; control subjects, 144), delivery with forceps was associated with a 10-fold increased risk of perineal injury (odds ratio, 10.8; 95% CI, 5.2-22.3) compared to noninstrumented deliveries. The association was similar after adjustment for age, race, parity, mode of delivery, tobacco use, episiotomy, duration of labor (stages 1 and 2), infant birth weight, epidural, and oxytocin use (odds ratio, 11.9; 95% CI, 4.7-30.4). Nulliparous women were at increased risk for tears (adjusted odds ratio, 10.0; 95% CI, 3.0-33.3) compared with multiparous patients, but parity did not reduce the association between forceps-assisted deliveries and anal sphincter injuries. Increasing fetal weight was also a risk factor in both unadjusted and adjusted analyses. The performance of a midline episiotomy was associated with an increased risk of anal sphincter tear compared with delivery without an episiotomy in the univariate analysis (odds ratio, 4.9; 95% CI, 2.5-9.6), but this association was reduced in the adjusted analysis (odds ratio, 2.5; 95% CI, 1.0-6.0). The increased duration of both the first and second stages of labor increased injury risk in the unadjusted, but not adjusted, analysis. No significant association was observed between case status and the use of oxytocin or epidural anesthesia. Greater, but not significant, increased risk was associated with maternal indications for operative delivery compared with fetal indications. CONCLUSION: Our results are consistent with recent reports that identify forceps delivery and nulliparity as risk factors for recognized anal sphincter injury at the time of vaginal delivery. Further investigation should focus on the determination of whether the association of injury to instrumentation is causal or, in fact, modifiable. Because of the established association between sphincteric muscular damage and anal incontinence, patients should be counseled about the risk of anal sphincter injury when operative vaginal delivery is contemplated. Such patients should be followed closely in the postpartum setting to assess for the development of potential anorectal complaints.     

Maternal serum alpha-fetoprotein levels in pregnancies among black and white women with fetal open spina bifida: a United States collaborative study.

In the present study second-trimester maternal serum alpha-fetoprotein levels were analyzed from 146 pregnancies associated with fetal open spina bifida to identify whether affected pregnancies from the black population were associated with higher maternal serum alpha-fetoprotein levels than their white counterparts. Pregnancies in black women not affected by open spina bifida are already known to have higher maternal serum alpha-fetoprotein levels. All of the cases were analyzed with gestational ages assigned by last menstrual period, and all maternal serum alpha-fetoprotein values were expressed as multiples of the median, to correct for differences in gestational age and assay among the 15 centers reporting data. The levels from affected pregnancies in white and black women fit log Gaussian distributions, with medians of 3.10 and 4.37 multiples of the median, respectively, on the basis of singleton, unaffected, white pregnancy medians. These results support adjustment of maternal serum alpha-fetoprotein values for race in black women; in addition, if a screening program's policy is to screen at a comparable risk in the two races, a higher maternal serum alpha-fetoprotein multiple of the median cutoff would be justified for black women.     

Determinants of intrapartum fetal death in a remote and indigent population in China.

OBJECTIVE: To explore the reasons for the high rate of intrapartum fetal death observed in a remote and indigent population in China. STUDY DESIGN: We conducted an epidemiologic analysis of determinants of intrapartum fetal death in a sample of 20,891 births in 18 hospitals participating in the Qingyuan Perinatal Surveillance System from January 1, 1997 to June 30, 1998. The main determinant examined was cesarean delivery; other determinants included mother's insurance status, residence, maternal age, infant's gender, parity, gestational age, birth weight, and obstetric complications. Rates of intrapartum fetal death within categories of various maternal and infant factors were first calculated and compared; adjusted odds ratios for intrapartum fetal death were then estimated by multiple logistic regression analysis. RESULTS: The intrapartum fetal death rate in this population was 5 per 1000 total births, which accounted for about one-third of all fetal deaths. Compared with vaginal delivery, elective cesarean delivery was associated with a 100% (i.e., no intrapartum fetal death among 1572 elective cesarean deliveries) and emergency cesarean delivery with a 88% reduction, in intrapartum fetal death. Other significant determinants were related to access to obstetric care (i.e., insurance status and residence). CONCLUSION: Lack of access to quality obstetric care is the major determinant of intrapartum fetal death in this population.     

