The Association of Alanine Aminotransferase in Early Pregnancy with Gestational Diabetes

Single and Joint Associations of Polycyclic Aromatic Hydrocarbon Exposure with Liver Function during Early Pregnancy

The individual and combined associations of polycyclic aromatic hydrocarbons (PAHs) metabolites on liver function during pregnancy are still lacking. We aimed to explore the connection between urinary PAH metabolites and liver function in early pregnant women in southwest China based on the Zunyi birth cohort. Ten urinary PAH metabolites and five liver function parameters during early pregnancy were measured. The associations of single PAHs with parameters of liver function were assessed using multiple linear regression. A Bayesian kernel machine regression (BKMR) model was used to evaluate the joint associations of the PAH mixture with outcomes. We found that each 1% increment of urinary 2-hydroxyphenanthrene (2-OH-PHE) was associated with 3.36% (95% CI: 0.40%, 6.40%) higher alanine aminotransferase (ALT) and 2.22% (95% CI: 0.80%, 3.67%) higher aspartate aminotransferase (AST). Each 1% increment in 1-hydroxy-phenanthrene (1-OH-PHE) was significantly associated with 7.04% (95% CI: 1.61%, 12.75%) increased total bile acid (TBA). Additionally, there was a significant positive linear trend between 2-OH-PHE and AST and 1-OH-PHE and TBA. BKMR also showed a significant positive association of PAH mixture with AST. Our results indicate that PAH metabolites were associated with increased parameters of liver function among early pregnant women. Early pregnant women should pay more attention to the adverse relationships between PAHs and liver function parameters to prevent environment-related adverse perinatal outcomes.

Diagnostic Approach to Elevated Liver Function Tests during Pregnancy: A Pragmatic Narrative Review

Liver disease is not uncommon during pregnancy and is associated with increased maternal and fetal/neonatal morbidity and mortality. Physiological changes during pregnancy, including a hyperestrogenic state, increase in circulating plasma volume and/or reduction in splanchnic vascular resistance, and hemostatic imbalance, may mimic or worsen liver disease. For the clinician, it is important to distinguish among the first presentation or exacerbation of chronic liver disease, acute liver disease non-specific to pregnancy, and pregnancy-specific liver disease. This last group classically includes conditions such as hyperemesis gravidarum, intrahepatic cholestasis of pregnancy, liver disorders associated with the pre-eclampsia spectrum, and an acute fatty liver of pregnancy. All of these disorders often share pathophysiological mechanisms, symptoms, and laboratory findings (such as elevated liver enzymes), but a prompt and correct diagnosis is fundamental to guide obstetric conduct, reduce morbidity and mortality, and inform upon the risk of recurrence or development of other chronic diseases later on in life. Finally, the cause of elevated liver enzymes during pregnancy is unclear in up to 30-40% of the cases, and yet, little is known on the causes and mechanisms underlying these alterations, or whether these findings are associated with worse maternal/fetal outcomes. In this narrative review, we aimed to summarize pragmatically the diagnostic work-up and the management of subjects with elevated liver enzymes during pregnancy.

Liver biomarkers, lipid metabolites, and risk of gestational diabetes mellitus in a prospective study among Chinese pregnant women

BACKGROUND

Liver plays an important role in maintaining glucose homeostasis. We aimed to examine the associations of liver enzymes and hepatic steatosis index (HSI, a reliable biomarker for non-alcoholic fatty liver disease) in early pregnancy with subsequent GDM risk, as well as the potential mediation effects of lipid metabolites on the association between HSI and GDM.

METHODS

In a birth cohort, liver enzymes were measured in early pregnancy (6-15 gestational weeks, mean 10) among 6,860 Chinese women. Multivariable logistic regression was performed to examine the association between liver biomarkers and risk of GDM. Pearson partial correlation and least absolute shrinkage and selection operator (LASSO) regression were conducted to identify lipid metabolites that were significantly associated with HSI in a subset of 948 women. Mediation analyses were performed to estimate the mediating roles of lipid metabolites on the association of HSI with GDM.

