Alcohol drinking and risk of small for gestational age birth

OBJECTIVE: To assess if alcohol drinking is a risk factor for small for gestational age (SGA) birth. METHODS: Case-control study. Cases were 555 women (mean age 31 years, range 16-43) who delivered SGA babies at the Clinica Luigi Mangiagalli and the Obstetric and Gynecology Clinic of the University of Verona. The controls were 1966 women (mean age 31 years, range 14-43) who gave birth at term (> or =37 weeks of gestation) to healthy infants of normal weight at the hospitals where cases had been identified. RESULTS: No increase in the risk of SGA birth was observed in women drinking one or two drinks/day in pregnancy, but three or more per day increased the risk: odds ratios (OR) were 3.2 (1.7-6.2) for > or =3 drinks during the first trimester, 2.7 (1.4-5.3) during the second and 2.9 (1.5-5.7) during the third. CONCLUSIONS: The study shows an increased risk of SGA births in mothers who drink > or =3 units/day of alcohol in pregnancy.     

Coffee drinking and risk of preterm birth

OBJECTIVES: We analysed the association between coffee drinking before and during the three trimesters of pregnancy and the risk of preterm birth of babies normal for gestational age (NGA) or small for gestational age (SGA). METHODS: Case-control study conducted in University clinics of North Italy. Cases were 502 women who delivered at <37 weeks of gestation. The controls included 1966 women who gave birth at term (>or=37 weeks of gestation) to healthy infants on randomly selected days at the hospitals where cases had been identified. RESULTS: There was inverse association for coffee consumption in the third trimester of pregnancy in SGA cases compared to NGA (heterogeneity test between OR: chi1(2)=5.6811 P<0.05). In comparison with not drinkers, all the ORs of overall intake of caffeine were closed near the unity for both SGA and NGA preterm birth. CONCLUSION: Compared with no consumption, a low consumption of coffee during pregnancy may not have significant effects on preterm birth.     

Maternal coffee drinking in pregnancy and risk of small for gestational age birth

OBJECTIVE: We have analysed the association between coffee drinking before and during the three trimesters of pregnancy and risk of small for gestational age (SGA) birth. METHODS: Cases were 555 women who delivered SGA births (ie <10th percentile according Italian standard). The controls included 1966 women who gave birth at term (>/=37 weeks of gestation) to healthy infants of normal weight. RESULTS: In comparison with nondrinkers, the ORs for SGA birth were 1.3 (95% confidence interval, CI, 0.9-1.9) for consumption of four or more cups of coffee/day before pregnancy, and 1.2 (95% CI 0.8-1.8), 1.2 (95% CI 0.8-1.8) and 0.9 (95% CI 0.6-1.4) for consumption of three or more cups of coffee/day during the first, second and third trimester of pregnancy, respectively. CONCLUSION: These findings were consistent in women who delivered preterm and at term births and were not affected by potential confounding such as smoking.     

Does lack of multinutrient supplementation during early pregnancy increase vulnerability to alcohol-related preterm or small-for-gestational-age births?

The objective of this study was to assess whether women who do not take multinutrient supplements during early pregnancy are more susceptible to the effects of low-to-moderate alcohol consumption on preterm birth and small-for-gestational-age birth (SGA) compared to women who do take multinutrients. This analysis included 800 singleton live births to mothers from a cohort of pregnant women recruited for a population-based cohort study conducted in the Kaiser Permanente Medical Care Program in Northern California. Participants were recruited in their first trimester of pregnancy and information about their alcohol use and supplement intake during pregnancy was collected. Preterm birth (n = 53, 7%) was defined as a delivery prior to 37 completed weeks of gestation and SGA birth (n = 124, 16%) was defined as birth weight less than the 10th percentile for the infant’s gestational age and sex compared to US singleton live births. A twofold increase in the odds of SGA birth attributed to low-to-moderate alcohol intake was found among multinutrient supplement non-users (95% CI: 1.1, 5.3). Yet, among multinutrient supplement users, there was no increased risk of an SGA birth for women who drank low-to-moderately compared to women who abstained (aOR: 0.97, 95% CI: 0.6, 1.6). Similar results emerged for preterm birth. Our findings provide marginal evidence that multinutrient supplementation during early pregnancy may modify the risk of SGA births and preterm birth associated with alcohol consumption during pregnancy and may have important implications for pregnant women and women of child-bearing age. However, future research needs to be conducted.     

