Change in observed birth weight associated with change in maternal cigarette smoking

Using data collected by the National Collaborative Perinatal Project of the National Institute of Neurological and Communicative Disorders and Stroke, the author paired on characteristics of their first study pregnancy 319 white women who reported a change in smoking habits for two successive pregnancies with 319 women who reported no change in smoking behavior. Matching was based upon similar birth weight, interval between births, smoking behavior, sex, and parity of the first of two study births. Divergent smoking behavior for each pair by the time of the second study birth allowed assessment of smoking as a treatment effect. Members of each pair who started smoking prior to the second birth while not smoking for the first, had infants with an average birth weight of 67 g less than infants of their controls who did not start smoking and 36 g less than their previous infant. Among infants whose mothers reported smoking prior to the first study birth, a significant increase in birth weight was observed over infants of controls for women who quit smoking prior to the second study birth (average, 169 g). Taken at face value, this rebound in birth weight is not consistent with an immutable, innate predisposition to lower birth weight among those disposed to smoking.     

Sensory-specific satiety in obese and normal-weight women

BACKGROUND: Sensory-specific satiety has been found to play an important role in food choice and meal termination, and it might be a factor contributing to obesity. OBJECTIVE: We hypothesized that obese and normal-weight people have different sensitivities to sensory-specific satiety for high-fat foods. DESIGN: Sensory-specific satiety was measured in 21 obese [x body mass index (BMI; in kg/m(2)): 33.1] and 23 normal-weight (BMI: 22.8) women who were matched for restrained eating behavior, physical activity, age, and smoking behavior. Food intake, appetite ratings, and liking scores before and after an ad libitum lunch were measured. Products differed in fat content and taste (ie, low-fat sweet, low-fat savory, high-fat sweet, and high-fat savory), and the subjects tested all 4 products. In the first study, sandwiches were tested; in the second study, snacks were tested. RESULTS: Sensory-specific satiety for all products was observed in both subject groups. No significant differences were observed between the obese and normal-weight subjects in either sensory-specific satiety or food intake for any of the products or product categories tested. Taste (sweet or savory) had a significantly (P < 0.05) stronger effect on sensory-specific satiety than did fat content. Appetite ratings strongly decreased after lunch, and appetite for a meal or snack after lunch was significantly higher in obese than in normal-weight subjects, whereas scores before lunch did not differ significantly. CONCLUSIONS: Obese and normal-weight people do not differ in their sensitivity to sensory-specific satiety, and factors other than fat content have the greatest effect on sensory-specific satiety.     

Relationships between cigarette smoking and weight control in young women

While multiple risk factors are associated with smoking, body weight concern is a significant risk factor for smoking among young women, including adolescents. This article explores the relationship between frequency of smoking and weight loss strategies among a nationally representative sample of high school females (n = 7,828). Adjusted odds ratios were generated for smoking, weight goals, and weight loss strategies, controlling for demographics. Daily smokers were two to four times more likely to fast, use pills, and purge to control their weight than nonsmokers. Tobacco control efforts for young women must address the influence of weight concern on smoking in this population.     

Weight change and the risk of gestational diabetes in obese women

BACKGROUND: Obesity is an established risk factor for gestational diabetes. It is not known whether this risk might be reduced through weight loss between pregnancies. We sought to determine whether weight loss between pregnancies reduced the risk of gestational diabetes among obese women. METHODS: We conducted a population-based cohort study of 4102 women with 2 or more singleton live births in Washington State between 1992 and 1998. All subjects were nondiabetic and obese (at least 200 lbs) at their first birth during these years. Weight change was calculated as the difference between prepregnancy weight for the 2 pregnancies. We estimated relative risks of gestational diabetes at the subsequent delivery through stratified analyses and Mantel-Haenszel estimates. RESULTS: Thirty-two percent of women lost weight between pregnancies, with a mean weight loss of 23 lbs. Women who lost at least 10 lbs between pregnancies had a decreased risk of gestational diabetes relative to women whose weight changed by less than 10 lbs (relative risk = 0.63; 95% confidence interval = 0.38-1.02, adjusted for age and weight gain during each pregnancy). Of the 61% of women who gained weight between pregnancies, the mean weight gain was 22 lbs. Women who gained at least 10 lbs had an increased risk of gestational diabetes (1.47; 1.05-2.04). CONCLUSIONS: Even moderate changes in prepregnancy weight can apparently affect the risk of gestational diabetes among obese women. This may offer further motivation for interventions aimed at reducing obesity among women of reproductive age.     

Pharmacokinetics of a combined oral contraceptive in obese and normal-weight women

Background

This study was conducted to compare oral contraceptive (OC) pharmacokinetics (PK) in normal-weight [body mass index (BMI) 19.0–24.9] and obese (BMI 30.0–39.9) women.

Study Design

During the third week of the third cycle of OC use, we admitted 15 normal-weight and 15 obese women for collection of 12 venous specimens over 24 h. Using radioimmunoassay techniques, we measured levels of ethinyl estradiol (EE) and levonorgestrel (LNG). During the same cycle, women underwent twice-weekly sonography to assess ovarian follicular development and blood draws to measure endogenous estradiol (E2) and progesterone levels.