RESULTS

Liver enzymes and HSI were associated with higher risks of GDM after adjustment for potential confounders, with ORs ranging from 1.42 to 2.24 for extreme-quartile comparisons (false discovery rate-adjusted P-trend ≤0.005). On the natural log scale, each SD increment of alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, and HSI was associated with a 1.15-fold (95% CI: 1.05, 1.26), 1.10-fold (1.01, 1.20), 1.21-fold (1.10, 1.32), 1.15-fold (1.04, 1.27), and 1.33-fold (1.18, 1.51) increased risk of GDM, respectively. Pearson partial correlation and LASSO regression identified 15 specific lipid metabolites in relation to HSI. Up to 52.6% of the association between HSI and GDM risk was attributed to the indirect effect of the HSI-related lipid score composed of lipid metabolites predominantly from phospholipids (e.g., lysophosphatidylcholine and ceramides) and triacylglycerol.

CONCLUSIONS

Elevated liver enzymes and HSI in early pregnancy, even within a normal range, were associated with higher risks of GDM among Chinese pregnant women. The association of HSI with GDM was largely mediated by altered lipid metabolism.

Elevated Hepatic Steatosis Index is Associated with the Development of Adverse Maternal, but Not Adverse Neonatal, Outcomes: A Retrospective Cohort Study

Objective

To determine whether an elevated hepatic steatosis index (HSI), a non-invasive test for possible metabolic dysfunction-associated fatty liver disease (MAFLD), is associated with the development of adverse pregnancy outcomes.

Material and Methods

A retrospective cohort study was conducted on adult women with singleton pregnancies who delivered at two tertiary hospitals from August 2014 to December 2017. Aspartate aminotransaminase (AST) and alanine aminotransaminase (ALT) levels obtained 12 months pre-gravid, or during pregnancy but prior to screening for gestational diabetes mellitus (GDM), were extracted and linked with oral glucose tolerance test results. The HSI was calculated using the following equation: 8 × (ALT/AST ratio) + BMI (+2 if female; +2 if diabetes mellitus present) and considered elevated if >36. Multiple logistic regression analysis was used to quantify the association between elevated HSI and each composite adverse pregnancy outcome after adjusting for independent maternal risk factors.

Results

Over 40-months, 11929 women were eligible and of these, 1885 had liver enzymes collected. Women with an elevated HSI (>36) were more likely multiparous and overweight/obese compared to those women with a non-elevated HSI (≤36). Elevated HSI was significantly associated with a composite of adverse maternal outcomes (adjusted odds ratio (aOR) 1.55 95% CI 1.11-2.17, p=0.01), although a non-significant increased risk of a composite of adverse neonatal outcomes occurred after multivariable adjustment (aOR 1.17, 95% CI 0.94-1.45, p=0.17).

Conclusion

Over and above known maternal risk factors, women with elevated HSI were more likely to develop adverse maternal, but not adverse neonatal outcomes.

Obstetric implications of maternal chronic hepatitis B virus infection

Antenatal screening for hepatitis B surface antigen seropositivity is widely adopted to identify pregnant women with chronic hepatitis B virus (HBV) infection in order to target their newborn infants for combined passive-active neonatal immunization to prevent the maternal-to-child transmission of HBV. It is less certain whether the presence of chronic HBV infection in these largely asymptomatic women could impact their pregnancy outcome. There is now gathering information in the literature, though sometimes conflicting, on the obstetric implications of chronic HBV infection. The conflicting data is most probably related to confounding factors such as the immunological phase of chronic HBV infection, viral genotype and activity, presence of hepatic inflammation and other co-existing liver disorders such as non-alcoholic fatty liver disease, and coinfection with other virus such as hepatitis C virus and micro-organisms, which are usually not examined, but which could have made significant influence on the occurrence of many of the pregnancy complications and adverse fetal and neonatal outcome. For pregnancy complications, the evidence suggests association with increased gestational diabetes mellitus, preterm birth, intrahepatic cholestasis of pregnancy, caesarean delivery, and postpartum haemorrhage, probably increased placental abruption and prelabour rupture of the membranes, and no effect or a reduction in the hypertensive disorders of pregnancy, especially preeclampsia. For perinatal outcome, there may be increased miscarriage and fetal malformations, and increase in both low birthweight and large-for-gestational age/macrosomic infants, as well as increased intrauterine fetal demise/stillbirth and fetal distress. However, most studies have not elaborated on the mechanisms or explanations of many of the adverse outcomes. Taken together, maternal chronic HBV infection increases the risk of adverse obstetric outcome overall, but further prospective studies are warranted to elucidate the reasons and mechanisms of, and with a view to mitigate, these adverse obstetric outcomes.