The effect of vaginal bleeding during pregnancy on preterm and small-for-gestational-age births: US National Maternal and Infant Health Survey, 1988

We examined the effects of vaginal bleeding during pregnancy on preterm and small-for-gestational-age (SGA) births using data from the 1988 US National Maternal and Infant Health Survey. We examined the severity of vaginal bleeding and separated the preterm births into subsets by the degree of prematurity (< 32, 32-33, 34-36 weeks' gestation). We also evaluated associations stratified by race. Multiple logistic regression analysis showed that vaginal bleeding was associated with an increased risk of preterm birth, with a more pronounced elevated risk for preterm birth before 34 weeks' gestation and a notably stronger association for more severe bleeding that occurred in both the first and the second half of pregnancy. Odds ratios, but not risk differences, for birth before 34 weeks' gestation were greater for white women with vaginal bleeding than for black women. There was no association between vaginal bleeding during pregnancy and SGA births.     

Hospitalizations in adolescence and early adulthood among Swedish men and women born preterm or small for gestational age

BACKGROUND: Preterm birth and reduced intrauterine growth appear to be related to morbidity in childhood and later adulthood. We studied whether the risk of all-cause hospitalization in adolescence and early adulthood differed between individuals who were born preterm or small for gestational age (SGA) compared with those born at term and appropriate for gestational age. METHODS: Using Swedish registries, we followed 304,275 men and women born in 1973-1975 for any hospitalizations occurring in 1987-1996. Preterm birth was defined as <37 weeks of gestation and SGA as babies smaller than 2 standard deviations below the mean weight for gestational length, according to Swedish standards. We created 3 mutually exclusive categories: "preterm" (<37 weeks and not SGA), "SGA" (SGA and not preterm), and "both preterm and SGA." The comparison group was all term births not SGA. Childhood socioeconomic characteristics were accounted for in the analyses. RESULTS: The overall risk of hospitalization was higher for men and women born SGA (adjusted odds ratio = 1.16; 95% confidence interval = 1.12-1.21), for those born preterm (1.06; 1.02-1.10), and for those born both preterm and SGA (1.42; 1.26-1.59). In addition to higher risks for previously reported adverse health outcomes, such as neurodevelopment sequelae and congenital anomalies, men and women born SGA or preterm were more likely to be hospitalized due to unspecified symptoms. SGA also appeared to be associated with genitourinary diseases and drug use. CONCLUSIONS: Men and women born SGA or preterm were at higher risk for hospitalization during adolescence and early adulthood, with men and women born SGA more at risk than those born preterm.     

Intergenerational influences affecting birth outcome. II. Preterm delivery and gestational age in the children of the 1958 British birth cohort

The 1958 British cohort study has data to investigate intergenerational effects on preterm delivery and on gestational age in non-preterm births, allowing for many confounders that may differ in the more pathological preterm babies. Previous results for all gestational ages have been inconsistent. The strongest and only likely independent intergenerational effect on non-preterm gestational age found is parental gestational age (adjusted regression coefficient = 0.067 weeks per week in mothers and 0.045 in fathers). The preterm analysis has low power; however, reported history of hypertension in mothers (any), in fathers and in the maternal grandmother (measured in the 1958 pregnancy) all significantly and independently increased the risk of preterm birth [OR = 1.7, 2.0, 1.5 respectively]. The absolute risk was particularly high in hypertensive mothers who had been preterm themselves (21%). Other possible intergenerational influences of height, weight, fetal growth and gestation were not significant enough and/or consistent enough between parents to speculate whether they are truly intergenerational or confounded by other factors acting during the pregnancy. Excepting mother's weight for height, no genetic or environmental influence studied affects both gestational age and fetal growth in term births. However, many maternal factors that reduce either fetal growth or gestation in term births are associated with increased risk of preterm birth.     

Pregnancy Complications and Calculated Cardiovascular Risk in Urban Women: Do We Envisage an Association?

