Maternal seafood intake during pregnancy, prenatal mercury exposure and child body mass index trajectories up to 8 years.

BACKGROUND: Maternal seafood intake during pregnancy and prenatal mercury exposure may influence children's growth trajectories. METHODS: This study, based on the Norwegian Mother, Father and Child Cohort Study (MoBa), includes 51 952 mother-child pairs recruited in pregnancy during 2002-08 and a subsample (n = 2277) with maternal mercury concentrations in whole blood. Individual growth trajectories were computed by modelling based on child's reported weight and length/height from 1 month to 8 years. We used linear mixed-effects regression analysis and also conducted discordant-sibling analysis. RESULTS: Maternal lean fish was the main contributor to total seafood intake in pregnancy and was positively but weakly associated with child body mass index (BMI) growth trajectory. Higher prenatal mercury exposure (top decile) was associated with a reduction in child's weight growth trajectory, with the estimates ranging from -130 g [95% Confidence Intervals (CI) = -247, -12 g] at 18 months to -608 g (95% CI = -1.102, -113 g) at 8 years. Maternal fatty fish consumption was positively associated with child weight and BMI growth trajectory, but only in the higher mercury-exposed children (P-interaction = 0.045). Other seafood consumption during pregnancy was negatively associated with child weight growth compared with no intake, and this association was stronger for higher mercury-exposed children (P-interaction = 0.004). No association was observed between discordant maternal seafood intake and child growth in the sibling analysis. CONCLUSIONS: Within a population with moderate seafood consumption and low mercury exposure, we found that maternal seafood consumption in pregnancy was associated with child growth trajectories, and the direction of the association varied by seafood type and level of prenatal mercury exposure. Prenatal mercury exposure was negatively associated with child growth. Our findings on maternal seafood intake are likely non-causal.

Old Question Revisited: Are High-Protein Diets Safe in Pregnancy?

BACKGROUND: A previous randomized dietary intervention in pregnant women from the 1970s, the Harlem Trial, reported retarded fetal growth and excesses of very early preterm births and neonatal deaths among those receiving high-protein supplementation. Due to ethical challenges, these findings have not been addressed in intervention settings. Exploring these findings in an observational setting requires large statistical power due to the low prevalence of these outcomes. The aim of this study was to investigate if the findings on high protein intake could be replicated in an observational setting by combining data from two large birth cohorts. METHODS: Individual participant data on singleton pregnancies from the Danish National Birth Cohort (DNBC) (n = 60,141) and the Norwegian Mother, Father and Child Cohort Study (MoBa) (n = 66,302) were merged after a thorough harmonization process. Diet was recorded in mid-pregnancy and information on birth outcomes was extracted from national birth registries. RESULTS: The prevalence of preterm delivery, low birth weight and fetal and neonatal deaths was 4.77%, 2.93%, 0.28% and 0.17%, respectively. Mean protein intake (standard deviation) was 89 g/day (23). Overall high protein intake (>100 g/day) was neither associated with low birth weight nor fetal or neonatal death. Mean birth weight was essentially unchanged at high protein intakes. A modest increased risk of preterm delivery [odds ratio (OR): 1.10 (95% confidence interval (CI): 1.01, 1.19)] was observed for high (>100 g/day) compared to moderate protein intake (80-90 g/day). This estimate was driven by late preterm deliveries (weeks 34 to <37) and greater risk was not observed at more extreme intakes. Very low (<60 g/day) compared to moderate protein intake was associated with higher risk of having low-birth weight infants [OR: 1.59 (95%CI: 1.25, 2.03)]. CONCLUSIONS: High protein intake was weakly associated with preterm delivery. Contrary to the results from the Harlem Trial, no indications of deleterious effects on fetal growth or perinatal mortality were observed.

Intake of dairy protein during pregnancy in IBD and risk of SGA in a Norwegian population-based mother and child cohort.

