Caffeine metabolites in umbilical cord blood, cytochrome P-450 1A2 activity, and intrauterine growth restriction

Association between maternal caffeine intake during pregnancy and child development at 6 and 12 months: The Japan Environment and Children's Study

BACKGROUND

Caffeine intake by pregnant women may have neurodevelopmental effects on the fetus due to adenosine antagonism. However, there are insufficient data and inconsistent results from epidemiological studies on the effect of maternal caffeine intake on child development.

AIMS

This study examined the association between mothers' estimated caffeine intake during pregnancy and their children's score on the Japanese version of the Ages & Stages Questionnaires™ (J-ASQ) at 6 and 12 months of age.

STUDY DESIGN

The study is a part of nationwide prospective birth-cohort study: the Japan Environment and Children's Study.

SUBJECTS

In total, 87,106 participants with the Food Frequency Questionnaire (FFQ) data and J-ASQ at 6 or 12 months of age were included in the study.

OUTCOME MEASURES

The data were analyzed by logistic regression analysis to determine whether the scores of the five subscales on the J-ASQ were below the cutoff point as the dependent variable.

RESULTS

The results showed that children born to mothers who consumed >300 mg caffeine per day had a 1.11-fold increased odds of gross motor developmental delay at 12 months of age (adjusted odds ratio [AOR] = 1.114 [95 % CI: 1.013-1.226]).

CONCLUSIONS

Issues in gross motor development can emerge prior to future developmental issues. Therefore, further studies on developmental outcomes in older children, including the future outcomes of the children who participated in this study, are needed.

Differences between Arterial and Venous Umbilical Cord Plasma Metabolome and Association with Parity

Umbilical cord blood is frequently used in health monitoring of the neonate. Results may be affected by the proportion of arterial and venous cord blood, the venous blood coming from the mother to supply oxygen and nutrients to the infant, and the arterial carrying waste products from the fetus. Here, we sampled arterial and venous umbilical cords separately from 48 newly delivered infants and examined plasma metabolomes using GC-MS/MS metabolomics. We investigated differences in metabolomes between arterial and venous blood and their associations with gestational length, birth weight, sex, and whether the baby was the first born or not, as well as maternal age and BMI. Using multilevel random forest analysis, a classification rate of 79% was achieved for arteriovenous differences (p = 0.004). Several monosaccharides had higher concentrations in the arterial cord plasma while amino acids were higher in venous plasma, suggesting that the main differences in the measured arterial and venous plasma metabolomes are related to amino acid and energy metabolism. Venous cord plasma metabolites related to energy metabolism were positively associated with parity (77% classification rate, p = 0.004) while arterial cord plasma metabolites were not. This underlines the importance of defining cord blood type for metabolomic studies.

Intrauterine growth restriction alters the activity of drug metabolising enzymes in the maternal-placental-fetal unit

PURPOSE

Ten percent of pregnancies are affected by intrauterine growth restriction (IUGR), and evidence suggests that affected neonates have reduced activity of hepatic cytochrome P450 (CYP) drug metabolising enzymes. Given that almost all pregnant individuals take medications and additional medications are often required during an IUGR pregnancy, we aimed to determine the impact of IUGR on hepatic CYP activity in sheep fetuses and pregnant ewes.

METHODS

Specific probes were used to determine the impact of IUGR on the activity of several CYP isoenzymes (CYP1A2, CYP2C19, CYP2D6 and CYP3A) in sheep fetuses and pregnant ewes. Probes were administered intravenously to the ewe at 132 days (d) gestation (term 150 d), followed by blood sampling from the maternal and fetal circulation over 24 h. Maternal and fetal liver tissue was collected at 139-140 d gestation, from which microsomes were isolated and incubated with probes. Metabolite and maternal plasma cortisol concentrations were measured using Liquid Chromatography - tandem mass spectrometry (LC-MS/MS).

RESULTS

Maternal plasma cortisol concentration and maternal hepatic CYP1A2 and CYP3A activity was significantly higher in IUGR pregnancies. Maternal hepatic CYP activity was higher than fetal hepatic CYP activity for all CYPs tested, and there was minimal CYP1A2 or CYP3A activity in the late gestation fetus when assessed using in vitro methods.

CONCLUSIONS

The physiological changes to the maternal-placental-fetal unit in an IUGR pregnancy have significant effects on maternal drug metabolism, suggesting changes in medications and/or doses may be required to optimise maternal and fetal health.

Association Between Maternal Caffeine Consumption and Metabolism and Neonatal Anthropometry: A Secondary Analysis of the NICHD Fetal Growth Studies-Singletons

IMPORTANCE

Higher caffeine consumption during pregnancy has been associated with lower birth weight. However, associations of caffeine consumption, based on both plasma concentrations of caffeine and its metabolites, and self-reported caffeinated beverage intake, with multiple measures of neonatal anthropometry, have yet to be examined.

OBJECTIVE

To evaluate the association between maternal caffeine intake and neonatal anthropometry, testing effect modification by fast or slow caffeine metabolism genotype.

DESIGN, SETTING, AND PARTICIPANTS

A longitudinal cohort study, the National Institute of Child Health and Human Development Fetal Growth Studies-Singletons, enrolled 2055 nonsmoking women at low risk for fetal growth abnormalities with complete information on caffeine consumption from 12 US clinical sites between 2009 and 2013. Secondary analysis was completed in 2020.

EXPOSURES

Caffeine was evaluated by both plasma concentrations of caffeine and paraxanthine and self-reported caffeinated beverage consumption measured/reported at 10-13 weeks gestation. Caffeine metabolism defined as fast or slow using genotype information from the single nucleotide variant rs762551 (CYP1A2*1F).

MAIN OUTCOMES AND MEASURES

Neonatal anthropometric measures, including birth weight, length, and head, abdominal, arm, and thigh circumferences, skin fold and fat mass measures. The β coefficients represent the change in neonatal anthropometric measure per SD change in exposure.

RESULTS

A total of 2055 participants had a mean (SD) age of 28.3 (5.5) years, mean (SD) body mass index of 23.6 (3.0), and 580 (28.2%) were Hispanic, 562 (27.4%) were White, 518 (25.2%) were Black, and 395 (19.2%) were Asian/Pacific Islander. Delivery occurred at a mean (SD) of 39.2 (1.7) gestational weeks. Compared with the first quartile of plasma caffeine level (≤28 ng/mL), neonates of women in the fourth quartile (>659 ng/mL) had lower birth weight (β = -84.3 g; 95% CI, -145.9 to -22.6 g; P = .04 for trend), length (β = -0.44 cm; 95% CI, -0.78 to -0.12 cm; P = .04 for trend), and head (β = -0.28 cm; 95% CI, -0.47 to -0.09 cm; P < .001 for trend), arm (β = -0.25 cm; 95% CI, -0.41 to -0.09 cm: P = .02 for trend), and thigh (β = -0.29 cm; 95% CI, -0.58 to -0.04 cm; P = .07 for trend) circumference. Similar reductions were observed for paraxanthine quartiles, and for continuous measures of caffeine and paraxanthine concentrations. Compared with women who reported drinking no caffeinated beverages, women who consumed approximately 50 mg per day (~ 1/2 cup of coffee) had neonates with lower birth weight (β = -66 g; 95% CI, -121 to -10 g), smaller arm (β = -0.17 cm; 95% CI, -0.31 to -0.02 cm) and thigh (β = -0.32 cm; 95% CI, -0.55 to -0.09 cm) circumference, and smaller anterior flank skin fold (β = -0.24 mm; 95% CI, -0.47 to -0.01 mm). Results did not differ by fast or slow caffeine metabolism genotype.