Most researches related to pregnancy complications and future cardiovascular disease, and their risk factors have been equivocal. Existence and extent of these complications, as a contributing factor to CVD risks, with underlying mechanisms of these associations, still remain uncertain. Hence, the current study tends to examine associations between “complicated pregnancies” with obesity markers known to be coherent reflections of cardiovascular health in urban women. A cross-sectional sample of 631 Punjabi Khatri (mean age: 33 ± 5.58 years) urban women was studied for associations of pregnancy diabetes mellitus, hypertensive disorders, preterm delivery, and size for GA with calculated 10-year CVD risk (based on the Framingham score). A wide range of obesity markers (BMI, waist circumference (WC), WHR, and WHtR) were measured 3–8 years postpregnancy to determine its association with complications during pregnancy. The association with the calculated 10-year CVD risk (≥10 %) based on the Framingham prediction score was 3.01 OR (2.11–3.72 CI) for pregnancy DM, 4.52 (3.68–4.93 CI) for preeclampsia/gestational hypertension, 2.16 (2.01–2.79 CI) for size at GA (SGA and LGA), 2.25 (1.91–2.85 CI) for preterm births, and 2.48 (2.08–3.98 CI) for abnormal birth weight when compared with women without pregnancy diabetes mellitus, preeclampsia/gestational hypertension, appropriate gestational age, full-term babies, and normal birth weight, respectively, in completely adjusted models. Therefore, HDP, pregnancy diabetes mellitus, and pregnancy outcomes are all associated with an increased risk of CVD 10 years later. Pregnancy may provide an opportunity to identify women at increased risk of CVD relatively early in life.     

Impact of maternal characteristics on the effect of maternal influenza vaccination on fetal outcomes

Background

Maternal infections during pregnancy have been associated with adverse fetal and infant health outcomes, and vaccination against influenza is the most effective tool to prevent morbidity and mortality due to seasonal and pandemic influenza. We evaluated the association between receipt of the inactivated seasonal influenza vaccine on preterm and small for gestational age (SGA) births, with the aim to assess racial and socioeconomic variations in vaccine effect.

Methods

We conducted a retrospective analysis of state-wide surveillance data from Georgia for the most recent four years available at the beginning of the study, a total of 8393 live births in Georgia from January 1, 2005 through December 31, 2008. We constructed multivariable logistic regression models and calculated odds ratios (OR) estimates with corresponding 95% confidence intervals (CI) to evaluate the effect of maternal influenza vaccination on SGA (birth weight <10th percentile for gestational age) and preterm (gestational age at birth <37 weeks) births while controlling for potential confounders.

Results

Among all women, we found significant strong associations between maternal influenza vaccination and reduced odds of a preterm birth during the widespread influenza activity period [OR = 0.39, 95% CI: 0.18, 0.83]. In this period, vaccination was protective against SGA births among women at higher risk for influenza related morbidity – women enrolled in the Women, Infant and Child (WIC) program [OR = 0.20, 95% CI: 0.04, 0.98] and Black women [OR = 0.15 95% CI: 0.02, 0.94]; maternal influenza vaccination was associated with reduced odds of a preterm birth among white women [OR = 0.34, 95% CI: 0.12, 0.91] and women of higher socio-economic status [OR = 0.30, 95% CI: 0.12, 0.74].

Conclusion

Influenza vaccination during pregnancy was significantly associated with reduced odds of small for gestational age and preterm births during the widespread influenza activity period. Vaccination effects varied by socio-demographic characteristics.     

兰州地区早产影响因素的研究

目的 探讨早产、自发性早产和医源性早产的相关高危因素.方法 回顾性调查2010年1月至2012年12月在甘肃省妇幼保健院住院分娩足月儿和早产儿的孕妇的住院资料,分娩足月活产儿5639例、早产儿540例,分为足月产组(≥37周孕龄)和早产组(<37周孕龄),比较早产组和足月产组发生早产的相关危险因素,以及自发性早产和医源性早产的相关高危因素.结果 ①Logistic回归分析发现教育年限(≥16年)(OR=0.61,95%CI:0.48~0.78)、家庭平均月收入(>3000元)(OR=0.62,95%CI:0.50~0.78)是早产发生的保护因素,而母亲妊娠合并症,比如妊娠期糖尿病(GDM)(OR=3.97,95%CI:1.70~9.25)、妊娠期高血压疾病(HDP)(OR=4.43,95%CI:3.35~5.87)、妊娠期胆汁淤积症(ICP)(OR=4.88,95%CI:3.25~7.32)是早产发生的独立高危因素.②按早产的病因分类,本研究中340例为自发性早产儿,余200例为医源性早产.经分层多因素非条件Logistic回归分析表明,与足月产相比,经产妇(OR=2.66,95%CI:1.87~3.76)、GDM(OR=4.52,95%CI:1.42~14.38),尤其是HDP孕妇(OR=14.19,95%CI:10.10~19.93)更易发生医源性早产,而ICP孕妇更多出现自发性流产(OR=12.875,95%CI:12.75~13.00).结论 应及早识别早产潜在的高危因素,加强围生期管理,以减少早产的发生,改善围生儿结局.     

