The Associations of Maternal Hemoglobin Concentration in Different Time Points and Its Changes during Pregnancy with Birth Weight Outcomes

Maternal hemoglobin (Hb) is related to nutritional status, which affects neonatal birth weight. However, it is very common for maternal Hb to fluctuate during pregnancy. To evaluate the associations of maternal Hb in different time points and its changes during pregnancy with neonatal birth weight, small for gestational age (SGA)/low birth weight (LBW) and large for gestational age (LGA)/macrosomia, we conducted this study by using data from the Electronic Medical Record System (EMRS) database of Zhoushan Maternal and Child Care Hospital in Zhejiang province, China. The pregnancy was divided into five periods: first, early-second, mediate-second, late-second, early-third and late-third trimesters; we further calculated the maternal Hb changes during pregnancy. Overall, the socio-demographic characteristics, health-related information and childbirth-related information of 24,183 mother–infant pairs were obtained. The average Hb concentration during the different periods were 123.95 ± 10.14, 117.95 ± 9.84, 114.31 ± 9.03, 113.26 ± 8.82, 113.29 ± 8.68 and 115.01 ± 8.85 g/L, respectively. Significant dose–response relationships between maternal Hb and birth weight were observed in the first, late-second and later trimesters (p non-linear < 0.05). Maternal Hb < 100 g/L was related to a high risk of LGA/macrosomia in the late-second (OR: 1.47, 95% CI: 1.18, 1.83) and later trimesters; additionally, high maternal Hb (>140 g/L) increased the risk of SGA/LBW in the first (OR: 1.26, 95% CI: 1.01, 1.57) and late-third trimesters (OR: 1.96, 95% CI: 1.20, 3.18). In addition, the increase in maternal Hb from the late-second to late-third trimesters had a positive correlation with SGA/LBW. In conclusion, maternal Hb markedly fluctuated during pregnancy; the negative dose–response association of maternal Hb in the late-second and third trimesters, and Hb change during pregnancy with neonatal birth weight outcomes were observed, respectively. Furthermore, the phenomenon of high Hb in the first trimester and after the late-second trimester and the increase of maternal Hb from the late-second to late-third trimesters more significantly increasing the risk of SGA/LBW should especially be given more attention. Its biological mechanism needs to be further explored.     

Preconception Hemoglobin Concentration and Risk of Low Birth Weight and Small-for-Gestational-Age: A Large Prospective Cohort Study in China

Less is known about the impact of maternal preconception anemia on birth outcomes. We aimed to examine associations between preconception hemoglobin (Hb) concentrations with risk of low birth weight (LBW) and small-for-gestational-age (SGA). This study was from a large population-based prospective cohort in China and included 124,725 women with singleton live births delivered at gestational ages of 28–45 weeks who were registered before pregnancy. Maternal Hb concentrations were measured during registration, and other health-related information was recorded prospectively. Logistic regression was used to evaluate the associations between preconception Hb concentrations with risk of LBW and SGA, adjusting for potential confounders. The results showed women with preconception anemia accounted for 22.28%. The incidences of LBW/SGA were 2.37%/6.30% among anemic women, and 2.01%/5.48% among non-anemic women, respectively. Preconception mild anemia increased by 17% (95% confidence interval (CI): 1.06, 1.28) and 14% (95% CI: 1.07, 1.21) the risk for LBW and SGA, while moderate-to-severe anemia had no significant association with LBW and SGA. Compared with the 120–129 g/L group, a U-shaped association was observed between preconception Hb concentrations with LBW and SGA. In conclusion, not only maternal anemia but also elevated Hb concentrations before pregnancy contribute to an increased risk of LBW and SGA.     