Machine learning risk score for prediction of gestational diabetes in early pregnancy in Tianjin, China

AIMS

This study aimed to develop a machine learning-based prediction model for gestational diabetes mellitus (GDM) in early pregnancy in Chinese women.

MATERIALS AND METHODS

We used an established population-based prospective cohort of 19,331 pregnant women registered as pregnant before the 15th gestational week in Tianjin, China, from October 2010 to August 2012. The dataset was randomly divided into a training set (70%) and a test set (30%). Risk factors collected at registration were examined and used to construct the prediction model in the training dataset. Machine learning, that is, the extreme gradient boosting (XGBoost) method, was employed to develop the model, while a traditional logistic model was also developed for comparison purposes. In the test dataset, the performance of the developed prediction model was assessed by calibration plots for calibration and area under the receiver operating characteristic curve (AUR) for discrimination.

RESULTS

In total, 1484 (7.6%) women developed GDM. Pre-pregnancy body mass index, maternal age, fasting plasma glucose at registration, and alanine aminotransferase were selected as risk factors. The machine learning XGBoost model-predicted probability of GDM was similar to the observed probability in the test data set, while the logistic model tended to overestimate the risk at the highest risk level (Hosmer-Lemeshow test p value: 0.243 vs. 0.099). The XGBoost model achieved a higher AUR than the logistic model (0.742 vs. 0.663, p < 0.001). This XGBoost model was deployed through a free, publicly available software interface (https://liuhongwei.shinyapps.io/gdm_risk_calculator/).

CONCLUSION

The XGBoost model achieved better performance than the logistic model.

Elevated Alanine Aminotransferase in Early Pregnancy and Subsequent Development of Gestational Diabetes and Preeclampsia

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is now considered as a hepatic manifestation of metabolic syndrome and elevated alanine aminotransferase (ALT) is commonly related to NAFLD in the absence of viral hepatitis or alcohol abuse. Previous studies have indicated that elevated ALT is associated with diabetes or metabolic syndrome in adults, but the clinical significance of ALT or NAFLD in pregnancy has not been well determined. The objective of this study was to determine the association between elevated ALT in early pregnancy and the development of gestational diabetes or preeclampsia in late pregnancy.

METHODS

In this retrospective cohort study, pregnant women who met the following inclusion criteria were included: 1) singleton pregnancy; 2) ALT levels were measured in antenatal outpatient clinic at 4-20 weeks of gestation; 3) patients were screened for gestational diabetes and delivered in Cheil General Hospital and Women's Healthcare Center. Cases with viral hepatitis or other liver diseases were excluded. The early ALT levels were divided into two groups (normal ALT [≤ 95th percentile] and elevated ALT [> 95th percentile]), and the frequency of gestational diabetes and preeclampsia was compared between the two groups of cases. Gestational diabetes was screened and diagnosed by two-step procedure (50 g oral glucose challenge test and 75 g glucose challenge test with World Health Organization [WHO] criteria).

RESULTS

A total of 2,322 women met the inclusion criteria. Cases with elevated early ALT levels (> 95th percentile) had a higher risk of subsequent gestational diabetes and preeclampsia (gestational diabetes by WHO criteria, 2.1% in normal ALT vs. 6.5% in elevated ALT, P < 0.01; preeclampsia, 1.0% in normal ALT vs. 4.1% in elevated ALT, P < 0.05). This relationship between elevated ALT and increased risk of gestational diabetes/preeclampsia remained significant after adjustment for maternal age and pre-pregnancy body mass index.

CONCLUSION

Elevated unexplained ALT in early pregnancy is associated with the risk of subsequent development of gestational diabetes and preeclampsia in late pregnancy.

The association of plasma levels of liver enzymes and risk of gestational diabetes mellitus: a systematic review and dose-response meta-analysis of observational studies

AIMS

Relationship between liver enzymes such as gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT), aspartate transaminase (AST) and alkaline phosphatase and risk of gestational diabetes mellitus (GDM) is a controversial issue. The aim of this systematic review and dose-response meta-analysis was to investigate the association between liver enzymes and risk of GDM in observational studies.