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.     

广西地区低出生体重儿危险因素分析

目的 分析广西地区低出生体重的危险因素,为制定低出生体重干预措施提供依据.方法 本研究为多中心横断面回顾性统计分析研究,以2018年广西大部分地区新生儿为研究对象,病例组共纳入37010例(占总数91.31％)低出生体重活产儿,对照组随机抽取54677例正常出生体重活产儿,采用孕产妇个案调查表收集相关孕产妇数据及新生儿...     

Risk factors for preterm, low birth weight and small for gestational age birth in urban Aboriginal and Torres Strait Islander women in Townsville

OBJECTIVES: To assess the characteristics of Indigenous births and to examine the risk factors for preterm (<37 weeks), low birth weight (<2,500 g) and small for gestational age (SGA) births in a remote urban setting. DESIGN: Prospective cohort of singleton births to women attending Townsville Aboriginal and Islander Health Services (TAIHS) for shared antenatal care between 1 January 2000 and 31 December 2003. MAIN OUTCOME MEASURES: Demographic, obstetric, and antenatal care characteristics are described. Risk factors for preterm birth, low birth weight and SGA births are assessed. RESULTS: The mean age of the mothers was 25.0 years (95% CI 24.5-25.5), 15.8% reported hazardous or harmful alcohol use, 15.1% domestic violence, 30% had an inter-pregnancy interval of less than 12 months and 9.2% an unwanted pregnancy. The prevalence of infection was 50.2%. Predictors of preterm birth were a previous preterm birth, low body mass index (BMI) and inadequate antenatal care, with the subgroup at greatest risk of preterm birth being women with a previous preterm birth and infection in the current pregnancy. Predictors of a low birth weight birth were a previous stillbirth, low BMI and an interaction of urine infection and non-Townsville residence; predictors of an SGA birth were tobacco use, pregnancy-induced hypertension and interaction of urine infection and harmful alcohol use. CONCLUSION: The prevalence of demographic and clinical risk factors is high in this group of urban Indigenous women. Strategies addressing potentially modifiable risk factors should be an important focus of antenatal care delivery to Indigenous women and may represent an opportunity to improve perinatal outcome in Indigenous communities in Australia.     

Effect of trihalomethane exposure on fetal development

Aims: To examine the effect of trimester specific and pregnancy average total trihalomethane (TTHM) exposure on infant birth weight, low birth weight, and intrauterine growth retardation in term births, as well as gestational age and preterm delivery in all births.

Methods: Cross sectional analysis of 56 513 singleton infants born to residents of Massachusetts during 1990. City specific aggregate data were used to estimate maternal exposure to TTHM concentration; individual maternal information was used to adjust for confounding.

Results: Increased pregnancy average and second trimester TTHM exposure were associated with small for gestational age and reductions in birth weight after adjusting for potential confounding variables. Compared to ≤60 µg/l, pregnancy average TTHM exposure over 80 µg/l was associated with a 32 g reduction in birth weight. There was a 23 g reduction in birth weight in infants born to mothers exposed to greater than 80 µg/l TTHM during the second trimester. For each 20 µg/l increase in TTHM, the estimated reduction in birth was 2.8 g for pregnancy average exposure and 2.6 g for second trimester exposure. An increased risk of small for gestational age births was found for pregnancy average (odds ratio (OR) 1.14; 95% CI 1.02 to 1.26) and second trimester (OR 1.13, 95% CI 1.03 to 1.24) TTHM levels greater than 80 µg/l. There was no evidence of an association between preterm delivery and increased TTHM levels, but there were slight increases in gestational duration associated with TTHM concentrations.

Conclusions: Maternal exposure to THMs may be associated with fetal growth retardation. Our findings are consistent with most previous work, although we generally found smaller effects of TTHMs on low birth weight and intrauterine growth retardation.

     

Is Maternal Smoking during Early Pregnancy a Risk Factor for All Low Birth Weight Infants?

Background

Low birth weight (LBW) infants do not form a homogeneous group; LBW can be caused by prematurity or poor fetal growth manifesting as small for gestational age (SGA) infants or intrauterine growth retardation. We aimed to clarify the relationship of maternal smoking with both SGA and preterm LBW infants.