CONCLUSIONS AND RELEVANCE

In this cohort study, small reductions in neonatal anthropometric measurements with increasing caffeine consumption were observed. Findings suggest that caffeine consumption during pregnancy, even at levels much lower than the recommended 200 mg per day of caffeine, are associated with decreased fetal growth.

Oxidative Stress in Preterm Infants: Overview of Current Evidence and Future Prospects

Preterm birth (PTB), defined as parturition prior to 37 weeks of gestation, is the leading cause of morbidity and mortality in the neonatal population. The incidence and severity of complications of prematurity increase with decreasing gestational age and birthweight. The aim of this review study is to select the most current evidence on the role of oxidative stress in the onset of preterm complication prevention strategies and treatment options with pre-clinical and clinical trials. We also provide a literature review of primary and secondary studies on the role of oxidative stress in preterm infants and its eventual treatment in prematurity diseases. We conducted a systematic literature search of the Medline (Pubmed), Scholar, and ClinicalTrials.gov databases, retroactively, over a 7-year period. From an initial 777 articles identified, 25 articles were identified that met the inclusion and exclusion criteria. Of these, there were 11 literature reviews: one prospective cohort study, one experimental study, three case-control studies, three pre-clinical trials, and six clinical trials. Several biomarkers were identified as particularly promising, such as the products of the peroxidation of polyunsaturated fatty acids, those of the oxidation of phenylalanine, and the hydroxyl radicals that can attack the DNA chain. Among the most promising drugs, there are those for the prevention of neurological damage, such as melatonin, retinoid lactoferrin, and vitamin E. The microbiome also has an important role in oxidative stress. In conclusion, the most recent studies show that a strong relationship between oxidative stress and prematurity exists and that, unfortunately, there is still little therapeutic evidence reported in the literature.

Impacts of Caffeine during Pregnancy

Epidemiological studies have revealed that caffeine consumption during pregnancy is associated with adverse gestational outcomes, yet the underlying mechanisms remain obscure. Recent animal studies with physiologically relevant dosages have begun to dissect adverse effects of caffeine during pregnancy with respect to oviduct contractility, embryo development, uterine receptivity, and placentation that jointly contribute to pregnancy complications. Interestingly, caffeine's effects are highly variable between individual animals under well-controlled experimental settings, suggesting the possibility of epigenetic regulation of these phenotypes, in addition to genetic variants. Moreover, caffeine exposure during sensitive windows of pregnancy may induce epigenetic changes in the developing fetus or even the germ cells to cause adult-onset diseases in subsequent generations. We discuss these research frontiers in light of emerging data.

Food and nutrient intake and adherence to dietary recommendations during pregnancy: a Nordic mother-child population-based cohort

Background

A woman's food intake during pregnancy has important implications not only for herself but also for the future health and well-being of her child. Suboptimal dietary quality has been consistently reported in many high-income countries, reflecting poor adherence to dietary guidelines.

Objective

This study aimed to explore the intake of food and nutrients in a cohort of pregnant women in Norway and their adherence to Nordic Nutrition Recommendations (NNR) and Norwegian food-based guidelines (NFG).

Design

We investigated the dietary intake in 1,674 pregnant women from the mother-child birth cohort, PreventADALL, recruited at approximately 18-week gestational age. Dietary intake was assessed by an electronic validated food frequency questionnaire (PrevFFQ) in the first half of pregnancy.

Results

Total fat intake was within the recommended intake (RI) range in most women; however, the contribution of saturated fatty acids to the total energy intake was above RI in the majority (85.2%) of women. Carbohydrate intake was below RI in 43.9% of the women, and 69.5% exceeded the RI of salt. Intakes of fiber, vegetables, and fish were high in a large part of the population. Many women had a high probability of inadequate intakes of the following key micronutrients during pregnancy: folate (54.4%), iron (49.6%), calcium (36.2%), vitamin D (28.7%), iodine (24.4%), and selenium (41.3%). A total of 22.8% women reported an alcohol intake of >1 g/day, and 4.4% reported an alcohol intake of >10 g/day. Women with higher educational levels showed a tendency towards healthier eating habits, except for higher intakes of alcohol and coffee, compared to women with lower educational level.

Discussion

Excessive saturated fat intake and limited intake of many important micronutrients during pregnancy were common, potentially increasing the risk for adverse pregnancy and birth outcomes.

Conclusions

This study highlights the need for improved nutritional guidance to pregnant women across all educational levels.

Caffeine consumption during early pregnancy impairs oviductal embryo transport, embryonic development and uterine receptivity in mice

Caffeine consumption has been widely used as a central nervous system stimulant. Epidemiological studies, however, have suggested that maternal caffeine exposure during pregnancy is associated with increased abnormalities, including decreased fertility, delayed conception, early spontaneous abortions, and low birth weight. The mechanisms underlying the negative outcomes of caffeine consumption, particularly during early pregnancy, remain unclear. In present study, we found that pregnant mice treated with moderate (5 mg/kg) or high (30 mg/kg) dosage of caffeine (intraperitoneally or orally) during preimplantation resulted in retention of early embryos in the oviduct, defective embryonic development, and impaired embryo implantation. Transferring normal blastocysts into the uteri of caffeine-treated pseudopregnant females also showed abnormal embryo implantation, thus indicating impaired uterine receptivity by caffeine administration. The remaining embryos that managed to implant after caffeine treatment also showed increased embryo resorption rate and abnormal development at mid-term stage, and decreased weight at birth. In addition to a dose-dependent effect, significant variations between individual mice under the same caffeine dosage were also observed, suggesting different sensitivities to caffeine, similar to that observed in human populations. Collectively, our data revealed that caffeine exposure during early pregnancy impaired oviductal embryo transport, embryonic development, and uterine receptivity, which are responsible for abnormal implantation and pregnancy loss. The study raises the concern of caffeine consumption during early stages of pregnancy.

Risk assessment of energy drinks with focus on cardiovascular parameters and energy drink consumption in Europe

To assess the possible cardiovascular risks associated with energy drink (ED) consumption in Europe, a comprehensive literature research was performed in regard to (i) possible ED-induced dose-dependent cardiovascular outcomes, (ii) ED consumption patterns in Europe and (iii) the risks of EDs in combination with alcohol. The identified intervention studies primarily investigated acute ED effects in young healthy adults. Moderate consumption of EDs corresponding to an acute caffeine intake of up to 200 mg did not result in clinically relevant cardiovascular changes in young healthy adults. However, high intake of EDs (about 1 L) was associated with moderate to severe adverse effects in some participants (i.a. prolonged QTc interval, palpitations). Studies have indicated that on some occasions, a substantial proportion of ED consuming children and adolescents (12% in 16 EU Member States) drink EDs in high quantities (≥1 L). This could pose a possible health risk to this group since adverse effects by such high ED consumption have been observed already in young healthy adults. Among further measures that might be considered to minimize this identified risk, policy makers could develop information and educational programs with the aim of raising public awareness.