METHODS

A comprehensive systematic literature search was conducted in MEDLINE/PubMed, SCOPUS and Web of Science databases up to September 2019. Combined odds ratios (ORs) with 95% confidence intervals (CIs) were evaluated by DerSimonian and Laird random-effects models. Dose-response analyses of these relationships were also carried out.

RESULTS

Eight studies with 25,451 participants containing 2549 cases were included in this study. Pooled results showed a significant association between GGT levels and risk of GDM (OR 2.10, 95% CI 1.14-3.86, I² 84%). In addition, random-effects model indicated a dramatic and direct significant association between GGT and risk of GDM in nonlinear (p < 0.001) and linear (p < 0.001) dose-response analysis. Associations between ALT and AST with risk of GDM were found to be non-significant (OR 1.32, 95% CI 0.91-1.90, I² 65% and OR 0.76, 95% CI 0.52-1.10, I² 16%, respectively).

CONCLUSION

This systematic review and dose-response meta-analysis highlights GGT as a significant and robust predictor of the incidence of GDM in pregnant women.

Hepatitis B - chronic carrier status and pregnancy outcomes: An obstetric perspective

Antenatal screening for hepatitis B surface antigen (HBsAg) only identifies women with hepatitis B virus (HBV) infection for neonatal immunoprophylaxis. It does not reflect the phase of chronic infection, viral genotype and activity, hepatic inflammation, or other co-existing liver disorders. Coinfection with other viruses and micro-organisms may also be present. These factors in various combinations can impact pregnancy outcomes, and they are probably responsible for the conflicting literature on this issue. Pregnancy complications may interact with maternal HBV infection and hepatitis flares, leading to serious and lethal complications. Hepatitis flares are common especially postpartum, and they are unpredictable and unpreventable with antiviral treatment. Evidence on the association between HBsAg seropositivity with gestational diabetes mellitus, preterm birth, increased foetal growth, and reduced pregnancy hypertensive disorders is stronger than other adverse pregnancy outcomes. Baseline assessment of liver function, and viral markers and activity, can delineate the truly high-risk pregnancies for close monitoring.

Implications of abnormal liver function in pregnancy and non-alcoholic fatty liver disease

Elevated liver enzyme levels can sometimes be encountered in asymptomatic pregnant women. Similar to non-pregnant subjects, women with elevated gamma glutamyltransferase or alanine aminotransferase in early pregnancy have increased risk of subsequent complications, especially gestational diabetes mellitus. In non-pregnant subjects, the commonest cause of abnormal liver function currently is non-alcoholic fatty liver disease. Risk factors include obesity, diabetes, and the metabolic syndrome. It can progress to hepatocellular carcinoma through the development of steatohepatitis, and has become the leading cause for liver transplantation in women. Found in as many as 16-18% of pregnant women, it is associated with an increased risk of pregnancy complications and abnormal foetal growth, which predisposes the offspring to the same problem subsequently. This condition probably explains the majority of the cases of "idiopathic" abnormal liver function in pregnancy, and should be looked out for in high-risk women owing to its implications on their long-term health outcome.

Fatty liver in pregnancy: a narrative review of two distinct conditions

Introduction: Fatty liver is rather common in pregnancy, occurring in two totally different conditions, i.e. nonalcoholic fatty liver disease (NAFLD) in pregnancy and acute fatty liver of pregnancy (AFLP). The former is a common condition, resulting by chance association because of the epidemics of obesity and the older age of many pregnant women in Western countries; the latter is a rare disease whose pathophysiology is still incompletely understood.Areas covered: We reviewed the evidence-based knowledge on fatty liver in/of pregnancy. For NAFLD, a few large retrospective and prospective studies identify immediate and late risks for both the mother and the fetus. For AFLP, only small retrospective studies are available, indicating that prompt delivery and eventual referral to Liver Units for liver support or transplantation are mandatory to avoid maternal and fetal death.Expert opinion: The number of pregnant women with fatty liver is expected to increase in the next years. Pharmacologic treatment of NAFLD might be postponed, even when new drugs are approved by health authorities for the general population. In the case of AFLP, we need to improve our ability to correctly identify and treat the most severe cases not resolving with delivery.