BACKGROUND: Patients with inflammatory bowel disease (IBD) tend to avoid dairy products to minimize abdominal pain and diarrhea. The aim of this study was to estimate the proportion of protein from dairy sources (PPDS) in mothers with and without IBD, and to explore the impact of PPDS on inadequate gestational weight gain (GWG) or small for gestational age (SGA) in IBD compared to non-IBD in the population-based Norwegian Mother, Father and Child Cohort Study (MoBa). METHODS: MoBa includes about 95,000 pregnant women recruited throughout Norway from 1999 to 2008. IBD phenotype and complications during pregnancy and delivery were ascertained. This study included 148 mothers with Crohn disease (CD) and 194 with ulcerative colitis and 68,858 non-IBD mothers. In mid-pregnancy participants answered a comprehensive semi-quantitative food frequency questionnaire assessing diet since the start of pregnancy. PPDS was ranked in quartiles. The two lowest quartiles were merged and considered to represent the lowest of three PPDS groups. We used logistic regression analyses to model multivariate associations, adjusting for potential confounders. RESULTS: The risk of belonging to the lowest PPDS group was twice as high in IBD mothers compared to non-IBD mothers (aOR = 2.02, 95% CI: 1.53, 2.67). Low compared to high PPDS strongly predicted inadequate GWG in CD (aOR = 4.22, 95% CI: 1.28, 13.92). Surprisingly, and in opposition to the non-IBD mothers, PPDS was positively associated with the risk of SGA in IBD mothers. IBD mother with low PPDS was associated with significantly lower risk of SGA than non-IBD mothers and IBD mothers with high PPDS (aOR = 0.19, 95% CI: 0.07, 0.50). The interaction term IBD/PPDS was the factor that linked SGA to IBD compared to non-IBD, and increased the association between IBD and SGA with a factor of three. CONCLUSION: This study shows that intake of dairy products is lower in IBD mothers than in non-IBD mothers, and further, that low intake of dairy products in IBD mothers is associated with reduced risk of SGA compared to non-IBD and IBD mothers with high PPDS.

Maternal dietary selenium intake is associated with increased gestational length and decreased risk of preterm delivery.

The first positive genome-wide association study on gestational length and preterm delivery showed the involvement of an Se metabolism gene. In the present study, we examine the association between maternal intake of Se and Se status with gestational length and preterm delivery in 72 025 women with singleton live births from the population-based, prospective Norwegian Mother, Father and Child Cohort Study (MoBa). A self-reported, semi-quantitative FFQ answered in pregnancy week 22 was used to estimate Se intake during the first half of pregnancy. Associations were analysed with adjusted linear and Cox regressions. Se status was assessed in whole blood collected in gestational week 17 (n 2637). Median dietary Se intake was 53 (interquartile range (IQR) 44-62) µg/d, supplements provided additionally 50 (IQR 30-75) µg/d for supplement users (n 23 409). Maternal dietary Se intake was significantly associated with prolonged gestational length (ß per sd = 0·25, 95 % CI, 0·07, 0·43) and decreased risk of preterm delivery (n 3618, hazard ratio per sd = 0·92, 95 % CI, 0·87, 0·98). Neither Se intake from supplements nor maternal blood Se status was associated with gestational length or preterm delivery. Hence, the present study showed that maternal dietary Se intake but not intake of Se-containing supplements, during the first half of pregnancy was significantly associated with decreased risk of preterm delivery. Further investigations, preferably in the form of a large randomised controlled trial, are needed to elucidate the impact of Se on pregnancy duration.

Intake of sucrose-sweetened soft beverages during pregnancy and risk of congenital heart defects (CHD) in offspring: a Norwegian pregnancy cohort study.

Studies report increased risk of congenital heart defects (CHD) in the offspring of mothers with diabetes, where high blood glucose levels might confer the risk. We explored the association between intake of sucrose-sweetened soft beverages during pregnancy and risk of CHD. Prospective cohort data with 88,514 pregnant women participating in the Norwegian Mother and Child Cohort Study was linked with information on infant CHD diagnoses from national health registers and the Cardiovascular Diseases in Norway Project. Risk ratios were estimated by fitting generalized linear models and generalized additive models. The prevalence of children with CHD was 12/1000 in this cohort (1049/88,514). Among these, 201 had severe and 848 had non-severe CHD (patent ductus arteriosus; valvular pulmonary stenosis; ventricular septal defect; atrial septal defect). Only non-severe CHD was associated with sucrose-sweetened soft beverages. The adjusted risk ratios (aRR) for non-severe CHD was 1.30 (95% CI 1.07-1.58) for women who consumed 25-70 ml/day and 1.27 (95% CI 1.06-1.52) for women who consumed ≥ 70 ml/day when compared to those drinking ≤ 25 ml/day. Dose-response analyses revealed an association between the risk of non-severe CHD and the increasing exposure to sucrose-sweetened soft beverages, especially for septal defects with aRR = 1.26 (95% CI 1.07-1.47) per tenfold increase in daily intake dose. The findings persisted after adjustment for maternal diabetes or after excluding mothers with diabetes (n = 19). Fruit juices, cordial beverages and artificial sweeteners showed no associations with CHD. The findings suggest that sucrose-sweetened soft beverages may affect the CHD risk in offspring.

Mortality and causes of death across the systemic connective tissue diseases and the primary systemic vasculitides.

