Chemical hair treatments and adverse pregnancy outcome among Black women in central North Carolina

Several studies suggest that toxic chemicals in hair products may be absorbed through the scalp in sufficient amounts to increase the risks of adverse health effects in women or their infants. This case-control study of 525 Black women from three counties in North Carolina who had delivered a singleton, liveborn infant examined whether exposure to chemicals used in hair straightening and curling increased the odds that the infant was preterm or low birth weight. Cases consisted of 188 preterm and 156 low birth weight births (for 123 women, their infant was both low birth weight and preterm). Controls were 304 women who delivered term and normal birth weight infants. Women who used a chemical hair straightener at any time during pregnancy or within 3 months prior to conception had an adjusted odds ratios (OR) of 0.7 (95% confidence interval (CI) 0.4-1.1) for preterm birth and 0.6 (95% CI 0.4-1.1) for low birth weight. Exposure to chemical curl products was also not associated with preterm delivery (adjusted OR = 0.9, 95% CI 0.5-1.8) or low birth weight (adjusted OR = 1.0, 95% CI 0.5-1.9). Despite this failure to find an association, continued search for risk factors to which Black women are uniquely exposed is warranted.     

The Impact of Migration on Pregnancy Outcomes Among Mexican-Origin Women

To examine the association between individual-level and state-level migration status in the United States (US) and the risk of preterm and low birth weight infants among Mexican-origin women. We performed secondary analysis of the 2003 US birth certificate data for 641,474 infants born to Mexican-origin Latina women. The dependent variables were prematurity and low birth weight. The primary independent variables were individual- (maternal) and state-level migration status. Logistic regression analysis estimated the relationship between maternal and state-level migration status, maternal and infant factors, and the risk of prematurity and low birth weight. Women who were born in Mexico had less education and use of prenatal care than US-born, Mexican-origin women but also fewer preterm or low birth weight infants. After adjusting for maternal and infant characteristics, women who were born and resided in Mexico at delivery were 37–64 % less likely to deliver preterm or low birth weight infants, and women who were born in Mexico and resided in the US had a 20–21 % lower risk as compared to women who were born and resided in the same US state. Women who delivered in states with a higher proportion of Mexican-origin mothers were slightly more likely to deliver a preterm infant and slightly less likely to give birth to a low birth weight infant. These findings support the perinatal advantage of Mexican-born women and provide evidence that both individual- as well as state-level migration factors influence perinatal outcomes.     

A comparison of recurrent and isolated small-for-gestational-age term births

In this study, based on total Western Australian singleton Caucasian births, women who had repeatedly given birth to small-for-gestational-age (SGA) term infants ('repeater' mothers) were compared with multiparous women who had had only one such infant ('non-repeater' mothers). Women with any preterm births were excluded. The study population comprised 678 repeater and 986 non-repeater mothers. Multiple logistic regression analysis indicated that weight loss or static weight in the third trimester of pregnancy, paternal smoking, low maternal birthweight, short maternal height and unknown family disease history were independent risk factors for repeater status compared with non-repeaters. The risk associated with paternal smoking was confined to mothers who were non-smokers themselves. There may have been a direct association between paternal smoking and recurrent fetal growth retardation or paternal smoking may have acted as a 'marker' for certain behavioural, environmental, social and economic factors which were not measured. Neonatal outcome was worse for the SGA infants of non-repeater mothers than for those of repeater mothers, although the latter were significantly more likely to weight less than 2500 grams.     

A comparison of recurrent and isolated small-for-gestational-age term births

Summary. In this study, based on total Western Australian singleton Caucasian births, women who had repeatedly given birth to small-for-gestational-age (SGA) term infants ('repeater' mothers) were compared with multiparous women who had had only one such infant ('non-repeater' mothers). Women with any preterm births were excluded. The study population comprised 678 repeater and 986 non-repeater mothers. Multiple logistic regression analysis indicated that weight loss or static weight in the third trimester of pregnancy, paternal smoking, low maternal birthweight, short maternal height and unknown family disease history were independent risk factors for repeater status compared with non-repeaters. The risk associated with paternal smoking was confined to mothers who were non-smokers themselves. There may have been a direct association between paternal smoking and recurrent fetal growth retardation or paternal smoking may have acted as a 'marker' for certain behavioural, environmental, social and economic factors which were not measured. Neonatal outcome was worse for the SGA infants of non-repeater mothers than for those of repeater mothers, although the latter were significantly more likely to weigh less than 2500 grams.     

