Is Coffee Good for Your Liver? Quitting Caffeine the Headache-Free Way. Trending Topics. What Parents Need to Know. Our expert discusses the evidence. Share this article via email with one or more people using the form below. In , a Scandinavian expert committee concluded that high caffeine intake may harm the fetus [ 5 ]. Human studies on adverse effects of caffeine have investigated spontaneous abortion, preterm delivery PTD , fetal death, congenital malformations and fetal growth restriction, with conflicting results for all outcomes [ 12 — 23 ].
PTD and small for gestational age SGA at birth are the pregnancy outcomes accounting for most of all neonatal mortality, as well as short-term and long-term morbidity [ 24 — 27 ]. Despite these prevalences, the complexity makes it difficult to measure the effect of a single environmental factor, except in large studies.
While some studies have found a higher risk for PTD [ 29 ] or early PTD [ 30 ] with increasing caffeine intake, most studies on caffeine intake have found no significant association with gestational length as summarized in the meta-analysis by Maslova et al.
Although PTD is a heterogeneous pregnancy outcome with different etiologies for example, for early versus late PTD or for iatrogenic versus spontaneous PTD [ 32 ] it has mostly been studied as one entity, which may obscure associations with subtypes of PTD. Approximately half of all studies report an adverse effect of caffeine intake on BW, while others have not found any significant associations.
Comparability among these studies is problematic due to the use of different standard growth curves or to incomplete or inaccurate assessment of caffeine exposure [ 5 , 20 ]. Peck et al. As mentioned above, there are methodological challenges in the assessment of caffeine intake, both from coffee and other sources. This also applies to preparation and processing, which may change the caffeine content of a beverage considerably.
Pregnancy is a time of rapid development and differentiation, therefore there might be a certain time window for a caffeine effect; repeated measurements during pregnancy may thus be desirable [ 20 ]. In summary, caffeine is consumed daily by many pregnant women, spontaneous PTD and SGA incur high medical and economic costs and studies on associations between caffeine and pregnancy outcomes are contradictory due to a number of challenges in study design.
With detailed reporting of caffeine intake from various sources and different coffee preparations, assessed at three different timepoints during pregnancy, as well as comprehensive information on lifestyle habits, health and socioeconomic status, MoBa provides a unique chance to study the association between caffeine intake and pregnancy outcomes. By taking caffeine intake from different sources into account, it might be possible to separate caffeine effects from other effects related to the respective sources.
The aim of the present study therefore was to examine the association between maternal caffeine intake from different sources and a gestational length, particularly the risk for spontaneous PTD with a subanalysis of early and late spontaneous PTD, and b BW and the risk for SGA.
The dataset is part of the MoBa cohort, initiated by and maintained at the Norwegian Institute of Public Health [ 28 ]. In brief, MoBa is a nationwide pregnancy cohort, including more than , pregnancies during the period to Women were recruited by postal invitation in connection with the routine ultrasound examination offered to all pregnant women in Norway at around 17 gestational weeks. Overall, Participants were asked to fill in questionnaires focused on general health status, lifestyle behavior and diet at gestational weeks 15 to 17 Q1 and 30 Q3.
At gestational week 22, they completed a food frequency questionnaire FFQ. All questionnaires are available on the Norwegian Institute of Public Health homepage [ 33 ]. This study used data from version 5 of the quality-assured data files made available for research in Informed written consent was obtained from each participant.
Of the , pregnancies included in MoBa version 5, , women gave birth to live-born singletons; 81, of these women had answered all three questionnaires. After exclusion of the following medical and pregnancy-related conditions 70, pregnancies remained in the study: diabetes mellitus, hypertension, autoimmune disease, inflammatory bowel disease, systemic lupus erythematosus, rheumatoid arthritis, scleroderma, other immune-compromised conditions, in vitro fertilization, pre-eclampsia, hypertension, gestational diabetes, placental abruption, placenta previa, cervical cerclage and serious fetal malformations.
If a woman participated with more than one pregnancy, only the first pregnancy was included, leaving 60, Finally, 59, women had complete data on pre-pregnancy weight and height.
Gestational age in days was determined by second-trimester ultrasound in The expected effect of caffeine on gestational length is minor; results are thus presented in hours instead of days. As there is still no consensus on standard growth curves, data were analyzed according to three standards based on Northern European populations: ultrasound-based growth curves according to Marsal [ 36 ], population-based growth curves according to Skjaerven [ 37 ] and customized growth curves according to Gardosi [ 38 ].
This implicates that gestational length is taken into account by the definition of our outcome variable and analysis were not adjusted for gestational age.
Percentage was used instead of the difference in g, as a slight weight difference matters much more if the expected BW for a preterm infant is very low compared with a normal-weight infant born at term. While the original outcome of the linear regression thus was a percentage of the expected BW, we chose to present the results in g for babies with an expected BW of 3, g, the rounded-out median BW in our study population actual median: 3, g.
