Effects of smoking reduction during pregnancy on the birth weight of term infants.

This study was undertaken to determine 1) whether reducing tobacco exposure during pregnancy increases the birth weight of term infants and 2) the relative effects of early- and late-pregnancy exposure to tobacco on infant birth weight. Data were obtained from the Smoking Cessation in Pregnancy project, conducted in public clinics in three states (Colorado, Maryland, and Missouri) between 1987 and 1991. Self-reported cigarette use and urine cotinine concentration were collected from 1,583 pregnant smokers at study enrollment and in the third trimester. General linear models were used to generate mean adjusted birth weights for women who reduced their tobacco exposure by 50 percent or more and for those who did not change their exposure. Regression smoothing techniques were used to characterize the relation between birth weight and early exposure and birth weight and third-trimester exposure. Reducing cigarette use was associated with an increase in mean adjusted birth weight of only 32 g, which was not significant (p = 0.33). As third-trimester cigarette use increased, birth weight declined sharply but leveled off at more than eight cigarettes per day. Findings were similar when urine cotinine concentration was used. Women who smoke during pregnancy may need to reduce to low levels of exposure (less than eight cigarettes per day) to improve infant birth weight.

Measures of maternal tobacco exposure and infant birth weight at term.

This study was undertaken to determine the relation between self-reported number of cigarettes smoked per day and urine cotinine concentration during pregnancy and to examine the relations between these two measures of tobacco exposure and birth weight. Data were obtained from the Smoking Cessation in Pregnancy project, conducted between 1987 and 1991. Cigarette smoking information and urine cotinine concentration were collected for 3,395 self-reported smokers who were receiving prenatal care at public clinics in three US states (Colorado, Maryland, and Missouri) and who delivered term infants. General linear models were used to quantify urine cotinine variability explained by the number of cigarettes smoked per day and to generate mean adjusted birth weights for women with different levels of tobacco exposure. Self-reported number of cigarettes smoked per day explained only 13.9% of the variability in urine cotinine concentration. Birth weight declined as tobacco exposure increased; however, the relation was not linear. The sharpest declines in birth weight occurred at low levels of exposure. Furthermore, urine cotinine concentration did not explain more variability in birth weight than did number of cigarettes smoked. These findings should be considered by researchers studying the effects of smoking reduction on birth outcomes.

The relationship between pregnancy intendedness and physical violence in mothers of newborns. The PRAMS Working Group.

OBJECTIVE: To determine if pregnancy intendedness is associated with physical violence, and to identify factors that modify this association. METHODS: Three to 6 months after delivery, we mailed a questionnaire to a population-based sample of 12,612 mothers of infants born during 1990 and 1991 in four states. We used multiple logistic regression to compute odds ratios. RESULTS: The state-specific prevalences (+/- standard error) of physical violence ranged from 3.8 +/- 0.5 to 6.9 +/- 0.8%; the prevalences of unwanted or mistimed pregnancies ranged from 36.9-46.3%. In each state, higher rates of physical violence were reported by women who had fewer than 12 years of education, lived in crowded conditions, participated in the Special Supplemental Food Program for Women, Infants, and Children, received no or delayed prenatal care, or were of races other than white, under 20 years old, or not married. Regardless of other attributes, women with unwanted or mistimed pregnancies reported higher rates of physical violence than women with intended pregnancies and accounted for 70% of women who reported physical violence. Overall, women with unwanted pregnancies had 4.1 (95% confidence interval 2.7-6.2) times the odds of experiencing physical violence than did women with intended pregnancies. This association was weaker for women with few social advantages than for those with more advantages. CONCLUSION: Physical violence toward women during the periconceptional and antenatal periods occurs in all sociodemographic groups. Women with unwanted or mistimed pregnancies are at an increased risk for violence by their partners compared with women with intended pregnancies.

Evaluation of the 1990 Centers for Disease Control and Prevention smoke-free policy.

PURPOSE: To determine the prevalence of tobacco use among Centers for Disease Control and Prevention (CDC)/Agency for Toxic Substances and Disease Registry (ATSDR) employees and the effect of the smoke-free policy on smoking behavior and air quality at work. DESIGN: A stratified telephone survey of 1181 CDC/ATSDR employees randomly selected from employee rosters. SETTING: CDC/ATSDR work sites in Atlanta, Georgia, and other major CDC locations throughout the United States and Puerto Rico. SUBJECTS: Randomly selected employees of CDC/ATSDR1, or about 22% of the total CDC/ATSDR population; 98% of eligible persons selected agreed to participate. MEASURES: Demographic and smoking history variables, attitudes toward and impact of the smoke-free policy on smoking behavior, and self-report changes in air quality were the measures used. RESULTS: Overall cigarette smoking prevalence was only 11.1%. One percent reported using chewing tobacco, 1.1% reported smoking a pipe, and 1.4% reported smoking cigars. Average self-reported, daily cigarette consumption significantly decreased after the smoking ban took effect. Overall, 90% of the employees supported the smoke-free policy, and 80% of the employees believed that smokers were complying with the smoke-free policy. Most employees believed that the air quality of work areas and nonwork areas (65% and 69%, respectively) had improved since the smoke-free policy was implemented. CONCLUSIONS: These findings are consistent with previous evaluations of smoke-free policies and suggest that most employees are generally supportive of workplace smoking restrictions. Such policies can also have a positive impact on smoking behavior and perceived air quality.

