Dose-dependent associations between prenatal caffeine consumption and small for gestational age, preterm birth, and reduced birthweight in the Japan Environment and Children's Study

Maternal caffeine intake during pregnancy and the risk of delivering a small for gestational age baby: Kuopio Birth Cohort

PURPOSE

High caffeine intake during pregnancy is associated with restricted fetal growth. We aimed to evaluate the association between maternal caffeine intake during early and late pregnancy and the risk of delivering a small for gestational age (SGA) baby.

METHODS

Kuopio Birth Cohort (KuBiCo) is a prospective cohort study including women whose pregnancies and deliveries were treated at the prenatal clinics in outpatient healthcare centers and in Kuopio University Hospital, Finland. Maternal diet and caffeine intake during the first (n = 2007) and third (n = 4362) trimester of pregnancy were assessed using a 160-item food frequency questionnaire (2013-2022). SGA was defined as birth weight corrected for gestational age below  - 2 standard deviations from the mean, according to the sex-specific Finnish fetal growth curves.

RESULTS

Altogether in 32 and 38% (1st and 3rd trimester) of all women and in 44 and 52% of coffee drinkers, caffeine intake exceeded the recommendation for caffeine intake ( ≤ 200 mg/day) during pregnancy. The women with moderate (51-200 mg/day) (aOR 1.87; 95% CI: 1.16-3.02) and high (> 200 mg/day) (aOR 1.51; 95% CI: 1.08-2.10) caffeine intake during the first trimester were in the highest risk of having an SGA newborn. Caffeine intake in the third trimester of pregnancy was not associated with SGA.

CONCLUSIONS

Moderate and high caffeine intake during early pregnancy is associated with SGA. As the results suggest that even moderate caffeine intake during the first trimester may increase the risk of SGA, the intake within recommendation limits does not necessarily appear to be safe for pregnant women and their newborns.

Hokkaido birth cohort study in Japan on the growth trajectory of children born with low birth weight until 7 years of age

BACKGROUND

Low birth weight (LBW) is a significant global health concern with potential health risks and developmental implications for infants. Catch-up growth, an accelerated growth following an inhibition period, may partially compensate for growth deficits in LBW children.

AIMS

This study investigated the prevalence of LBW and catch-up growth in height, weight, and body mass index (BMI) among LBW children in Japan, identified factors associated with LBW, and explored the potential for catch-up growth at different ages up to seven years.

STUDY DESIGN AND SUBJECTS

The Hokkaido birth cohort study included 20,926 pregnant Japanese women recruited during their first trimester from 37 hospitals and clinics. Follow-up assessments were conducted in children up to seven years of age, tracking LBW children's growth and development using the Maternal and Child Health Handbook, and providing valuable insights into catch-up growth patterns.

OUTCOME MEASURES

LBW was defined as a neonatal birth weight of <2500 g. The primary outcomes were catch-up growth in height, weight, and BMI at different ages. Z-scores were calculated to assess growth parameters with catch-up growth, defined as a change in z-score (> 0.67) between two time points.

RESULTS AND CONCLUSIONS

A LBW was prevalent in 7.6 % of the cohort, which was lower than that reported in other Japanese studies. Among LBW children, 19.3 % achieved catch-up growth in height by age seven, and 10.6 % in weight. Catch-up growth in LBW children could partially offset these deficits. Further research will help understand the long-term outcomes and inform interventions for healthy development.

Caffeine intake during pregnancy and adverse outcomes: An integrative review

Caffeine intake during pregnancy is common. Caffeine crosses the placenta, raising concerns about its possible deleterious effects on the developing embryo/fetus. Studies on this subject show conflicting results, and still there is no consensus on the recommended dose of caffeine during pregnancy. We performed an integrative review with studies from six databases, using broad MESH terms to allow the identification of publications that addressed the outcomes of caffeine use during pregnancy, with no date limit for publications, in English and Portuguese language. The research returned 16,192 articles. After removing duplicates, screening by title, abstract and full-text, we evaluated 257 and included 59 articles. We found association between caffeine intake and pregnancy loss, low birth weight, cardiac and genital anomalies, higher body mass, and neurodevelopmental and neurobehavioral outcomes. The effects were often dose dependent. No association with prematurity has been demonstrated, but one study showed a small reduction in gestational age with increasing doses of caffeine intake. Defining a safe dose for caffeine intake during pregnancy is a challenging task due to the heterogeneity in study designs and results, as well as the difficulty of reliably assessing the amount of caffeine consumed. In some studies, exposures below the recommended level of caffeine intake during pregnancy (200 mg/day), as suggested by the guidelines, were associated with pregnancy loss, low birth weight, cardiac and genital anomalies, higher body mass, and neurodevelopmental and neurobehavioral outcomes. Well-designed studies with reliable quantification of caffeine intake are needed to assess the safety of low doses during pregnancy.