Results

Obese women had a lower area under the curve (AUC; 1077.2 vs. 1413.7 pg?h/mL) and lower maximum values (85.7 vs. 129.5 pg/mL) for EE than normal-weight women (p=.04 and <0.01, respectively); EE trough levels were similar between BMI groups. The similar, but smaller, differences in their LNG levels for AUC and maximum values (C_max) were not statistically significant. While peak values differed somewhat, the LNG trough levels were similar for obese and normal-weight women (2.6 and 2.5 ng/mL, respectively). Women with greater EE AUC had smaller follicular diameters (p=.05) and lower E2 levels (p=.04). While follicular diameters tended to be larger among obese women, these differences were not statistically significant.

Conclusion

OC hormone peak levels are lower among obese women compared to normal-weight women, but their trough levels are similar. In this small study, the observed PK differences did not translate into more ovarian follicular activity among obese OC users.     

The effect of cigarette smoking on the risk of preeclampsia and gestational hypertension

This case-control study assessed the relation of cigarette smoking during pregnancy to the risk of preeclampsia and gestational hypertension. All subjects were primiparous women without a history of high blood pressure who gave birth in Quebec City or Montreal, Canada, hospitals between 1984 and 1986. Cases (172 women with preeclampsia and 251 with gestational hypertension) and 505 controls were interviewed at the hospital after delivery. Adjusted relative risks were estimated by polychotomous logistic regression. Compared with women who had never smoked, women who were smokers at the onset of pregnancy had a reduced risk of preeclampsia (relative risk = 0.51, 95% confidence interval 0.34-0.77). Relative risks of preeclampsia decreased with increases in the number of cigarettes smoked daily at the onset of pregnancy: Relative risks among smokers of less than 11, 11-20, and more than 20 cigarettes per day were 0.79, 0.56, and 0.38, respectively (test for trend: p = 0.0002). The protective effect of smoking on preeclampsia was stronger for women who continued to smoke after 20 weeks of pregnancy. While smoking tended to reduce the risk of gestational hypertension, this effect was less evident than that for preeclampsia. Relative risks varied little with severity of disease as based on gestational age at the onset of hypertension, maximal blood pressure and, for preeclampsia, amount of proteinuria. The reduction in mean birth weight attributable to smoking during pregnancy was similar among cases and controls. Nicotine inhibition of thromboxane A2 production might explain the decreased risk of pregnancy-induced hypertension among smokers. Despite these findings, the harmful consequences of smoking on pregnancy outcome outweigh its protective effect against pregnancy-induced hypertension.     

Work in pregnancy and birth weight for gestational age.

In a recent report on prematurity and work in pregnancy based on the Montreal survey noteworthy increases in both preterm births (less than 37 weeks) and infants of low birth weight (less than or equal to 2500 g) were found in women in certain specific occupations or whose work entailed heavy lifting, shift work, long hours, or great fatigue. Because of the large overlap between preterm births and low birth weight, the latter was further analysed with allowance for gestational age in order better to separate factors retarding fetal growth from those shortening gestation. The association of low birth weight with specific occupations, long working hours, and fatigue largely disappeared, suggesting that the effect of these factors was to shorten gestation. By contrast, the association with lifting heavy weights and with shift work persisted, suggesting that these factors retarded fetal growth as well as increasing the risk of preterm birth.     

Predictors and outcomes of excess gestational weight gain among low-income pregnant women

Low-income women were interviewed and their post-natal records were retrieved (n = 160) to assess prevalence of excess gestational weight gain and its socio-demographic predictors. More than half of the women (64%) gained excess weight during pregnancy, with an average of 10 lbs in excess of Institute of Medicine guidelines. Logistic regression indicated that women that started pregnancy at an obese body mass index; who were African American or having an unplanned pregnancy were at significant risk of gaining excess weight in pregnancy. Intervention to prevent excess weight gain during pregnancy is critical in addressing obesity epidemic in the United States and worldwide.     

新生儿出生体重变化趋势及与分娩结局的关系

目的:分析新生儿出生体重变化趋势,探讨其与分娩结局的关系。方法:以海南某医院2005～2009年全部产科分娩病历为样本,分析新生儿体重变化及新生儿结局。结果:近5年新生儿出生体重平均值为(3 144.36 g±516.47)g,足月单胎出生体重平均值为(3 222.1 3 g±411.74)g,5年间不同年份相比较,出生体重平均值无统计学差异(F=1.321,P=0.26),5年低出生体重儿总数195例(8.1%),正常体重儿2 125例(87.8%),巨大胎儿99例(4.1%)。5年来低出生体重儿、正常体重儿、巨大胎儿的发生率保持平衡,无统计学差异(2χ=13.34,P=0.10)。低出生体重儿的1 m in窒息率与5 m in窒息率、新生儿死亡率均高于正常体重儿与巨大胎儿(2χ=26.45,P<0.05),正常体重儿与巨大胎儿之间1 m in窒息发生率无统计学差异(2χ=2.79,P=0.10),5 m in新生儿窒息发生率无统计学差异(2χ=2.39,P=0.15),新生儿死亡发生率无统计学差异(2χ=0.42,P=0.50)。结论:新生儿出生体重变化趋势平衡,低出生体重是导致新生儿窒息和死亡的主要危险因素。应着力于提高孕周,防止早产,提高新生儿存活率。     