Objectives: Studies assessing relative mortality risks across the spectrum of systemic inflammatory rheumatic diseases are largely missing. In this study, we wanted to estimate standard mortality ratios (SMRs) and causes of death in an ethnically homogeneous cohort covering all major CTDs and primary systemic vasculitides (PSVs). Methods: We prospectively followed all incident CTD and PSV cases included in the Norwegian CTD and vasculitis registry (NOSVAR) between 1999 and 2015. Fifteen controls for each patient matched for sex and age were randomly drawn from the Norwegian National Population Registry. Causes of death were obtained from the National Cause of Death Register, death certificates and hospital charts. Results: The cohort included 2140 patients (1534 with CTD, 606 with PSV). During a mean follow-up time of 9 years, 279 of the patients (13%) died, compared with 2864 of 32 086 (9%) controls (P < 0.001). Ten years after diagnosis, the lowest survival was 60% in dcSSc, 73% in anti-synthetase syndrome (ASS) and 75% in lcSSc. In the CTD group, the highest SMRs were observed in dcSSc (SMR 5.8) and ASS (SMR 4.1). In the PSV group, Takayasu arteritis (SMR 2.5) and ANCA-associated vasculitis (SMR 1.5) had the highest SMRs. Major causes of death were cardiovascular disease (CTD 27%, PSV 28%), neoplasms (CTD 25%, PSV 27%), chronic respiratory disease (CTD 20%, PSV10%) and infections (CTD 9%, PSV 16%). Conclusion: We observed premature deaths across the spectrum of CTDs and PSVs, with highest SMRs in dcSSc and ASS. The overall mortality was highest in the CTD group.

Gestational weight gain across continents and ethnicity: systematic review and meta-analysis of maternal and infant outcomes in more than one million women.

BACKGROUND: The association between Institute of Medicine (IOM) guidelines and pregnancy outcomes across ethnicities is uncertain. We evaluated the associations of gestational weight gain (GWG) outside 2009 IOM guidelines, with maternal and infant outcomes across the USA, western Europe and east Asia, with subgroup analyses in Asia. The aim was to explore ethnic differences in maternal prepregnancy body mass index (BMI), GWG and health outcomes across these regions. METHODS: Systematic review, meta-analysis and meta-regression of observational studies were used for the study. MEDLINE, MEDLINE In-Process, Embase and all Evidence-Based Medicine (EBM) Reviews were searched from 1999 to 2017. Studies were stratified by prepregnancy BMI category and total pregnancy GWG. Odds ratio (ORs) 95% confidence intervals (CI) applied recommended GWG within each BMI category as the reference. Primary outcomes were small for gestational age (SGA), preterm birth and large for gestational age (LGA). Secondary outcomes were macrosomia, caesarean section and gestational diabetes. RESULTS: Overall, 5874 studies were identified and 23 were included (n = 1,309,136). Prepregnancy overweight/obesity in the USA, Europe and Asia was measured at 42%, 30% and 10% respectively, with underweight 5%, 3% and 17%. GWG below guidelines in the USA, Europe and Asia was 21%, 18% and 31%, and above was 51%, 51% and 37% respectively. Applying regional BMI categories in Asia showed GWG above guidelines (51%) was similar to that in the USA and Europe. GWG below guidelines was associated with a higher risk of SGA (USA/Europe [OR 1.51; CI 1.39, 1.63]; Asia [1.63; 1.45, 1.82]) and preterm birth (USA/Europe [1.35; 1.17, 1.56]; Asia [1.06; 0.78, 1.44]) than GWG within guidelines. GWG above guidelines was associated with a higher risk of LGA (USA/Europe [1.93; 1.81, 2.06]; Asia [1.68; 1.51 , 1.87]), macrosomia (USA/Europe [1.87; 1.70, 2.06]; Asia [2.18; 1.91, 2.49]) and caesarean (USA/Europe [1.26; 1.21, 1.33]; Asia [1.37; 1.30, 1.45]). Risks remained elevated when regional BMI categories were applied for GWG recommendations. More women in Asia were categorised as having GWG below guidelines using World Health Organization (WHO) (60%) compared to regional BMI categories (16%), yet WHO BMI was not accompanied by increased risks of adverse outcomes. CONCLUSIONS: Women in the USA and western Europe have higher prepregnancy BMI and higher rates of GWG above guidelines than women in east Asia. However, when using regional BMI categories in east Asia, rates of GWG above guidelines are similar across the three continents. GWG outside guidelines is associated with adverse outcomes across all regions. If regional BMI categories are used in east Asia, IOM guidelines are applicable in the USA, western Europe and east Asia.

Prenatal iron exposure and childhood type 1 diabetes.