Caffeine exposure during pregnancy, small for gestational age birth and neonatal outcome - results from the Norwegian Mother and Child Cohort Study

BACKGROUND

Maternal caffeine intake has repeatedly been linked to babies being born small for gestational age (SGA). SGA babies are known to be at increased risk for adverse neonatal outcomes. The aim of this study was to explore the associations between prenatal caffeine exposure and neonatal health.

METHODS

The study is based on 67,569 full-term singleton mother-infant pairs from the Norwegian Mother and Child Cohort Study. Caffeine consumption from different sources was self-reported in gestational week 22. Neonatal compound outcomes, namely (1) morbidity/mortality and (2) neonatal intervention, were created based on the Medical Birth Registry of Norway. Adjusted logistic regression was performed.

RESULTS

Caffeine exposure was associated to SGA (OR = 1.16, 95%CI: 1.10; 1.23) and being born SGA was significantly associated with neonatal health (OR = 3.09, 95%CI: 2.54; 3.78 for morbidity/mortality; OR = 3.94, 95%CI: 3.50; 4.45 for intervention). However, prenatal caffeine exposure was neither associated with neonatal morbidity/mortality (OR = 1.01, 95%CI: 0.96; 1.07) nor neonatal intervention (OR = 1.02, 95%CI: 1.00; 1.05 for a 100 mg caffeine intake increase). Results did not change after additional adjustment for SGA status.

CONCLUSIONS

Moderate prenatal caffeine exposure (< 200 mg/day) does not seem to impair neonatal health, although prenatal caffeine exposure is associated with the child being born SGA and SGA with neonatal health. We suggest diversity in neonatal outcomes of SGA infants according to the underlying cause of low birth weight.

Residential mobility of pregnant women and implications for assessment of spatially-varying environmental exposures

Health studies on spatially-varying exposures (e.g., air pollution) during pregnancy often estimate exposure using residence at birth, disregarding residential mobility. We investigated moving patterns in pregnant women (n = 10,116) in linked cohorts focused on Connecticut and Massachusetts, U.S., 1988-2008. Moving patterns were assessed by race/ethnicity, age, marital status, education, working status, population density, parity, income, and season of birth. In this population, 11.6% of women moved during pregnancy. Movers were more likely to be younger, unmarried, and living in urban areas with no previous children. Among movers, multiple moves were more likely for racial/ethnic minority, younger, less educated, unmarried, and lower income women. Most moves occurred later in pregnancy, with 87.4% of first moves in the second or third trimester, although not all cohort subjects enrolled in the first few weeks of pregnancy. Distance between first and second residence had a median value of 5.2 km (interquartile range 11.3 km, average 57.8 km, range 0.0-4277 km). Women moving larger distances were more likely to be white, older, married, and work during pregnancy. Findings indicate that residential mobility may impact studies of spatially-varying exposure during pregnancy and health and that subpopulations vary in probability of moving, and timing and distance of moves.

Interaction between maternal caffeine intake during pregnancy and CYP1A2 C164A polymorphism affects infant birth size in the Hokkaido study

BackgroundCaffeine, 1,3,7-trimethylxanthine, is widely consumed by women of reproductive age. Although caffeine has been proposed to inhibit fetal growth, previous studies on the effects of caffeine on infant birth size have yielded inconsistent findings. This inconsistency may result from failure to account for individual differences in caffeine metabolism related to polymorphisms in the gene for CYP1A2, the major caffeine-metabolizing enzyme.MethodsFive hundred fourteen Japanese women participated in a prospective cohort study in Sapporo, Japan, from 2002 to 2005, and 476 mother-child pairs were included for final analysis.ResultsCaffeine intake was not significantly associated with mean infant birth size. When caffeine intake and CYP1A2 C164A genotype were considered together, women with the AA genotype and caffeine intake of ≥300 mg per day had a mean reduction in infant birth head circumference of 0.8 cm relative to the reference group after adjusting for confounding factors. In a subgroup analysis, only nonsmokers with the AA genotype and caffeine intake of ≥300 mg per day had infants with decreased birth weight (mean reduction, 277 g) and birth head circumference (mean reduction, 1.0 cm).ConclusionNonsmokers who rapidly metabolize caffeine may be at increased risk for having infants with decreased birth size when consuming ≥300 mg of caffeine per day.

Second-Trimester Maternal Serum Paraxanthine, CYP1A2 Activity, and the Risk of Severe Preeclampsia

OBJECTIVE

To measure the association between second-trimester maternal caffeine intake and caffeine metabolism through the CYP1A2 system and the risk of subsequent severe preeclampsia.

METHODS

This was a nested case-control study of women who had undergone second-trimester screening for fetal aneuploidy and had banked serum available for analysis. The outcome of interest was severe preeclampsia, and exposures were serum paraxanthine (1,7-dimethylxanthine), measured through high-performance liquid chromatography, and CYP1A2 activity, assessed by paraxanthine/caffeine ratios.

RESULTS

We identified 51 cases of severe preeclampsia from our population of 3,992 women (1.3%), of whom 33 had sufficient serum for analysis. These were compared with 99 healthy women. Median paraxanthine concentrations were not significantly higher in women in the control group than women in the case group (96.4 ng/mL compared with 38.0 ng/mL, P=.12), and higher serum paraxanthine was not associated with lower odds of severe preeclampsia (odds ratio [OR] 0.72, confidence interval [CI] 0.48-1.08). However, we found a significantly higher paraxanthine/caffeine ratio in women in the control group than women in the case group (0.37 compared with 0.23, P=.02) and a decreased risk of preeclampsia per every log standard deviation increase in paraxanthine/caffeine ratio (OR 0.53, 95% CI 0.31-0.90).

CONCLUSION

Faster caffeine metabolism in the second trimester, assessed by paraxanthine/caffeine ratios, is associated with a reduced risk of subsequent severe preeclampsia.

LEVEL OF EVIDENCE

II.

Maternal Caffeine Intake During Pregnancy and Child Cognition and Behavior at 4 and 7 Years of Age

Although caffeine is commonly consumed during pregnancy, there are few reports on the association of in utero caffeine exposure with offspring cognition or behavior during childhood. We evaluated the association of maternal serum paraxanthine, caffeine's primary metabolite, at <20 and ≥26 weeks' gestation with the child's intelligence quotient (IQ) and problem behaviors at ages 4 and 7 years among 2,197 mother-child pairs. The mothers were controls from a case-control study of caffeine metabolites and spontaneous abortion that was nested within the Collaborative Perinatal Project (multiple US sites, 1959-1974). Associations of paraxanthine (adjusted for maternal age, race, education, smoking, prepregnancy weight, gestational age at blood draw, and child sex) with mean IQ were assessed by linear regression and associations with problem behaviors by logistic regression. Paraxanthine concentration at ≥26 weeks' gestation manifested an inverted-J-shaped association with child's IQ at age 7 years, with a peak difference (vs. undetectable) of 0.65 points at 750 µg/L (66th percentile) and a decrement thereafter. Paraxanthine at <20 weeks was linearly associated with internalizing behavior at age 4 years (for a 500-µg/L increase, odds ratio = 1.3, 95% confidence interval: 1.1, 1.5). None of the remaining 12 associations approached statistical significance. We conclude that over a range of values applicable to most pregnant women, there was no meaningful association of serum paraxanthine level with childhood IQ or problem behaviors.