Fish intake in pregnant women and its impact on maternal-fetal health status

OBJECTIVE

The objective was to evaluate the consumption of fish in pregnant women and its association with maternal and infant outcomes.

MATERIAL AND METHODS

In this observational study carried out at the La Fe University and Polytechnic Hospital in Valencia, 300 pregnant women participated. The participants were divided into 2 groups according to their fish consumption during pregnancy for comparison. The χ2 test or ANOVA test were applied for comparisons for qualitative and quantitative variables respectively.

RESULTS

It was observed that 49% of women consumed adequate amounts of fish during pregnancy (2 or 3 weekly servings). Significant differences were observed for iron supplementation (higher in women with inadequate fish consumption), threatened pregnancy loss (higher in women with inadequate fish consumption), infant size (better in women with adequate fish consumption), and arterial O2 pressure (better in women with adequate fish consumption). In regard to the other components of the dietary pattern, no differences were observed but the adequacy of intake for grains and white meat was very poor (less than 5.0%).

CONCLUSIONS

Half of the women met the recommendations for fish intake during pregnancy and presented an overall healthier eating pattern but without statistical significance.

Relationship between caffeine intake and small for gestational age and preterm birth: a dose-response meta-analysis

Our meta-analysis aimed to determine the dose-response relationship between caffeine intake and risk of small for gestational age (SGA) and preterm birth (PB). A systematic search of PubMed, Web of science and Scopus was done from inception to January 2023 using relevant keywords. All case-control and cohort studies reported in English were included if the exposure of interest was caffeine intake during pregnancy, the outcome of interest was spontaneous SGA and PB, and multivariable-adjusted odds ratios (ORs) or risk ratios were provided or could be calculated. In all, 22 studies (15 cohort studies and seven case-control studies) were included in this review. Examining the association of caffeine intake with risk of PB, no significant relationship was found (Pooled ES: 1.04; 95% CI: 0.95 to 1.14, P = 0.019). Findings from this meta-analysis demonstrated that caffeine intake had a significantly higher risk of SGA respectively (Pooled ES: 1.28; 95% CI: 1.16 to 1.41, P < 0.001). A dose-response analysis proposed that an increase of 100 mg caffeine per day was associated with a 13% greater risk of SGA. This study confirmed that caffeine intake raises the risk of SGA. However, the risk of PB was not found to be reliably associated with maternal caffeine consumption.

Population attributable fraction of risk factors for low birth weight in the Japan Environment and Children's Study

BACKGROUND

Low birth weight (LBW), which is considered a birth weight of <2500  g, poses significant health problems for children. However, population attributable fraction (PAF) of risk factors for LBW have not been well studied.

OBJECTIVE

We aimed to re-evaluate associations between risk factors for LBW reported in previous studies that used the Japan Environment and Children's Study (JECS) data, and to estimate the magnitude of risk using PAF.

METHODS

Data including 91,559 mother-child dyads were obtained from JECS. Risk factors identified by previous studies that used JECS data were used to calculate odds ratios for LBW using a Bayesian logistic regression model. Based on calculated odds ratios, the PAF was calculated.

RESULTS

Parity, history of adenomyosis, hypertension disorder of pregnancy, maternal age at birth, prepregnancy body mass index, gestational weight gain (GWG), maternal smoking and lead (Pb) exposure were all significantly associated with LBW. The sum of the PAF of all factors was 79.4 %, with the largest PAF among single risk factors being GWG (16.5 %); the environmental portion of the PAF (Pb exposure, 14.6 % + maternal smoking, 12.1 %) surpassed the PAF of GWG.

CONCLUSION

Our findings suggest that the number of births classified as LBW can be reduced by approximately 27% if Pb exposure is reduced to the lowest quartile and maternal smoking is eliminated. Further investigations are needed to identify unknown risk factors for LBW.