Associations between Maternal Dietary Patterns and Infant Birth Weight in the NISAMI Cohort: A Structural Equation Modeling Analysis

The mother’s diet during pregnancy is associated with maternal and child health. However, there are few studies with moderation analysis on maternal dietary patterns and infant birth weight. We aim to analyse the association between dietary patterns during pregnancy and birth weight. A prospective cohort study was performed with pregnant women registered with the prenatal service (Bahia, Brazil). A food frequency questionnaire was used to evaluate dietary intake. Birth weight was measured by a prenatal service team. Statistical analyses were performed using factor analysis with a principal component extraction technique and structural equation modelling. The mean age of the pregnant women was 27 years old (SD: 5.5) and the mean birth weight was 3341.18 g. It was observed that alcohol consumption (p = 0.05) and weight-gain during pregnancy (p = 0.05) were associated with birth weight. Four patterns of dietary consumption were identified for each trimester of the pregnancy evaluated. Adherence to the “Meat, Eggs, Fried Snacks and Processed foods” dietary pattern (pattern 1) and the “Sugars and Sweets” dietary pattern (pattern 4) in the third trimester directly reduced birth weight, by 98.42 g (Confidence interval (CI) 95%: 24.26, 172.59) and 92.03 g (CI 95%: 39.88, 165.30), respectively. It was also observed that insufficient dietary consumption in the third trimester increases maternal complications during pregnancy, indirectly reducing birth weight by 145 g (CI 95%: −21.39, −211.45). Inadequate dietary intake in the third trimester appears to have negative results on birth weight, directly and indirectly, but more studies are needed to clarify these causal paths, especially investigations of the influence of the maternal dietary pattern on the infant gut microbiota and the impacts on perinatal outcomes.     

Diet Quality Is Associated with a High Newborn Size and Reduction in the Risk of Low Birth Weight and Small for Gestational Age in a Group of Mexican Pregnant Women: An Observational Study

A high-quality diet during pregnancy may have positive effects on fetal growth and nutritional status at birth, and it may modify the risk of developing chronic diseases later in life. The aim of this study was to evaluate the association between diet quality and newborn nutritional status in a group of pregnant Mexican women. As part of the ongoing Mexican prospective cohort study, OBESO, we studied 226 healthy pregnant women. We adapted the Alternated Healthy Eating Index-2010 for pregnancy (AHEI-10P). The association between maternal diet and newborn nutritional status was investigated by multiple linear regression and logistic regression models. We applied three 24-h recalls during the second half of gestation. As the AHEI-10P score improved by 5 units, the birth weight and length increased (β = 74.8 ± 35.0 g and β = 0.3 ± 0.4 cm, respectively, p < 0.05). Similarly, the risk of low birth weight (LBW) and small for gestational age (SGA) decreased (OR: 0.47, 95%CI: 0.27–0.82 and OR: 0.55, 95%CI: 0.36–0.85, respectively). In women without preeclampsia and/or GDM, the risk of stunting decreased as the diet quality score increased (+5 units) (OR: 0.62, 95%IC: 0.40–0.96). A high-quality diet during pregnancy was associated with a higher newborn size and a reduced risk of LBW and SGA in this group of pregnant Mexican women.     

Maternal Obesity and Risk of Low Birth Weight,Fetal Growth Restriction,and Macrosomia: Multiple Analyses

The associations between maternal pre-pregnancy obesity and low birth weight (LBW, <2500 g) remain inconclusive. Therefore, birth weight in a Polish prospective cohort of 912 mothers was investigated depending on the pre-pregnancy body mass index (BMI). The whole cohort and the subgroup of gestational weight gain (GWG) in the range of the Institute of Medicine (IOM) recommendations, as well as ‘healthy’ women (who did not develop diabetes or hypertension in this pregnancy) were investigated. Adjusted odds ratios (AOR) of the newborn outcomes (with 95% confidence intervals, CI) for obesity (BMI ≥ 30 kg/m²) vs. normal BMI (18.5−24.9 kg/m²) were calculated using multiple logistic regression. Risk profiles (in the Lowess method) were presented for BMI values (kg/m²) and threshold BMI values were calculated. (1) In the cohort, LBW affected 6.6% of pregnancies, fetal growth restriction (FGR) 2.3%, and macrosomia 10.6%. (2) The adjusted risk of macrosomia was more than three-fold higher for obesity compared to normal BMI in the whole cohort (AOR = 3.21 (1.69−6.1), p < 0.001) and the result was maintained in the subgroups. A 17-fold higher adjusted LBW risk for obesity was found (AOR = 17.42 (1.5−202.6), p = 0.022), but only in the normal GWG subgroup. The FGR risk profile was U-shaped: in the entire cohort, the risk was more than three times higher for obesity (AOR = 3.12 (1.02−9.54), p = 0.045) and underweight (AOR = 3.84 (1.13−13.0), p = 0.031). (3) The risk profiles showed that the highest BMI values were found to be associated with a higher risk of these three newborn outcomes and the threshold BMI was 23.7 kg/m² for macrosomia, 26.2 kg/m² for LBW, and 31.8 kg/m² for FGR. These results confirm the multidirectional effects of obesity on fetal growth (low birth weight, fetal growth restriction, and macrosomia). The results for LBW were heavily masked by the effects of abnormal gestational weight gain.     

