The association between maternal smoking and hyperemesis gravidarum: a meta-analysis

Nausea and vomiting in pregnancy (NVP) in Chinese pregnant women: a cross-sectional study

BACKGROUND

This study addresses the scarcity of research on nausea and vomiting in pregnancy (NVP) in China. It aims to explore the current NVP status in the country using validated questionnaires, analyze associated factors, and provide a useful reference for future research. The study also compares results from different assessment tools.

METHODS

Online questionnaires were utilized to gather data from 535 pregnant women across 24 provinces. Demographic, pregnancy, and NVP-related information were collected. NVP severity was assessed using Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) and the Rhodes Index of Nausea, Vomiting, and Retching (RINVR) scales. Ordinal logistic regression identified factors linked to NVP severity. Differences between PUQE and RINVR assessments were compared.

RESULTS

NVP prevalence exceeded 90%, with 96.1% assessed by PUQE and 90.8% by RINVR. Incidence decreased from nausea to retching and vomiting. Severe NVP correlated with reduced gestational weight gain, younger age, fewer gestational weeks, and living in North (all P values < 0.05). There was moderate consistency between PUQE and RINVR assessments. The NVP prevalence assessed by the PUQE is higher than that assessed by the RINVR in the same population. However, the proportion of NVP levels above moderate assessed by RINVR is greater than that assessed by PUQE.

CONCLUSIONS

NVP is highly prevalent among Chinese pregnant women, with nausea being predominant. RINVR assessments may be better able to identify severe NVP, thereby improving the low treatment rates for severe NVP.

GDF15 linked to maternal risk of nausea and vomiting during pregnancy

GDF15, a hormone acting on the brainstem, has been implicated in the nausea and vomiting of pregnancy, including its most severe form, hyperemesis gravidarum (HG), but a full mechanistic understanding is lacking1-4. Here we report that fetal production of GDF15 and maternal sensitivity to it both contribute substantially to the risk of HG. We confirmed that higher GDF15 levels in maternal blood are associated with vomiting in pregnancy and HG. Using mass spectrometry to detect a naturally labelled GDF15 variant, we demonstrate that the vast majority of GDF15 in the maternal plasma is derived from the feto-placental unit. By studying carriers of rare and common genetic variants, we found that low levels of GDF15 in the non-pregnant state increase the risk of developing HG. Conversely, women with β-thalassaemia, a condition in which GDF15 levels are chronically high5, report very low levels of nausea and vomiting of pregnancy. In mice, the acute food intake response to a bolus of GDF15 is influenced bi-directionally by prior levels of circulating GDF15 in a manner suggesting that this system is susceptible to desensitization. Our findings support a putative causal role for fetally derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by prepregnancy exposure to the hormone, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

Systematic replication of smoking disease associations using survey responses and EHR data in the All of Us Research Program

OBJECTIVE

The All of Us Research Program (All of Us) aims to recruit over a million participants to further precision medicine. Essential to the verification of biobanks is a replication of known associations to establish validity. Here, we evaluated how well All of Us data replicated known cigarette smoking associations.

MATERIALS AND METHODS

We defined smoking exposure as follows: (1) an EHR Smoking exposure that used International Classification of Disease codes; (2) participant provided information (PPI) Ever Smoking; and, (3) PPI Current Smoking, both from the lifestyle survey. We performed a phenome-wide association study (PheWAS) for each smoking exposure measurement type. For each, we compared the effect sizes derived from the PheWAS to published meta-analyses that studied cigarette smoking from PubMed. We defined two levels of replication of meta-analyses: (1) nominally replicated: which required agreement of direction of effect size, and (2) fully replicated: which required overlap of confidence intervals.

RESULTS

PheWASes with EHR Smoking, PPI Ever Smoking, and PPI Current Smoking revealed 736, 492, and 639 phenome-wide significant associations, respectively. We identified 165 meta-analyses representing 99 distinct phenotypes that could be matched to EHR phenotypes. At P < .05, 74 were nominally replicated and 55 were fully replicated. At P < 2.68 × 10-5 (Bonferroni threshold), 58 were nominally replicated and 40 were fully replicated.