Impact of prenatal exposure to mercury and selenium on neurodevelopmental delay in children in the Japan environment and Children's study using the ASQ-3 questionnaire: A prospective birth cohort

Neurodevelopmental delay is associated with neurodevelopmental disorders. Prenatal metal exposure can potentially cause neurodevelopmental delays in children. This study examines whether prenatal exposure to mercury (Hg) and selenium (Se) is associated with the risk of neurodevelopmental delays in children up to 4 years of age. Children enrolled in a prospective birth cohort of the Japan Environment and Children's Study were examined. Hg and Se levels in maternal (nchild = 48,731) and cord (nchild = 3,083) blood were analyzed by inductively coupled plasma-mass spectrometry. Neurodevelopmental delays were assessed in children between the ages of 0.5 to 4 years using the Ages and Stages Questionnaires, Third Edition. The association between exposure and outcomes was examined using the generalized estimation equation models. In maternal blood, compared to participants with Se levels in the first quartile (83.0 to < 156 ng/g), the odds ratio (95 % confidence intervals) for problem-solving ability in children of mothers in the third (168 to < 181 ng/g) and fourth quartiles (181 to 976 ng/g) were 1.08 (1.01 to 1.14) and 1.10 (1.04 to 1.17), respectively. Furthermore, communication, gross and fine motor skills, and problem-solving delays were also observed. However, prenatal Hg levels in maternal and cord blood and Se levels in the latter were not associated with neurodevelopmental delays in children. Thus, the findings of this study suggest an association between Se levels in maternal blood and slightly increased risks of neurodevelopmental delays in children up to the age of 4 years.

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.

Prenatal alcohol exposure and adverse fetal growth restriction: findings from the Japan Environment and Children's Study

BACKGROUNDS

Japanese studies on the association between maternal alcohol consumption and fetal growth are few. This study assessed the effect of maternal alcohol consumption on fetal growth.

METHODS

This prospective birth cohort included 95,761 participants enrolled between January 2011 and March 2014 in the Japan Environment and Children's Study. Adjusted multiple linear and logistic regression models were used to assess the association between prenatal alcohol consumption and infant birth size.

RESULTS

Consumption of a weekly dose of alcohol in the second/third trimester showed a significant negative correlation with standard deviation (SD; Z) scores for body weight, body length, and head circumference at birth, respectively. Consumption of a weekly dose of alcohol during the second/third trimester had a significant positive correlation with incidences of Z-score ≤ -1.5 for birth head circumference. Associations between alcohol consumption in the second/third trimester and Z-score ≤ -1.5 for birth weight or birth length were not significant. Maternal alcohol consumption in the second/third trimester above 5, 20, and 100 g/week affected body weight, body length, and head circumference at birth, respectively.

CONCLUSION

Low-to-moderate alcohol consumption during pregnancy might affect fetal growth. Public health policies for pregnant women are needed to stop alcohol consumption during pregnancy.

IMPACT

This study examined the association between maternal alcohol consumption and fetal growth restriction in 95,761 pregnant Japanese women using the prospective birth cohort. Maternal alcohol consumption in the second/third trimester more than 5, 20, and 100 g/week might affect fetal growth in body weight, body length, and head circumference, respectively. The findings are relevant and important for educating pregnant women on the adverse health effects that prenatal alcohol consumptions have on infants.

Gene-environment interactions related to maternal exposure to environmental and lifestyle-related chemicals during pregnancy and the resulting adverse fetal growth: a review

Background

There are only limited numbers of reviews on the association of maternal-child genetic polymorphisms and environmental and lifestyle-related chemical exposure during pregnancy with adverse fetal growth. Thus, this article aims to review: (1) the effect of associations between the above highlighted factors on adverse fetal growth and (2) recent birth cohort studies regarding environmental health risks.

Methods

Based on a search of the PubMed database through August 2021, 68 epidemiological studies on gene-environment interactions, focusing on the association between environmental and lifestyle-related chemical exposure and adverse fetal growth was identified. Moreover, we also reviewed recent worldwide birth cohort studies regarding environmental health risks.