Birth Weight among Singletons Born to Foreign-Born Mothers in Taiwan: A Population-Based Birth Register Study

Background

We compared the birth weight of newborns born to foreign-born mothers (FBMs) and Taiwan-born mothers (TBMs), using data from the 2005–2006 Taiwan Birth Registry of singleton live births.

Methods

The Wilcox–Russell method, data restriction, and multiple linear regression were used to analyze the data. The rates of low birth weight (<2500 g) with 95% confidence intervals were computed for TBMs, and for each of the nationalities of FBMs.

Results

The mean birth weight of newborns of FBMs was 3157 g, which was higher than that of newborns of TBMs (3109 g). On analysis using the Wilcox–Russell method, both the rate and residual proportion of low-birth-weight (LBW) births were lower among newborns of FBMs (4.1% and 1.1%, respectively) than among newborns of TBMs (5.9% and 1.7%, respectively). After adjusting for sex, mode of delivery, maternal age, smoking status, predisposing maternal risk factors, and condition during pregnancy, the newborns of FBMs weighed 72.9 g (95% CI, 68.8 g to 77.0 g) more than the newborns of TBMs. When data were restricted to mothers without any adverse conditions and adjusted for maternal age, the differences in birth weight between the 2 groups remained unchanged. The rates of LBW deliveries among FBMs in Taiwan were significantly lower than those in their respective countries of origin.

Conclusions

In Taiwan, newborns of FBMs had a higher birth weight than those of TBMs, even after accounting for potential confounding factors, and had lower rates of LBW deliveries than did mothers in their respective countries of origin.Key words: birth weight, transnational marriage, foreign-born mothers     

Drinking-Water Herbicide Exposure in Indiana and Prevalence of Small-for-Gestational-Age and Preterm Delivery

Background

Atrazine and other corn herbicides are routinely detected in drinking water. Two studies on potential association of atrazine with small-for-gestational-age (SGA) and preterm birth prevalence found inconsistent results. Moreover, these studies did not control for individual-level potential confounders.

Objectives

Our retrospective cohort study evaluated whether atrazine in drinking water is associated with increased prevalence of SGA and preterm birth.

Methods

We developed atrazine concentration time series for 19 water systems in Indiana from 1993 to 2007 and selected all births (n = 24,154) based on geocoded mother’s residences. Log-binomial models were used to estimate prevalence ratios (PRs) for SGA and preterm delivery in relation to atrazine concentrations during various periods of the pregnancy. Models controlled for maternal demographic characteristics, prenatal care and reproductive history, and behavioral risk factors (smoking, drinking, drug use).

Results

Atrazine in drinking water during the third trimester and the entire pregnancy was associated with a significant increase in the prevalence of SGA. Atrazine in drinking water > 0.1 μg/L during the third trimester resulted in a 17–19% increase in the prevalence of SGA compared with the control group (< 0.1 μg/L). Mean atrazine concentrations over the entire pregnancy > 0.644 μg/L were associated with higher SGA prevalence than in the control group (adjusted PR = 1.14; 95% confidence interval, 1.03–1.24). No significant association was found for preterm delivery.

Conclusions

We found that atrazine, and perhaps other co-occurring herbicides in drinking water, is associated with an increased prevalence of SGA, but not preterm delivery.     