Effects of restricted caffeine intake by mother on fetal, neonatal and pregnancy outcomes

BACKGROUND

Maternal caffeine consumption during pregnancy may have adverse effects on fetal, neonatal and maternal outcomes.

OBJECTIVES

This review investigates the effects of restricting caffeine intake by mothers on fetal, neonatal and pregnancy outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (16 January 2015), scanned bibliographies of published studies and corresponded with investigators.

SELECTION CRITERIA

Randomised controlled trials (RCTs) including quasi-RCTs investigating the effect of caffeine and/or supplementary caffeine versus restricted caffeine intake or placebo on pregnancy outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

Two studies met the inclusion criteria but only one contributed data for the prespecified outcomes. Caffeinated instant coffee (568 women) was compared with decaffeinated instant coffee (629 women) and it was found that reducing the caffeine intake of regular coffee drinkers (3+ cups/day) during the second and third trimester by an average of 182 mg/day did not affect birthweight (g) (mean difference (MD) 20.00, 95% confidence interval (CI) -48.68 to 88.68; one study, 1197 participants; low quality evidence), preterm birth (risk ratio (RR) 0.81, 95% CI 0.48 to 1.37; one study, 1153 participants; low quality evidence) or small-for-gestational age (RR 0.97, 95% 0.57 to 1.64; one study, 1150 participants). Risk of bias was moderate in both studies.Two outcomes were assessed and assigned a quality rating using the GRADE methods. Evidence for these two outcomes (birthweight and preterm birth) was assessed as of low quality, with downgrading decisions due to the relatively small sample sizes and the wide confidence interval of the one included trial that contributed data. Neither of the studies reported on any of the other primary outcomes (low birthweight; first trimester fetal loss; perinatal mortality; fetal hypoxia; fetal tachycardia) or on any of the reviews neonatal or maternal outcomes.

AUTHORS' CONCLUSIONS

There is insufficient evidence to confirm or refute the effectiveness of caffeine avoidance on birthweight or other pregnancy outcomes. There is a need to conduct high-quality, double-blinded RCTs to determine whether caffeine has any effect on pregnancy outcome.

Caffeine intake during pregnancy and adverse birth outcomes: a systematic review and dose-response meta-analysis

Caffeine is commonly consumed during pregnancy, crosses the placenta, with fetal serum concentrations similar to the mother's, but studies of birth outcome show conflicting findings. We systematically searched Medline and Embase for relevant publications. We conducted meta-analysis of dose-response curves for associations between caffeine intake and spontaneous abortion, stillbirth, preterm delivery, low birth weight and small for gestational age (SGA) infants. Meta-analyses included 60 unique publications from 53 cohort and case-control studies. An increment of 100 g caffeine was associated with a 14 % (95 % CI 10-19 %) increase in risk of spontaneous abortion, 19 % (5-35 %) stillbirth, 2 % (-2 to 6 %) preterm delivery, 7 % (1-12 %) low birth weight, and 10 % (95 % CI 6-14 %) SGA. There was substantial heterogeneity in all models, partly explained by adjustment for smoking and previous obstetric history, but not by prospective assessment of caffeine intake. There was evidence of small-study effects such as publication bias. Greater caffeine intake is associated with an increase in spontaneous abortion, stillbirth, low birth weight, and SGA, but not preterm delivery. There is no identifiable threshold below which the associations are not apparent, but the size of the associations are generally modest within the range of usual intake and are potentially explained by bias in study design or publication. There is therefore insufficient evidence to support further reductions in the maximum recommended intake of caffeine, but maintenance of current recommendations is a wise precaution.

Effects of restricted caffeine intake by mother on fetal, neonatal and pregnancy outcome

BACKGROUND

Maternal caffeine consumption during pregnancy may have adverse effects on fetal, neonatal and maternal outcomes.

OBJECTIVES

This review investigates the effects of restricting caffeine intake by mothers on fetal, neonatal and pregnancy outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2012), scanned bibliographies of published studies and corresponded with investigators.

SELECTION CRITERIA

Randomised controlled trials (RCTs) including quasi-RCTs investigating the effect of caffeine and/or supplementary caffeine versus restricted caffeine intake or placebo on pregnancy outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

Two studies met the inclusion criteria but only one contributed data for the prespecified outcomes. Caffeinated instant coffee (568 women) was compared with decaffeinated instant coffee (629 women) and it was found that reducing the caffeine intake of regular coffee drinkers (3+ cups/day) during the second and third trimester by an average of 182 mg/day did not affect birthweight or length of gestation.

AUTHORS' CONCLUSIONS

There is insufficient evidence to confirm or refute the effectiveness of caffeine avoidance on birthweight or other pregnancy outcomes. There is a need to conduct high-quality, double-blinded RCTs to determine whether caffeine has any effect on pregnancy outcome.

Maternal caffeine intake during pregnancy is associated with birth weight but not with gestational length: results from a large prospective observational cohort study

BACKGROUND

Pregnant women consume caffeine daily. The aim of this study was to examine the association between maternal caffeine intake from different sources and (a) gestational length, particularly the risk for spontaneous preterm delivery (PTD), and (b) birth weight (BW) and the baby being small for gestational age (SGA).

METHODS

This study is based on the Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health. A total of 59,123 women with uncomplicated pregnancies giving birth to a live singleton were identified. Caffeine intake from different sources was self-reported at gestational weeks 17, 22 and 30. Spontaneous PTD was defined as spontaneous onset of delivery between 22+0 and 36+6 weeks (n = 1,451). As there is no consensus, SGA was defined according to ultrasound-based (Marsal, n = 856), population-based (Skjaerven, n = 4,503) and customized (Gardosi, n = 4,733) growth curves.

RESULTS

The main caffeine source was coffee, but tea and chocolate were the main sources in women with low caffeine intake. Median pre-pregnancy caffeine intake was 126 mg/day (IQR 40 to 254), 44 mg/day (13 to 104) at gestational week 17 and 62 mg/day (21 to 130) at gestational week 30. Coffee caffeine, but not caffeine from other sources, was associated with prolonged gestation (8 h/100 mg/day, P <10-7). Neither total nor coffee caffeine was associated with spontaneous PTD risk. Caffeine intake from different sources, measured repeatedly during pregnancy, was associated with lower BW (Marsal-28 g, Skjaerven-25 g, Gardosi-21 g per 100 mg/day additional total caffeine for a baby with expected BW 3,600 g, P <10-25). Caffeine intake of 200 to 300 mg/day increased the odds for SGA (OR Marsal 1.62, Skjaerven 1.44, Gardosi 1.27, P <0.05), compared to 0 to 50 mg/day.

CONCLUSIONS

Coffee, but not caffeine, consumption was associated with marginally increased gestational length but not with spontaneous PTD risk. Caffeine intake was consistently associated with decreased BW and increased odds of SGA. The association was strengthened by concordant results for caffeine sources, time of survey and different SGA definitions. This might have clinical implications as even caffeine consumption below the recommended maximum (200 mg/day in the Nordic countries and USA, 300 mg/day according to the World Health Organization (WHO)) was associated with increased risk for SGA.

