Weight gain associated with prenatal smoking cessation in white, non-Hispanic women

Maternal characteristics associated with gestational weight gain in France: a population-based, nationally representative study

OBJECTIVES

To provide nationally representative estimates of gestational weight gain (GWG) and identify maternal characteristics associated with inadequate GWG in France.

DESIGN

A population-based study using data from the French National Perinatal Survey: 2010 and 2016.

SETTING

All maternity units in metropolitan, mainland France (n=535 in 2010; n=493 in 2016).

PARTICIPANTS

Singleton live births with GWG data (N=24 850).

PRIMARY OUTCOME MEASURES

GWG was calculated as end of pregnancy minus pre-pregnancy weight (kg) and categorised as 'insufficient', 'adequate', or 'excessive' using 2009 Institute of Medicine thresholds. Classification accounted for pre-pregnancy body mass index (BMI) (kg/m²; underweight (<18.5), normal weight (18.5-24.9), overweight (25-29.9), obese (≥30)) and gestational age at birth. We estimated average GWG and the percentage of women in each GWG category. Polytomous logistic regression identified characteristics associated with GWG adequacy.

RESULTS

Average GWG was 13.0 kg (SD 5.6), with 26.8% of women gaining insufficiently, 37.0% adequately and 36.1% excessively. Among other factors, insufficient GWG was associated with underweight (vs normal weight; adjusted OR (aOR) 1.4, 95% CI 1.2 to 1.5) and obese (aOR 1.5, 95% CI 1.4 to 1.7) BMI. Excessive GWG was associated with overweight (aOR 2.8, 95% CI 2.6 to 3.1) and obese BMI (aOR 3.3, 95% CI 2.9 to 3.6). Examining obesity classes separately, odds of insufficient GWG increased from obesity class I to III, while odds of excessive GWG decreased from obesity class I to III. Primiparity (insufficient: aOR 0.9, 95% CI 0.9 to 1.0; excessive: aOR 1.2, 95% CI 1.2 to 1.3), maternal characteristics indicative of lower socioeconomic status, and continuing or quitting smoking during pregnancy were also associated with inadequate GWG.

CONCLUSIONS

In France, insufficient and excessive GWG are common. For optimal outcomes, clinician education, with special attention to the needs of higher risk/vulnerable groups, is needed to ensure all women receive appropriate advice for recommended GWG.

Biochemically confirmed smoking cessation and gestational weight gain

BACKGROUND

Prenatal smoking cessation has substantial health benefits for mothers and offspring, but concerns about weight gain may be a barrier to quitting. We quantified gestational weight gain associated with biochemically confirmed smoking cessation.

METHODS

Data originated from a randomized controlled cessation trial: Smoking Cessation in Pregnancy project (1987-1991). We calculated gestational weight gain using self-reported prepregnancy weight and measured weight at 30-34 weeks of gestation. We used linear regression to estimate adjusted mean differences in gain for quitters versus continuing smokers by the last trimester. The effects of quitting earlier (by 2nd trimester) versus later (by 3rd trimester) were calculated. We assessed the percentages who gained weight according to Institute of Medicine (IOM) recommendations within 2 weeks of a full-term delivery.

RESULTS

At 30-34 weeks, nulliparous and multiparous quitters gained an average of 3.0 pounds (95% CI 0.9-5.1 pounds) (1.4 kg [0.4-2.3 kg]) and 6.6 pounds (95% CI 4.3-8.9 pounds) (3.0 kg [1.9-4.0 kg]) more, respectively, than continuing smokers. Weight gain in early quitters did not differ significantly from that in late quitters. Quitters were more likely than continuing smokers to gain above current guidelines (60.3% vs 46.3%) and were less likely to gain below guidelines (11.5% vs 21.6%) (P = 0.002).

CONCLUSIONS

Although quitters had modest additional weight gain by 30-34 weeks compared to continuing smokers, a high proportion in both groups gained in excess of IOM recommendations. Both quitters and continuing smokers may need support to achieve optimal gestational weight gain.

Are women who quit smoking at high risk of excess weight gain throughout pregnancy?

Background

Smoking cessation has been reported to be associated with high total gestational weight gain (GWG), which itself is a risk factor for adverse maternal-infant outcomes. Recent studies have criticized conventional single measures of GWG, since they may lead to biased results. Therefore, we aimed to compare patterns of GWG based on serial antenatal weight measurements between women who: never smoked, quit during pregnancy, continued to smoke.