Folic acid supplements modify the adverse effects of maternal smoking on fetal growth and neonatal complications

Maternal smoking during pregnancy leads to increased risks of neonatal complications. The use of folic acid supplements might reduce the adverse effects of smoking. We examined whether folic acid supplement use modifies the associations of maternal smoking with first trimester plasma homocysteine concentrations, fetal growth characteristics, and risks of neonatal complications. The associations were studied in 6294 mothers participating in a prospective population-based cohort study in The Netherlands. Main outcomes measurements were first trimester plasma homocysteine concentrations, fetal growth characteristics, and neonatal complications, including preterm birth, low birth weight, and small-size-for-gestational-age. Continued maternal smoking was associated with higher first trimester plasma homocysteine concentrations [difference 0.52 μmol/L (95% range = 0.20, 2.14)], lower third trimester fetal weight (difference -44 g (95% CI = -57, -31)], and birth weight [difference -148 g (95% CI = -179, -118)]. There were significant interactions between maternal smoking and folic acid supplements on all outcome measures (all P-interaction < 0.040). Among mothers who continued smoking during pregnancy, those who did not use folic acid supplements had the highest risk of delivering a child with low birth weight [OR = 3.45 (95% CI = 1.25, 9.54)] compared to those who did use periconceptional folic acid supplements. No significant effects were observed for the risks of preterm birth and small-size-for-gestational-age at birth. Our results suggest that some adverse effects of maternal smoking on fetal growth and neonatal outcomes might be reduced by the use of folic acid supplements. The observed interaction seems to be mainly driven by smoking in the first trimester only.     

Geographic Variation in the Association between Ambient Fine Particulate Matter (PM2.5) and Term Low Birth Weight in the United States

Background

Studies on the association between prenatal exposure to fine particulate matter ≤ 2.5 μm in aerodynamic diameter (PM_2.5) and term low birth weight (LBW) have resulted in inconsistent findings. Most studies were conducted in snapshots of small geographic areas and no national study exists.

Objectives

We investigated geographic variation in the associations between ambient PM_2.5 during pregnancy and term LBW in the contiguous United States.

Methods

A total of 3,389,450 term singleton births in 2002 (37–44 weeks gestational age and birth weight of 1,000–5,500 g) were linked to daily PM_2.5 via imputed birth days. We generated average daily PM_2.5 during the entire pregnancy and each trimester. Multi-level logistic regression models with county-level random effects were used to evaluate the associations between term LBW and PM_2.5 during pregnancy.

Results

Without adjusting for covariates, the odds of term LBW increased 2% [odds ratio (OR) = 1.02; 95% CI: 1.00, 1.03] for every 5-μg/m³ increase in PM_2.5 exposure during the second trimester only, which remained unchanged after adjusting for county-level poverty (OR = 1.02; 95% CI: 1.01, 1.04). The odds did change to null after adjusting for individual-level predictors (OR = 1.00; 95% CI: 0.99, 1.02). Multi-level analyses, stratified by census division, revealed significant positive associations of term LBW and PM_2.5 exposure (during the entire pregnancy or a specific trimester) in three census divisions of the United States: Middle Atlantic, East North Central, and West North Central, and significant negative association in the Mountain division.

Conclusions

Our study provided additional evidence on the associations between PM_2.5 exposure during pregnancy and term LBW from a national perspective. The magnitude and direction of the estimated associations between PM_2.5 exposure and term LBW varied by geographic locations in the United States.

Citation

Hao Y, Strosnider H, Balluz L, Qualters JR. 2016. Geographic variation in the association between ambient fine particulate matter (PM_2.5) and term low birth weight in the United States. Environ Health Perspect 124:250–255; http://dx.doi.org/10.1289/ehp.1408798     

Determinants of low birth weight among HIV-infected pregnant women in Tanzania.

