The Myometrium in Pregnant Women with Obesity

Effects of Liquid Fructose Supplementation and Chronic Unpredictable Stress on Uterine Contractile Activity in Nonpregnant Rats

Increased fructose consumption and chronic stress, the major characteristics of modern lifestyle, impact human health; however, the consequences of their combination on the uterus remain understudied. In this study, we investigated contractile activity, morphology, and intracellular activity of antioxidant enzymes in uteri from virgin Wistar rats subjected to liquid fructose supplementation and/or unpredictable stress over 9 weeks. Contractile activity and uterine response to oxytocin or adrenaline were examined ex vivo using isolated bath chambers. Fructose supplementation, irrespective of stress, affected uterine morphology by increasing endometrium while decreasing myometrium volume density, attenuated uterine response to increasing doses of oxytocin, and increased glutathione peroxidase activity. Stress, irrespective of fructose, attenuated dose-dependent adrenaline-induced uterine relaxation. Stress, when applied solely, decreased mitochondrial superoxide dismutase activity. In the combined treatment, irregular estrous cycles and both reduced response to oxytocin and to adrenaline (as a consequence of fructose consumption and exposure to stress), along with fructose-related alteration of uterine morphology, were detected. In conclusion, fructose and stress affect uterine contractile activity, irrespective of each other, by inducing completely distinct responses in isolated uteri. In the combined treatment, the effects of both factors were evident, suggesting that the combination exerts more detrimental effects on the uterus than each factor individually.

Altered DNA methylation and Dnmt expression in obese uterus may cause implantation failure

Obesity is defined by increased adipose tissue volume and has become a major risk factor for reproduction. Recent studies have revealed a substantial link between obesity and epigenetics. The epigenome is dynamically regulated mainly by DNA methylation. DNA methylation, which is controlled by DNA methyltransferases (Dnmts), has been widely studied because it is essential for imprinting and regulation of gene expression. In our previous study, we showed that the levels of Dnmt1, Dnmt3a and global DNA methylation was dramatically altered in the testis and ovary of high-fat diet (HFD)-induced obese mice. However, the effect of HFD on Dnmts and global DNA methylation in mouse uterus has not yet been demonstrated. Therefore, in the present study, we aimed to evaluate the effect of HFD on the level of Dnmt1, Dnmt3a, Dnmt3b, Dnmt3l and global DNA methylation in uterus. Our results showed that HFD significantly altered the levels of Dnmts and global DNA methylation in the uterus. The total expression of Dnmt1, Dnmt3a and Dnmt3b was significantly upregulated, while level of Dnmt3l and global DNA methylation were dramatically decreased (p < 0.05). Furthermore, we observed that the expression of Dnmt3b and Dnmt3l was significantly increased in endometrium including gland and epithelium (p < 0.05). Although Dnmt3b was the only protein whose expression significantly increased, the level of global DNA methylation and Dnmt3l significantly decreased in stroma and myometrium (p < 0.05). In conclusion, our results show for the first time that obesity dramatically alters global DNA methylation and expression of Dnmts, and decreased DNA methylation and Dnmt expression may cause abnormal gene expression, especially in the endometrium.

Excessive Pregestational Weight and Maternal Obstetric Complications: The Role of Adipokines

There is a high frequency of overweight and obesity in women of reproductive age. Women who start pregnancy with overweight or obesity have an increased risk of developing maternal obstetric complications such as gestational hypertension, pre-eclampsia, gestational diabetes mellitus, postpartum hemorrhage, and requiring C-section to resolve the pregnancy with a higher risk of C-section surgical site infection. Excessive weight in pregnancy is characterized by dysregulation of adipokines, the functions of which partly explain the predisposition of pregnant women with overweight or obesity to these maternal obstetric complications. This review compiles, organizes, and analyzes the most recent studies on adipokines in pregnant women with excess weight and the potential pathophysiological mechanisms favoring the development of maternal pregnancy complications.

Ubhayasekera K, Kjölhede P, Bergquist J, Blomberg M. The association between maternal body mass index and serial plasma oxytocin levels during labor

OBJECTIVE

To evaluate the association between maternal body mass index (BMI) and plasma oxytocin (OT) levels at different OT infusion rates in labor.

METHODS

A prospective observational study analyzing serial plasma samples in laboring women with OT infusion. The women were categorized into three groups, women with non-obesity (BMI 18.5-29.9, n = 12), obesity (BMI 30.0-34.9, n = 13), and morbid obesity (BMI ≥ 35.0, n = 15). Plasma OT was analyzed using tandem mass spectrometry.

RESULTS

Except for a low positive correlation between OT levels and BMI and significantly increased plasma OT levels in women with morbid obesity at the OT infusion rate of 3.3 mU/min, no significant differences in OT levels between the BMI groups were found. Further, the inter-individual differences in OT levels were large and no dose-dependent increase of OT levels was seen.

CONCLUSIONS

Other factors than plasma OT levels may be more likely to determine the clinical response of OT infusion in women with obesity. Perhaps the observed clinical need and individual response would be a better predictor of plasma OT levels than a pre-determined OT infusion rate. The OT dosage guidelines for labor augmentation should be individualized according to clinical response rather than generalized.