Integrating smoking cessation into routine public prenatal care: the Smoking Cessation in Pregnancy project.

OBJECTIVES: In 1986, the state health departments of Colorado, Maryland, and Missouri conducted a federally-funded demonstration project to increase smoking cessation among pregnant women receiving prenatal care and services from the Women, Infants, and Children (WIC) program in public clinics. METHODS: Low-intensity interventions were designed to be integrated into routine prenatal care. Clinics were randomly assigned to intervention or control status; pregnant smokers filled out questionnaires and gave urine specimens at enrollment, in the eighth month of pregnancy, and postpartum. Urine cotinine concentrations were determined at CDC by enzyme-linked immunosorbent assay and were used to verify self-reported smoking status. RESULTS: At the eighth month of pregnancy, self-reported quitting was higher for intervention clinics than control clinics in all three states. However, the cotinine-verified quit rates were not significantly different. CONCLUSIONS: Biochemical verification of self-reported quitting is essential to the evaluation of smoking cessation interventions. Achieving changes in smoking behavior in pregnant women with low-intensity interventions is difficult.

Smoking, pregnancy, and source of prenatal care: results from the Pregnancy Risk Assessment Monitoring System. The Pregnancy Risk Assessment Monitoring System Working Group.

OBJECTIVE: To assess the impact of current smoking intervention efforts and to target future efforts by describing the relationships between maternal smoking, smoking cessation, and source of prenatal care. METHODS: We used population-based data from 6319 mothers who delivered live-born infants during 1988 and 1989 in Maine, Michigan, Oklahoma, and West Virginia. The number of women sampled per state ranged from 1490-2659; state-specific response rates ranged from 66-84%. Analysis weights adjusted for selection probability and non-response. RESULTS: The prevalences of maternal smoking before, during, and after pregnancy among women receiving publicly funded prenatal care were 2.3-3.4 times the comparable prevalences among privately insured women receiving prenatal care from private providers. Although many smokers reduced or quit smoking during pregnancy, most resumed or increased their smoking to nearly pre-pregnancy levels by 3-6 months postpartum. CONCLUSIONS: Interventions should target the very high levels of smoking among the 27% of women receiving publicly funded prenatal care. However, from a population perspective, the greatest potential for reduction in smoking is among patients of private providers, who care for 61% of pre-pregnancy smokers.

Trends in obstetric operative procedures, 1980 to 1987.

OBJECTIVES: Increasing rates of cesarean deliveries have received widespread attention in recent years, as concern in the United States about unnecessary surgical procedures has increased. However, little information has been published on the national trends of other operative obstetric procedures occurring during deliveries. METHODS: We analyzed data from the National Hospital Discharge Survey to examine trends in the use of forceps, vacuum extraction, and cesarean section from 1980 through 1987. RESULTS: The rate of cesarean sections increased by 48%, while the rate of forceps procedures declined by 43%. Although the risk of cesarean section was significantly increased for older women, the risk of forceps and vacuum extraction procedures did not vary by age. Women with private insurance were significantly more likely to receive a cesarean section (rate ratio [RR] = 1.2), forceps procedure (RR = 1.7), and vacuum extraction procedure (RR = 1.8) than were women without private insurance. CONCLUSIONS: As pressure mounts to decrease the national cesarean section rate from 24% to 15% by the year 2000, attention should also be given to surveillance of other operative delivery procedures.

Smoking during pregnancy: prevalence, effects, and intervention strategies.

Smoking prevalence rates have been declining in the United States, but an estimated 25 percent of pregnant women continue to smoke. Smoking during pregnancy is considered one of the leading, preventable causes of low birthweight. Research attributes 21 to 39 percent of low birthweight to smoking during pregnancy, although the exact mechanism of the effect is not completely understood. Several well-designed studies have shown that pregnant smokers are more likely to stop smoking if they are provided with systematic interventions. This overview describes adverse consequences, prevalence, possible mechanisms of action, and prenatal smoking-cessation programs that have proved effective. A five-step approach is outlined for clinicians who want to counsel their prenatal clients.