Liver Enzymes in Early to Mid-pregnancy, Insulin Resistance, and Gestational Diabetes Risk: A Longitudinal Analysis

Background: Liver enzymes may be implicated in glucose homeostasis; liver enzymes progressively change during pregnancy but longitudinal data during pregnancy in relation to insulin resistance and gestational diabetes (GDM) risk are lacking. We investigated longitudinal associations of γ-glutamyl transferase (GGT) and alanine aminotransferase (ALT) with insulin secretion and resistance markers across early to mid-pregnancy and subsequent GDM risk. Methods: Within the prospective Pregnancy Environment and Lifestyle Study cohort, 117 GDM cases were ascertained and matched to 232 non-GDM controls in a nested case-control study. Fasting blood samples were collected at two clinic visits (CV1, gestational weeks 10-13; CV2, gestational weeks 16-19). Linear mixed model and conditional logistic regression were used, adjusting for major risk factors for GDM. Results: In repeated measure analysis, after adjusting for confounders including body mass index and waist-to-hip ratio, GGT per standard deviation increment was associated with elevated fasting glucose and HOMA-IR (% change = 1.51%, 95% CI 0.56-2.46% and 7.43%, 95% CI 1.76-13.11%, respectively) and decreased adiponectin (% change = -2.86%, 95% CI-5.53 to -0.20%) from CV1 to CV2. At CV1 and CV2, GGT levels comparing the highest versus lowest quartile were associated with 3.01-fold (95% CI 1.32-6.85) and 3.51-fold (95% CI 1.37-8.97) increased risk of GDM, respectively. Progressively increased (<median at CV1, ≥median at CV2) and stably high (≥median at both CV1 and CV2) GGT levels were associated with 3.89- and 2.39-fold increased risk of GDM, compared to stably low levels (<median at both CV1 and CV2), respectively (both P < 0.05). Similar but non-significant trends were observed for ALT. Conclusion: Elevated levels of GGT in early and mid-pregnancy, even within the conventional normal range, and its progressive increase from early to mid-pregnancy may be implicated in the pathogenesis of GDM, highlighting its potential to inform early screening or preventive strategies to mitigate subsequent risk of GDM.

Liver triacylglycerol content and gestational diabetes: effects of moderate energy restriction

AIMS/HYPOTHESIS

Women with a history of gestational diabetes mellitus (GDM) have raised liver triacylglycerol. Restriction of energy intake in type 2 diabetes can normalise glucose control and liver triacylglycerol concentration but it is not known whether similar benefits could be achieved in GDM. The aim of this work was to examine liver triacylglycerol accumulation in women with GDM and the effect of modest energy restriction.

METHODS

Sixteen women with GDM followed a 4 week diet (5 MJ [1200 kcal]/day). Liver triacylglycerol, before and after diet and postpartum, was measured by magnetic resonance. Insulin secretion and sensitivity were assessed before and after diet. Twenty-six women who underwent standard antenatal care for GDM (matched for age, BMI, parity and ethnicity) were used as a comparator group.

RESULTS

Fourteen women, who completed the study, achieved a weight loss of 1.6 ± 1.7 kg over the 4 week dietary period. Mean weight change was -0.4 kg/week in the study group vs +0.3 kg/week in the comparator group (p = 0.002). Liver triacylglycerol level was normal but decreased following diet (3.7% [interquartile range, IQR 1.2-6.1%] vs 1.8% [IQR 0.7-3.1%], p = 0.004). There was no change in insulin sensitivity or production. Insulin was required in six comparator women vs none in the study group (eight vs two required metformin). Blood glucose control was similar for both groups. The hypo-energetic diet was well accepted.

CONCLUSIONS/INTERPRETATION

Liver triacylglycerol in women with GDM was not elevated, unlike observations in non-pregnant women with a history of GDM. A 4 week hypo-energetic diet resulted in weight loss, reduced liver triacylglycerol and minimised pharmacotherapy. The underlying pathophysiology of glucose metabolism appeared unchanged.

Early Pregnancy Biochemical Predictors of Gestational Diabetes Mellitus

PURPOSE OF REVIEW

Universal oral glucose tolerance-based screening is employed to identify pregnant women with gestational diabetes mellitus (GDM), as treatment of this condition decreases the risk of associated complications. A simple and accurate blood test which identifies women at low or high risk for GDM in the first trimester would have the potential to decrease costs and improve outcomes through prevention or treatment. This review summarizes published data on early pregnancy biomarkers which have been tested as predictors of GDM.