Results

Thirty studies examined gene-smoking associations with adverse fetal growth. Sixteen maternal genes significantly modified the association between maternal smoking and adverse fetal growth. Two genes significantly related with this association were detected in infants. Moreover, the maternal genes that significantly interacted with maternal smoking during pregnancy were cytochrome P450 1A1 (CYP1A1), X-ray repair cross-complementing protein 3 (XRCC3), interleukin 6 (IL6), interleukin 1 beta (IL1B), human leukocyte antigen (HLA) DQ alpha 1 (HLA-DQA1), HLA DQ beta 1 (HLA-DQB1), and nicotinic acetylcholine receptor. Fetal genes that had significant interactions with maternal smoking during pregnancy were glutathione S-transferase theta 1 (GSTT1) and fat mass and obesity-associated protein (FTO). Thirty-eight studies examined the association between chemical exposures and adverse fetal growth. In 62 of the 68 epidemiological studies (91.2%), a significant association was found with adverse fetal growth. Across the studies, there was a wide variation in the analytical methods used, especially with respect to the genetic polymorphisms of interest, environmental and lifestyle-related chemicals examined, and the study design used to estimate the gene-environment interactions. It was also found that a consistently increasing number of European and worldwide large-scale birth cohort studies on environmental health risks have been conducted since approximately 1996.

Conclusion

There is some evidence to suggest the importance of gene-environment interactions on adverse fetal growth. The current knowledge on gene-environment interactions will help guide future studies on the combined effects of maternal-child genetic polymorphisms and exposure to environmental and lifestyle-related chemicals during pregnancy.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.21-00033.

Changes in e-cigarette and cigarette use during pregnancy and their association with small-for-gestational-age birth

BACKGROUND

Despite increased e-cigarette use, limited research has focused on changes in e-cigarette and combustible cigarette use around pregnancy and the subsequent effects on infant health.

OBJECTIVE

This study aimed to characterize changes in e-cigarette and cigarette use from before to during pregnancy and examine their associations with small-for-gestational-age birth.

STUDY DESIGN

This was a secondary data analysis of 2016-2018 data of the US Pregnancy Risk Assessment Monitoring System. We analyzed women aged ≥18 years who had a recent live birth (unweighted: n=105,438; weighted: n=5,446,900). Women were grouped on the basis of their self-reported e-cigarette and/or cigarette use 3 months before pregnancy (exclusive e-cigarette users, exclusive cigarette smokers, dual users, and nonusers) and change in e-cigarette and cigarette use during pregnancy (continuing use, quitting, switching, and initiating use). Small-for-gestational-age was defined as a birthweight below the 10th percentile for infants of the same sex and gestational age. We described the distributions of women's sociodemographic and pregnancy characteristics in both weighted and unweighted samples. We used multivariable log-binomial regression models to estimate the relative risks for the associations between changes in e-cigarette and cigarette use during pregnancy and risk of small-for-gestational-age, adjusting for significant covariates.

RESULTS

The rates of cessation during pregnancy were the highest among exclusive e-cigarette users (weighted percentage, 80.7% [49,378/61,173]), followed by exclusive cigarette users (54.4% [421,094/773,586]) and dual users (46.4% [69,136/149,152]). Among exclusive e-cigarette users, continued users of e-cigarettes during pregnancy had a higher risk of small-for-gestational-age than nonusers (16.5% [1849/11,206]) vs 8.8% [384,338/4,371,664]; confounder-adjusted relative risk, 1.52 [95% confidence interval, 1.45-1.60]), whereas quitters of e-cigarettes had a similar risk of small-for-gestational-age with nonusers (7.7% [3730/48,587] vs 8.8% [384,338/4,371,664]; relative risk, 0.84 [95% confidence interval, 0.82-0.87]). Among exclusive cigarette users, those who completely switched to e-cigarettes during pregnancy also had a similar risk of small-for-gestational-age with nonusers (7.6% [259/3412] vs 8.8% [384,338/4,371,664]; relative risk, 0.83 [95% confidence interval, 0.73-0.93]). Among dual users before pregnancy, the risk of small-for-gestational-age decreased from 23.2% (7240/31,208) (relative risk, 2.53 [95% confidence interval, 2.47-2.58]) if continuing use to 16.9% (6617/39,142) (relative risk, 1.88 [95% confidence interval, 1.83-1.92]) if only quitting e-cigarettes or 15.1% (1254/8289) (relative risk, 1.61 [95% confidence interval, 1.52-1.70]) if only quitting cigarettes and further to 11.2% (7589/67,880) (relative risk, 1.23 [95% confidence interval, 1.20-1.25]) if both quitting e-cigarettes and cigarettes during pregnancy, compared with nonusers.