The Impact of Prior Poor Birth Outcomes on Smoking Behavior on Subsequent Pregnancies: Analysis of the National PRAMS Data

Objectives The link between cigarette smoking and poor birth outcomes has been well established. However, there is paucity of research investigating the effect of previous history of poor birth outcomes on smoking behavior during subsequent pregnancies. The present study seeks to determine whether a previous preterm or low birth weight delivery impacts maternal smoking during the subsequent pregnancy. Methods Data from the National Pregnancy Risk Assessment Monitoring System (PRAMS) was analyzed. Multiparous women who currently had singleton birth were included in the analysis (N = 137,297). Previous poor birth outcome and smoking were defined based on the PRAMS question that asked women whether their immediate previous baby was born preterm or low birth weight and if they smoked during the index pregnancy. Results Approximately 16.3 % of the women who reported previous poor birth outcome also reported smoking during the subsequent pregnancy. Multiple logistic regression analysis revealed that women who had previous poor birth outcome had 22 % higher odds of smoking during the subsequent pregnancy. Similarly, the odds of smoking during pregnancy were 30 and 13 % higher among women who had previous low birth weight and preterm birth, respectively. Conclusions Women who experienced previous preterm or low birth weight baby had higher prevalence of smoking during the subsequent pregnancy. The occurrence of a preterm/low birth weight may present a critical intervention point for providers to educate women on the risks of repeated poor birth outcomes and provide intervention programs to address high-risk behaviors.     

Association Between Changes in Smoking Habits in Subsequent Pregnancy and Infant Birth Weight in West Virginia

West Virginia has one of the highest prenatal smoking prevalence rates in the nation. While overall national prenatal smoking rates have been declining, the prevalence rates in West Virginia continue to climb. Smoking in pregnancy has been associated with deleterious health outcomes in infants, including decreased birth weight. Yet, minimal research has been done on changes in smoking behaviors over time and the association of the changes in infant birth weights. The aim of the current study is to examine the change in prenatal smoking status of West Virginia women and the associated changes in infant birth weights. Population-based secondary data analysis was conducted using West Virginia birth certificates for all singleton infant siblings born between 1989 and 2006, linked based on mother. Infants born to women who smoked during pregnancy had significantly lower birth weights than infants born to non-smokers. Repeated measures analysis used to examine the changes with time showed that women who smoked during their first pregnancy but refrained from smoking during their subsequent pregnancy had significantly increased birth weight for the second infant, and conversely, infants born to women who initiated smoking with the subsequent pregnancy had significantly decreased birth weight compared to the previous infant. Findings of the study may be used to inform and to guide the development of population focused interventions to decrease maternal prenatal smoking in first and in subsequent pregnancies in an effort to improve infant birth weight outcomes.     

Second Births to Teenage Mothers: Risk Factors For Low Birth Weight and Preterm Birth

