Maternal pregnancy-specific anxiety is associated with child executive function at 6-9 years age.

Because fetal brain development proceeds at an extremely rapid pace, early life experiences have the potential to alter the trajectory of neurodevelopment, which may increase susceptibility for developmental and neuropsychiatric disorders. There is evidence that prenatal maternal stress and anxiety, especially worries specifically related to being pregnant, influence neurodevelopmental outcomes. In the current prospective longitudinal study, we included 89 women for whom serial data were available for pregnancy-specific anxiety, state anxiety, and depression at 15, 19, 25, 31, and 37 weeks gestation. When the offspring from the target pregnancy were between 6 and 9 years of age, their executive function was assessed. High levels of mean maternal pregnancy-specific anxiety over the course of gestation were associated with lower inhibitory control in girls only and lower visuospatial working memory performance in boys and girls. Higher-state anxiety and depression also were associated with lower visuospatial working memory performance. However, neither state anxiety nor depression explained any additional variance after accounting for pregnancy-specific anxiety. The findings contribute to the literature supporting an association between pregnancy-specific anxiety and cognitive development and extend our knowledge about the persistence of this effect until middle childhood.

Effect of prenatal glucocorticoid treatment on size at birth among infants born at term gestation.

OBJECTIVE: To determine whether prenatal treatment with a single course of glucocorticoids (GCs) affects size at birth among full-term infants independent of fetal size before GC administration or exposure to preterm labor (PTL). STUDY DESIGN: In all, 105 full-term infants were recruited into three study groups (30 GC treated; 60 controls matched for gestational age (GA) at birth and sex; and 15 PTL controls without GC exposure). Size of the infants was estimated before treatment using two-dimensional (2D) ultrasound and by direct measurement at birth. RESULTS: Length, weight and head circumference at birth were smaller among GC-treated infants compared with matched controls (P's<0.01), although fetal size did not differ before treatment (P's>0.2). Exposure to PTL did not account for this effect. CONCLUSIONS: Prenatal treatment with a single course of GCs was associated with a reduction in size at birth among infants born at term gestation. This effect cannot be explained by differences in fetal size before treatment or exposure to PTL.

Placental blood flow and the risk of preterm delivery.

The goal of this analysis was to estimate the influence of variation in uterine artery and umbilical artery resistance indices (RIs) measured across gestation on variation in the risk of preterm delivery (PTD). Analyses were carried out on data collected in a longitudinal study of 523 gravidas. Uterine and umbilical artery RIs were measured on three occasions during pregnancy (16-20 weeks gestation; 21-29 weeks gestation; and 30-36 weeks gestation). Data were analyzed using the Cox proportional hazards regression model. The primary outcome variable was birth prior to 37 weeks gestation. We found that for mothers who delivered preterm the mean uterine artery RI was consistently larger across all gestational ages, while the mean umbilical artery RI decreased significantly more slowly across gestation than for their term counterparts. In analyses pooled by type of delivery, we found that the hazard ratio (HR) for PTD was statistically significant for either uterine artery RI (HR=2.26, 95% CI: 1.65, 3.11) or umbilical artery RI (HR=3.47, 95% CI: 2.43, 4.95) after adjusting for statistically significant covariates. In stratified analyses, the hazard ratio for PTD was also positively associated with an increased uterine or umbilical artery RI in both spontaneous and indicated deliveries. Our data suggest that pregnancies with either a higher uterine or umbilical artery RI across gestation are more likely to be affected by PTD suggesting that disordered placentation resulting in compromised placental blood flow may be an important pathway to PTD.

Prolonged periods without food intake during pregnancy increase risk for elevated maternal corticotropin-releasing hormone concentrations.