Iron overload due to environmental or genetic causes have been associated diabetes. We hypothesized that prenatal iron exposure is associated with higher risk of childhood type 1 diabetes. In the Norwegian Mother and Child cohort study (n = 94,209 pregnancies, n = 373 developed type 1 diabetes) the incidence of type 1 diabetes was higher in children exposed to maternal iron supplementation than unexposed (36.8/100,000/year compared to 28.6/100,000/year, adjusted hazard ratio 1.33, 95%CI: 1.06-1.67). Cord plasma biomarkers of high iron status were non-significantly associated with higher risk of type 1 diabetes (ferritin OR = 1.05 [95%CI: 0.99-1.13] per 50 mg/L increase; soluble transferrin receptor: OR = 0.91 [95%CI: 0.81-1.01] per 0.5 mg/L increase). Maternal but not fetal HFE genotypes causing high/intermediate iron stores were associated with offspring diabetes (odds ratio: 1.45, 95%CI: 1.04, 2.02). Maternal anaemia or non-iron dietary supplements did not significantly predict type 1 diabetes. Perinatal iron exposures were not associated with cord blood DNA genome-wide methylation, but fetal HFE genotype was associated with differential fetal methylation near HFE. Maternal cytokines in mid-pregnancy of the pro-inflammatory M1 pathway differed by maternal iron supplements and HFE genotype. Our results suggest that exposure to iron during pregnancy may be a risk factor for type 1 diabetes in the offspring.

Pregnancy-Related Risk Factors Are Associated With a Significant Burden of Treated Hypertension Within 10 Years of Delivery: Findings From a Population-Based Norwegian Cohort.

BACKGROUND: The association between pregnancy complications and women's later cardiovascular disease has, primarily, been evaluated in studies lacking information on important covariates. This report evaluates the prospective associations between pregnancy-related risk factors (preeclampsia/eclampsia, gestational hypertension, pregestational and gestational diabetes mellitus, preterm delivery, and fetal growth restriction) and pharmacologically treated hypertension within 10 years after pregnancy, while adjusting for a wide range of covariates. METHODS AND RESULTS: Prepregnancy normotensive women participating in the MoBa (Norwegian Mother and Child Cohort Study) from January 2004 through July 2009 were linked to the Norwegian Prescription Database to identify women with pharmacologically treated hypertension beyond the postpartum period of 3 months. The burden of hypertension associated with pregnancy-related risk factors was evaluated using an attributable fraction method. A total of 1480 women developed pharmacologically treated hypertension within the follow-up among 60 027 women (rate of hypertension, 3.6/1000 person-years). The proportion of hypertension associated with a history of preeclampsia/eclampsia, gestational hypertension, preterm delivery, and pregestational or gestational diabetes mellitus was 28.6% (95% confidence interval, 25.5%-31.6%) on the basis of multivariable analyses adjusting for numerous covariates. The proportion was similar for women with a healthy prepregnancy body mass index (18.5-24.9 kg/m2; attributable fraction (AF)% 25.9%; 95% confidence interval, 21.3%-30.3%), but considerably higher for nulliparous women at baseline within the first 5 years of follow-up. Small-for-gestational age, however, did not increase subsequent hypertension risk in multivariable analyses. CONCLUSIONS: A structured postpartum follow-up of high-risk women identified through pregnancy-related risk factors would facilitate personalized preventive strategies to postpone or avoid onset of premature cardiovascular events.

Nausea and vomiting in pregnancy - association with pelvic girdle pain during pregnancy and 4-6 months post-partum.

BACKGROUND: To better understand previous associations reported regarding nausea and vomiting in pregnancy (NVP) and pelvic girdle pain (PGP), an investigation into timing of symptom onset for NVP and PGP in pregnancy, as well as the association of NVP with PGP 4-6 months post-partum was performed. We hypothesised that women with NVP symptoms would be most susceptible to experiencing persistence of PGP post-partum. METHODS: Fifty two thousand six hundred seventy-eight pregnancies from the Norwegian Mother and Child Cohort Study were analysed regarding nausea, vomiting, pelvic girdle pain, and health outcome data collected from questionnaires answered between gestation weeks 15, 20, 30, and 6 months post-partum. Logistic regression was used. RESULTS: Women experiencing NVP and PGP together (6.9%) were heaviest in the sample, youngest at menarche and had highest proportion with education ≤12 years. The primiparous women in this group had the lowest timespan from menarche to pregnancy. Women with nausea alone (NP) and NVP had higher odds of PGP 4-6 months post-partum (adjusted odds ratio, aOR = 2.14, 95% CI 1.70-2.71, and aOR = 2.83, 95% CI 2.25-3.57, respectively), compared to symptom-free women. NP/NVP symptoms appeared early in the first trimester, while PGP symptoms appeared later in pregnancy. Women with longer durations of nausea and/or vomiting had a higher proportion of PGP compared to shorter duration women. CONCLUSIONS: Women with NP and NVP had increased odds of PGP 4-6 months post-partum, and women with a long duration of nausea and/or vomiting had a higher proportion of PGP than women with shorter duration, both during pregnancy and 4-6 months post-partum. This finding suggests a synergistic relationship between NP/NVP and PGP.