CONTEXT: Teenagers are more likely than older women to have a low-birth-weight infant or a preterm birth, and the risks may be particularly high when they have a second birth. Identifying predictors of these outcomes in second teenage births is essential for developing preventive strategies.
METHODS: Birth certificate data for 1993–2002 were linked to identify second births to Milwaukee teenagers. Predictors of having a low-birth-weight second infant or a preterm second birth were identified using logistic regression.
RESULTS: The same proportion of first and second infants were low-birth-weight (12%), but second births were more likely than first births to be preterm (15% vs. 12%). In analyses that adjusted for demographic, pregnancy and behavioral characteristics, the odds that a second infant was low-birth-weight or preterm were elevated if the mother smoked during pregnancy (odds ratios, 2.2 and 1.9, respectively), had inadequate prenatal weight gain (1.8 and 1.4), had an interpregnancy interval of less than 18 months (1.6–2.9 and 1.4–2.3) or was black (2.7 and 1.7). Women who had received an adequate level of prenatal care had reduced odds of both outcomes (0.6 and 0.4). Women younger than 16 also had increased odds of having a low-birth-weight second infant. Further adjustment for socioeconomic characteristics yielded largely the same results. In addition, women who were unmarried or did not identify a father were at increased risk of both outcomes (1.5 for each), and poor women were at risk of having a low-birth-weight infant (1.3).
CONCLUSIONS: Predictors of poor birth outcomes include modifiable behaviors. Prenatal interventions addressing these behaviors could help improve outcomes.     

Race differences in the proportion of low birth weight attributable to maternal cigarette smoking in a low-income population

PURPOSE: To quantify race differences in the public health impact of maternal cigarette smoking on infant birth weight and to estimate the proportion of low birth weight births that could be prevented by maternal smoking cessation. DESIGN: A cohort that consisted of 77,751 mother-infant pairs was evaluated retrospectively. SETTING: Statewide study of Women, Infants and Children participants in North Carolina. SUBJECTS: African-American and non-Hispanic white women who delivered a single live infant during 1988, 1989, or 1990. MEASURES: Logistic regression estimates of the relative risk of low birth weight births for smokers were used to calculate adjusted population attributable risk percentages for smoking. Separate population attributable risk percentages were calculated for total low birth weight, moderately low birth weight, and very low birth weight, and all estimates were adjusted for prepregnancy body mass index, gestational weight gain, age, education, parity, and timing of entry into prenatal care. RESULTS: Non-Hispanic whites had a much higher prevalence of smoking and were heavier smokers than African-Americans. For both moderately low birth weight and very low birth weight, the population attributable risk percentages for smoking were twice as high for non-Hispanic whites than for African-Americans. Overall, after adjustment, 30.7% of low birth weight births among non-Hispanic whites and 14.4% of low birth weight births among African-Americans were attributable to smoking. CONCLUSIONS: Although the public health impact of maternal cigarette smoking on infant birth weight was twice as high for non-Hispanic whites as for African-Americans in this low-income population, smoking cessation by all low-income pregnant women would result in significant improvements in infant health and well-being.     

Factors Predicting Birth Weight in a Low-Risk Sample: The Role of Modifiable Pregnancy Health Behaviors

Objectives: The purpose of the present study was to examine background and modifiable pregnancy health behavior factors predicting infant birthweight in an economically and educationally disadvantaged sample with low medical risk. Methods: Participants were recruited from a family practice center in rural Appalachia. Participants: Over 220, predominantly Caucasian and lower SES women with low risk pregnancies were included in the sample. Data were collected through systematic chart review. Half of the women smoked during pregnancy and over 10% gave birth to low birth weight (LBW; < 2500 g) babies. Results: Compared with those who gave birth to normal weight newborns, women with LBW babies had more miscarriages, but did not differ significantly on other background factors. Women who delivered LBW babies gained less weight during pregnancy and were more likely to smoke than remaining women. After control for background factors, modifiable pregnancy health behavior factors (weight gain, prenatal care, smoking, alcohol and substance use) accounted for over 11% of birth weight variance, with nearly 7% attributable solely to smoking. Conclusions: Pregnancy smoking was the strongest behavioral predictor of LBW in this economically and educationally disadvantaged rural sample, suggesting that efforts to reduce LBW in similar populations should include targeting pregnancy smoking.     