Methods

The study population comprised pregnant women who registered at the Koshu City between January 1, 1995, and December 31, 2000, and their children. We performed multivariate analyses using multiple logistic regression models to clarify the relationship of maternal smoking during pregnancy with the SGA outcome and preterm birth in LBW infants.

Results

In this study period, 1,329 pregnant women responded to questionnaires, and infant data were collected from 1,100 mothers (follow-up rate: 82.8%). The number of LBW infants was 81 (7.4%). In this cohort, maternal smoking during early pregnancy was associated with LBW and the SGA outcome. Maternal smoking during early pregnancy was a risk factor for LBW with SGA outcome and for LBW with full-term birth. However, it was not a risk factor for LBW with appropriate weight for gestational age (AGA) and LBW with preterm birth.

Conclusion

These results suggested that LBW with AGA and LBW with preterm birth were associated with other risk factors that were not considered in this study, such as periodontal disease. For the prevention of LBW, not only abstinence from smoking during pregnancy but also other methods such as establishing a clinical setting should be adopted.Key words: Infant, Low Birth Weight; Pregnancy; Risk Factors; Smoking     

Medical termination of pregnancy during the second versus the first trimester and its effects on subsequent pregnancy

Objective

The objective was to compare the risks of preterm birth, low birth weight, small for gestational age (SGA) infants and placental complications in subsequent pregnancy after second vs. first trimester medical termination of pregnancy (MTOP) in primigravid women.

Study Design

A total of 88,522 women who underwent termination of pregnancy during 2000–2009 were identified using Finnish health registers. Of them, primigravid women who underwent MTOP and had subsequent pregnancy ending in live birth up to the end of 2009 (n= 3843) were included in the study. The incidences and risks of preterm birth, low birth weight, SGA infants and placental complications after first- (n= 3427) vs. second-trimester MTOP (n= 416) were compared.

Results

Differences between the study groups in the incidences of preterm birth (3.9% in both groups), low birth weight (3.9% in the second- vs. 3.2% in the first-trimester group), SGA infants (2.4% vs. 2.5%) and placental complications (1.9% vs. 2.6%) were statistically insignificant. Second-trimester MTOP was associated with similar risks of preterm birth, low birth weight, SGA infants and placental complications compared with first-trimester MTOP after adjustment for background characteristics. After second-trimester MTOP, 51.2% of women underwent surgical evacuation, and 4.3% were diagnosed with infection. The differences in the risks of preterm birth, low birth weight, SGA infants and placental complications were statistically insignificant between women with vs. without these complications following second-trimester MTOP.

Conclusions

Second-trimester MTOP among primigravid women did not increase the risks of preterm birth, low birth weight, SGA infants or placental complications in subsequent pregnancy compared with first-trimester MTOP.

Implications

The present study suggests that medical termination of pregnancy in primigravid women during second vs. first trimester does not increase the risks of adverse outcomes in subsequent pregnancy and delivery. The data are of value when counseling women undergoing second-trimester TOP.     

Effect of interpregnancy interval on adverse perinatal outcomes — a national study

Background

The interpregnancy interval (IPI) has been reported to influence the outcome of pregnancy and birth. We performed a national study in Israel to determine the impact of IPI on multiple adverse perinatal outcomes.

Study Design

This longitudinal cohort study used birth certificates of siblings born to the same biological mother, with at least one previous birth and a subsequent singleton pregnancy. Adverse pregnancy outcomes included preterm delivery, very preterm birth, small for gestational age (SGA), very SGA (VSGA), early neonatal death and major congenital malformations. Multivariate logistic regression was performed for each outcome.

Results

The study included 440,838 of a total of 846,845 reported live births in Israel over 5 years; excluded were primiparas (32%), multifetal births (4.9%) and those with incomplete data (10.9%). For IPIs shorter than 6 months, there were significantly increased risks for preterm birth (OR=1.23), SGA (OR=1.14), VSGA (OR=1.15), early neonatal death (OR=1.62) and congenital malformations (OR=1.14). Intervals of 60 months or longer had higher risks for preterm birth (OR=1.39) and VSGA (OR=1.16).

Conclusion

Optimal IPI recommendation of >11 months is an accessible and low-cost means to improve multiple adverse perinatal outcomes.     