DISCUSSION

Most phenotypes found in published meta-analyses associated with smoking were nominally replicated in All of Us. Both survey and EHR definitions for smoking produced similar results.

CONCLUSION

This study demonstrated the feasibility of studying common exposures using All of Us data.

Fetally-encoded GDF15 and maternal GDF15 sensitivity are major determinants of nausea and vomiting in human pregnancy

Human pregnancy is frequently accompanied by nausea and vomiting that may become severe and life-threatening, as in hyperemesis gravidarum (HG), the cause of which is unknown. Growth Differentiation Factor-15 (GDF15), a hormone known to act on the hindbrain to cause emesis, is highly expressed in the placenta and its levels in maternal blood rise rapidly in pregnancy. Variants in the maternal GDF15 gene are associated with HG. Here we report that fetal production of GDF15, and maternal sensitivity to it, both contribute substantially to the risk of HG. We found that the great majority of GDF15 in maternal circulation is derived from the feto-placental unit and that higher GDF15 levels in maternal blood are associated with vomiting and are further elevated in patients with HG. Conversely, we found that lower levels of GDF15 in the non-pregnant state predispose women to HG. A rare C211G variant in GDF15 which strongly predisposes mothers to HG, particularly when the fetus is wild-type, was found to markedly impair cellular secretion of GDF15 and associate with low circulating levels of GDF15 in the non-pregnant state. Consistent with this, two common GDF15 haplotypes which predispose to HG were associated with lower circulating levels outside pregnancy. The administration of a long-acting form of GDF15 to wild-type mice markedly reduced subsequent responses to an acute dose, establishing that desensitisation is a feature of this system. GDF15 levels are known to be highly and chronically elevated in patients with beta thalassemia. In women with this disorder, reports of symptoms of nausea or vomiting in pregnancy were strikingly diminished. Our findings support a causal role for fetal derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by pre-pregnancy exposure to GDF15, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

Hyperemesis Gravidarum: Strategies to Improve Outcomes

Hyperemesis gravidarum (HG) is a debilitating and potentially life-threatening pregnancy disease marked by weight loss, malnutrition, and dehydration attributed to unrelenting nausea and/or vomiting; HG increases the risk of adverse outcomes for the mother and child(ren). The complexity of HG affects every aspect of a woman's life during and after pregnancy. Without methodical intervention by knowledgeable and proactive clinicians, life-threatening complications may develop. Effectively managing HG requires an understanding of both physical and psychosocial stressors, recognition of potential risks and complications, and proactive assessment and treatment strategies using innovative clinical tools.

Early maternal weight gain as a risk factor for SGA in pregnancies with hyperemesis gravidarum: a 15-year hospital cohort study

BACKGROUND

Inadequate maternal weight gain increases the risk of small-for-gestational age (SGA) infants. Women with hyperemesis gravidarum (HG) are at risk of significant early pregnancy weight loss and insufficient total pregnancy weight gain. Recent studies have implied that weight gain during the first half of pregnancy is more crucial to pregnancy outcome than total weight gain. The aim of this study was to investigate whether not regaining prepregnancy weight by 13-18 weeks of gestation contributed to not reaching minimum body mass index (BMI)-specific total pregnancy weight gain and influenced the risk of SGA outcome in HG pregnancies.

METHODS

In this retrospective 15-year cohort (2002-2016) of women hospitalized due to hyperemesis gravidarum, we reviewed individual patient hospital files and corresponding outpatient maternity records to collect prepregnancy BMI and weight, pregnancy weight gain (spanning 3-week intervals), delivery weight and foetal outcomes. BMI and total pregnancy weight gain goals were categorized according to the Institute of Medicine (IOM) 2009 guidelines: BMI < 18,5 kg/m2: 12.5-18 kg, 18.5-24.9 kg/m2: 11.5-16 kg, 25-29.9 kg/m2: 7-11.5 kg and > 30 kg/m2: 5-9 kg. Birth weight was categorized as SGA if less than the 10th percentile of sex- and gestational length-specific Norwegian neonatal weight charts. Nonparametric tests were used to compare weight categories, and logistic regression was used to predict the odds ratio (OR) of inadequate total pregnancy weight gain or SGA delivery.