Racial differences in cesareans: an analysis of U.S. 2001 National Inpatient Sample Data

OBJECTIVE: To evaluate racial differences in potentially unnecessary cesareans in the United States. METHODS: The 2001 Healthcare Cost and Utilization Project Nationwide Inpatient Sample database was used to analyze various maternal demographic and clinical parameters among women having cesarean deliveries. For the purpose of our study, if there were no diagnoses related to cesarean delivery on the discharge certificate, the cesarean was classified as potentially unnecessary RESULTS: Using our methodology, 11% of 540,174 primary and 65% of 371,863 repeat cesareans for the year 2001 in the United States were classified as potentially unnecessary. After controlling for age, payment source, ZIP income, admission day, region of the country, and hospital size, location, and teaching status, black women had a higher likelihood of having potentially unnecessary primary cesareans when compared with white (P < .001) or Hispanic women (P < .001). White women had a higher likelihood of having potentially unnecessary repeat cesareans than black women (P < .001), although the magnitude of the odds ratio for race was not as striking as in primary cesarean. Potentially unnecessary primary cesareans were also more likely to occur in women aged 35 years or older, Medicare patients, weekend admissions, or those residing in the South or Northeast. Potentially unnecessary repeat cesareans were more likely to occur in women younger than 35 years, in rural hospitals, and in weekday admissions. CONCLUSION: In the United States, racial differences exist in the proportion of cesarean deliveries that are potentially unnecessary. Further exploration of these differences is warranted. LEVEL OF EVIDENCE: III.     

Racial/Ethnic Differences in Correlates of Spontaneous and Medically-Indicated Late Preterm Births among Adolescents

Study Objective

To investigate the racial/ethnic differences in the correlates of spontaneous and medically-indicated late preterm birth (LPTB), defined as deliveries between 34 0/7 and 36 6/7 weeks gestation, among US adolescents.

Trends and risk factors of stillbirth in New Jersey 1997–2005

Introduction: The purpose of this study was to examine the trends in the rates of stillbirth by race and ethnicity and to determine the risk factors of stillbirth. Methods: We used New Jersey data (1997–2005) for live births and fetal deaths. Cox proportional hazards model was used to estimate the risk of stillbirth associated with maternal risk factors and pregnancy complications. Results: The rate of stillbirth was 4.4/1000 total births (3.4 for white and 7.9 for black non-Hispanics and 4.4 for Hispanics/1000 total births). The rates of stillbirth decreased from 3.8 in 1997 to 2.7/1000 total births in 2005 for white non-Hispanics but remained unchanged for other race/ethnicity groups. Adjusted relative risks for the risk factors associated with stillbirth were 1.3 (95% CI, 1.2–1.4) for maternal age ≥ 35 years, 1.9 (95% CI, 1.7–2.1) for black non-Hispanics, 2.8 (95% CI, 2.4–3.3) for no prenatal care, 40.2 (95% CI, 36.9–43.9) for placental abruption, 5.3 (95% CI, 3.4–8.2) for eclampsia, 3.5 (95% CI, 2.8–4.3) for diabetes mellitus and 1.7 (95% CI, 1.3–2.2) for preeclampsia. Conclusion: There was a decline in the rate of stillbirth but there were persistent racial disparities with the highest rates of stillbirth for black non-Hispanics.     

Associated factors and outcomes of persistent occiput posterior position: A retrospective cohort study from 1976 to 2001.

OBJECTIVE: To identify maternal and fetal risk factors associated with persistent occiput posterior position at delivery, and to examine the association of occiput posterior position with subsequent obstetric outcomes. METHODS: This is a retrospective cohort study of 30 839 term, cephalic, singleton births. Women with persistent occiput posterior (OP) position at delivery were compared to those with occiput anterior (OA) position. Demographics, obstetric history, and labor management were evaluated and subsequent obstetric outcomes examined. Potential confounding variables were controlled for using multivariate logistic regression analysis. RESULTS: The overall frequency of OP position was 8.3% in the study population. When compared to Caucasians, a higher rate of OP was observed among African-Americans (OR = 1.4, 95% CI 1.25-1.64) while no other racial/ethnic differences were noted. Other associated factors included nulliparity, maternal age > or =35, gestational age > or =41 weeks, and birth weight >4000 g, as well as artificial rupture of the membranes (AROM) and epidural anesthesia (p < 0.001 for all). Persistent OP was associated with increased rates of operative vaginal (OR = 4.14, 95% CI 3.57-4.81) and cesarean deliveries (OR = 13.45, 95% CI 11.94-15.15) and other peripartum complications including third or fourth degree perineal lacerations (OR = 2.38, 95% CI 2.03-2.79), and chorioamnionitis (OR = 2.10, 95% CI 1.81-2.44). CONCLUSION: Epidural use, AROM, African-American ethnicity, nulliparity, and birth weight >4000 g are associated with persistent OP position at delivery, with higher rates of operative deliveries and obstetric complications. This information can be useful in counseling patients regarding risks and associated outcomes of persistent OP position.     