Caffeine reduces 11β-hydroxysteroid dehydrogenase type 2 expression in human trophoblast cells through the adenosine A(2B) receptor

Maternal caffeine consumption is associated with reduced fetal growth, but the underlying molecular mechanisms are unknown. Since there is evidence that decreased placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) is linked to fetal growth restriction, we hypothesized that caffeine may inhibit fetal growth partly through down regulating placental 11β-HSD2. As a first step in examining this hypothesis, we studied the effects of caffeine on placental 11β-HSD2 activity and expression using our established primary human trophoblast cells as an in vitro model system. Given that maternal serum concentrations of paraxanthine (the primary metabolite of caffeine) were greater in women who gave birth to small-for-gestational age infants than to appropriately grown infants, we also studied the effects of paraxanthine. Our main findings were: (1) both caffeine and paraxanthine decreased placental 11β-HSD2 activity, protein and mRNA in a concentration-dependent manner; (2) this inhibitory effect was mediated by the adenosine A(2B) receptor, since siRNA-mediated knockdown of this receptor prevented caffeine- and paraxanthine-induced inhibition of placental 11β-HSD2; and (3) forskolin (an activator of adenyl cyclase and a known stimulator of 11β-HSD2) abrogated the inhibitory effects of both caffeine and paraxanthine, which provides evidence for a functional link between exposure to caffeine and paraxanthine, decreased intracellular levels of cAMP and reduced placental 11β-HSD2. Taken together, these findings reveal that placental 11β-HSD2 is a novel molecular target through which caffeine may adversely affect fetal growth. They also uncover a previously unappreciated role for the adenosine A(2B) receptor signaling in regulating placental 11β-HSD2, and consequently fetal development.

Regulation of cardiovascular development by adenosine and adenosine-mediated embryo protection

Few signaling molecules have as much potential to influence the developing mammal as the nucleoside adenosine. Adenosine levels increase rapidly with tissue hypoxia and inflammation. Adenosine antagonists include the methylxanthines caffeine and theophylline. The receptors that transduce adenosine action are the A1, A2a, A2b, and A3 adenosine receptors (A1AR, A2aAR, A2bAR, and A3AR). We examined how adenosine acts via A1ARs to influence embryo development. Transgenic mice were studied along with embryo cultures. Embryos lacking A1ARs were markedly growth retarded following intrauterine hypoxia exposure. Studies of mice selectively lacking A1AR in the heart identify the heart as a key site of adenosine's embryo-protective effects. Studies of isolated embryos showed that adenosine plays a key role in modulating embryo cardiac function, especially in the setting of hypoxia. When pregnant mice were treated during embryogenesis with the adenosine antagonist caffeine, adult mice had abnormal heart function. Adenosine acts via A1ARs to play an essential role in protecting the embryo against intrauterine stress, and adenosine antagonists, including caffeine, may be an unwelcome exposure for the embryo.

Maternal caffeine intake and its effect on pregnancy outcomes

OBJECTIVE

Estimation of the maternal caffeine intake during pregnancy and its influence on pregnancy duration, birthweight and Apgar score of the newborn.

STUDY DESIGN

The research was conducted on pregnant women who gave birth at the Clinic of Obstetrics, Gynaecology and Oncology, 2nd Faculty of Medicine, Medical University of Warsaw. It covered unifetal pregnancies without diseases (N=509). Research data were collected by direct questionnaire supplemented with data from patients' records. Statistical analysis employed a multivariate logistic regression model and a non-parametric Spearman's rank correlation coefficient.

RESULTS

98.4% of pregnant women consume no more than 300 mg of caffeine per day. Pregnant women who smoke and older women consume more caffeine than non-smokers and younger women [β 1.95 (95% CI: 1.02-2.88)] and [β 0.68 (95% CI: 0.05-1.3)] respectively. There is no association between maternal caffeine intake during pregnancy and the risk of premature birth, the birthweight or the Apgar score of newborns.

CONCLUSION

Caffeine intake of no more than 300 mg per day during pregnancy does not affect pregnancy duration and the condition of the newborn.

Cord blood metabolomic profiling in intrauterine growth restriction

A number of metabolic abnormalities have been observed in pregnancies complicated by intrauterine growth restriction (IUGR). Metabolic fingerprinting and clinical metabolomics have recently been proposed as tools to investigate individual phenotypes beyond genomes and proteomes and to advance hypotheses on the genesis of diseases. Non-targeted metabolomic profiling was employed to study fetal and/or placental metabolism alterations in IUGR fetuses by liquid chromatography high-resolution mass spectrometry (LC-HRMS) analysis of cord blood collected soon after birth. Samples were collected from 22 IUGR and 21 appropriate for gestational age (AGA) fetuses. Birth weight differed significantly between IUGR and AGA fetuses (p < 0.001). Serum samples were immediately obtained and deproteinized by mixing with methanol at room temperature and centrifugation; supernatants were lyophilized and reconstituted in water for analysis. LC-HRMS analyses were performed on an Orbitrap mass spectrometer linked to a Surveyor Plus LC. Samples were injected into a 1.0 × 150-mm Luna C18 column. Spectra were collected in full-scan mode at a resolution of approximately 30,000. Data were acquired over the m/z range of 50-1,000, with measurements performed in duplicate. To observe metabolic variations between the two sets of samples, LC-HRMS data were analyzed by a principal component analysis model. Many features (e.g., ionic species with specific retention times) differed between the two classes of samples: among these, the essential amino acids phenylalanine, tryptophan, and methionine were identified by comparison with available databases. Logistic regression coupled to a receiver-operating characteristic curve identified a cut-off value for phenylalanine and tryptophan, which gave excellent discrimination between IUGR and AGA fetuses. Non-targeted LC-HRMS analysis of cord blood collected at birth allowed the identification of significant differences in relative abundances of essential amino acids between IUGR and AGA fetuses, emerging as a promising tool for studying metabolic alterations.

Caffeine and insulin resistance in pregnancy

Outside pregnancy, acute caffeine consumption is associated with insulin resistance. We investigated if during pregnancy plasma concentrations of caffeine and its metabolite, paraxanthine, were associated with insulin resistance. Caffeine, paraxanthine, glucose, and insulin were measured and insulin resistance estimated by homeostasis model assessment (HOMA) in banked samples from 251 fasting subjects at mean gestational age of 20.3 ± 2.0 weeks. Analysis of covariance and adjusted logistic regression were performed. Most (96.4%) women had caffeine and/or paraxanthine present. Caffeine concentrations in the upper two quartiles (>266 ng/mL) were associated with threefold higher odds of having higher insulin resistance estimated by log HOMA ≥75th percentile (third quartile odds ratio [OR], 3.02; 95% confidence interval [CI]: 1.21 to 7.54 and fourth quartile OR, 2.95; 95% CI: 1.19 to 7.31). Paraxanthine concentrations in the upper quartile (>392 ng/mL) were also associated with threefold higher odds of having higher insulin resistance (OR, 3.04; 95% CI: 1.28 to 7.25). Adjusted mean HOMA in the first caffeine-to-paraxanthine ratio quartile was 1.5 ± 2.2 versus 1.3 ± 2.3 in the fourth quartile ( P < 0.01). Both high caffeine and paraxanthine concentrations were associated with insulin resistance, but slow versus fast metabolism did not make an important difference.

A non-invasive method based on saliva to characterize transthyretin in familial amyloidotic polyneuropathy patients using FT-ICR high-resolution MS

PURPOSE

To identify, characterize and perform a relative quantification of human transthyretin (TTR) variants in human saliva.