Methods

Participants (N = 509) of our longitudinal study were recruited from seven antenatal clinics in Southwestern Ontario. Serial GWG measurements were abstracted from medical charts, while information on smoking status was obtained from a self-administered questionnaire at a median gestational age of 32 (27–37) weeks. GWG patterns were assessed by fitting piecewise mixed-effects models. First trimester weight gains and weekly rates for the last two trimesters were compared by smoking status.

Results

During the first trimester, women who never smoked and those who quit during pregnancy gained on average 1.7 kg (95 % CI: 1.4–2.1) and 1.2 kg (0.3–2.1), respectively, whereas women who continued smoking gained more than twice as much (3.5 kg, 2.4–4.6). Weekly rate of gain in the second and third trimesters was highest in women who quit smoking (0.60 kg/week, 0.54–0.65), approximately 20 and 50 % higher than in women who never smoked and those who smoked during pregnancy, respectively.

Conclusions

In this longitudinal study to examine GWG by smoking status based on serial GWG measurements, we found that women who quit smoking experienced a rapid rate of gain during the last two trimesters, suggesting that this high-risk group may benefit from targeted interventions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-1056-z) contains supplementary material, which is available to authorized users.

Association of Restraint and Disinhibition to Gestational Weight Gain among Pregnant Former Smokers

INTRODUCTION

Gaining excessive weight during pregnancy is associated with immediate maternal and fetal complications as well as longer term obesity. Prepregnancy body mass index, age, and smoking cessation have been related to gestational weight gain (GWG); however, less is known about how eating behaviors, that may be amenable to modification and have been related to weight gain outside of pregnancy, affect GWG.

METHODS

The present study evaluated the relationship of dietary restraint and disinhibition to GWG in a sample of women (n=248) who quit smoking before or early in pregnancy. Women self-reported height and prepregnancy weight during their third trimester. GWG was calculated by subtracting prepregnancy weight from third trimester weight. The Three-Factor Eating Questionnaire assessed restraint and disinhibition.

RESULTS

Average GWG was 14.60 (±7.64) kg and 47% of women had a GWG greater than the Institute of Medicine recommendations. Linear regression models were used to examine restraint and disinhibition as correlates of GWG, and multinomial logistic regressions were utilized to determine whether eating behaviors were associated with inadequate or excessive GWG. Restraint was associated positively with total GWG, but disinhibition was not associated with GWG. Thus, conscious attempts to restrict intake were associated with GWG beyond the influence of covariates.

CONCLUSION

These findings highlight the potential influence of modifiable eating behaviors on GWG and demonstrate the need for additional research to determine how these behaviors relate to GWG over the course of pregnancy.

Prediction of gestational weight gain - a biopsychosocial model

OBJECTIVE

To examine the influence of health behaviours and psychological well-being on gestational weight gain using a biopsychosocial model.

DESIGN

A prospective cohort study of pregnant women consecutively recruited at their first antenatal care visit. A self-administered questionnaire was used to collect data on health behaviours and psychological well-being in early pregnancy. Linear regression and logistic regression were used to identify predictors of total weight gain in kilograms and weight gain outside the current Institute of Medicine recommendations, respectively.

SETTING

A maternity hospital in the Republic of Ireland.

SUBJECTS

Data on 799 women were analysed.

RESULTS

Pre-pregnant BMI ≥30·0 kg/m2, short stature, parity >0, decreased food intake and absence of health insurance predicted lower absolute gestational weight gain, while foreign nationality, consumption of takeaway meals more than once weekly and increased food intake predicted higher absolute gestational weight gain. Overweight and obesity, foreign nationality, increased food intake and height >170 cm were risk factors for excessive weight gain, while antenatal depression was protective against excessive weight gain. Notably, physical activity measures were not related to the gestational weight gain outcomes. Pre-pregnancy overweight and increased food intake were the strongest predictors of excessive gestational weight gain.

CONCLUSIONS

None of the psychological well-being measures examined, with the exception of antenatal depression, was associated with any of the weight gain outcomes. The behavioural predictors of gestational weight gain were increased food intake and takeaway consumption. Public health promotions should target pre-pregnancy BMI and pregnancy-associated change in food intake.