OBJECTIVE: Fasting during pregnancy stimulates preterm delivery in animals and increases women's risk for preterm delivery. Fasting stimulates hypothalamic corticotropin-releasing hormone production in animals. Elevated maternal corticotropin-releasing hormone concentrations are associated with preterm birth. We hypothesized that prolonged periods without food during pregnancy increase maternal corticotropin-releasing hormone concentrations, which lead to preterm delivery. STUDY DESIGN: In the Behavior in Pregnancy Study, we examined prolonged periods without eating during pregnancy and corticotropin-releasing hormone concentrations and gestational age at delivery with multivariate logistic regression analysis (n = 237). RESULTS: Prolonged periods without food lasting 13 hours or longer were associated with elevated maternal corticotropin-releasing hormone concentrations compared with prolonged periods without food lasting less than 13 hours at two time points during pregnancy, controlling for pregravid body mass index, energy intake, income, race, smoking, and maternal age (18-20 weeks: adjusted odds ratio, 2.5; 95% CI, 0.9-7.1; 28-30 weeks: adjusted odds ratio, 1.7; 95% CI, 0.7-4.2). There was an inverse, linear relationship between maternal corticotropin-releasing hormone concentrations and gestational age at delivery. CONCLUSIONS: Prolonged periods without food intake during pregnancy are associated with elevated maternal corticotropin-releasing hormone concentrations and with preterm delivery.

Stress, infection and preterm birth: a biobehavioural perspective.

Preterm birth is currently the most important problem in maternal-child health in the United States. Epidemiological studies have suggested that two factors, maternal stress and maternal urogenital tract infection, are significantly and independently associated with an increased risk of spontaneous preterm birth. These factors are also more prevalent in the population of sociodemographically disadvantaged women who are at increased risk for preterm birth. Studies of the physiology of parturition suggest that neuroendocrine and immune processes play important roles in the physiology and pathophysiology of normal and preterm parturition. However, not all women with high levels of stress and/or infection deliver preterm, and little is understood about factors that modulate susceptibility to pathophysiological events of the endocrine and immune systems in pregnancy. We present here a comprehensive, biobehavioural model of maternal stress and spontaneous preterm delivery. According to this model, chronic maternal stress is a significant and independent risk factor for preterm birth. The effects of maternal stress on preterm birth may be mediated through biological and/or behavioural mechanisms. We propose that maternal stress may act via one or both of two physiological pathways: (a) a neuroendocrine pathway, wherein maternal stress may ultimately result in premature and/or greater degree of activation of the maternal-placental-fetal endocrine systems that promote parturition; and (b) an immune/inflammatory pathway, wherein maternal stress may modulate characteristics of systemic and local (placental-decidual) immunity to increase susceptibility to intrauterine and fetal infectious-inflammatory processes and thereby promote parturition through pro-inflammatory mechanisms. We suggest that placental corticotropin-releasing hormone may play a key role in orchestrating the effects of endocrine and inflammatory/immune processes on preterm birth. Moreover, because neuroendocrine and immune processes extensively cross-regulate one another, we further posit that exposure to both high levels of chronic stress and infectious pathogens in pregnancy may produce an interaction and multiplicative effect in terms of their combined risk for preterm birth. Finally, we hypothesise that the effects of maternal stress are modulated by the nature, duration and timing of occurrence of stress during gestation. A discussion of the components of this model, including a theoretical rationale and review of the available empirical evidence, is presented. A major strength of this biobehavioural perspective is the ability to explore new questions and to do so in a manner that is more comprehensive than has been previously attempted. We expect findings from this line of proposed research to improve our present state of knowledge about obstetric risk assessment for preterm birth by determining the characteristics of pregnant women who are especially susceptible to stress and/or infection, and to broaden our understanding of biological (endocrine, immune, and endocrine-immune interactions) mechanisms that may translate social adversity during pregnancy into pathophysiology, thereby suggesting intervention strategies.

Maternal plasma corticotropin-releasing hormone associated with stress at 20 weeks' gestation in pregnancies ending in preterm delivery.