Maternal caffeine intake during pregnancy and childhood growth and overweight: results from a large Norwegian prospective observational cohort study.

OBJECTIVES: To study the association between maternal caffeine intake during pregnancy and the child's weight gain and overweight risk up to 8 years. DESIGN: Prospective nationwide pregnancy cohort. SETTING: The Norwegian Mother and Child Cohort Study. PARTICIPANTS: A total of 50 943 mothers recruited from 2002 to 2008 and their children, after singleton pregnancies, with information about average caffeine intake assessed at mid-pregnancy. OUTCOME MEASURE: Child's body size information at 11 age points from 6 weeks to 8 years. We defined excess growth in infancy as a WHO weight gain z-score of >0.67 from birth to age 1 year, and overweight according to the International Obesity Task Force. We used a growth model to assess individual growth trajectories. RESULTS: Compared with pregnant women with low caffeine intake (<50 mg/day, 46%), women with average (50-199 mg/day, 44%), high (≥200-299 mg/day, 7%) and very high (≥300 mg/day, 3%) caffeine intakes had an increased risk of their child experiencing excess growth in infancy, after adjustment for confounders (OR=1.15, 95% CI 1.09 to 1.22, OR=1.30, 95% CI 1.16 to 1.45, OR=1.66, 95% CI 1.42 to 1.93, respectively). In utero exposure to any caffeine was associated with higher risk of overweight at age 3 years and 5 years, while the association persisted at 8 years, only for very high exposures. Any caffeine intake was associated with increased body mass index from infancy to childhood. Children prenatally exposed to caffeine intake >200 mg/day had consistently higher weight. Very high caffeine exposures were associated with higher weight gain velocity from infancy to age 8 years. CONCLUSION: Any caffeine consumption during pregnancy is associated with a higher risk of excess infant growth and of childhood overweight, mainly at preschool ages. Maternal caffeine intake may modify the overall weight growth trajectory of the child from birth to 8 years. This study adds supporting evidence for the current advice to reduce caffeine intake during pregnancy.

Dietary acrylamide intake during pregnancy and postnatal growth and obesity: Results from the Norwegian Mother and Child Cohort Study (MoBa).

BACKGROUND: Prenatal acrylamide exposure has been negatively associated with fetal growth but the association with child growth is unknown. OBJECTIVES: We studied the association between prenatal acrylamide exposure and child postnatal growth up to 8 years in the Norwegian Mother and Child Cohort Study (MoBa). METHODS: In 51,952 mother-child pairs from MoBa, acrylamide intake during pregnancy was estimated by combining maternal food intake with food concentrations of acrylamide. Mothers reported their child's weight and length/height up to 11 times between 6 weeks and 8 years. Weight and height growth trajectories were modelled using Jenss-Bayley's growth model. Logistic regression models were used to study the association with overweight/obese status at 3, 5 and 8 years, as identified using the International Obesity Task Force cut-offs. Linear mixed-effect models were used to explore associations with overall growth. RESULTS: At 3 years, the adjusted odds ratios (95% Confidence Intervals (CI)) of being overweight/obese were 1.10 (1.02, 1.20), 1.12 (1.04, 1.22) and 1.21 (1.11, 1.31) by increasing prenatal acrylamide exposure quartile. Similar dose-response associations were found at 5 and 8 years. Acrylamide intake during pregnancy was associated with higher weight growth velocity in childhood. Children exposed at the highest level had 22 g (95% CI: 8, 37), 57 g (95% CI: 32, 81), and 194 g (95% CI: 110, 278) higher weight at 0.5, 2, and 8 years, respectively, compared to their low exposed peers. CONCLUSIONS: Children prenatally exposed to acrylamide in the highest quartile experienced a moderate increase in weight growth velocity during early childhood that resulted in a moderately increased prevalence of overweight/obesity compared to peers in the lowest quartile. Our study is the first to link prenatal acrylamide exposure and postnatal growth.

Lack of Association Between Maternal or Neonatal Vitamin D Status and Risk of Childhood Type 1 Diabetes: A Scandinavian Case-Cohort Study.

Studies on vitamin D status during pregnancy and risk of type 1 diabetes mellitus (T1D) lack consistency and are limited by small sample sizes or single measures of 25-hydroxyvitamin D (25(OH)D). We investigated whether average maternal 25(OH)D plasma concentrations during pregnancy are associated with risk of childhood T1D. In a case-cohort design, we identified 459 children with T1D and a random sample (n = 1,561) from the Danish National Birth Cohort (n = 97,127) and Norwegian Mother and Child Cohort Study (n = 113,053). Participants were born between 1996 and 2009. The primary exposure was the estimated average 25(OH)D concentration, based on serial samples from the first trimester until delivery and on umbilical cord plasma. We estimated hazard ratios using weighted Cox regression adjusting for multiple confounders. The adjusted hazard ratio for T1D per 10-nmol/L increase in the estimated average 25(OH)D concentration was 1.00 (95% confidence interval: 0.90, 1.10). Results were consistent in both cohorts, in multiple sensitivity analyses, and when we analyzed mid-pregnancy or cord blood separately. In conclusion, our large study demonstrated that normal variation in maternal or neonatal 25(OH)D is unlikely to have a clinically important effect on risk of childhood T1D.