Risk factors for excessive gestational weight gain in a healthy, nulliparous cohort

OBJECTIVE

Excessive gestational weight gain (GWG) is associated with adverse maternal and child outcomes and contributes to obesity in women. Our aim was to identify early pregnancy factors associated with excessive GWG, in a contemporary nulliparous cohort.

METHODS

Participants in the SCOPE study were classified into GWG categories ("not excessive" versus "excessive") based on pregravid body mass index (BMI) using 2009 Institute of Medicine (IOM) guidelines. Maternal characteristics and pregnancy risk factors at 14-16 weeks were compared between categories and multivariable analysis controlled for confounding factors.

RESULTS

Of 1950 women, 17% gained weight within the recommended range, 74% had excessive and 9% inadequate GWG. Women with excessive GWG were more likely to be overweight (adjOR 2.9 (95% CI 2.2-3.8)) or obese (adjOR 2.5 (95% CI 1.8-3.5)) before pregnancy compared to women with a normal BMI. Other factors independently associated with excessive GWG included recruitment in Ireland, younger maternal age, increasing maternal birthweight, cessation of smoking by 14-16 weeks, increased nightly sleep duration, high seafood diet, recent immigrant, limiting behaviour, and decreasing exercise by 14-16 weeks. Fertility treatment was protective.

CONCLUSIONS

Identification of potentially modifiable risk factors for excessive GWG provides opportunities for intervention studies to improve pregnancy outcome and prevent maternal obesity.

Effect of smoking cessation on gestational and postpartum weight gain and neonatal birth weight

OBJECTIVE

To examine the association among smoking cessation, gestational and postpartum weight gain, and neonatal birth weight.

METHODS

We analyzed prospectively collected data from 1,774 women with term singleton pregnancies. Smoking status during pregnancy was categorized as nonsmokers, smokers, and quitters; and smoking status 1 year postpartum as nonsmokers, smokers, relapsed quitters, and sustained quitters. The association between smoking status and gestational weight gain, weight gain 1 year postpartum, and neonatal birth weight was tested by linear regression analysis, and the association between smoking status and neonatal birth weight less than the 10th percentile for gestational age and sex was tested by multivariable logistic regression analysis.

RESULTS

Gestational weight gain at 16 weeks of gestation was comparable for nonsmokers, smokers, and quitters. The adjusted mean gestational weight gain at 37 weeks of gestation was 2.0 kg (95% confidence interval [CI] 1.5-2.6) higher in quitters compared with nonsmokers. The rate of neonatal birth weight less than the 10th percentile was 21.7% among smokers, 8.0% among quitters, and 7.4% among nonsmokers. The adjusted odds ratio (OR) for birth weight less than 10th percentile was 3.6 (95% CI 2.5-5.2) in neonates born to smokers; the risk was similar for quitters (OR 1.0, 95% CI 0.6-1.6). One year after delivery, sustained quitters had a 2.4-kg (95% CI 1.6-3.1) higher adjusted postpartum weight gain than nonsmokers.

CONCLUSION

Smoking cessation is associated with gestational as well as postpartum weight gain. However, smoking cessation is associated with a substantially lower rate of neonatal birth weight less than the 10th percentile.

LEVEL OF EVIDENCE

II.

Prenatal smoking cessation intervention and gestational weight gain

BACKGROUND

Quitting smoking is often associated with weight gain and prenatal cessation may lead to increased gestational weight gain (GWG). Although previous reports have suggested a link between prenatal smoking cessation and GWG, no studies have examined the relationship between cessation and guideline-recommended GWG, and there is little information about the relationship between the timing of prenatal cessation and GWG. Thus, we examine GWG among women in a community prenatal smoking cessation program and assess the relationship between the timing of prenatal cessation GWG.

METHODS

Pregnant women from care clinics serving economically disadvantaged women who participated in a smoking cessation intervention offered free of charge, self-reported weight, and provided biochemical verification of smoking. Relationships between duration of cessation and GWG were evaluated in t-tests and regression models. GWG was calculated from self-reported weight before pregnancy and self-reported weight at the last visit before delivery.

FINDINGS

Women who quit earlier during pregnancy had greater GWG (16.9 ± 7.5 kg) than did those who never quit (13.6 ± 8.9). After adjusting for timing of weight assessment and prepregnancy body mass index, however, GWG was not different between women who did and did not quit.