RESULTS

Out of 892 women hospitalized for HG during 2002-2016, 784 had a pregnancy lasting > 24 weeks, of which 746 were singleton pregnancies with follow-up until delivery. Among these women, 42 were classified as underweight, 514 as normal weight, 230 as overweight and 102 as obese before pregnancy. Not regaining prepregnancy weight by week 13-18 was an independent predictor of inadequate total gestational weight gain with an OR of 7.05 (95% CI 4.24-11.71) and an independent predictor for SGA outcome with an OR of 2.66 (95% CI 1.11-6.34), even when adjusted for total pregnancy weight gain, prepregnancy BMI, parity, age and smoking status.

CONCLUSION

Inadequate total maternal weight gain and not regaining prepregnancy weight by week 13-18 may be considered independent risk factors for delivering a baby that is small for gestational age in pregnancies with hyperemesis gravidarum. Achieving adequate weight gain during the first trimester in HG pregnancies is important for the foetal outcome, underscoring the importance of nutritional treatment during this period.

Exposure to Tobacco, Environmental Tobacco Smoke and Nicotine in Pregnancy: A Pragmatic Overview of Reviews of Maternal and Child Outcomes, Effectiveness of Interventions and Barriers and Facilitators to Quitting

The aim of this review of reviews was to collate the latest evidence from systematic reviews about the maternal and child health outcomes of being exposed to tobacco and nicotine during pregnancy; the effectiveness of interventions designed to reduce these exposures, and barriers to and facilitators of smoking cessation during pregnancy. Two databases were searched to obtain systematic reviews published from 2010 to 2019. Pertinent data from 76 articles were summarized using a narrative synthesis (PROSPERO reference: CRD42018085896). Exposure to smoke or tobacco in other forms during pregnancy is associated with an increased risk of obstetric complications and adverse health outcomes for children exposed in-utero. Counselling interventions are modestly effective, while incentive-based interventions appear to substantially increase smoking cessation. Nicotine replacement therapy is effective during pregnancy but the evidence is not conclusive. Predictors and barriers to smoking cessation in pregnancy are also discussed. Smoking during pregnancy poses substantial risk to mother's and child's health. Psychosocial interventions and nicotine replacement therapy (NRT) appear to be effective in helping pregnant women quit smoking. Barriers to smoking cessation must be identified and steps taken to eradicate them in order to reduce smoking among pregnant women. More research is needed on smoking cessation medications and e-cigarettes.

Leisure-time physical activity before pregnancy and risk of hyperemesis gravidarum: a population-based cohort study

INTRODUCTION

Women who experience severe nausea and vomiting in early pregnancy are less likely to participate in leisure-time physical activity (LTPA) during pregnancy. Whether LTPA before pregnancy is associated with hyperemesis gravidarum (HG) has not yet been studied. The aim of the study was to estimate associations between prepregnancy LTPA and HG in pregnancy.

METHODS

We present data from 37,442 primiparous women with singleton pregnancies enrolled in The Norwegian Mother and Child Cohort Study. Prepregnancy LTPA was self-reported by questionnaire in pregnancy week 17. HG was reported in week 30 and defined as prolonged nausea and vomiting in pregnancy requiring hospitalisation before the 25th gestational week. We estimated the crude and adjusted associations between LTPA and HG using multiple logistic regression. We assessed effect modification by prepregnancy BMI or smoking by stratified analysis and interaction terms.

RESULTS

A total of 398 (1.1%) women developed HG. Before pregnancy 56.7% conducted LTPA at least 3 times weekly, while 18.4% of women conducted LTPA less than once a week. Compared to women reporting LTPA 3 to 5 times weekly, women reporting no LTPA before pregnancy had an increased odds of HG (adjusted odds ratio (aOR) 1.69; 95% confidence interval (CI), 1.20 to 2.37). LTPA-HG associations differed by prepregnancy BMI but not by prepregnancy smoking.

DISCUSSION

Lack of LTPA before pregnancy was associated with an increased odds of HG. Due to few cases of HG and thereby low statistical power, one need to be cautious when interpreting the results of this study.