BACKGROUND: Low birth weight (LBW) increases the risk of infant death, but little is known about its causes among HIV-infected populations in sub-Saharan Africa. OBJECTIVE: We assessed sociodemographic, nutritional, immunologic, parasitic, and infant risk factors for birth weight, LBW, and small-for-gestational-age (SGA) status in a cohort of 822 HIV-positive women enrolled in a clinical trial of vitamin supplementation and pregnancy outcomes in Dar es Salaam, Tanzania. DESIGN: Women were enrolled at prenatal care clinics during their second trimester, at which time blood, stool, urine, and genital specimens were collected, and anthropometric measurements and sociodemographic data were recorded. Birth weight was measured at hospital delivery. RESULTS: The mean (+/-SD) birth weight was 3015 +/- 508 g, 11.1% of newborns weighed <2500 g (LBW), and 11.5% were SGA. In multivariate analyses, maternal weight at enrollment and a low CD8 cell count were inversely associated with LBW. Advanced-stage HIV disease, previous history of preterm birth, Plasmodium falciparum malaria, and any helmintic infection were associated with higher risk of LBW. The intestinal parasites Entamoeba histolytica and Strongyloides stercoralis were predictors of LBW despite their low prevalence in the cohort. In a multivariate-adjusted linear regression model, BMI, midupper arm circumference, a CD4 cell count <200 x 10(6) cells/L (200 cells/mm(3)), primiparity, maternal literacy, and infant HIV infection at birth were significantly associated with birth weight in addition to risk factors included in the LBW model. Determinants of SGA included maternal weight, low serum vitamin E concentration, candidiasis, malaria, and infant HIV infection at birth. CONCLUSION: Prevention of HIV disease progression and vertical transmission, improved nutritional status, and better management of malaria and intestinal parasitic infections are likely to reduce the incidence of LBW in Tanzania.     

空气污染物对出生体重影响的研究

目的研究空气污染物可吸入颗粒物（PM10）、二氧化硫（SO2）、二氧化氮（NO2）对新生儿出生体重的影响。方法收集了广东某地2003—2005年分娩时孕满37周的围产数据。调查的因素包括产妇的年龄、职业、文化、出生地、是否有准生证、孕周、是否有高危因素、末次月经时间、分娩日期、孕次、产次；产妇丈夫的职业、文化；新生儿的性别、出生身高、体重。用2002—2005年的空气污染数据估计暴露水平。结果性别、母亲年龄、母亲职业、母亲原地址、孕期高危情况、孕次、是否有准生证分组，出生体重组间差异有统计学意义；不同孕期PM10、SO2、NO2暴露分组之间出生体重差异有统计学意义。多元线性回归分析显示可吸入颗粒物PM10、SO2、NO2浓度每增加10μg/m^3，出生体重分别减少1．90～3．94g、1．65～2．73g、2．70～3．76g。结论空气污染物与低出生体重有关，空气污染对妊娠结局的影响值得关注。     

Weight loss during pregnancy is associated with adverse pregnancy outcomes among HIV-1 infected women

In a prospective study of 1002 pregnant, HIV-1 infected Tanzanian women, we examined the incidence of fetal death, preterm delivery, low birth weight (LBW), and small for gestational age (SGA) births in relation to maternal anthropometry at the first prenatal visit, weight loss, and low weight gain during pregnancy. Anthropometric measurements were obtained monthly during the 2nd and 3rd trimesters. Low maternal height and weight at the first visit were significantly related to lower mean birth weight and increased risk of SGA, but not to preterm delivery. Maternal stature < 150 cm was significantly related to fetal death. Weight loss during pregnancy, defined as a negative slope of the regression of weight measurements on the week of gestation, occurred in 10% of the women. It was related to increased relative risk (RR) of fetal death (RR = 1.83, 95% CI = 0.93, 3.57), preterm delivery (RR = 1.85, 95% CI = 1.40, 2.44), and LBW (RR = 2.85, 95% CI = 1.69, 4.79) after adjusting for multivitamin supplementation, height, primiparity, baseline weight, malaria, CD4 cell count, HIV disease stage, and intestinal parasitoses. The significant association with fetal death was stronger for weight loss during the 2nd trimester, whereas increased risks of preterm delivery and LBW were higher for weight loss during the 3rd. Similar but weaker associations were found with low weight gain during pregnancy (slope < 25th percentile). We conclude that poor anthropometric status at the first prenatal visit and weight loss during pregnancy among HIV-1 infected women are strong risk factors for adverse pregnancy outcomes.     