EXPERIMENTAL DESIGN

Serum and saliva samples were collected from healthy and familial amyloidotic polyneuropathy (FAP) patients, proteins separated by SDS-PAGE, TTR bands excised, in-gel digested and analyzed by MALDI-FTICR.

RESULTS

We identified and performed a relative quantification of mutated and native TTR forms in human saliva, based on FTICR-MS. The results are quantitatively identical to the ones obtained with human serum. In FAP patients subjected to cadaveric liver transplant, the TTR mutant form is no longer detected in saliva, while in patients receiving a domino liver from a FAP donor the mutant form of TTR becomes detectable in saliva, thus demonstrating the serum origin of TTR in saliva.

CONCLUSIONS AND CLINICAL RELEVANCE

Saliva TTR originates in serum and the ratio of mutant to native TTR is preserved. The method provides a non-invasive detection of mutated TTR and a relative quantification of TTR forms. Diagnostic and disease prognosis of FAP is crucial at early stages of the disease and after liver transplantation, the only curative therapy. A suitable non-invasive method was developed for monitoring the most important FAP biomarker in human saliva.

Disposition kinetics of caffeine and paraxanthine in Nile tilapia (Oreochromis niloticus): characterization of the main metabolites

The reproductive and developmental toxicities of caffeine (CA) reported in mammals have been linked with the characteristics of its kinetic disposition. Because undesirable reproductive effects in fish have also been reported, and considering that CA has been found worldwide at relatively high concentrations in most bodies of waters, this study evaluated the disposition kinetics of CA and its main metabolite paraxanthine (1,7-dimethylxanthine; PX) in Nile tilapia after a single intraperitoneal administration (4 mg/kg). CA showed rapid absorption, first-order elimination with biexponential decay, rapid intercompartmental transfer, wide distribution in almost the entire body water (apparent volume of distribution [Vd(ss)] 0.45 l/kg), terminal elimination half-life (t(1/2) (β)) 4.08 h, and systemic clearance (Cl) 0.75 ml/min/kg; there were no important differences between parameters determined in plasma or in other organs (liver and gills). PX was rapidly formed in liver, showing saturable-kinetic properties in this organ, with V(max) 8.11 μg/g h and K(m) 12.58 μg/g. The terminal elimination linear process was similar between matrices, with a half-life (t(1/2 el)) 2.12 h, Vd(ss) 0.35 l/kg, and Cl 1.24 ml/min/kg. CA in tilapia was extensively metabolized to 1-methyl-uric acid and 1-methyl-xanthine in all of the organs studied. Metabolic and kinetic patterns were comparable with those reported for mammals. The observation of a concentration-dependent kinetic of PX is an important finding. Thus, toxicities of CA in fish would appear to be similar to those in mammals and should be considered in the risk assessments for this species, especially during the early stages of development.

Adverse and protective influences of adenosine on the newborn and embryo: implications for preterm white matter injury and embryo protection

Few signaling molecules have the potential to influence the developing mammal as the nucleoside adenosine. Adenosine levels increase rapidly with tissue hypoxia and inflammation. Adenosine antagonists include the methylxanthines caffeine and theophylline. The receptors that transduce adenosine action are the A1, A2a, A2b, and A3 adenosine receptors (ARs). In the postnatal period, A1AR activation may contribute to white matter injury in the preterm infant by altering oligodendrocyte (OL) development. In models of perinatal brain injury, caffeine is neuroprotective against periventricular white matter injury (PWMI) and hypoxic-ischemic encephalopathy (HIE). Supporting the notion that blockade of adenosine action is of benefit in the premature infant, caffeine reduces the incidence of bronchopulmonary dysplasia and CP in clinical studies. In comparison with the adverse effects on the postnatal brain, adenosine acts via A1ARs to play an essential role in protecting the embryo from hypoxia. Embryo protective effects are blocked by caffeine, and caffeine intake during early pregnancy increases the risk of miscarriage and fetal growth retardation. Adenosine and adenosine antagonists play important modulatory roles during mammalian development. The protective and deleterious effects of adenosine depend on the time of exposure and target sites of action.

Evaluation of the reproductive and developmental risks of caffeine

A risk analysis of in utero caffeine exposure is presented utilizing epidemiological studies and animal studies dealing with congenital malformation, pregnancy loss, and weight reduction. These effects are of interest to teratologists, because animal studies are useful in their evaluation. Many of the epidemiology studies did not evaluate the impact of the "pregnancy signal," which identifies healthy pregnancies and permits investigators to identify subjects with low pregnancy risks. The spontaneous abortion epidemiology studies were inconsistent and the majority did not consider the confounding introduced by not considering the pregnancy signal. The animal studies do not support the concept that caffeine is an abortafacient for the wide range of human caffeine exposures. Almost all the congenital malformation epidemiology studies were negative. Animal pharmacokinetic studies indicate that the teratogenic plasma level of caffeine has to reach or exceed 60 µg/ml, which is not attainable from ingesting large amounts of caffeine in foods and beverages. No epidemiological study described the "caffeine teratogenic syndrome." Six of the 17 recent epidemiology studies dealing with the risk of caffeine and fetal weight reduction were negative. Seven of the positive studies had growth reductions that were clinically insignificant and none of the studies cited the animal literature. Analysis of caffeine's reproductive toxicity considers reproducibility and plausibility of clinical, epidemiological, and animal data. Moderate or even high amounts of beverages and foods containing caffeine do not increase the risks of congenital malformations, miscarriage or growth retardation. Pharmacokinetic studies markedly improve the ability to perform the risk analyses.

Correlation between serum caffeine levels and changes in cytokine profile in a cohort of preterm infants

OBJECTIVE

To determine changes in cytokine levels associated with caffeine treatment in a cohort of preterm infants.

STUDY DESIGN

For this observational prospective study, we collected clinical data from 26 preterm infants (≤ 30 weeks gestational age). In addition to caffeine levels, cytokine profiles in peripheral blood (PB) and tracheal aspirates (TA) were determined with enzyme-linked immunosorbent assay at birth, before and after (at 24 hours and 1 week) initiation of caffeine. Non-parametric statistics were applied.

RESULTS

Included infants were 26.9 ± 1.7 weeks gestational age and weighed 985 ± 202 g. At birth, all cytokine concentrations were significantly greater in TA than PB. Serum caffeine levels were 11.1 μg/mL (interquartile range, 1.85) at approximately 24 hours post-load and 16.4 (8.7) μg/mL at 1 week on treatment. At approximately 24 hours post-load, interleukin (IL)-10 levels decreased by 47.5% (P = .01) in PB and 38.5% (P = .03) in TA, whereas other cytokine levels remained unchanged. At 1 week, caffeine levels were correlated (U-shaped) with changes in proinflammatory tumor necrosis factor-α (R(2) = 0.65; P = .0008), interleukin (IL)-1β (R(2) = 0.73; P = .0007), and IL-6 (R(2) = 0.59; P = .003), whereas inversely correlated (linear) with the anti-inflammatory IL-10 (R(2) = 0.64; P = .0008). Altogether, caffeine, at serum levels ≥ 20 μg/mL, was associated with a proinflammatory profile after 1 week of treatment.

CONCLUSIONS

Caffeine treatment for apnea of prematurity correlates with changes in cytokine profile. Caffeine levels ≥ 20 μg/mL are associated with a proinflammatory profile in our cohort of preterm infants.