RECENT FINDINGS

A large number of first-trimester biochemical predictors of GDM have been reported, mostly in small case-control studies. These include glycemic markers (fasting glucose, post-load glucose, hemoglobin A1C), inflammatory markers (C-reactive protein, tumor necrosis factor-alpha), insulin resistance markers (fasting insulin, sex hormone-binding globulin), adipocyte-derived markers (adiponectin, leptin), placenta-derived markers (follistatin-like-3, placental growth factor, placental exosomes), and others (e.g., glycosylated fibronectin, soluble (pro)renin receptor, alanine aminotransferase, ferritin). A few large studies suggest that first-trimester fasting glucose or hemoglobin A1C may be useful for identifying women who would benefit from early GDM treatment. To translate the findings from observational studies of first-trimester biomarkers for GDM to clinical practice, trials or cost-effectiveness analyses of screening and treatment strategies based on these novel biomarkers are needed.

The association of early unexplained elevated alanine aminotransferase with large-for-gestational-age birthweight

BACKGROUND

Nonalcoholic fatty liver disease causes hepatic insulin resistance and is associated with metabolic syndrome. Elevated levels of alanine aminotransferase are associated with nonalcoholic fatty liver disease. The effect of hepatic insulin resistance is not only increased glycogen breakdown but also liberation of free fatty acids due to increased lipolysis. Both of these fuel sources are associated with macrosomia. There is little known about the impact of maternal nonalcoholic fatty liver disease on excessive fetal growth.

OBJECTIVE

The purpose of this study was to investigate the association of early elevated alanine aminotransferase with large-for-gestational-age birthweight.

STUDY DESIGN

This is a secondary analysis from a nested case-control study of maternal alanine aminotransferase values measured between 8-18 weeks and subsequent gestational diabetes. We included women with singleton gestations with complete delivery information and without known diabetes, liver disease, or moderate self-reported alcohol use during pregnancy. We used inverse probability weighting to standardize the population and minimize selection bias. We calculated population-based birthweight z scores and defined large for gestational age as ≥90th percentile for gestational age. We compared maternal baseline characteristics with analysis of variance, Fisher exact test, or Wilcoxon rank sum. We then performed conditional logistic regression to evaluate the relationship between alanine aminotransferase and large for gestational age adjusting for maternal age, body mass index, parity, gestational diabetes, smoking, and maternal weight gain.

RESULTS

We identified 26 cases of large for gestational age out of 323 mother-infant dyads. The mean maternal body mass index was higher in the large-for-gestational-age group compared to controls (33.7 [SD 4.3] vs 28.9 [SD 6.5], P = .002). Large-for-gestational-age babies were less likely to be male (8 [31%] vs 172 [58%], P = .01) and had a higher mean gestational age (39.5 [SD 0.9] vs 38.4 [SD 2.3] weeks, P = .01). Maternal and infant characteristics were otherwise similar. The mean alanine aminotransferase among the large-for-gestational-age cases was 28 (SD 37) U/L compared to 16 (SD 8) U/L for controls. Each unit increase in log-transformed alanine aminotransferase was associated with a 3-fold odds of large for gestational age (adjusted odds ratio, 3.05; 95% confidence interval, 2.27-4.10; P < .0001), and alanine aminotransferase ≥90th percentile (26 U/L) was associated with a 4-fold increased odds of large for gestational age (adjusted odds ratio, 4.03; 95% confidence interval, 2.84-5.70; P < .0001). This association was unchanged when analysis was restricted only to women without gestational diabetes with a glucose loading test <120 mg/dL (log-transformed alanine aminotransferase: adjusted odds ratio, 3.05; 95% confidence interval, 1.04-8.96; P = .04, and alanine aminotransferase ≥90th percentile: adjusted odds ratio, 4.21; 95% confidence interval, 1.20-14.82; P = .03).

CONCLUSION

Unexplained elevated alanine aminotransferase in the first trimester was associated with a 4-fold increase in the odds of large-for-gestational-age birthweight even in the absence of clinical glucose intolerance. This may represent the impact of maternal nonalcoholic fatty liver on the fetal developmental milieu.