广西平果县和德保县壮族人群低出生体重的影响因素研究

目的 分析壮族人群低出生体重发生情况,探讨低出生体重儿的影响因素。方法 选取在广西平果县人民医院、妇幼保健院及德保县妇幼保健院2012年1月1日~2015年6月1日出生的4 915例壮族活产新生儿为研究对象,收集一般人口学资料及低出生体重相关的影响因素,采用多因素Logistic回归方法分析低出生体重儿的影响因素。结果 低出生体重儿358例,低出生体重率为7.28%。母亲孕龄≥35岁（OR=1.72）、身高150 cm以下（OR=2.75）、孕早期体质指数（body mass index,BMI）<18.5 kg/m2（OR=1.68）、血红蛋白浓度<110 g/L（OR=1.50）、孕中期增重少（OR=1.57）、流产史（OR=1.76）、妊娠期高压（OR =5.32）、多产次（OR=1.51）、孕期产前检查少于8次（OR=2.10）等为低出生体重儿发生的危险因素;母亲孕早期BMI≥24.0 kg/m2（OR=0.26）、分娩孕周37周及以上（OR =0.06）、单胎（OR=0.04）等为保护因素。结论 母亲孕龄、身高、孕早期BMI、血红蛋白浓度、流产史、妊娠期高血压、孕期产前检查次数等是壮族人群低出生体重的影响因素,应采取综合措施预防和减少低出生体重儿的发生。     

Lower birth weight and increased body fat at school age in children prenatally exposed to modern pesticides: a prospective study

Background

Evidence for an association between exposure during pregnancy to trihalomethanes (THMs) in drinking water and impaired fetal growth is still inconsistent and inconclusive, in particular, for various exposure routes. We examined the relationship of individual exposures to THMs in drinking water on low birth weight (LBW), small for gestational age (SGA), and birth weight (BW) in singleton births.

Methods

We conducted a cohort study of 4,161 pregnant women in Kaunas (Lithuania), using individual information on drinking water, ingestion, showering and bathing, and uptake factors of THMs in blood, to estimate an internal dose of THM. We used regression analysis to evaluate the relationship between internal THM dose and birth outcomes, adjusting for family status, education, smoking, alcohol consumption, body mass index, blood pressure, ethnic group, previous preterm, infant gender, and birth year.

Results

The estimated internal dose of THMs ranged from 0.0025 to 2.40 mg/d. We found dose-response relationships for the entire pregnancy and trimester-specific THM and chloroform internal dose and risk for LBW and a reduction in BW. The adjusted odds ratio for third tertile vs. first tertile chloroform internal dose of entire pregnancy was 2.17, 95% CI 1.19-3.98 for LBW; the OR per every 0.1 μg/d increase in chloroform internal dose was 1.10, 95% CI 1.01-1.19. Chloroform internal dose was associated with a slightly increased risk of SGA (OR 1.19, 95% CI 0.87-1.63 and OR 1.22, 95% CI 0.89-1.68, respectively, for second and third tertile of third trimester); the risk increased by 4% per every 0.1 μg/d increase in chloroform internal dose (OR 1.04, 95% CI 1.00-1.09).

Conclusions

THM internal dose in pregnancy varies substantially across individuals, and depends on both water THM levels and water use habits. Increased internal dose may affect fetal growth.     

Association of light-to-moderate alcohol drinking in pregnancy with preterm birth and birth weight: elucidating bias by pooling data from nine European cohorts

Women who drink light-to-moderately during pregnancy have been observed to have lower risk of unfavourable pregnancy outcomes than abstainers. This has been suggested to be a result of bias. In a pooled sample, including 193 747 live-born singletons from nine European cohorts, we examined the associations between light-to-moderate drinking and preterm birth, birth weight, and small-for-gestational age in term born children (term SGA). To address potential sources of bias, we compared the associations from the total sample with a sub-sample restricted to first-time pregnant women who conceived within six months of trying, and examined whether the associations varied across calendar time. In the total sample, drinking up to around six drinks per week as compared to abstaining was associated with lower risk of preterm birth, whereas no significant associations were found for birth weight or term SGA. Drinking six or more drinks per week was associated with lower birth weight and higher risk of term SGA, but no increased risk of preterm birth. The analyses restricted to women without reproductive experience revealed similar results. Before 2000 approximately half of pregnant women drank alcohol. This decreased to 39% in 2000–2004, and 14% in 2005–2011. Before 2000, every additional drink was associated with reduced mean birth weight, whereas in 2005–2011, the mean birth weight increased with increasing intake. The period-specific associations between low-to-moderate drinking and birth weight, which also were observed for term SGA, are indicative of bias. It is impossible to distinguish if the bias is attributable to unmeasured confounding, which change over time or cohort heterogeneity.