CONCLUSION

Quitting earlier in pregnancy is associated with greater GWG, but women who do and do not quit do not differ on total GWG. Despite increased GWG with early cessation, the maternal and fetal health benefits of prenatal smoking cessation outweigh risks of potential risks of excessive GWG.

Determinant factors of insufficient and excessive gestational weight gain and maternal-child adverse outcomes

OBJECTIVE

To estimate the magnitude and determinant factors of insufficient and excessive gestational weight gain (GWG) and its relation with maternal-child adverse outcomes.

METHODS

This was a prospective study with 173 pregnant women and their newborns monitored at a primary health care facility in Rio de Janeiro. Multinomial regression models were employed, having as the outcome the adequacy of GWG (insufficient, adequate, or excessive). Covariables were classified as biological, socioeconomic, reproductive, behavioral, and nutritional.

RESULTS

Forty-one percent of pregnant women had insufficient GWG and 22.0% had excessive GWG. Pregestational overweight was associated with insufficient GWG (odds ratio [OR] 0.19, 95% confidence interval [CI] 0.05-0.78), and pregestational obesity was associated with excessive GWG (OR 4.66, 95% CI 1.34-19.08). Also associated with insufficient GWG were a stature <157 cm (OR 2.25, 95% CI 1.03-4.93) and ages 25-29 y (OR 3.70, 95% CI 1.26-10.84) and >or=30 y (OR 2.88, 95% CI 1.13-7.35) compared with the reference group (18-24 y). Age <12 y at menarche (OR 4.97, 95% CI 1.51-16.30) and being a former smoker (OR 5.18, 95% CI 1.62-16.52) demonstrated an association with excessive GWG compared with non-smokers (reference group). Sixty percent of pregnant women with excessive GWG delivered by cesarean section compared with 39.8% with adequate or insufficient GWG (P < 0.05). Prevalence of macrosomia in the excessive GWG group was 23.5% compared with 4.5% for pregnant women with insufficient GWG (P < 0.001).

CONCLUSION

Different determinant factors related to insufficient and excessive GWG were observed, which can be identified in the beginning of pregnancy, thus predicting unfavorable gestational outcomes. An increased percentage of women presented GWGs outside recommended levels.

Relationships between prenatal smoking cessation, gestational weight gain and maternal lifestyle characteristics

OBJECTIVES

To describe maternal characteristics and lifestyle factors associated with prenatal smoking habits and to appraise the effect of quitting smoking in early gestation on maternal weight gain during pregnancy.

METHODS

This is a follow-up study of 1753 women who gave birth in 1984/1985 in Stockholm, Sweden. Multivariate logistic models were used to evaluate the association between smoking cessation and weight gain above the American Institute of Medicine (IOM) recommendations, based on pre-pregnancy BMI.

RESULTS

About 22% of all participants identified themselves as current smokers and 11.6% reported smoking cessation during pregnancy. Smokers were more likely to be single mothers and reported low quality of breakfast (e.g. eating only 1 food group at breakfast). Non-smokers were older, more likely to be married and have a healthier lifestyle. Quitters also adopted healthier eating habits (e.g. improvement in their breakfast quality). Women who quit smoking gained, on average, 15.3 kg (SD 4.4) during pregnancy, non-smokers gained 14.1 kg (SD 4.0) and smokers gained 13.8 kg (SD 4.3). Quitters gained significantly more weight than both non-smokers and smokers (p<0.001). Smoking cessation was significantly associated with gaining weight above IOM recommendations, even after controlling for potential confounders (OR: 2.0; 95%CI: 1.4-3.0; p<or=0.0001).

CONCLUSIONS

In this population, smoking cessation in early pregnancy doubled the likelihood of gaining excess weight. This finding highlights the need for supportive measures to help control weight gain among women who quit smoking during pregnancy.

Determinants of weight gain in pregnant women attending a public prenatal care facility in Rio de Janeiro, Brazil: a prospective study, 2005-2007

The objective of this study was to evaluate the determinants of weight gain during pregnancy. The study adopted a prospective cohort design with four follow-up waves and included a sample of 255 pregnant women that received prenatal care at a public health care facility in Rio de Janeiro, Brazil. A mixed-effects linear longitudinal regression model was used, having as the dependent variable the weight assessed in four follow-up waves, and as independent variables: demographic, socioeconomic, reproductive, behavioral, and nutritional data. Mean weight gain was 0.413kg per gestational week, consistent with recommendations by the Institute of Medicine. Per capita family income and smoking were associated with total weight gain during gestation. According to the longitudinal multiple linear regression model, age (² = 0.6315), menarche (² = -2.3861), triglycerides (² = 0.0437), blood glucose (² = 0.1544), and adequacy of energy consumption (² = -0.0642) were associated with gestational weight gain. Special attention should be given to these sub-groups, due to increased risk of excessive weight gain.