Caffeine, selected metabolic gene variants, and risk for neural tube defects

BACKGROUND

Investigations of maternal caffeine intake and neural tube defects (NTDs) have not considered genetic influences. Caffeine metabolism gene effects were examined in the National Birth Defects Prevention Study.

METHODS

Average daily caffeine was summed from self-reported coffee, tea, soda, and chocolate intake for mothers of 768 NTD cases, and 4143 controls delivered from 1997 to 2002. A subset of 306 NTD and 669 control infants and their parents were genotyped for CYP1A2*1F, NAT2 481C>T, and NAT2 590G>A. CYP1A2*1F was classified by fast or slow oxidation status, and NAT2 variants were categorized into rapid or slow acetylation status. Case-control logistic regression analyses, family-based transmission/disequilibrium tests and log-linear analyses, and hybrid log-linear analyses were conducted to produce odds ratios (ORs) or relative risks (RRs) and 95% confidence intervals (CIs) for caffeine intake and maternal and infant gene variants, and to examine interaction effects.

RESULTS

NTDs were independently associated with infant slow NAT2 acetylator status (RR, 2.00; 95% CI, 1.10-3.64) and maternal CYP1A2*1F fast oxidation status (OR, 1.49; 95% CI, 1.10-2.03). Mothers who consumed caffeine, oxidized CYP1A2*1F quickly, and acetylized NAT2 slowly had a nonsignificantly elevated estimated risk for an NTD-affected pregnancy (OR, 3.10; 95% CI, 0.86-11.21). Multiplicative interaction effects were observed between maternal caffeine and infant CYP1A2*1F fast oxidizer status (p(interaction) = 0.03).

CONCLUSIONS

The association identified between maternal CYP1A2*1F fast oxidation status and NTDs should be examined further in the context of the other substrates of CYP1A2. Maternal caffeine and its metabolites may be associated with increased risk for NTD-affected pregnancies in genetically susceptible subgroups.

A review of the epidemiologic evidence concerning the reproductive health effects of caffeine consumption: a 2000-2009 update

This review of human studies of caffeine and reproductive health published between January 2000 and December 2009 serves to update the comprehensive review published by Leviton and Cowan (2002). The adverse reproductive outcomes addressed in this review include: (1) measures of subfecundity; (2) spontaneous abortion; (3) fetal death; (4) preterm birth; (5) congenital malformations; and (6) fetal growth restriction. Methodologic challenges and considerations relevant to investigations of each reproductive endpoint are summarized, followed by a brief critical review of each study. The evidence for an effect of caffeine on reproductive health and fetal development is limited by the inability to rule out plausible alternative explanations for the observed associations, namely confounding by pregnancy symptoms and smoking, and by exposure measurement error. Because of these limitations, the weight of evidence does not support a positive relationship between caffeine consumption and adverse reproductive or perinatal outcomes.

Effects of restricted caffeine intake by mother on fetal, neonatal and pregnancy outcome

BACKGROUND

Maternal caffeine consumption during pregnancy may have adverse effects on fetal, neonatal and maternal outcomes.

OBJECTIVES

This review investigates the effects of restricting caffeine intake by mothers on fetal, neonatal and pregnancy outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2008), scanned bibliographies of published studies and corresponded with investigators.

SELECTION CRITERIA

Randomised controlled trials including quasi-randomised controlled trials (RCTs) investigating the effect of caffeine and/or supplementary caffeine versus restricted caffeine intake or placebo on pregnancy outcome.

DATA COLLECTION AND ANALYSIS

The two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

One study met the inclusion criteria. Caffeinated instant coffee (568 women) was compared with decaffeinated instant coffee (629 women) and it was found that reducing the caffeine intake of regular coffee drinkers (3+ cups/day) during the second and third trimester by an average of 182 mg/day did not affect birthweight or length of gestation.

AUTHORS' CONCLUSIONS

There is insufficient evidence to confirm or refute the effectiveness of caffeine avoidance on birthweight or other pregnancy outcomes. There is a need to conduct high-quality, double-blinded RCTs to determine whether caffeine has any effect on pregnancy outcome.

Maternal caffeine intake during pregnancy and risk of fetal growth restriction: a large prospective observational study

OBJECTIVE

To examine the association of maternal caffeine intake with fetal growth restriction.

DESIGN

Prospective longitudinal observational study.

SETTING

Two large UK hospital maternity units.

PARTICIPANTS

2635 low risk pregnant women recruited between 8-12 weeks of pregnancy. Investigations Quantification of total caffeine intake from 4 weeks before conception and throughout pregnancy was undertaken with a validated caffeine assessment tool. Caffeine half life (proxy for clearance) was determined by measuring caffeine in saliva after a caffeine challenge. Smoking and alcohol were assessed by self reported status and by measuring salivary cotinine concentrations.

MAIN OUTCOME MEASURES

Fetal growth restriction, as defined by customised birth weight centile, adjusted for alcohol intake and salivary cotinine concentrations.

RESULTS

Caffeine consumption throughout pregnancy was associated with an increased risk of fetal growth restriction (odds ratios 1.2 (95% CI 0.9 to 1.6) for 100-199 mg/day, 1.5 (1.1 to 2.1) for 200-299 mg/day, and 1.4 (1.0 to 2.0) for >300 mg/day compared with <100 mg/day; test for trend P<0.001). Mean caffeine consumption decreased in the first trimester and increased in the third. The association between caffeine and fetal growth restriction was stronger in women with a faster compared to a slower caffeine clearance (test for interaction, P=0.06).

CONCLUSIONS

Caffeine consumption during pregnancy was associated with an increased risk of fetal growth restriction and this association continued throughout pregnancy. Sensible advice would be to reduce caffeine intake before conception and throughout pregnancy.

Variation in CYP1A2 activity and its clinical implications: influence of environmental factors and genetic polymorphisms

CYP1A2 is involved in the metabolism of several widely used drugs and endogenous compounds, and in the activation of procarcinogens. Both genetic and environmental factors influence the activity of this enzyme. The current knowledge regarding factors influencing the activity of CYP1A2 is summarized in this review. Substrates, inhibitors and inducers of CYP1A2 activity, as well as phenotyping probes, are discussed. The functional significance and clinical importance of CYP1A2 gene polymorphisms are reviewed and interethnic differences in the distribution of CYP1A2 variant alleles and haplotypes are summarized. Finally, future perspectives for the possible clinical applications of CYP1A2 genotyping are discussed.

Chocolate consumption in pregnancy and reduced likelihood of preeclampsia

BACKGROUND

Preeclampsia is a major pregnancy complication with cardiovascular manifestations. Recent studies suggest that chocolate consumption may benefit cardiovascular health.

METHODS

We studied the association of chocolate consumption with risk of preeclampsia in a prospective cohort study of 2291 pregnant women who delivered a singleton livebirth between September 1996 and January 2000. Chocolate consumption was measured by self report in the first and third trimesters, and by umbilical cord serum concentrations of theobromine, the major methylxanthine component of chocolate. Preeclampsia was assessed by detailed medical record review for 1943 of the women. We derived adjusted odds ratios (aOR) and 95% confidence intervals (CIs) from logistic regression models controlling for potential confounders.