OBJECTIVE: This study tested the hypothesis that maternal stress is associated with elevated maternal levels of corticotropin releasing hormone and activation of the placental-adrenal axis before preterm birth. STUDY DESIGN: In a behavior in pregnancy study, 524 ethnically and socioeconomically diverse women were followed up prospectively and evaluated at 3 gestational ages: 18 to 20 weeks, 28 to 30 weeks, and 35 to 36 weeks. Maternal variables included demographic data, medical conditions, perceived stress level, and state anxiety. Maternal plasma samples were collected at each gestational age. Eighteen case patients with spontaneous onset of preterm labor were matched against 18 control subjects who were delivered at term, and their samples were assayed for corticotropin-releasing hormone, adrenocorticotropic hormone, and cortisol by means of radioimmunoassay. Statistical tests were used to examine mean differences in these hormones. In addition, the relationship between stress level and each hormone was tested with a Pearson correlation coefficient and hierarchic multiple regressions in each group. RESULTS: Patients who had preterm delivery had significantly higher plasma corticotropin-releasing hormone levels than did control subjects at all 3 gestational ages (P <.0001). Analyses did not find any differences in reported levels of stress between 18 to 20 weeks' gestation and 28 to 30 weeks' gestation. A hierarchic multiple regression indicated that maternal stress level at 18 to 20 weeks' gestation and maternal age accounted for a significant amount of variance in corticotropin-releasing hormone at 28 to 30 weeks' gestation, after controlling for corticotropin-releasing hormone at 18 to 20 weeks' gestation (P <. 001). In addition, patients who were delivered preterm had significantly elevated plasma levels of adrenocorticotropic hormone at all 3 gestational ages (P <.001) and significantly elevated cortisol levels at 18 to 20 weeks' gestation and 28 to 30 weeks' gestation (P <.001). CONCLUSION: Maternal plasma levels of corticotropin-releasing hormone are significantly elevated at as early as 18 to 20 weeks' gestation in women who are subsequently delivered preterm. Changes in corticotropin-releasing hormone between 18 to 20 weeks' gestation and 28 to 30 weeks' gestation are associated with maternal age and stress level at 18 to 20 weeks' gestation. Maternal stress and corticotropin-releasing hormone levels may be potential markers for the patient at risk for preterm birth. Activation of the placental maternal pituitary-adrenal axis is consistent with the classic endocrine response to stress.

Corticotrophin-releasing hormone and CRH-binding protein. Differences between patients at risk for preterm birth and hypertension.

BACKGROUND: During pregnancy in the second and third trimester there is a progressive rise in plasma CRH thought to be secreted by the placenta. Plasma CRH-BP inactivates CRH, which may prevent its peripheral action on the maternal pituitary and myometrium. In the last few weeks of pregnancy CRH-BP decreases, thereby causing an increase in free CRH or a CRH/CRH-BP complex available to play a role in the onset of parturition. OBJECTIVE: We tested the hypothesis that differences in CRH, CRH-BP, or a CRH/CRH-BP complex in patients at risk for preterm birth (PTB) and hypertension (HYP) account for the differences in the timing of parturition. METHODS: From a Behavior in Pregnancy Study database, we identified 18 patients who had spontaneous PTB and 23 patients who developed HYP. Both groups were case controlled and matched with patients who delivered at term (Normal). Maternal plasma samples had been appropriately collected from these patients at 18-20, 28-30, and 35-36 weeks gestational age. CRH levels were measured by double antibody RIA kit and the CRH-BP by a immunoradiometric technique. A CRH-BP/CRH dimer complex index was calculated. Statistical analysis was done using Kruskal-Wallis test for two cases. RESULTS: Maternal CRH (pg/ml) in the PTB cases compared to the HYP cases was significantly elevated at all three time periods. Maternal CRH-BP (pg/ml) in the PTB versus HYP cases was significantly lower at all three time periods in the PTB cases compared to the HYP cases. Maternal CRH-BP/CRH dimer complex index was significantly lower in the PTB cases at all three time periods than either the controls or the HYP cases, suggesting excessive CRH. The mean GA at delivery for the PTB cases was significantly lower than the control or HYP cases. CONCLUSIONS: These results suggest that those patients at risk for PTB have significantly elevated CRH, lower CRH-BP, and a reduced CRH-BP/CRH dimer complex index at all three time periods of assessment.

Maternal hematologic changes during pregnancy and the effect of iron status on preterm delivery in a West Los Angeles population.