Prenatal weight gain following smoking cessation

OBJECTIVE

To evaluate the association of changes in smoking habit with maternal weight gain.

STUDY DESIGN

We questioned 4000 pregnant women > or =20 years about previous and current smoking habits during a second trimester visit to general prenatal clinics in 6 Brazilian cities, from 1991 to 1995, and followed their weight, through chart review, to term.

RESULTS

Of women who reported stopping smoking (915, 23% of the total), 240 (26.2%) stopped during pregnancy. The median number of cigarettes smoked/day among those who reported continued smoking (717, 18%) decreased from 10 to 5 with pregnancy. In linear regression models adjusting for age, educational attainment, ethnicity, prepregnancy body mass index, parity and clinical center, ex-smokers gained 1.03 kg (95%CI 0.59-1.46) more than those reporting never smoking, this difference being greater: 1.54 kg (95%CI 0.78-2.30) in those who reported quitting while pregnant. The size of weight gain in both continuing smokers and ex-smokers was proportional to the reduction in daily number of cigarettes smoked during pregnancy, being 0.38 kg (95%CI 0.07-0.68) greater for each 10 cigarettes reduced (p=0.007).

CONCLUSION

Decreasing the quantity of cigarettes smoked in pregnancy, although important for maternal and child health, is associated with maternal weight gain.

Cross-sectional study of weight gain and increase in BMI throughout pregnancy

OBJECTIVE

To generate reliable new reference ranges for weight gain and increase in body mass index (BMI) during pregnancy from a large population.

STUDY DESIGN

In a prospective cross-sectional study at the Obstetric outpatient clinic, Zurich University Hospital, weight gain and BMI, before gestation and at the booking visit, were determined in 4034 pregnant women with accurately dateable singleton pregnancies (Caucasian: N = 3242, Asian (predominantly from Sri Lanka, Thailand and the Philippines): N = 578 and Black: N = 214). Women with known insulin-dependent diabetes mellitus before pregnancy were excluded. Fifth, 50th and 95th centiles were presented for Caucasians and corresponding centile curves for Asians and Blacks. Simple and multiple regression analyses were performed for various risk factors. A significance level of P < 0.05 was used in all tests.

RESULTS

Mean weight gain was 15.5+/-5.9 kg (34.2+/-13.0 lb) at term with values >25.4 kg (56.0 lb) and <5.7 kg (12.6 lb) for the 95th and the 5th centile, respectively. Mean BMI increased slightly and steadily to 28 kgm(-2) at term. Parity and pre-pregnancy BMI were significant determinants in Caucasians. Weight gain and BMI was slightly lower in Asians and Blacks.

CONCLUSIONS

BMI centile curves have the advantage in that they consider height during the whole course of pregnancy. It may be an additional helpful tool in controlling weight gain in pregnancy. Further studies are required to determine the prognostic implications of values > or = 95th centile and < or = 5th centile.

Combined effects of maternal smoking status and dietary intake related to weight gain and birth size parameters

OBJECTIVE

To investigate the interaction of smoking status and dietary intake during pregnancy and its relationship to maternal weight gain and birth size parameters.

DESIGN

An observational prospective study.

SETTING

Free-living conditions.

POPULATION

Four hundred and eight healthy pregnant Icelandic women.

METHODS

Maternal smoking status, lifestyle factors and dietary habits were evaluated with questionnaires. Intake of foods and supplements was also estimated with a semiquantitative food frequency questionnaire for the previous 3 months. All questionnaires were filled out between 11 and 15 weeks and between 34 and 37 weeks of gestation. Smoking status in relation to optimal and/or excessive weight gain during pregnancy was represented with logistic regression controlling for potential confounding factors.

MAIN OUTCOME MEASURES

Maternal weight gain, smoking status, dietary intake and birthweight.