Association of Maternal Longitudinal Hemoglobin with Small for Gestational Age during Pregnancy: A Prospective Cohort Study

Background: Few studies have investigated the association of maternal longitudinal hemoglobin (Hb) with small for gestational age during pregnancy. The current study examined the associations of maternal Hb concentrations and Hb changes throughout the middle and late stages of pregnancy with small for gestational age (SGA) in a large prospective cohort study. Methods: This was a prospective cohort study, which enrolled pregnant women at 8–16 weeks of gestation and followed up regularly. Maternal Hb concentrations were measured at the middle (14–27 weeks) and late (28–42 weeks) stages of pregnancy, and the Hb change from the middle to late stage of pregnancy was assessed. The Log-Poisson regression model was used to identify the association of maternal Hb with SGA, including the implications of Hb during specific pregnancy periods and Hb change across the middle to late stages of pregnancy. Of the total 3233 singleton live births, 208 (6.4%) were SGA. After adjusting for potential confounders, compared with Hb 110–119 g/L, Hb ≥ 130 g/L at late pregnancy was significantly associated with a higher risk of SGA (adjusted RR: 2.16; 95% CI: 1.49, 3.13). When Hb changes from the middle to late stages of pregnancy were classified by tertiles, the greatest change in the Hb group (<−6.0 g/L) was significantly associated with a lower risk of SGA (adjusted RR: 0.56; 95% CI: 0.37, 0.85) compared with the intermediate group (−6.0~1.9 g/L). In conclusion, for women at low risk of iron deficiency, both higher Hb concentrations in late pregnancy and less Hb reduction during pregnancy were associated with an increased risk of SGA.     

The association between maternal influenza vaccination during pregnancy and adverse birth outcomes in the United States: Pregnancy risk Assessment Monitoring System (PRAMS)

ObjectiveInfluenza vaccination during pregnancy is highly recommended. We examined the association between maternal influenza vaccination and adverse birth outcomes.MethodsThis cross-sectional study used data from the Pregnancy Risk Assessment Monitoring System (PRAMS) during 2012–2017. The primary exposure was the receipt of influenza vaccination during pregnancy. Low birth weight (LBW), preterm birth (PTB), and small for gestational age (SGA) were the primary outcomes. We conducted multivariable logistic regression models to estimate the adjusted odds ratios (AOR) and 95% confidence intervals (CI). Covariates used to adjust confounding included maternal age, marital status, education, race and ethnicity, insurance status before pregnancy, and smoking status. For a subgroup in 2012–2015, we analyzed the association between influenza vaccination in each trimester and adverse birth outcomes.ResultsDuring 2012–2017, compared with unvaccinated women, women vaccinated during pregnancy had a lower risk of LBW and PTB. During 2012–2015, maternal influenza vaccination in the 1st and 3rd trimesters was associated with a reduced risk of LBW and PTB, and vaccination in the 3rd trimester had a greater protective effect than in the 1st trimester. Influenza vaccination was not associated with SGA regardless of trimester.ConclusionsOur findings suggest that influenza vaccination during pregnancy is a safe and effective way to protect newborns.     

广西南宁市低出生体重发生情况及高危因素分析

目的 分析广西南宁市新生儿低出生体重(LBW)发生现状,并对高危因素进行研究,为该地区制定针对性的妇幼保健措施提供依据.方法 基于《广西桂妇儿健康管理信息系统》收集2018年在广西南宁市建档的孕产妇人口学特征、孕期情况、产检与分娩记录及新生儿资料,采用描述流行病学分析方法对LBW发生情况进行分析,并采用单、多因素分析方...     