RESULTS

Preeclampsia developed in 3.7% (n = 63) of 1681 women. Cord serum theobromine concentrations were negatively associated with preeclampsia (aOR = 0.31; CI = 0.11-0.87 for highest compared with lowest quartile). Self-reported chocolate consumption estimates also were inversely associated with preeclampsia. Compared with women consuming under 1 serving of chocolate weekly, women consuming 5+ servings per week had decreased risk: aOR = 0.81 with consumption in the first 3 months of pregnancy (CI = 0.37-1.79) and 0.60 in the last 3 months (0.30-1.24).

CONCLUSIONS

Our results suggest that chocolate consumption during pregnancy may lower risk of preeclampsia. However, reverse causality may also contribute to these findings.

Modest maternal caffeine exposure affects developing embryonic cardiovascular function and growth

Caffeine consumption during pregnancy is reported to increase the risk of in utero growth restriction and spontaneous abortion. In the present study, we tested the hypothesis that modest maternal caffeine exposure affects in utero developing embryonic cardiovascular (CV) function and growth without altering maternal hemodynamics. Caffeine (10 mg.kg(-1).day(-1) subcutaneous) was administered daily to pregnant CD-1 mice from embryonic days (EDs) 9.5 to 18.5 of a 21-day gestation. We assessed maternal and embryonic CV function at baseline and at peak maternal serum caffeine concentration using high-resolution echocardiography on EDs 9.5, 11.5, 13.5, and 18.5. Maternal caffeine exposure did not influence maternal body weight gain, maternal CV function, or embryo resorption. However, crown-rump length and body weight were reduced in maternal caffeine treated embryos by ED 18.5 (P < 0.05). At peak maternal serum caffeine concentration, embryonic carotid artery, dorsal aorta, and umbilical artery flows transiently decreased from baseline at ED 11.5 (P < 0.05). By ED 13.5, embryonic aortic and umbilical artery flows were insensitive to the peak maternal caffeine concentration; however, the carotid artery flow remained affected. By ED 18.5, baseline embryonic carotid artery flow increased and descending aortic flow decreased versus non-caffeine-exposed embryos. Maternal treatment with the adenosine A(2A) receptor inhibitor reproduced the embryonic hemodynamic effects of maternal caffeine exposure. Adenosine A(2A) receptor gene expression levels of ED 11.5 embryo and ED 18.5 uterus were decreased. Results suggest that modest maternal caffeine exposure has adverse effects on developing embryonic CV function and growth, possibly mediated via adenosine A(2A) receptor blockade.

Placental passage of benzoic acid, caffeine, and glyphosate in an ex vivo human perfusion system

Ex vivo perfusion of the human term placenta is a method to study placental transfer without extrapolation from animal to human and with no ethical concerns for mother and child. However, ex vivo placenta perfusion has a limited potential within chemical screening and testing as the method is time-consuming. This study was an attempt to construct data needed to develop quantitative structure-activity relationship (QSAR) models that are able to predict placental transfer of new compounds. Placental transfer is a biological activity that statistically may be related to the physiochemical properties of a given group of compounds. Benzoic acid, caffeine, and glyphosate were chosen as model compounds because they are small molecules with large differences in physiochemical properties. Caffeine crossed the placenta by passive diffusion. The initial transfer rate of benzoic acid was more limited in the first part of the perfusion compared to caffeine, but reached the same steady-state level by the end of perfusion. The transfer of glyphosate was restricted throughout perfusion, with a lower permeation rate, and only around 15% glyphosate in maternal circulation crossed to the fetal circulation during the study period.

Maternal caffeine administration and cerebral oxygenation in near-term fetal sheep

The authors test the null hypothesis that maternal caffeine administration will not significantly alter fetal cerebral oxygenation. The authors measured fetal arterial blood gases, cortical tissue O(2) tension (tPO(2)), sagittal sinus blood gases, and laser Doppler cerebral blood flow in response to a 30-minute caffeine infusion (400 mg intravenously) into 7 near-term pregnant ewes, and they calculated fractional O(2) extraction and relative cerebral metabolic rate for O(2) (CMRO(2)). Following maternal caffeine infusion, both fetal cortical tPO(2) and sagittal sinus (HbO(2)) decreased significantly, from 10.7 +/- 0.9 to 6.8 +/- 1.1 Torr and from 46% +/- 2% to 37% +/- 6%, respectively. This was associated with significant 20% to 30% increases in fractional O(2) extraction and CMRO( 2). Fetal arterial blood gas values did not change significantly. In conclusion, maternal caffeine administration significantly decreases cerebral oxygenation without affecting systemic oxygenation in fetal sheep. The authors speculate that for a fetus that may be otherwise compromised, this increase in CMRO(2) with decreased cortical tPO(2) could present a problem.

Parental characteristics as predictors of birthweight

BACKGROUND

Previous studies provided conflicting results on the relevance of parental characteristics for offspring's size at birth. The objective of this study was to investigate parental predictors of birthweight.

METHODS

In this cross-sectional study, 34,063 women in the Nurses' Mother's Cohort were queried about parental characteristics during the pregnancy with and birthweight of their nurse daughter.

RESULTS

The predictive linear regression model of birthweight included 13 factors and the majority of the predictive power came from parental anthropometric factors. In the adjusted analysis, daily consumption of each additional glass of milk was associated with an increase of approximately 6 g in birthweight (P for trend = 0.01) and daily consumption of each additional cup of coffee was associated with a decrease of approximately 10 g in birthweight (P for trend < 0.0001). Drinking 1-2, 3-4 and 5+ cups of coffee daily was associated with a 28% [95% confidence interval (CI) 0.12, 0.47], 30% (95% CI 0.10, 0.55) and 63% (95% CI 0.25, 1.12) increase, respectively, in the odds of intrauterine growth restriction when compared with non-drinkers.

CONCLUSIONS

The present study confirmed several previously reported determinants of birthweight. Maternal dietary intake of milk and coffee during pregnancy may influence fetal growth.

Effect of reducing caffeine intake on birth weight and length of gestation: randomised controlled trial

OBJECTIVE

To estimate the effect of reducing caffeine intake during pregnancy on birth weight and length of gestation.

DESIGN

Randomised double blind controlled trial.

SETTING

Denmark.

PARTICIPANTS

1207 pregnant women drinking at least three cups of coffee a day, recruited before 20 weeks' gestation.

INTERVENTIONS

Caffeinated instant coffee (568 women) or decaffeinated instant coffee (629 women).

MAIN OUTCOME MEASURES

Birth weight and length of gestation.

RESULTS

Data on birth weight were obtained for 1150 liveborn singletons and on length of gestation for 1153 liveborn singletons. No significant differences were found for mean birth weight or mean length of gestation between women in the decaffeinated coffee group (whose mean caffeine intake was 182 mg lower than that of the other group) and women in the caffeinated coffee group. After adjustment for length of gestation, parity, prepregnancy body mass index, and smoking at entry to the study the mean birth weight of babies born to women in the decaffeinated group was 16 g (95% confidence interval -40 to 73) higher than those born to women in the caffeinated group. The adjusted difference (decaffeinated group-caffeinated group) of length of gestation was -1.31 days (-2.87 to 0.25).

CONCLUSION

A moderate reduction in caffeine intake in the second half of pregnancy has no effect on birth weight or length of gestation.

TRIAL REGISTRATION

Clinical Trials NCT00131690 [ClinicalTrials.gov].