Standard deviation and percentiles used are based on the reference population in these publications, not on our study population, which is a highly selected subpopulation of the MoBa population, as described above. The MoBa FFQ is a semiquantitative questionnaire designed to record dietary habits and intake of dietary supplements during the first four to five months of pregnancy.
Women reported their beverage consumption in cups per day, week or month. One cup was defined as ml. In the case of black tea, one cup was defined as ml.
One glass of sugar-sweetened or diet cola, energy drink or chocolate milk was defined as ml. Other caffeine sources reported were sandwich spread, desserts, cakes and sweets containing cocoa [ 33 ]. Caffeine and nutrient calculations were performed using FoodCalc [ 39 ] and the Norwegian Food Composition Table [ 40 ]. For the purpose of this analysis, we compiled a caffeine database presenting the caffeine concentration in the main food and beverage items, depending on manner of preparation in the case of coffee, contributing to caffeine intake in the Norwegian diet Table 1.
Information about caffeine concentrations in coffee, tea and cocoa was obtained from published reports [ 5 , 41 ]. Caffeine concentration in soft and energy drinks was based on both figures from published reports [ 41 ] and the brewing industry.
Coffee houses offered information on the content of coffee in different coffee drinks. The amount of caffeine in cocoa containing food items like chocolate was calculated based on data provided by the chocolate and food industry. The validation study showed that the MoBa FFQ is a valid instrument for assessing habitual diet during the first four to five months of pregnancy. No participants in the validation study had intake of caffeine from soft drinks. Food items like soft drinks, chocolate and sweets are more likely to be misreported than most other food items.
These data allowed following a participant's caffeine consumption from the three main caffeine sources from the time before pregnancy until gestational week All analyses were based on the more detailed FFQ caffeine intake data, except when the association between caffeine intake and pregnancy outcomes at different timepoints was studied using Q1 and Q3 data.
Information on maternal age at delivery and the baby's sex was available from the MBRN. Women reported smoking habits during pregnancy in Q1 and were categorized as non-smokers, occasional or daily smokers.
Passive smoking and use of other nicotine sources were considered to be dichotomous variables. Persistent nausea at the time of answering the FFQ was used as a dichotomous variable.
Caffeine intake in relation to maternal characteristics was studied with the Kruskal-Wallis test. Associations between caffeine intake and gestational length and BW were studied with linear regression both in an unadjusted model and adjusted for the covariates mentioned above. We visually inspected residual plots to check if model assumptions were reasonably fulfilled. Odds ratios OR for caffeine intake and categorical outcome variables were estimated using logistic regression, both unadjusted and adjusted, as above.
Subanalyses were performed in the subgroups of non-smokers and non-coffee drinkers. Figure 1 shows the distribution of total caffeine intake as registered in the FFQ. Caffeine intake related to maternal characteristics is presented in Table 2 : older, unmarried and smoking women with higher parity, history of PTD, lower pre-pregnancy BMI, less nausea, higher energy intake and higher household income had significantly higher caffeine intake.
Percentage of total caffeine intake per caffeine source. Sources of caffeine intake according to quintiles of total caffeine intake.
A total of 49, women delivered spontaneously with a median gestational length of days IQR to days. Gestational length as well as its residuals were left skewed, but we preferred to use the original data scale for easier interpretation.
However, linear regression with all different caffeine sources included in the same model revealed that only coffee caffeine was significantly associated with gestational length. As we found that coffee is the dominant source of caffeine in high-caffeine consumers, these findings could be explained by a threshold model implying that only coffee drinkers reach the threshold associated with altered gestational length.
To rule out this possibility, we compared the coffee caffeine intake categorized into five groups no intake and for the remaining subjects quartiles 0 to 8. There were 1, cases of spontaneous PTD in the study population early spontaneous PTDs and 1, late spontaneous PTDs , compared to 27, controls, according to our strict inclusion and exclusion criteria.
There was no significant association between total or coffee caffeine intake and the odds for overall, early or late spontaneous PTD Table 4. At all timepoints studied, total and coffee caffeine intake was consistently associated with increased gestational length.
Total caffeine intake, as well as caffeine intake from the individual sources, was associated with lower BW Table 5. The dependent variable in the linear regression was the difference between reported actual BW and expected BW, calculated as percentage of the expected BW.
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Thank you for sharing our content. A message has been sent to your recipient's email address with a link to the content webpage. Caffeine is a natural stimulant consumed throughout the world. This article reviews caffeine and its health effects, both good and bad. An average cup of coffee contains 95 mg of caffeine, but some types contain over mg.
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This article discusses how much caffeine you can safely consume during pregnancy. Share on Pinterest.
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