A systematic review of dietary interventions for gestational weight gain and gestational diabetes in overweight and obese pregnant women

Purpose

The number of overweight and obese women is increasing in the obstetric population. The aim of this study was to review studies that reported results related to the efficacy of dietary interventions on gestational weight gain (GWG) or the prevention of gestational diabetes (GDM) in overweight and obese women.

Methods

The search was performed using the CINAHL, PubMed, Scopus and Medic electronic databases and limited to the years between 2000 and March 2016. This systematic review includes 15 research articles of which 12 were randomized controlled trials, and three were controlled trials. Three main categories emerged as follows: (1) the types of interventions, (2) the contents of the interventions and (3) the efficacy of the intervention on GWG and the prevention of GDM. The quality of the selected studies was evaluated using the AHRQ Methods Reference Guide for Effectiveness and Comparative Effectiveness Reviews.

Results

Of the selected 15 studies, eight included a specified diet with limited amounts of nutrients or energy, and the others included a dietary component along with other components. Ten studies reported significant differences in the measured outcomes regarding GWG or the prevention of GDM between the intervention and the control groups.

Conclusions

This review confirms the variability in the strategies used to deliver dietary interventions in studies aiming to limit GWG and prevent GDM in overweight and obese women. Inconsistency in the provider as well as the content of the dietary interventions leaves the difficulty of summarizing the components of effective dietary interventions.

     

Impact of preeclampsia and gestational hypertension on birth weight by gestational age

The predominant etiologic theory of preeclampsia is that reduced uteroplacental perfusion is the unique pathogenic process in the development of preeclampsia. Decreased uteroplacental blood flow would result in lower birth weights. To date, no study has assessed the effect of preeclampsia on birth weight by gestational age. Thus, the authors conducted a retrospective cohort study based on 97,270 pregnancies that resulted in delivery between 1991 and 1996 at 35 hospitals in northern and central Alberta, Canada. Differences in mean birth weight between women with preeclampsia and normotensive women ranged from -547.5 g to 239.5 g for gestational age categories ranging from < or = 32 weeks to > or = 2 weeks. The birth weights were statistically significantly lower among mothers with preeclampsia who delivered at < or = 37 weeks, with an average difference of -352.5 g. However, the birth weights were not lower among preeclamptic mothers who delivered after 37 weeks (average difference of 49.0 g). In Alberta, 61.2% of preeclamptic patients gave birth after 37 weeks of gestation. The authors conclude that babies born to mothers with preeclampsia at term have fetal growth similar to that of babies born to normotensive mothers. This finding does not endorse the currently held theory that reduced uteroplacental perfusion is the unique pathophysiologic process in preeclampsia.     

The effect of cigarette taxes on smoking among men and women

The literature contains numerous studies that estimate the effect of cigarette taxes on smoking across various population groups. Although the conclusions are split, most US studies find that men are more responsive to cigarette taxes than women. This paper shows that these results are due to the failure to control for state-specific gender gaps in smoking rates that are correlated with cigarette taxes. When gender-specific state fixed effects are included to control for these gaps, the results indicate that women are nearly twice as responsive to cigarette taxes as are men. Since the econometric specification controls for variation in the tax response by household income, it is unlikely to be responsible for the difference.     

Adolescent smoking in pregnancy and birth outcomes

INTRODUCTION: Cigarette smoking amongst pregnant adolescents is a preventable risk factor associated with low birthweight (<2,500 g), preterm birth (<37 weeks) and infant mortality. The aim of this study was to compare birth outcomes of adolescents who smoke during pregnancy with those who do not and to construct their birthweight-for-gestational-age curves. METHODS: A retrospective cohort analysis of 534 adolescents (10 cigarettes daily had babies with larger birthweight reduction (P = 0.001). CONCLUSION: Almost half of all adolescents smoked during their pregnancy. Birthweight-for-gestational-age curves of smoking adolescents showed a marked fall-off in weight from 36 weeks of gestation, and at least 10% of adolescent smokers showed fetal growth restriction from before 32 weeks of gestation.     

The effects of excise taxes and regulations on cigarette smoking

We estimate a generalized linear model to examine adult and teenage cigarette demand. Out analysis focuses on the extent to which excise taxes and regulations restricting smoking in public places affect cigarette consumption. The adult results indicate that the price elasticity of demand is unstable over time, ranging from 0.06 in 1970 to -0.23 in 1985. These estimates are lower than most found in previous studies. The teenage price elasticity does not differ statistically from the estimates for adults. Additionally, regulations restricting smoking in public places have a significant effect on both adult and teenage cigarette demand.