This study was conducted to document the prevalence of anemia and high hematocrit during pregnancy and examine their effect on delivering preterm in a predominantly Hispanic population. The sample consisted of women receiving prenatal care from the public health clinics in the West Los Angeles from 1983 to 1986 (n = 7589). Multivariate logistic regression was used to isolate the role of anemia and high hematocrit from other factors that may influence birth outcome. The prevalence of anemia was approximately 9% at the initiation of prenatal care and at 28-32 weeks' gestation. Only anemia at 28-32 weeks was significantly associated with a preterm birth, even after adjusting for several confounders [Adjusted Odds Ratio (AOR) 1.83 95% Cl = 1.21, 2.77]. A high hematocrit that occurred in 9.6% of the population at 28-32 weeks was inversely associated with a preterm birth (AOR 0.78, 95% Cl = 0.44, 1.39). There was little differentiation of these risk factors when analyzing the etiological pathways of a preterm birth. These results indicate for the first time in a predominantly Hispanic population that despite routine iron supplementation, anemia still occurs in pregnant women and it can predict a preterm delivery.

Predictors of poor maternal weight gain from baseline anthropometric, psychosocial, and demographic information in a Hispanic population.

OBJECTIVE: To identify which baseline factors best predict poor maternal weight gain among Hispanics. SAMPLE: Pregnancy and outcome data collected prospectively from 4,791 Hispanic women attending public prenatal clinics in West Los Angeles, Calif, from 1983 through 1986. METHODS: Prepregnancy weight was categorized into weight status groups using body mass index (BMI). Poor total weight gain (based on a mean gestational age at last measurement, which was at 35 weeks) was defined as less than 21 lb for women with BMI less than 26 and less than 10 lb for women with BMI of 26 or greater. Analyses used Student's t test, chi 2, and multivariate regression techniques (linear and logistic). RESULTS: Poor total weight gain was identified in 29% of the women. For women who were underweight or normal weight before pregnancy, the only factor associated with increasing the risk of poor total weight gain was short stature (adjusted odds ratio [AOR] = 1.5, 95% confidence interval [CI] = 1.24, 1.84). The following factors decreased the risk: being US born (AOR = 0.61, 95% CI = 0.37, 1.00); being primiparous and under 29 years old (for < 20 years AOR = 0.69, 95% CI = 0.51, 0.92 and for 20 to 29 years AOR = 0.63, 95% CI = 0.49, 0.81); planning the pregnancy (AOR = 0.82, 95% CI = 0.67, 1.00); and having a close relative die during the pregnancy (AOR = 0.65, 95% CI = 0.44, 0.95). For obese and overweight women, physical abuse by the baby's father increased the risk (AOR = 3.19, 95% CI = 1.27, 8.01) of poor total weight gain, whereas receiving financial support from the baby's father decreased the risk (AOR = 0.59, 95% CI = 0.37, 0.95). APPLICATIONS/CONCLUSIONS: These baseline factors could aid in targeting nutrition and other social services earlier to pregnant Hispanic women. By strategically targeting pregnant women in greatest need of services, improvements in birth outcomes may be enhanced.

Placenta previa percreta with bladder involvement: new considerations and review of the literature.

Placenta previa percreta is a life-threatening condition. Antenatal diagnosis is important to establish and to optimize a plan of management. When bladder invasion occurs, other potential complications can result, including massive hemorrhage and the development of disseminated intravascular coagulation. Numerous modalities have been used successfully to treat these patients, but hysterectomy at delivery is the treatment most commonly used. A case of placenta previa percreta with suspected bladder invasion was diagnosed in a 35-year-old woman by routine office ultrasound examination at 19 weeks 6 days' gestation. She was managed conservatively until 36 weeks 3 days' gestation, at which time she underwent a modified classical Cesarean section after amniocentesis to confirm fetal lung maturity. The placenta was left in situ immediately postpartum. The patient underwent a prophylactic embolization of her hypogastric arteries and received methotrexate chemotherapy. Eight weeks later, she developed a low-grade coagulopathy and underwent a total abdominal hysterectomy. Conservative management intrapartum is thought to be appropriate, to avoid the risk of severe hemorrhage at the time of delivery. However, elective hysterectomy ought to be considered earlier (2-4 weeks postpartum) than the time suggested in the literature, to avoid the development of further complications, including coagulopathy.

The effect of thigh-length support stockings on the hemodynamic response to ambulation in pregnancy.