Prenatal mercury exposure, maternal seafood consumption and associations with child language at five years.

BACKGROUND: Methyl mercury (MeHg) is a well-known neurotoxin and evidence suggests that also low level exposure may affect prenatal neurodevelopment. Uncertainty exists as to whether the maternal MeHg burden in Norway might affect child neurodevelopment. OBJECTIVE: To evaluate the association between prenatal mercury exposure, maternal seafood consumption and child language and communication skills at age five. METHODS: The study sample comprised 38,581 mother-child pairs in the Norwegian Mother and Child Cohort Study. Maternal mercury blood concentration in gestational week 17 was analysed in a sub-sample of 2239 women. Prenatal mercury exposure from maternal diet was calculated from a validated FFQ answered in mid-pregnancy. Mothers reported children's language and communications skills at age five by a questionnaire including questions from the Ages and Stages Questionnaire (ASQ), the Speech and Language Assessment Scale (SLAS) and the Twenty Statements about Language-Related Difficulties (language 20). We performed linear regression analyses adjusting for maternal characteristics, nutritional status and socioeconomic factors. RESULTS: Median maternal blood mercury concentration was 1.03µg/L, dietary mercury exposure was 0.15µg/kgbw/wk, and seafood intake was 217g/wk. Blood mercury concentrations were not associated with any language and communication scales. Increased dietary mercury exposure was significantly associated with improved SLAS scores when mothers had a seafood intake below 400g/wk in the adjusted analysis. Sibling matched analysis showed a small significant adverse association between those above the 90th percentile dietary mercury exposure and the SLAS scores. Maternal seafood intake during pregnancy was positively associated with the language and communication scales. CONCLUSION: Low levels of prenatal mercury exposure were positively associated with language and communication skills at five years. However, the matched sibling analyses suggested an adverse association between mercury and child language skills in the highest exposure group. This indicates that prenatal low level mercury exposure still needs our attention.

Dietary Patterns in women with Inflammatory Bowel Disease and Risk of Adverse Pregnancy Outcomes: Results from The Norwegian Mother and Child Cohort Study (MoBa).

Background: The aim of the study was to examine dietary patterns and risk of adverse pregnancy outcomes among mothers with inflammatory bowel disease (IBD) in the Norwegian Mother and Child Cohort Study (MoBa). Method: MoBa enrolled participants from all over Norway between 1999 and 2008, and the study comprised 83,988 mothers, of whom there were 183 mothers with Crohn's disease (CD) and 240 with ulcerative colitis (UC). An additional questionnaire was submitted to mothers with IBD in 2013. We extracted three exploratory dietary patterns: a "Prudent," a "Western," and a "Traditional" pattern. We explored the relationship between dietary patterns and IBD and dietary patterns and adverse pregnancy outcomes: small for gestational age (SGA) and preterm delivery (PTD). Results: IBD mothers had a significantly lower adherence to the Traditional dietary pattern [mean score -0.10 (95% CI: - 0.2 - - 0.01)] than non-IBD mothers. In IBD mothers, middle and high adherence to the Traditional dietary pattern was associated with lower risk of SGA [OR tertile 2 vs. tertile 1: 0.44 (95% CI: 0.20 - 0.97) and OR tertile 3 vs. tertile 1: 0.23 (95% CI: 0.08-0.61)] than in IBD and non-IBD mothers with low adherence. In the IBD-subset analyses, similar results were demonstrated for UC mothers [OR tertile 2 vs. tertile 1: 0.21 (95% CI: 0.05 - 0.80) and OR tertile 3 vs. tertile 1: 0.16 (95% CI: 0.04 - 0.60)]. Conclusion: In IBD mothers, higher adherence to a Traditional dietary pattern, characterized by high consumption of lean fish, fish products, potatoes, rice porridge, cooked vegetables, and gravy, was associated with lower risk of SGA.

Maternal cell phone use in early pregnancy and child's language, communication and motor skills at 3 and 5 years: the Norwegian mother and child cohort study (MoBa).