Association between infant birth weight and maternal cardiovascular risk factors in the health, aging, and body composition study

PURPOSE: Mothers who deliver a low-birth-weight (LBW) infant may themselves be at excess risk for cardiovascular disease. We investigated whether older women who bore LBW infants had higher blood pressure, lipid, glucose, insulin, interleukin 6 (IL-6), and C-reactive protein concentrations, and pulse wave velocity compared to women with normal-weight births. METHODS: Participants were 446 women with a mean age of 80 years and 47% black. Women reported birth weight and complications for each pregnancy. Analysis was limited to first births not complicated by hypertension or preeclampsia. RESULTS: Women who had delivered a first-birth infant weighing less than 2500 g had a lower body mass index (BMI) compared with women with a normal-weight (>or=2500 g) infant (26.7 versus 28.4 kg/m2; p=0.02), but they had a larger abdominal circumference for BMI (97.9 versus 95.5 cm; p=0.05). They also were marginally more likely to be administered antihypertensive medication (p=0.06). After adjustment for BMI, race, and age, women with a history of a small infant had elevations in systolic blood pressure (p=0.05) and greater IL-6 levels (p=0.02) and were more insulin resistant (p=0.05) compared with women with a normal-weight infant. CONCLUSIONS: These findings suggest that a history of LBW delivery identifies women with elevated cardiovascular risk factors.     

孕期被动吸烟对妊娠并发症及妊娠结局的影响

目的了解孕期被动吸烟发生情况,并探讨其对妊娠并发症及结局的影响。方法选取2012年4月―2013年3月在我国15家医疗保健机构分娩的8926例单胎活产产妇作为研究对象,使用自制调查问卷收集孕期被动吸烟发生情况、妊娠并发症和结局等信息,采用单因素和多因素Logistic回归分析模型分析孕期被动吸烟对妊娠并发症及结局的影响。结果共1801例产妇在孕期经历被动吸烟。控制混杂因素后,孕期经历被动吸烟的产妇妊娠期糖尿病(gestational diabetes mellitus,GDM)的发生风险是非被动吸烟者的1.359倍(95%CI:1.146~1.612,P<0.001),胎膜早破的风险为1.290倍(95%CI:1.095~1.520,P=0.002),早产的风险为1.367倍(95%CI:1.155~1.619,P<0.001),娩出低出生体重儿的风险为1.341倍(95%CI:1.079~1.668,P=0.008)。与非被动吸烟者相比,平均每周被动吸烟天数≥4天者胎膜早破、早产和低出生体重儿的发生风险分别为非被动吸烟者的1.402倍(95%CI:1.104~1.780,P=0.006)、1.690倍(95%CI:1.339~2.132,P<0.001)和1.584倍(95%CI:1.172~2.141,P=0.023)。结论被调查产妇孕期被动吸烟率较高,孕期经历被动吸烟能够增加妊娠期糖尿病、胎膜早破、早产和低出生体重儿的发生风险。     

Preconception homocysteine and B vitamin status and birth outcomes in Chinese women

BACKGROUND: The associations between homocysteine, B vitamin status, and pregnancy outcomes have not been examined prospectively. OBJECTIVE: We assessed the associations of preconception homocysteine and B vitamin status with preterm birth and birth of low-birth-weight (LBW) and small-for-gestational-age (SGA) infants in Chinese women. DESIGN: This was a case-control study of women aged 21-34 y. Preterm cases (n = 29) delivered living infants at <37 wk gestation; term controls (n = 405) delivered infants at > or =37 wk. LBW cases (n = 33) had infants weighing <2500 g; normal-birth-weight controls (n = 390) had infants weighing > or =2500 g. SGA cases (n = 65) had infants below the 10th percentile of weight-for-gestational-age; appropriate-for-gestational-age controls (n = 358) had infants above this cutoff. Nonfasting plasma concentrations of homocysteine, folate, and vitamins B-6 and B-12 were measured before conception. RESULTS: Elevated homocysteine (> or =12.4 micro mol/L) was associated with a nearly 4-fold higher risk of preterm birth (OR: 3.6; 95% CI: 1.3, 10.0; P < 0.05). The risk of preterm birth was 60% lower among women with vitamin B-12 > or =258 pmol/L than among vitamin B-12-deficient women (OR: 0.4; 95% CI: 0.2, 0.9; P < 0.05) and was 50% lower among women with vitamin B-6 > or =30 nmol/L than among vitamin B-6-deficient women (OR: 0.5; 95% CI: 0.2, 1.2; NS). Folate status was not associated with preterm birth, and homocysteine and B vitamin status were not associated with LBW or SGA status. CONCLUSIONS: Elevated homocysteine and suboptimal vitamin B-12 and B-6 status may increase the risk of preterm birth. These results need to be confirmed in larger prospective studies.     