OBJECTIVE: Our purpose was to determine the effect of thigh-length support stockings on hemodynamic response when pregnant subjects change from the sitting to the lateral recumbent position and then after standing with ambulation. STUDY DESIGN: Eighteen subjects in the late second and early third trimester of pregnancy acted as their own controls. The cardiovascular status of the subjects was assessed by a noninvasive technique--thoracic electrical bioimpedance before and after wearing support stockings for 1 week. Urine catecholamines were measured in 13 patients before and after wearing support stocking to assess the release of catecholamines. Samples were collected after the subjects had been in the lateral recumbent position 40 minutes and again 40 minutes later after standing with ambulation. RESULTS: Heart rate and mean arterial blood pressure decreased significantly when subjects changed from the sitting to the lateral recumbent position and then increased with ambulation. Wearing compression stockings significantly increased mean arterial pressure and afterload in all three positions. Position change from lateral recumbent to standing and ambulation marginally increased urinary dopamine levels (p = 0.097) and significantly increased norepinephrine levels (p = 0.006). CONCLUSIONS: There are significant hemodynamic changes in pregnant subjects when they change from the sitting position to the lateral recumbent position and then change to standing with ambulation. Support stocking have a significant mechanical effect: they significantly increase afterload and systemic vascular resistance by preventing pooling of blood in the lower extremities. There may also be a biochemical effect that results in less catecholamine release. These results suggest that compression stockings could play an important role in supporting the circulation during ambulation.

Maternal underweight status and inadequate rate of weight gain during the third trimester of pregnancy increases the risk of preterm delivery.

This study examines the differences in the pattern of weight gain according to trimesters of pregnancy for women who delivered term vs. preterm and analyzes the independent effect of prepregnancy weight status and rate of weight gain on delivering preterm. The differential effects of these variables on the etiological pathways of prematurity (preterm labor and preterm rupture of the amniotic membranes) were also examined. Data were collected prospectively from 7589 pregnant women receiving care in public health clinics in the West Los Angeles area. Eighty percent of women identified themselves as being of Hispanic origin. Multivariate logistic regression techniques were used to isolate the role of each nutritional variable from other factors that may influence birth outcome. Women who delivered preterm had patterns of weight gain similar to women delivering term infants. Underweight status (body mass index < 19.8 kg/m2) before pregnancy nearly doubled the likelihood of delivering preterm [adjusted odds ratio (AOR) 1.98, 95% confidence interval (CI) = 1.33, 2.98). Inadequate weight gain in the third trimester defined as < 0.34, 0.35, 0.30 and 0.30 kg/wk for underweight, normal weight, overweight and obese women, respectively, increased the risk by a similar magnitude (AOR 1.91, 95% CI = 1.40, 2.61). Slight differentiation of these risk factors occurred when analyzing the etiological pathways of preterm birth. Preconceptional nutrition counseling and promotion of adequate weight gain during the third trimester of pregnancy should be components of public health programs designed to decrease the prevalence of preterm birth.

Using ICD-9 codes to identify indications for primary and repeat cesarean sections: agreement with clinical records.

Aggregate databases are increasingly being used to evaluate appropriateness of care, and, for cesarean sections, Anderson and Lomas' International Classification of Diseases, 9th Revision (ICD-9), coding hierarchy is a widely used tool. The aim of this study was to assess the validity of the hierarchy and expand its applicability to repeat cesareans. Hospital records of 1885 singleton cesareans were reviewed. Clinical indications and ICD-9 hierarchical codes were concordant for 83% of primary and 86% of repeat cesareans; modification allowed elective repeat cesareans to be distinguished from indicated procedures. The Anderson and Lomas ICD-9 hierarchy is a valid tool for assessing indications for cesarean. The current modification improves its clinical utility and expands its application to repeat procedures.

Plasma levels of atrial natriuretic peptide in normal and hypertensive pregnancies: a meta-analysis.