Methylenetetrahydrofolate Reductase (MTHFR) Gene Polymorphism and Infant’s Anthropometry at Birth

Identification of causal factors that influence fetal growth and anthropometry at birth is of great importance as they provide information about increased risk of disease throughout life. The association between maternal genetic polymorphism MTHFR(677)C>T and anthropometry at birth has been widely studied because of its key role in the one-carbon cycle. MTHFR(677) CT and TT genotypes have been associated with a greater risk of low birth weight, especially in case of deficient intake of folic acid during pregnancy. This study aimed to analyze the association between the maternal MTHFR(677)C>T genetic polymorphism and anthropometry at birth in a population with adequate folate consumption. We included 694 mother–newborn pairs from a prospective population-based birth cohort in Spain, in the Genetics, Early life enviroNmental Exposures and Infant Development in Andalusia (GENEIDA) project. Women were genotyped for MTHFR(677)C>T SNP by Q-PCR using TaqMan© probes. Relevant maternal and newborn information was obtained from structured questionnaires and medical records. Results showed that maternal MTHFR(677)C>T genotype was associated with newborn anthropometry. Genotypes CT or CT/TT showed statistically significant associations with increased or decreased risk of large-for-gestational-age (LGA) or small-for-gestational-age (SGA) based on weight and height, depending on the newborn’s sex, as well as with SGA in premature neonates. The relationships between this maternal genotype and anthropometry at birth remained despite an adequate maternal folate intake.     

孕早期家用化学品使用与妊娠结局关系

目的 探讨孕早期家用化学品使用与3种不良妊娠结局（早产、低出生体重、小于胎龄儿）的关联情况。方法 选取在安徽省合肥、芜湖、马鞍山市妇幼保健部门进行孕产期保健体检并分娩单胎活产儿的10 269名育龄妇女为研究对象,分析不同特征育龄妇女孕早期家用化学品使用情况与不良妊娠结局关系。结果 美白霜的使用频率最高,其他家用化学品的使用频率较低,6 827人（66.5%）表示几乎不使用除美白霜以外的家用化学品;调查对象早产、低出生体重、小于胎龄儿发生率分别为3.4%、1.8%、3.2%;以几乎不用为对照组,二项logistic回归结果显示,家用化学品使用与低出生体重（RR=1.11,95%CI=0.83～1.49）、小于胎龄儿之间（RR=1.07,95%CI=0.85～1.33）无统计学关联,甚至在早产组呈现出一种保护效应（RR=0.73,95%CI=0.58～0.91）。结论育龄妇女孕早期家用化学品使用与3种不良妊娠结局不存在关联。     

The Relation of Maternal Birth Weight to African-American and Non-Latina White Twin Pregnancy Outcomes: A Population-Based Study

Objectives The authors investigated the association between maternal birth weight and adverse birth outcome as measured by rates of low birth weight (<2500 g, LBW), preterm birth (<37 weeks, PTB), and small for gestational age (weight <10th percentile for gestational age, SGA) among African American and White twin pregnancies. Methods Stratified and multivariable regression analyses were performed on the Illinois transgenerational dataset of non-Latina African American and non-Latina White twin pairs (born 1989–1991) and their mothers (born 1956–1976). Results Former LBW (n = 104) and non-LBW (n = 742) African American mothers had LBW rates in both twins of 76 and 56 %, respectively; RR (95 % CI) = 1.4 (1.2–1.6). Former LBW (n = 105) and non-LBW (n = 2136) White mothers had LBW rates in both twins of 41 and 34 %, respectively; RR = 1.2 (0.9–1.5). In multivariable regression models, the adjusted (controlling for maternal age, education, marital status, parity, prenatal care usage, and cigarette smoking) RR of LBW in both twins among former LBW (compared to non-LBW) African American and White mothers equaled 1.4 (1.2–1.6) and 1.2 (0.9–1.5), respectively. Maternal LBW was associated with a modestly increased risk of PTB but not SGA among African American twin pregnancies: adjusted RR = 1.3 (1.1–1.4) and 1.1 (0.8–1.5), respectively. Conclusions In African American twin pregnancies, maternal LBW is a risk factor for LBW in both twins. Further research is needed to determine whether a similar generational association occurs among non-Latina White twin pregnancies.     