BACKGROUND: Cell phone use during pregnancy is a public health concern. We investigated the association between maternal cell phone use in pregnancy and child's language, communication and motor skills at 3 and 5 years. METHODS: This prospective study includes 45,389 mother-child pairs, participants of the MoBa, recruited at mid-pregnancy from 1999 to 2008. Maternal frequency of cell phone use in early pregnancy and child language, communication and motor skills at 3 and 5 years, were assessed by questionnaires. Logistic regression was used to estimate the associations. RESULTS: No cell phone use in early pregnancy was reported by 9.8% of women, while 39%, 46.9% and 4.3% of the women were categorized as low, medium and high cell phone users. Children of cell phone user mothers had 17% (OR = 0.83, 95% CI: 0.77, 0.89) lower adjusted risk of having low sentence complexity at 3 years, compared to children of non-users. The risk was 13%, 22% and 29% lower by low, medium and high maternal cell phone use. Additionally, children of cell phone users had lower risk of low motor skills score at 3 years, compared to children of non-users, but this association was not found at 5 years. We found no association between maternal cell phone use and low communication skills. CONCLUSIONS: We reported a decreased risk of low language and motor skills at three years in relation to prenatal cell phone use, which might be explained by enhanced maternal-child interaction among cell phone users. No evidence of adverse neurodevelopmental effects of prenatal cell phone use was reported.

Effect of dietary interventions during weaning period on parental practice and lipoproteins and vitamin D status in two-year-old children.

Objective: Evaluate if a two-day course for parents on nutrition and applied baby food preparation had an effect on child's intake of home-made foods, lipid concentration, and vitamin D status. Design: Randomized controlled trial at age 6 months and follow-up at ages 15 and 24 months. Setting: Four health care clinics in Kristiansand, Norway. Subjects: Thirty-nine pairs of 6-month-old children and their parents in the intervention group and 20 pairs in the control group. Results: At age 15 months, the intervention group had lower intakes of ready-made porridge (2.0 vs. 5.8 servings per week (p < 0.05)), lower intake of canned baby food (2.9 vs. 6.3 servings per week (p < 0.05)) and higher intakes of home-made porridge (4.8 servings vs. 0.9 servings per week (p < 0.001)) compared with the control group. The intervention group had higher HDL cholesterol concentrations at 2 years than the control group, 1.08 mol/l compared to 0.89 mol/l (p < 0.05). Conclusions: This is the first study to show that providing dietary information and applied baby food preparation to parents during the weaning period may have impact on the children's diet at 15 and 24 months and improve their lipid profile. Our results call for studies with more power and longer follow-up.

Breast-feeding and Infant Hospitalization for Infections: Large Cohort and Sibling Analysis.

OBJECTIVES: Breast-feeding may protect against infections, but its optimal duration remains controversial. We aimed to study the association of the duration of full and any breast-feeding with infections the first 18 months of life. METHODS: The Norwegian Mother and Child study (MoBa) is a prospective birth cohort which recruited expecting mothers giving birth from 2000 to 2009. We analyzed data from the full cohort (n = 70,511) and sibling sets (n = 21,220) with parental report of breast-feeding and infections. The main outcome measures were the relative risks (RRs) for hospitalization for infections from 0 to 18 months by age at introduction of complementary foods and duration of any breast-feeding. RESULTS: Although we found some evidence for an overall association between longer duration of full breast-feeding and lower risk of hospitalizations for infections, 7.3% of breast-fed children who received complementary foods at 4 to 6 months of age compared to 7.7% of those receiving complementary foods after 6 months were hospitalized (adjusted RR 0.95, 95% confidence interval 0.88-1.03). Higher risk of hospitalization was observed in those breast-fed 6 months or less (10.0%) compared to ≥12 months (7.6%, adjusted RR 1.22, 95% confidence interval 1.14-1.31), but with similar risks for 6 to 11 months versus ≥12 months. Matched sibling analyses, minimizing the confounding from shared maternal factors, showed nonsignificant associations and were generally weaker compared with the cohort analyses. CONCLUSIONS: Our results support the recommendation to fully breast-feed for 4 months and to continue breast-feeding beyond 6 months, and suggest that protection against infections is limited to the first 12 months.

Low Calcium Intake in Midpregnancy Is Associated with Hypertension Development within 10 Years after Pregnancy: The Norwegian Mother and Child Cohort Study.