RESULTS

Women who smoked throughout pregnancy were unlikely to gain optimal weight or more (OR 0.51, 95% CI 0.27-0.97), whereas smoking cessation in connection with pregnancy ('former smokers') doubled the risk of excessive weight gain (OR 2.03, 95% CI 1.24-3.35). The latter association was no longer significant after adjustment for dietary factors and other confounding factors. Former smokers ate the least amount of fruit and vegetables (fruit: 129 versus 180 and 144 g/day (median), P= 0.038; vegetables: 53 versus 76 and 72 g/day, P= 0.026 for former smokers, nonsmokers and smokers, respectively). Birthweight was lowest among infants born to smokers, but birthweight was similar for former smokers and nonsmokers (3583 +/- 491 g versus 3791 +/- 461 g and 3826 +/- 466 g, respectively; P= 0.003).

CONCLUSIONS

Smoking cessation in early pregnancy or pre-pregnancy is not associated with low birthweight. It is, however, associated with excessive maternal weight gain and a low fruit and vegetable intake.

Cigarette Smoking and Low Maternal Weight Gain in Medicaid-Eligible Pregnant Women

OBJECTIVES

Weight gain during pregnancy (termed maternal weight gain) is an important predictor of maternal and infant health. This analysis was conducted to examine if cigarette smoking during pregnancy was associated with low maternal weight gain, as defined by the Institute of Medicine's (IOM) recommendations, independent of caloric intake.

METHODS

The participants were 265 Medicaid-eligible, pregnant women. Data were self-reported. Low maternal weight gain was defined as gaining less than the IOM recommendation for a given prepregnancy body mass index (BMI). Logistic regression was used to determine if smokers had greater odds of low maternal weight gain independent of caloric intake.

RESULTS

Approximately 21% of the participants were self-reported smokers. No difference was observed in mean maternal weight gain between smokers and nonsmokers (14.4 kg vs. 13.9 kg, respectively, p = 0.80). However, a greater proportion of smokers were categorized as having low maternal weight gain compared with nonsmokers (35.7% vs. 31.1%). Unadjusted regression analysis showed that the odds of low maternal weight gain were 1.34 times greater for smokers than nonsmokers (odds ratio [OR] = 1.34, 95% confidence interval [CI] 0.73, 2.67). The OR did not materially change after adjustment for daily caloric intake, age, and length of gestation. In addition, the data suggest that the more cigarettes smoked, the higher the odds of having low maternal weight gain.

CONCLUSIONS

The results suggest that cigarette smoking is associated with low maternal weight gain, as defined by the IOM recommendations, independent of caloric intake.

Effets maternels et fœtaux d'une prise de poids maternelle excessive au cours de la grossesse dans une population de patientes de poids normal avant la grossesse

OBJECTIVE

To study the effects of increased gestational weight gain in women of normal prepregnant weight.

PATIENTS AND METHODS

We compared 174 patients gaining more than 18 kg to 174 patients gaining between 9 and 15 kg. Body mass index was normal for every woman included in the study.

RESULTS

Weight gain > or =18 kg was associated with increased risk of vascular complications (5.2% vs. 1.1%, P < 0.05) but not with increased risk of mellitus diabetes (5.2% vs. 4.0%, NS). Weight gain > or =18 kg prolonged labor length (414.4 +/- 147 min vs. 376.5 +/- 166.4 min, P < 0.05) and increased the rate of cesarean section (19.5% vs. 10.3%, P < 0.05). Neonatal outcome was similar in both groups, mean birth weight was greater (3413.6 +/- 427.0 g vs. 3163.4 +/- 495.1 g, P < 0.05) and the frequency of infants weighing more than 4000 g at birth was increased (8.0% vs. 4.0%, P < 0.05) among women gaining more than 18 kg.

CONCLUSION

Excess weight gain in pregnancy affects gestational and delivery outcomes and results in higher frequency of fetal macrosomia. These results confirm recommendations on weight gain in pregnancy as guidelines for pregnant women.

Relationships between cigarette smoking during pregnancy, gestational age, maternal weight gain, and infant birthweight

OBJECTIVE

To estimate the effect of smoking on infant birthweight independent of gestational age and maternal weight gain during pregnancy.

METHODS

Stepwise regression was used to identify sets of maternal and infant characteristics not modified by prenatal smoking that were predictors of infant birthweight, gestational age, and net maternal weight gain. These were then included in regression analyses to assess the effects of smoking, as measured by cigarette consumption, exhaled carbon monoxide, or urinary cotinine on gestational age, net maternal weight gain, and infant birthweight.