CONCLUSION

Among exclusive e-cigarette users, quitting e-cigarettes during pregnancy normalized the risk of small-for-gestational-age. Among exclusive cigarette users, quitting smoking or completely switching to e-cigarettes normalized small for gestational age risk. Among dual users, smoking cessation has a greater effect than quitting e-cigarettes only, although discontinuing the use of both may lead to the greatest reduction in the risk of small-for-gestational-age.

P-gp expression inhibition mediates placental glucocorticoid barrier opening and fetal weight loss

BACKGROUND

Prenatal adverse environments can cause fetal intrauterine growth retardation (IUGR) and higher susceptibility to multiple diseases after birth, related to multi-organ development programming changes mediated by intrauterine overexposure to maternal glucocorticoids. As a glucocorticoid barrier, P-glycoprotein (P-gp) is highly expressed in placental syncytiotrophoblasts; however, the effect of P-gp on the occurrence of IUGR remains unclear.

METHODS

Human placenta and fetal cord blood samples of IUGR fetuses were collected, and the related indexes were detected. Pregnant Wistar rats were administered with 30 mg/kg·d (low dose) and 120 mg/kg·d (high dose) caffeine from gestational day (GD) 9 to 20 to construct the rat IUGR model. Pregnant mice were administered with caffeine (120 mg/kg·d) separately or combined with sodium ferulate (50 mg/kg·d) from gestational day GD 9 to 18 to confirm the intervention target on fetal weight loss caused by prenatal caffeine exposure (PCE). The fetal serum/placental corticosterone level, placental P-gp expression, and related indicator changes were analyzed. In vitro, primary human trophoblasts and BeWo cells were used to confirm the effect of caffeine on P-gp and its mechanism.

RESULTS

The placental P-gp expression was significantly reduced, but the umbilical cord blood cortisol level was increased in clinical samples of the IUGR neonates, which were positively and negatively correlated with the neonatal birth weight, respectively. Meanwhile, in the PCE-induced IUGR rat model, the placental P-gp expression of IUGR rats was decreased while the corticosterone levels of the placentas/fetal blood were increased, which were positively and negatively correlated with the decreased placental/fetal weights, respectively. Combined with the PCE-induced IUGR rat model, in vitro caffeine-treated placental trophoblasts, we confirmed that caffeine decreased the histone acetylation and expression of P-gp via RYR/JNK/YB-1/P300 pathway, which inhibited placental and fetal development. We further demonstrated that P-gp inducer sodium ferulate could reverse the inhibitory effect of caffeine on the fetal body/placental weight. Finally, clinical specimens and other animal models of IUGR also confirmed that the JNK/YB-1 pathway is a co-regulatory mechanism of P-gp expression inhibition, among which the expression of YB-1 is the most stable. Therefore, we proposed that YB-1 could be used as the potential early warning target for the opening of the placental glucocorticoid barrier, the occurrence of IUGR, and the susceptibility of a variety of diseases.

CONCLUSIONS

This study, for the first time, clarified the critical role and epigenetic regulation mechanism of P-gp in mediating the opening mechanism of the placental glucocorticoid barrier, providing a novel idea for exploring the early warning, prevention, and treatment strategies of IUGR.

Caffeine use during pregnancy: prevalence of use and newborn consequences in a cohort of French pregnant women

Many pregnant women, in the world, drink caffeine-containing beverages. Maternal caffeine consumption during pregnancy may have adverse effects on foetus but results are conflicting. Our goals were to estimate the prevalence of caffeine use in a cohort of French pregnant women using maternal self-reports and to evaluate the association between caffeine consumption during pregnancy and delivery and newborn characteristics. All pregnant women who gave birth in a large French urban area during a limited period of time were included (in total 724 mothers were included). Coffee, tea or cola consumption as well as pregnancy and neonate characteristics were analysed. The mean consumption of caffeine per day slightly decreased from the first to the third trimester of pregnancy: 587 caffeine users, with a consumption of caffeine of 59.2 ± 61.5 mg/day during the first trimester as compared to 577 consumers (54.3 ± 55.4 mg/day) during the third trimester, respectively. A significant decrease of neonates' birth length was observed when mothers were using at least 100 mg/day (or two cups) of caffeine during the second and third trimesters but this difference was no longer significant after adjustment on potential confounding factors such as tobacco use. The potential existence of other confounders (e.g. poorer dietary habits or other lifestyle variables) that might also be associated with reduced birth length, may not be excluded. Caffeine use during pregnancy was associated with reduced birth length but this effect was no longer significant after adjustment on potential confounding variables.