Predictive factors of Hyperemesis Gravidarum: A systematic review

PURPOSE

Hyperemesis gravidarum (HG) is the main cause of hospitalization during the first trimester of pregnancy. Although it has been associated with serious complications, little is known about its predictive factors. The aim of this systematic review was to search for and critically appraise the studies that investigate the predictive factors for HG.

METHODS

Search strategy included PubMed, CENTRAL and EMBASE databases (till December 2017). All studies examining risk factors for HG were included. Screening of available studies was carried out by two reviewers, as well as the quality assessment of the included studies, based on the Newcastle-Ottawa Scale for observational studies.

RESULTS

The search located 308 articles, of which 14 observational studies (four low-, eight medium- and two high-quality), involving 1400 women who met the eligibility criteria. In four studies, there was no association between Helicobacter (H.) Pylori infection and HG, in contrast to two studies which demonstrated such an association. Pre-pregnancy body mass index (BMI), adipose tissue, maternal age, leptin, ghrelin, beta-chorionic gonadotropin (β-hCG), total (T₄) and free thyroxine (fT₄) correlated with HG in various studies, and could be considered as predictive markers. Regarding the high-quality evidence, a cohort study associated leptin and nephatin-1 with HG, whereas a cross-sectional study found no association between H. pylori infection and HG.

CONCLUSIONS

More studies of high quality and adequate sample size have to be carried out to identify the predictive factors for HG.

Effect of severe hyperemesis gravidarum on maternal vascular endothelial health: evaluation of soluble adhesion molecules

Purpose: This study aimed to clarify the effect of severe hyperemesis gravidarum (sHG) on maternal vascular endothelial health with evaluation of soluble adhesion molecules.Method: The study population consisted of two groups of pregnant participants between 18 and 35 years of age who were between 5 and 13 weeks of gestation: sHG group and a healthy control group. A group of 26 participants whose pregnancies were complicated by sHG was compared with 26 healthy participants regarding serum levels of the soluble adhesion molecules such as E-selectin, soluble intracellular cell adhesion molecule 1 (sICAM-1), and soluble vascular cell adhesion molecule one (sVCAM-1), as well as other biochemical markers. The two groups had similar baseline characteristics.Results: Maternal baseline characteristics were similar in both groups. Serum levels of E-selectin (p < .001), sICAM-1 (p < .001), and sVCAM-1 (p < .001) were higher in the sHG group compared with the control group. Higher blood urea nitrogen, creatinine, and sodium levels, serum osmolarity, and urine density (p < .001, < .001, .006, .041, and .001, respectively) were also observed in the sHG group compared with the control group.Conclusions: The findings of this study indicated that sHG could impact endothelial cell function and these changes represented hypovolemia and dehydration caused by severe vomiting. Large-scale studies are required to understand the clinical importance of this finding regarding the long-term consequences and underlying mechanisms of elevated sICAM-1, sVCAM-1, and sE-selectin synthesis.

Smoking and placenta previa: a meta-analysis

OBJECTIVE

Previous studies found a positive association between placenta previa and smoking during pregnancy. However, the results of these studies are inconsistent. The aim was to perform meta-analysis of the association between smoking during pregnancy and placenta previa.

METHODS

Major electronic databases, including PubMed, Web of Science, and Scopus were searched until June 2015. The heterogeneity across studies was explored by Q-test and I² statistic. The possibility of publication bias was assessed using Begg's and Egger's tests. The results were reported using odds ratio (OR) estimate with its 95% confidence intervals using a random-effects model.

RESULTS

The literature search yielded 991 publications until October 2015 with 9,094,443 participants. Based on the random effect model, compared to nonsmoker women, the estimated OR and RR of placenta previa was 1.42 (95% CI: 1.30, 1.54) and 1.27 (95% CI: 1.18, 1.35), respectively.

CONCLUSIONS

There is sufficient documents based on the observational studies that smoking during pregnancy is significantly associated with an increased risk of placenta previa. Therefore, smoking during pregnancy can be considered as a predictor of placenta previa.