RESULTS

After adjustment for nonmodifiable factors, smoking accounted for 1.5-3.1% of the variance in gestational age at delivery. It accounted for 5.3-7.7% of the variance in net maternal weight gain after adjustment for nonmodifiable factors and gestational age. After adjustment for gestational age and net maternal weight gain, and the nonmodifiable factors, smoking accounted for 2.7-5.2% of the variance in infant birthweight.

CONCLUSIONS

Most of the gain in infant birthweight on quitting smoking is due to the independent effect of smoking on fetal growth restriction, with much smaller gains related to increased maternal weight gain and a slightly longer gestational age.

Psychosocial thriving during late pregnancy: relationship to ethnicity, gestational weight gain, and birth weight

OBJECTIVE

To test the relationships between psychosocial thriving (depressive symptoms, health-related lifestyle) and gestational weight gain and birth weight. To test the influences of ethnicity on the relationships between psychosocial thriving and gestational weight gain and birth weight.

DESIGN

Baseline data taken from the Austin New Mothers Study.

SETTING

A community hospital in Texas.

PARTICIPANTS

305 low-risk African American, Hispanic, and White women with full-term pregnancies, singleton births, and Medicaid coverage.

MAIN MEASURES

Center for Epidemiologic Studies Depression Scale, Self Care Inventory, Food Habits Questionnaire, gestational weight gain, and birth weight.

RESULTS

Newborns of African American women had lower birth weights (3,240 g) than newborns of Hispanic (3,422 g) or White women (3,472 g), even though no ethnic differences were found among the mothers on psychosocial variables. Late in pregnancy, women had high levels and prevalence (> 70%) of depressive symptoms regardless of ethnicity, and 50% exceeded recommended gestational weight gains. In full regression models, psychosocial variables were not significant predictors of gestational weight gain or birth weight. Ethnicity also was not a significant moderator of weight outcomes.

CONCLUSIONS

Psychosocial thriving late in pregnancy was unrelated to gestational weight gain or birth weight. Ethnicity did not moderate psychosocial-weight relationships. Although ethnic differences were not found on psychosocial variables, high levels of depressive symptoms and greater than recommended gestational weight gains were prevalent. These findings have implications for maternal health during and beyond pregnancy.

Pregnancy weight gain: still controversial

During the 20th century, recommendations for maternal weight gain in pregnancy were controversial, ranging from rigid restriction to encouragement of ample gain. In 1990, the Institute of Medicine (IOM) recommended weight-gain ranges with the primary goal of improving infant birth weight. These guidelines were widely adopted but not universally accepted. Critics have argued that the IOM's recommendations are unlikely to improve perinatal outcomes and may actually increase the risk of negative consequences to both infants and mothers. We systematically reviewed studies that examined fetal and maternal outcomes according to the IOM's weight-gain recommendations in women with a normal prepregnancy weight. These studies showed that pregnancy weight gain within the IOM's recommended ranges is associated with the best outcome for both mothers and infants. However, weight gain in most pregnant women is not within the IOM's ranges. All of the studies reviewed were observational and there is a compelling need to conduct experimental studies to examine interventional strategies to improve maternal weight gain with the objective of optimizing health outcomes.

Sociocultural and behavioral influences on weight gain during pregnancy

Studies have consistently identified a positive association between prenatal weight gain and birth weight. Much less, however, is known about factors that may influence women to gain weight within currently recommended ranges. The importance of this issue is suggested by recent reports indicating that only 30-40% of women actually gain weight within these ranges. This paper examines demographic, sociocultural, and behavioral factors that are associated with, and may influence risk of, low prenatal weight gain among adult women with low and normal body mass indexes. Available data suggest that these factors include ethnicity, socioeconomic status, age, education, pregnancy intendedness or wantedness, prenatal advice, and psychosocial characteristics such as attitude toward weight gain, social support, depression, stress, anxiety, and self-efficacy. Potential theoretical models for these associations include biological, behavioral, and mixed pathways. The design of targeted intervention studies will depend on further identification and characterization of sociocultural and behavioral risk factors that, along with reproductive and nutritional characteristics, may predict which women are most likely to have inadequate prenatal weight gain.