Background: Low dietary calcium intake may be a risk factor for hypertension, but studies conflict.Objective: We evaluated the ability to predict hypertension within 10 y after delivery based on calcium intake during midpregnancy.Methods: The Norwegian Mother and Child Cohort Study of women delivering in 2004-2009 was linked to the Norwegian Prescription Database (2004-2013) to ascertain antihypertensive medication usage >90 d after delivery. Women with hypertension before pregnancy were excluded, leaving 60,027 mothers for analyses. Age and energy-adjusted cubic splines evaluated dose-response curves, and Cox proportional hazard analyses evaluated HR and 95% CIs by calcium quartiles adjusting for 7 covariates. Analyses were stratified by gestational hypertension and by sodium-to-potassium intake ratio (<0.76 compared with ≥0.76).Results: Participants had a mean ± SD age of 30.5 ± 4.6 y, a body mass index (in kg/m2) of 24.0 ± 4.3 before pregnancy, and a mean follow-up duration of 7.1 ± 1.6 y. Cubic spline graphs identified a threshold effect of low calcium intake only within the range of dietary inadequacy related to increased risk. The lowest calcium quartile (≤738 mg/d; median: 588 mg/d), relative to the highest quartile (≥1254 mg/d), had an HR for hypertension of 1.34 (95% CI: 1.05, 1.70) among women who were normotensive during pregnancy, and an HR of 1.62 (95% CI: 1.14, 2.35) among women who had gestational hypertension, after adjusting for covariates. Women with gestational hypertension, who were in the lowest quartile of calcium intake, and who had a high sodium-to-potassium intake ratio had a risk of hypertension more than double that of their counterparts with a calcium intake in the highest quartile. Results were attenuated by adjusting for covariates (HR: 1.92; 95% CI: 1.09, 3.39).Conclusions: The results suggest that low dietary calcium intake may be a risk factor or risk marker for the development of hypertension, particularly for women with a history of gestational hypertension.

Association of Gestational Weight Gain With Maternal and Infant Outcomes: A Systematic Review and Meta-analysis.

IMPORTANCE: Body mass index (BMI) and gestational weight gain are increasing globally. In 2009, the Institute of Medicine (IOM) provided specific recommendations regarding the ideal gestational weight gain. However, the association between gestational weight gain consistent with theIOM guidelines and pregnancy outcomes is unclear. OBJECTIVE: To perform a systematic review, meta-analysis, and metaregression to evaluate associations between gestational weight gain above or below the IOM guidelines (gain of 12.5-18 kg for underweight women [BMI <18.5]; 11.5-16 kg for normal-weight women [BMI 18.5-24.9]; 7-11 kg for overweight women [BMI 25-29.9]; and 5-9 kg for obese women [BMI ≥30]) and maternal and infant outcomes. DATA SOURCES AND STUDY SELECTION: Search of EMBASE, Evidence-Based Medicine Reviews, MEDLINE, and MEDLINE In-Process between January 1, 1999, and February 7, 2017, for observational studies stratified by prepregnancy BMI category and total gestational weight gain. DATA EXTRACTION AND SYNTHESIS: Data were extracted by 2 independent reviewers. Odds ratios (ORs) and absolute risk differences (ARDs) per live birth were calculated using a random-effects model based on a subset of studies with available data. MAIN OUTCOMES AND MEASURES: Primary outcomes were small for gestational age (SGA), preterm birth, and large for gestational age (LGA). Secondary outcomes were macrosomia, cesarean delivery, and gestational diabetes mellitus. RESULTS: Of 5354 identified studies, 23 (n = 1 309 136 women) met inclusion criteria. Gestational weight gain was below or above guidelines in 23% and 47% of pregnancies, respectively. Gestational weight gain below the recommendations was associated with higher risk of SGA (OR, 1.53 [95% CI, 1.44-1.64]; ARD, 5% [95% CI, 4%-6%]) and preterm birth (OR, 1.70 [1.32-2.20]; ARD, 5% [3%-8%]) and lower risk of LGA (OR, 0.59 [0.55-0.64]; ARD, -2% [-10% to -6%]) and macrosomia (OR, 0.60 [0.52-0.68]; ARD, -2% [-3% to -1%]); cesarean delivery showed no significant difference (OR, 0.98 [0.96-1.02]; ARD, 0% [-2% to 1%]). Gestational weight gain above the recommendations was associated with lower risk of SGA (OR, 0.66 [0.63-0.69]; ARD, -3%; [-4% to -2%]) and preterm birth (OR, 0.77 [0.69-0.86]; ARD, -2% [-2% to -1%]) and higher risk of LGA (OR, 1.85 [1.76-1.95]; ARD, 4% [2%-5%]), macrosomia (OR, 1.95 [1.79-2.11]; ARD, 6% [4%-9%]), and cesarean delivery (OR, 1.30 [1.25-1.35]; ARD, 4% [3%-6%]). Gestational diabetes mellitus could not be evaluated because of the nature of available data. CONCLUSIONS AND RELEVANCE: In this systematic review and meta-analysis of more than 1 million pregnant women, 47% had gestational weight gain greater than IOM recommendations and 23% had gestational weight gain less than IOM recommendations. Gestational weight gain greater than or less than guideline recommendations, compared with weight gain within recommended levels, was associated with higher risk of adverse maternal and infant outcomes.