Increased risk of preterm delivery in women residing near thermal power plants in Taiwan

In this article, the researchers studied the prevalence of preterm births for women living near thermal power plants. The prevalence of delivery of preterm birth infants was significantly higher among women living within 3 km of a thermal power plant than among women living within 3-4 km of a plant. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, infant gender, and birth site), the adjusted odds ratio was 1.14 (95% confidence interval, 1.01-1.30) for delivery of preterm infants for women living close to the thermal power plants. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy, although a semiecological study cannot confirm a direct causal relationship.     

The relationship between prenatal health behavior advice and low birth weight.

OBJECTIVES: The purposes of the study were (a) to examine the relationship between the health behavior advice recommended by the Public Health Service Expert Panel on the Content of Prenatal Care and the risk of low birth weight and (b) to describe the type and frequency of health behavior advice offered to a group of pregnant women. METHODS: The authors used data from the National Institute of Child Health and Human Development/Missouri Maternal and Infant Health Survey, a follow-back survey of women who had delivered very low birth weight infants and of matched control subjects who had delivered moderately low birth weight and normal birth weight infants. Frequency distributions for different types of prenatal health behavior advice were examined for the 2205 participants, and logistic regression analyses were used to determine whether there was a relationship between birth weight and receiving the advice recommended by the Expert Panel. RESULTS: Only 10.4% of mothers reported receiving all seven types of health behavior advice recommended by the Expert Panel. Women who did not receive all seven types of advice were 1.5 times more likely to deliver a very low birth weight infant than a normal birth weight infant. CONCLUSIONS: Further research is needed to better understand the relationship between health education and birth weight.     

Increased Risk of Preterm Delivery in Women Residing near Thermal Power Plants in Taiwan

In this article, the researchers studied the prevalence of preterm births for women living near thermal power plants. The prevalence of delivery of preterm birth infants was significantly higher among women living within 3 km of a thermal power plant than among women living within 3–4 km of a plant. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, infant gender, and birth site), the adjusted odds ratio was 1.14 (95% confidence interval, 1.01–1.30) for delivery of preterm infants for women living close to the thermal power plants. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy, although a semiecological study cannot confirm a direct causal relationship.     

The traditional humoral food habits of pregnant Vietnamese–Australian women and their effect on birth weight

Vietnamese-Australian women have infants with lower birth weight than Australian-born women. Traditional humoral food habits, based on ancient Chinese medicine, are more likely to be followed during life changes like pregnancy. These food habits may influence maternal energy intake, weight gain and therefore infant birth weight. This study determined the proportion of pregnant Vietnamese women in southwestern Sydney who practise traditional humoral food habits, and their effect on birth weight. A cohort of 113 pregnant Vietnamese-born women were questioned on smoking status, height, weight, parity, food practices and demographics. Dietary intake was measured in each trimester. Known risk factors and infant birth weights were collected from medical records for participants and nonresponders. Fifty-seven per cent practised the traditional food habits. There were no differences in energy intake or weight gain between the two groups. After adjusting for confounders, birth weight was estimated to be 3257 g (95 per cent confidence interval (CI) 3205 to 3309) and 3272 g (CI 3211 to 3333) for the infants of traditional and nontraditional women respectively. Following humoral food habits does not appear to affect birth weight. Women who choose to follow these traditions should not be discouraged from doing so.     