Does smoking by pregnant women influence IQ, birth weight, and developmental disabilities in their infants? A methodological review and multivariate analysis

Neuropsychologists are asked frequently to address the issue of the cause of a variety of central nervous system problems that may affect higher cortical function. One such issue is the relationship of maternal smoking to adverse reproductive outcomes involving neocortical insult including mental retardation, learning disabilities, attention-deficit hyperactivity disorder, and other insults that may be related to prolonged hypoxic states in utero. The instant paper develops the issue of causation as a scientific inquiry, reviews several traditional, applicable models, and critiques these models. An additional model of motility is proposed and discussed. The issue of the relationship of maternal smoking to adverse reproductive outcomes is then addressed from a review perspective along with new empirical analyses, the latter demonstrating that researchers tend to draw causal conclusions independent of whether the respective design of their studies would support conclusions about the causation of an event. Causal conclusions in the absence of causal designs have often lead to incomplete and incorrect conclusions. It is necessary to match conclusions not only to the outcomes of a research project but also to its design and accompanying limitations.

Prenatal weight gain patterns and infant birthweight associated with maternal smoking

BACKGROUND

Maternal smoking during pregnancy is recognized as an important and modifiable risk factor for low infant birthweight. The objective of this study was to compare the effects of maternal smoking status on prenatal weight gain and infant birthweight, and to determine if maternal weight gain mediates the effect of smoking cessation on infant birthweight.

METHODS

This prospective study of 341 white, non-Hispanic pregnant smokers, never smokers, and women who stopped smoking during pregnancy used multivariate analysis of variance to evaluate prenatal weight gain patterns. Multiple regression was used to investigate the effects of smoking status and maternal weight gain on infant birthweight.

RESULTS

Women who stopped smoking gained on average 39.68 lb during pregnancy. Smokers gained 32.75 lb, and never smokers gained 34.16 lb. Women who stopped gained significantly more weight than both smokers and never smokers (p = 0.01). Rates of weight gain differed significantly beginning in the second trimester, when women who stopped smoking gained more weight than never smokers (2.57 lb, 99% CI = 0.46, 8.07) and continued during the third trimester, with those who stopped smoking gaining more weight than both smokers (4.31 lb, 99% CI = 1.88, 12.00) and never smokers (1.25 lb, 99% CI = 0.56, 10.49). Infant birthweight differences were significant for women who stopped smoking versus continuing smokers (292 g, 99% CI = 145, 440) and for never smokers versus continuing smokers (253 g, 99% CI = 104, 401). Controlling for baseline maternal body mass index and infant gender, smoking status and weight gain each contributed significantly to infant birthweight (p < 0.001). No evidence of interaction between smoking status and weight gain on infant birthweight was found.

CONCLUSIONS

Maternal smoking status significantly affects prenatal weight gain and infant birthweight, but smoking cessation protects against lower birthweight through mechanisms other than increased maternal weight gain or different weight gain patterns.

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.

Postpartum return to smoking: who is at risk and when

PURPOSE

Despite high rates of spontaneous and assisted smoking cessation during pregnancy, postpartum maintenance is disappointingly low. Predictors of return to smoking remain unclear, thus limiting the development of interventions that could protect the health of women and their children. This study followed women who had participated in a prenatal smoking cessation intervention trial and successfully stopped smoking to address two aims: (1) describe the probability of relapse in confirmed quitters during the first 6 months after the birth, and (2) identify factors that increase relapse.

DESIGN

Prospective design during pregnancy and retrospective report at 6 months postpartum used survival analysis with return to smoking as the dependent variable and the Cox proportional hazards regression technique.

MEASURES

Questionnaires were used at the first prenatal visit and telephone interviews at the 26th week of pregnancy and 6 months postpartum. Nonsmoking after the 20th week was measured by urine cotinine tests (m = 3); nonsmoking postpartum was measured by retrospective self-report.

SETTING

The setting was an HMO-based group practice in Los Angeles.

SUBJECTS

Subjects were white, black, and Hispanic women (n = 127) available for follow-up.

RESULTS

The proportion of the sample classified as relapsers at 6 months postpartum was 62.9%. The final model identified the following risk factors for smoking: taking puffs in late pregnancy and having friends who smoke at the first prenatal visit, less confidence in mid-pregnancy that they could maintain nonsmoking postpartum, and a partner who smokes postpartum.

CONCLUSIONS

Intervention should begin in late pregnancy, and smoking networks, including partner smoking, should be addressed.