Maternal caffeine consumption and pregnancy outcomes: a narrative review with implications for advice to mothers and mothers-to-be

OBJECTIVES

Caffeine is a habit-forming substance consumed daily by the majority of pregnant women. Accordingly, it is important that women receive sound evidence-based advice about potential caffeine-related harm. This narrative review examines evidence of association between maternal caffeine consumption and negative pregnancy outcomes, and assesses whether current health advice concerning maternal caffeine consumption is soundly based.

METHODS

Database searches using terms linking caffeine and caffeinated beverages to pregnancy outcomes identified 1261 English language peer-reviewed articles. Screening yielded a total of 48 original observational studies and meta-analyses of maternal caffeine consumption published in the past two decades. The articles reported results for one or more of six major categories of negative pregnancy outcomes: miscarriage, stillbirth, low birth weight and/or small for gestational age, preterm birth, childhood acute leukaemia, and childhood overweight and obesity.

RESULTS

Of 42 separate sets of findings reported in 37 observational studies, 32 indicated significantly increased caffeine-related risk and 10 suggested no or inconclusive associations. Caffeine-related increased risk was reported with moderate to high levels of consistency for all pregnancy outcomes except preterm birth. Of 11 studies reporting 17 meta-analyses, there was unanimity among 14 analyses in finding maternal caffeine consumption to be associated with increased risk for the four outcome categories of miscarriage, stillbirth, low birth weight and/or small for gestational age, and childhood acute leukaemia. The three remaining meta-analyses were also unanimous in reporting absence of a reliable association between maternal caffeine consumption and preterm birth. No meta-analyses were identified for childhood overweight and obesity, although four of five original observational studies reported significant associations linking maternal caffeine consumption to that outcome category.

CONCLUSIONS

The substantial majority finding from observational studies and meta-analyses is that maternal caffeine consumption is reliably associated with major negative pregnancy outcomes. Reported findings were robust to threats from potential confounding and misclassification. Among both observational studies and meta-analyses, there were frequent reports of significant dose-response associations suggestive of causation, and frequent reports of no threshold of consumption below which associations were absent. Consequently, current evidence does not support health advice that assumes 'moderate' caffeine consumption during pregnancy is safe. On the contrary, the cumulative scientific evidence supports pregnant women and women contemplating pregnancy being advised to avoid caffeine.

A hierarchical procedure to select intrauterine and extrauterine factors for methodological validation of preterm birth risk estimation

Background

Etiopathogenesis of preterm birth (PTB) is multifactorial, with a universe of risk factors interplaying between the mother and the environment. It is of utmost importance to identify the most informative factors in order to estimate the degree of PTB risk and trace an individualized profile. The aims of the present study were: 1) to identify all acknowledged risk factors for PTB and to select the most informative ones for defining an accurate model of risk prediction; 2) to verify predictive accuracy of the model and 3) to identify group profiles according to the degree of PTB risk based on the most informative factors.

Methods

The Maternal Frailty Inventory (MaFra) was created based on a systematic review of the literature including 174 identified intrauterine (IU) and extrauterine (EU) factors. A sample of 111 pregnant women previously categorized in low or high risk for PTB below 37 weeks, according to ACOG guidelines, underwent the MaFra Inventory. First, univariate logistic regression enabled p-value ordering and the Akaike Information Criterion (AIC) selected the model including the most informative MaFra factors. Second, random forest classifier verified the overall predictive accuracy of the model. Third, fuzzy c-means clustering assigned group membership based on the most informative MaFra factors.

Results

The most informative and parsimonious model selected through AIC included Placenta Previa, Pregnancy Induced Hypertension, Antibiotics, Cervix Length, Physical Exercise, Fetal Growth, Maternal Anxiety, Preeclampsia, Antihypertensives. The random forest classifier including only the most informative IU and EU factors achieved an overall accuracy of 81.08% and an AUC of 0.8122. The cluster analysis identified three groups of typical pregnant women, profiled on the basis of the most informative IU and EU risk factors from a lower to a higher degree of PTB risk, which paralleled time of birth delivery.

Conclusions

This study establishes a generalized methodology for building-up an evidence-based holistic risk assessment for PTB to be used in clinical practice. Relevant and essential factors were selected and were able to provide an accurate estimation of degree of PTB risk based on the most informative constellation of IU and EU factors.

Supplementary Information

The online version contains supplementary material available at (10.1186/s12884-021-03654-3).