TRIAL REGISTRATION

Clinical trial registration: ClinicalTrials.gov ID NCT04093479.

The role of apelinergic system in metabolism and reproductive system in normal and pathological conditions: an overview

Lifestyle changes have made metabolic disorders as one of the major threats to life. Growing evidence demonstrates that obesity and diabetes disrupt the reproductive system by affecting the gonads and the hypothalamus-pituitary-gonadal (HPG) axis. Apelin, an adipocytokine, and its receptor (APJ) are broadly expressed in the hypothalamus nuclei, such as paraventricular and supraoptic, where gonadotropin-releasing hormone (GnRH) is released, and all three lobes of the pituitary, indicating that apelin is involved in the control of reproductive function. Moreover, apelin affects food intake, insulin sensitivity, fluid homeostasis, and glucose and lipid metabolisms. This review outlined the physiological effects of the apelinergic system, the relationship between apelin and metabolic disorders such as diabetes and obesity, as well as the effect of apelin on the reproductive system in both gender. The apelin-APJ system can be considered a potential therapeutic target in the management of obesity-associated metabolic dysfunction and reproductive disorders.

The Apelinergic System in Pregnancy

The apelinergic system is a highly conserved pleiotropic system. It comprises the apelin receptor apelin peptide jejunum (APJ) and its two peptide ligands, Elabela/Toddler (ELA) and apelin, which have different spatiotemporal localizations. This system has been implicated in the regulation of the adipoinsular axis, in cardiovascular and central nervous systems, in carcinogenesis, and in pregnancy in humans. During pregnancy, the apelinergic system is essential for embryo cardiogenesis and vasculogenesis and for placental development and function. It may also play a role in the initiation of labor. The apelinergic system seems to be involved in the development of placenta-related pregnancy complications, such as preeclampsia (PE) and intrauterine growth restriction, but an improvement in PE-like symptoms and birth weight has been described in murine models after the exogenous administration of apelin or ELA. Although the expression of ELA, apelin, and APJ is altered in human PE placenta, data related to their circulating levels are inconsistent. This article reviews current knowledge about the roles of the apelinergic system in pregnancy and its pathophysiological roles in placenta-related complications in pregnancy. We also discuss the challenges in translating the actors of the apelinergic system into a marker or target for therapeutic interventions in obstetrics.

Pharmacological Interventions in Labor and Delivery

While there is not a wide range of pregnancy-specific drugs, there are some very specific high-risk areas of obstetric care for which unique pharmacological approaches have been established. In preterm birth, labor induction and augmentation, and the management of postpartum hemorrhage, these pharmacological approaches have become the bedrock in managing some of the most common and problematic areas of antenatal and intrapartum care. In this review, we summarize the existing established and emerging evidence that supports and broadens these pharmacological approaches to obstetric management and its impact on clinical practice. It is clear that existing therapeutics are limited. They have largely been developed from our knowledge of the physiology of the myometrium and act on hormonal receptors and their signaling pathways or on ion channels influencing excitability. Newer drugs in development are mostly refinements of these two approaches, but novel agents from plants and improved formulations are also discussed.

Effects of labor induction in obesity with delayed pregnancy: A retrospective study based on Chinese obese primipara

OBJECTIVE

To test the hypothesis that obese primiparous women with an unfavorable cervix in delayed pregnancy may experience a worse induction of labor.

STUDY DESIGN

In total, 467 primiparas with poor cervical condition and delayed pregnancy (gestational age [GA]: >40weeks) were divided into an obese primiparas group (body mass index [BMI] >30kg/m²; n=166) and a non-obese primiparas group (BMI < 30kg/m²; (n=301). Labor was induced by various methods, double balloon, dinoprostone inserts, and amniotomy combined with oxytocin depending on the Bishop score. Experimental data were analyzed by Statistical Product Service Solutions (SPSS).

RESULTS

BMI in the obese primiparas group was higher than in the non-obese group (33.91 ± 2.67 versus 24.09 ± 5.78, p<0.001), and there were significant differences in uterine tone and duration of contractions between the two groups in the second stage of labour (p=0.041, p=0.026, respectively).The rate of cesarean section (CS) was significantly higher in the primiparas group (23.49% versus 12.29%; P=0.002). There was a significant difference between the two groups in terms of the duration of time to vaginal delivery (VD) (18h versus 8h; P <0.001) while the duration until VD in the obese primiparas group within 12 hours and 24 hours was significantly longer (P <0.001). After adjusting for possible confounders, caesarean section rates remained high in the obese primiparas women (OR: 2.564;95%CI1.919,3.864;P<0.001). Similarly, after adjusting for the same confounding factors, obese primiparas women increased the duration until VD within 24 h by 3.598 hours.

CONCLUSION

Obese primiparas with an unfavorable cervix in delayed pregnancy have a significantly higher risk of CS and a longer duration until VD than non-obese primiparas during labor induction.