OBJECTIVE: Our goals were (1) to use meta-analysis to determine whether pregnancy and the puerperium are accompanied by alterations in plasma atrial natriuretic peptide levels when compared with the nonpregnant state and (2) to evaluate the additional effects of hypertensive disease during pregnancy on plasma atrial natriuretic peptide levels. STUDY DESIGN: Articles measuring atrial natriuretic peptide levels during pregnancy were reviewed. Data from articles meeting inclusion criteria were abstracted, and a meta-analysis was performed with the use of the maximum likelihood methods of Jennrich and Schluchter (Biometrics 1986;42:805-20). RESULTS: The mean atrial natriuretic peptide level in nonpregnant control subjects was 28.7 pg/ml (95% confidence interval 22.5 to 36.7). The mean plasma atrial natriuretic peptide level rose 41% to 40.5 pg/ml (95% confidence interval 31.7 to 51.8) in the third trimester (p < 0.0001). It was 71.1 pg/ml (95% confidence interval 51.2 to 98.7) or 148% greater than the mean nonpregnant level during the first week post partum (p < 0.0001). Compared with levels in pregnant control subjects, plasma atrial natriuretic peptide levels increased 52% to 52.1 pg/ml (95% confidence interval 32.9 to 82.5) in women with gestational hypertension (p < 0.005) and 130% to 78.8 pg/ml (95% confidence interval 52.3 to 118.8) in women with preeclampsia (p < 0.0001). Chronic hypertension did not significantly alter atrial natriuretic peptide levels. CONCLUSIONS: The 41% increase in atrial natriuretic peptide levels in the third trimester suggests that atrial stretch receptors sense the expanded blood volume as normal to moderately increased. The rise in atrial natriuretic peptide during the first week post partum is consistent with known hemodynamic changes and suggests that atrial natriuretic peptide may be involved in the postpartum diuresis. The marked increase in plasma atrial natriuretic peptide levels observed in preeclampsia is not likely to result from elevated arterial pressures alone but may reflect underlying factors unique to this disease process.

Institute of Medicine maternal weight gain recommendations and pregnancy outcome in a predominantly Hispanic population.

OBJECTIVES: To describe gestational weight gain patterns by pre-pregnancy weight and trimester of pregnancy, and to examine the risk of preterm birth associated with pre-pregnancy weight and gestational weight gain using various definitions of adequacy based on the Institute of Medicine (IOM) standard. METHODS: We used data collected prospectively from 8736 pregnant women receiving care in public health clinics in the West Los Angeles area. Pre-pregnancy weight was based on self-report obtained at the initial visit. Maternal weight was measured at each prenatal visit, allowing for the calculation of total weight gain and the rate of weight gain during each trimester. RESULTS: Women underweight before pregnancy (body mass index less than 19.8) had the greatest risk of delivering preterm (crude relative risk 1.7, P < .05). Similarities in patterns of weight gain were seen between women of low weight and normal pre-pregnancy weight status, as well as between overweight and obese women. Compared to the IOM recommendations for total weight gain, 47.8% of underweight women and 36.6% of normal-weight women gained the recommended amount. In contrast, 52% and more than 75% of overweight and obese women, respectively, had excessive gains. Inadequate weight gain during the third trimester as opposed to excessive gain, defined specifically for each pre-pregnancy weight status, was predictive of preterm birth. CONCLUSIONS: Weight monitoring during pregnancy continues to have clinical applications for the prediction of poor birth outcomes. Weight gain less than 90% the IOM recommendation in the third trimester may serve as an indicator for identifying women at risk of delivering preterm.

Repeat cesareans: how many are elective?

OBJECTIVE: To describe the clinical indications for repeat cesarean delivery and to compare these with indications for primary procedures. METHODS: We reviewed cesarean deliveries at our academic nonprofit hospital during 1992 (n = 1885). The indication for the procedure was abstracted based on surgeon operative reports and discharge ICD-9 codes (International Classification of Diseases, Clinical Modification, 9th Edition). RESULTS: The hospital cesarean rate was 28.7%; 34% of these were repeat procedures (n = 643). Elective cesarean delivery was the leading cause of repeat cesareans, followed by "other" indications, dystocia, breech, and fetal distress. In contrast, dystocia was the leading cause for primary cesarean, followed by fetal distress, "other," and breech presentation. One hundred women (15.6%) undergoing repeat cesarean had absolute or relative contraindications to a trial of labor. CONCLUSIONS: Indications for cesareans using hierarchies based on ICD-9 codes do not attempt to differentiate categories of indications for repeat cesarean. Current recommendations for lowering cesarean rates by increasing vaginal birth after previous cesarean are based on aggregate data and do not recognize that some repeat cesareans are clinically indicated. A coding system designed to distinguish elective from indicated repeat cesareans would be useful for future prospective studies.

The West Los Angeles Preterm Birth Prevention Project. I. Program impact on high-risk women.