The Association Between Second Hand Smoke and Low Birth Weight and Preterm Delivery

To determine the association between maternal exposure to SHS and low birth weight and preterm delivery. This cross-sectional study was carried out in the four main governmental hospitals dealing with deliveries in the north of Jordan. A consecutive 8,490 women who delivered in these hospitals between April 2007 and September 2007 were included in the study after excluding those who reported active smoking during the current pregnancy. Pre-structured questionnaire and review of hospital records were used to collect data about maternal background, obstetric history, medical history, and data related to second hand smoke exposure. Overall, 13.8% of women gave birth to a preterm baby and 10.0% gave birth to a low birth weight baby. About 12.6% of women who were exposed to SHS delivered low birth weight babies compared to 7.7% for non exposed women. The rate of preterm delivery among the exposed group was significantly higher than that among the non-exposed group (17.2 vs. 10.6%). In the multivariate analysis, exposure to SHS during pregnancy was significantly associated with increased odds of low birth weight (OR = 1.56 (95% CI 1.31, 1.89)) and preterm delivery (OR = 1.61 (95% CI: 1.30, 1.99)). Exposure of women to SHS during pregnancy is associated with increased odds of low birth weight and preterm delivery. Health care professionals should carry out educational programs to increase awareness and understanding of pregnant women and their husbands about the harmful effects of second hand smoke on birth outcomes.     

妊娠晚期血红蛋白浓度与早产和低出生体重关系的研究

目的分析妊娠晚期血红蛋白(Hb)浓度与早产和低出生体重之间的关系。方法研究对象为江苏和浙江省4个县(市)在1995—2000年间分娩的102 489名妇女。按妊娠晚期Hb浓度分四组比较各组早产和低出生体重的发生率;采用logistic回归模型控制年龄、职业、文化程度、孕次、产检次数和妊高征等因素后,估计Hb与早产和低出生体重的关联程度。结果妊娠晚期贫血患病率为48.2%,以轻度和中度贫血为主。轻、中度贫血不增加早产和低出生体重的风险。当Hb为90～99 g/L时,早产和低出生体重的发生率最低;当Hb升高或降低时,早产和低出生体重的风险均呈增加趋势。Hb为70～119 g/L时,早产和低出生体重的风险变化不大,但重度贫血和高血红蛋白则显著增加早产和低出生体重的风险:Hb<70 g/L组早产和低出生体重的OR(95%CI)分别为1.8(1.0～3.3)和4.0(2.1～7.5);Hb≥130 g/L组的早产和低出生体重的OR(95%CI)为1.2(1.0～1.4)和1.5 (1.2～1.9)。结论妊娠晚期Hb水平与早产和低出生体重的风险之间均呈"U"形趋势,妊娠晚期重度贫血以及高血红蛋白均是早产和低出生体重的危险因素。     

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.     

Factors affecting birth weight in Kuwait. Part II: Pregnancy characteristics and health factors.

The aim of this was to determine the mean birth weight of Kuwaiti infants, the incidence of low birth weight and the impact of maternal age, smoking, health status, parents' consanguinity and pregnancy characteristics on infants' birth weight. The study was conducted in the major maternity hospital in Kuwait where the body weight of 1995 newborn infants was recorded shortly after birth. Data describing maternal age, duration of pregnancy, sex of the infant and maternal illness during pregnancy were recorded. Mothers were interviewed to collect data on duration between present and last pregnancy, birth order of the infant, parents' consanguinity and frequency of smoking. The results show that the mean birth weight was 3.5 Kg and the incidence of low birth weight was 3.4%. The results illustrate that young mothers were more liable to have small infants while old mothers were more liable to deliver a very heavy or low birth weight infant. The weight of the newborn infant was positively correlated with duration of pregnancy, duration between present and last pregnancy and birth order. The mean birth weight of male infants (3.51 Kg) was higher than females (3.47 Kg). Parents' consanguinity and maternal smoking had a slight effect on infants' birth weight. The results show that diabetic mothers delivered large babies. On the contrary, the incidence of low birth weight was highest (7.0%) among infants of hypertensive mothers.