Maternal Dietary Selenium Intake during Pregnancy Is Associated with Higher Birth Weight and Lower Risk of Small for Gestational Age Births in the Norwegian Mother,Father and Child Cohort Study

Selenium is an essential trace element involved in the body’s redox reactions. Low selenium intake during pregnancy has been associated with low birth weight and an increased risk of children being born small for gestational age (SGA). Based on data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Medical Birth Registry of Norway (MBRN), we studied the association of maternal selenium intake from diet and supplements during the first half of pregnancy (n = 71,728 women) and selenium status in mid-pregnancy (n = 2628 women) with birth weight and SGA status, according to population-based, ultrasound-based and customized growth standards. An increase of one standard deviation of maternal dietary selenium intake was associated with increased birth weight z-scores (ß = 0.027, 95% CI: 0.007, 0.041) and lower SGA risk (OR = 0.91, 95% CI 0.86, 0.97) after adjusting for confounders. Maternal organic and inorganic selenium intake from supplements as well as whole blood selenium concentration were not associated with birth weight or SGA. Our results suggest that a maternal diet rich in selenium during pregnancy may be beneficial for foetal growth. However, the effect estimates were small and further studies are needed to elucidate the potential impact of selenium on foetal growth.     

低出生体重与产前检查质量的回顾性分析

目的 探讨新生儿低出生体重(LBW)(出生体重＜2500 g)发生率与产前检查质量的关系.方法 采用Kessner's评定方法,对2008年1月至2009年12月在西安交通大学医学院第一附属医院产科产前检查的2964例单胎活产孕妇中,进行《产前检查问卷》调查.剔除缺项≥5项的问卷,共计回收有效问卷2928份,回收率为98.79％.对符合纳入标准的2928例单胎活产儿孕妇的产前检查质量进行评价.按照产前检查质量标准,将其分为充分组(n=1262)、居中组(n=1502)和不足组(n=164).采取回顾性分析方法于产后(2～7)d,依照《孕产妇产前检查手册》或门诊及住院病历记录3组孕妇的一般情况及其产前检查、孕期患病和分娩等情况.采用非条件logistic逐步回归分析法分析与LBW发生的相关危险因素及其与产前检查质量的关系(本研究遵循的程序符合本院人体试验委员会所制定的伦理学标准,得到该委员会批准,征得受试对象知情同意并与之签署临床研究知情同意书).3组孕妇孕前体重指数(BMI)、本次妊娠胎数比较,差异无统计学意义(P＞0.05).结果 LBW儿发生率在充分组、居中组和不足组分别为3.49％(44/1262),5.26％(79/1502)和19.51％ (32/164).产前检查不足组LBW儿发生率最高,与其他两组比较,差异有统计学意义(P＜0.01).LBW儿发生的相关危险因素包括:①孕妇年龄;②婚姻状况;③是否有妊娠合并症;④分娩地点;⑤孕期体重增加;⑥分娩孕周等,与产前检查质量密切相关(r=0.83,0.69,0.85,-0.68,-0.71,-0.74;P＜0.05).LBW儿发生与产次无相关性(r=0.26,P＞0.05).本组LBW儿与正常体重儿(≥2500 g)母亲的产前检查质量、年龄、婚姻状况、产次、是否有妊娠合并症、分娩地点、孕期体重增加、分娩孕周等比较,差异有统计学意义(x2=96.05,58.84,21.41,52.38,38.10,33.44,66.32,258.42;P＜0.05).与正常体重儿比较,LBW儿母亲孕期平均接受产前检查次数较少[(7.6±3.1)次vs.(5.4±2.9)次;t=9.16,P＜0.01];产前检查充分组较居中组LBW儿发生率低(OR=0.51,95％CI:0.35～0.72).调整孕妇年龄、孕期体重增加、妊娠并发症、产前检查医院类别及分娩孕周后,产前检查次数较少,仍是LBW儿发生的危险因素(OR=4.56,95％CI:3.02～6.84).结论 采用Kessner's评定方法评估产前检查质量相对客观准确,产前检查次数较少,是LBW儿发生的独立危险因素.