OBJECTIVE: The primary objective of this prospective study was to test whether preterm birth prevention education plus increased clinic visits and selected prophylactic interventions reduce preterm birth. STUDY DESIGN: Eight West Los Angeles prenatal county clinics, comparable with respect to selected demographics, were randomized to be either experimental or control clinics. High-risk patients in all clinics were identified with a risk scoring system derived from a similar population. High-risk patients (N = 1774) in experimental clinics were offered a program of education and more frequent visits and were randomized to receive various secondary intervention protocols in addition to the basic interventions of education and more frequent visits. Control clinic patients (N = 880) received standard county care. RESULTS: Preterm birth rates were 19% lower among the experimental high-risk patients (7.4% vs 9.1%), and differences were significant (p < 0.05) when preterm risk was taken into account. There was no evidence to suggest that the secondary interventions provided added benefit over the primary intervention protocol of preterm birth prevention education and increased visits. CONCLUSION: The 19% reduction in preterm birth rate observed in the experimental clinics suggest an overall program benefit from a protocol that offered education, more frequent visits, and greater attention given to patients while the selected interventions were applied.

Effect of pregnancy on the vasodepressor response to atrial natriuretic factor.

OBJECTIVE: We attempted to determine whether pregnancy alters the vasodepressor response to both physiologic and pharmacologic infusions of atrial natriuretic factor 99-126. STUDY DESIGN: Ten virgin and 10 pregnant (17 +/- 1 days of gestation) conscious, unrestrained Sprague-Dawley rats with chronic indwelling vascular catheters were studied. Mean arterial pressure and heart rate were measured in response to steady-state infusions of either saline solution or increasing concentrations of atrial natriuretic factor (range 5 to 2560 ng.kg-1.min-1). RESULTS: Basal mean arterial pressure was significantly lower in pregnant rats than in virgin rats (89 +/- 3 vs 97 +/- 2 mm Hg, p < 0.02). Atrial natriuretic factor induced significant dose-dependent decreases in mean arterial pressure and heart rate in virgin and pregnant rats (p < 0.001). The hypotensive effects of atrial natriuretic factor were blunted in the pregnant rats only in response to the highest concentrations of atrial natriuretic factor administered (-27 +/- 3 mm Hg in pregnant rats vs -43 +/- 3 mm Hg in virgin rats, p < 0.005). CONCLUSIONS: The vasodepressor response to physiologic infusions of atrial natriuretic factor was not affected by pregnancy status. However, pharmacologic infusions of atrial natriuretic factor resulted in a blunted vasodepressor response in the pregnant animals. This may be due to alterations in vascular atrial natriuretic factor receptors, changes in the clearance rate of atrial natriuretic factor, or the modulating effects of other vasoactive hormones.

Maternal tobacco use and substance abuse: reported prevalence rates and associations with the delivery of small for gestational age neonates.

OBJECTIVE: To determine the changes in reported prevalence rates of tobacco use and substance abuse in a population of pregnant women, as well as to evaluate the associations between such use and sociodemographic characteristics and the delivery of small for gestational age (SGA) neonates. METHODS: We studied 7741 women who delivered at Cedars-Sinai Medical Center from 1986-1990. Antenatal and delivery information was entered prospectively into the computerized perinatal data base. Subjects were classified according to tobacco use and substance abuse status. We defined SGA as a birth weight less than the tenth percentile for gestational age at delivery. Univariate and multivariate analyses were used to determine the associations between SGA and tobacco use, substance abuse, and sociodemographic characteristics. RESULTS: We found that the reported prevalence rates of tobacco use and substance abuse declined between 1986-1990 (10 versus 6% and 7 versus 2%, respectively; P < .001). Tobacco use and substance abuse were reported as being highest in black women (11 and 6%) and lowest in Asian and Hispanic women (4 and 3%), a significant difference (P < .001). Tobacco use and race-ethnicity were found to have the strongest independent associations with SGA. The incidence of SGA was highest in black women identified as tobacco users and substance abusers. CONCLUSIONS: The reported rates of tobacco use and substance abuse varied by year, race-ethnicity, and insurance status. There were significant associations between maternal tobacco use, substance abuse, and race-ethnicity and the incidence of SGA neonates.