Maternal age and incidence of low birth weight at term: a population study

A total of 184,567 singleton live births with gestational ages of 40 weeks were examined from the 1980-1984 Illinois birth certificate data to determine the independent effect of maternal age on the incidence of low birth weight at term. The incidence is highest in mothers less than 17 years of age (3.2%) and gradually declines with advancing maternal age to reach 1.3% in women aged 25 to 34 years. It increases to 1.7% for those greater than 35 years of age. To separate out the independent effect of maternal age on the incidence of low birth weight infants at term, the presence of other maternal factors, such as race, education, parity, marital status, and prenatal care, were adjusted by use of a series of multiple logistic regression analyses. All of these analyses consistently demonstrated that the adjusted risk for low birth weight at term is the lowest in teenagers and increases with advancing maternal age. These results indicate that the high incidence of this factor in young mothers apparently reflects their poor sociodemographic and prenatal care status. Advancing maternal age is associated with a decreased potential for fetal growth, possibly reflecting biologic aging of maternal tissues and systems or the cumulative effects of disease.     

Racial patterns in the effects of tobacco use on fetal growth.

OBJECTIVE: The aim of this study was to characterize the interaction between the effects on fetal growth of maternal smoking and race by means of race-specific growth normograms. STUDY DESIGN: A case-control study was performed on white and African American mothers who were delivered at 2 hospitals in metropolitan Atlanta between February 1993 and December 1994. The study population consisted of 621 small for gestational age infants and their mothers and 324 appropriate for gestational age infants and their mothers. Face-to-face interviews with mothers and detailed anthropometric measurements of neonates were performed. Relationships among tobacco use, race, and fetal growth were evaluated by means of multiple logistic regression. The chi(2) test of trend was performed to assess a dose-response relationship between smoking and fetal growth. RESULTS: Mothers of small for gestational age neonates were significantly more likely than control mothers to be single (52% versus 40%), to be primiparous (47% versus 37%), to have a low body mass index (26% versus 17%), to have hypertension (22% versus 15%), and to use alcohol (15% versus 9%). Mothers of small for gestational age infants were significantly more likely than control mothers to smoke (26% versus 12%) and to smoke more cigarettes (P <.05). After controlling for potential confounders cigarette smoking in the second trimester was significantly associated with small for gestational age infants in both races (whites <1 pack/d adjusted odds ratio 3.82, 1-2 packs/d adjusted odds ratio 4.86, >2 packs/d crude odds ratio; African Americans <1 pack/d adjusted odds ratio 2. 35, 1-2 packs/d adjusted odds ratio 2.52). The chi(2) test of trend results were consistent with a dose-response relationship between smoking and small for gestational age infants (whites chi(2) = 14.06, P <.0001, African Americans chi(2) = 7.99). Comparison between the 2 races of the adverse effects of smoking on fetal growth showed no significant difference. CONCLUSION: Self-reported maternal smoking during the second trimester is associated with fetal growth restriction in a dose-response manner. According to race-specific growth normograms no significant difference in the effects of tobacco use on fetal growth was found between white and African American women.     

Chorionic villus sampling significantly affects fetal cardiovascular function.

OBJECTIVE: To assess the effects of chorionic villus sampling (CVS) on fetal heart rate (FHR). METHODS: A prospective longitudinal study was conducted among 300 patients undergoing transabdominal CVS between 8 and 13 weeks of gestation. Duration of the procedure, number of needle passes, sample weight, maternal age, fetal gender, and FHR response to CVS were recorded. RESULTS: The FHR before but not after CVS was inversely correlated with gestational age (r = -0.406, p < 0.001). Conversely, following CVS, no correlation was observed between FHR and gestational age (r = -0.06, p = 0.27). The difference between FHR after CVS and that obtained before CVS (delta FHR) increased with increasing gestational age at sampling (r = 0.372, p < 0.0001), decreased with increasing specimen weight (r = -0.16, p = 0.01) and increased with increasing maternal age (r = 0.22, p < 0.0001). Duration of the procedure, fetal gender and number of needle passes did not affect delta FHR. Multiple logistic regression indicated that gestational age at CVS and maternal age but not the other variables significantly affected delta FHR and together they accounted for over 22% of the variance (R(2) = 0.224, p < 0.0001). CONCLUSIONS: In summary, our results suggest that acute fetal hemodynamic changes accompany CVS and that these changes vary with gestational age.