The Endocannabinoid System and Its Relationship to Human Reproduction.

The endocannabinoid system is among the most important regulators of human reproduction. It already applies at the level of the sperm and the egg, plays an important role in the fertilization of the egg, its implantation, regulates the function of the placenta and participates in childbirth. The aim of this work is to summarize the knowledge accumulated so far and to show that the endocannabinoid system must be perfectly regulated in order to maintain a physiological pregnancy from implantation to delivery. Only an exceptional interplay of enzymes such as NAPE-PDL or FAAH, endogenous cannabinoids and cannabinoid receptors CB1 and CB2 can ensure the proper functioning of the reproductive organs and thus lead to delivery on time. Changes in the endocannabinoid system can lead to a number of pathological conditions, e.g., during blastocyst implantation, retardation of embryo development, impaired placental function or miscarriage. Soon, we can expect not only an understanding of all the regulatory events associated with the endocannabinoid system and other regulatory systems that participate in reproduction, but also several possibilities for pharmacotherapeutic interventions that can modify the formation, degradation and effect of endocannabinoids. It cannot be ruled out that some components of the endocannabinoid system could become a marker for monitoring pregnancy and childbirth.

The Endocannabinoid System - The Prediction of Spontaneous Preterm Birth in High-Risk Women: Protocol of a Study.

Spontaneous preterm birth (sPTB) is a major cause of perinatal morbidity and mortality, even in developed countries. Prediction of sPTB is therefore a valuable tool to reduce the associated risks. The current standard for the prediction of sPTB consists, in addition to anamnestic data, of previous sPTB and previous second trimester miscarriage, measurement of cervical length by transvaginal ultrasound (TVU CL) together with assessment of fetal fibronectin levels in cervicovaginal fluid. Other evaluation parameters, such as the level of endocannabinoids in the pregnant woman's blood, could increase the sensitivity of this management. Endocannabinoids (eCBs) are a part of the endocannabinoid system (ECS); out of them anandamide (arachidonoyl-ethanolamide, AEA), in particular, plays an important role in the regulation of pregnancy and childbirth. We present the protocol for an open, non-randomized study to evaluate concentrations of AEA and other endocannabinoids: 2 linoleoylglycerol (2-AG), 2 linoleoylglycerol (2-LG), 2 oleoylglycerol (2-OG), and 2 arachidonoyldopamine (2-ADOPA or also NADA) in the blood of pregnant women as potential predictors of sPTB. In a total of 230 women with a history of sPTB or miscarriage, eCBs levels between 22 and 28 weeks of gestation will be assessed from maternal blood, in addition to the standard procedure. The aim of the study is to determine the relationship between blood concentrations of the endocannabinoids tested and the risk of sPTB. The results of this study will describe the prognostic significance of maternal blood eCBs levels for sPTB, and could subsequently enable improved screening programs for early identification of sPTB.

Steroids, steroid associated substances and gestational diabetes mellitus.

As gestational diabetes mellitus (GDM) is both a frequent and serious complication, steroid levels in pregnancy are extremely elevated and their role in pregnancy is crucial, this review focuses on the role of steroids and related substances in the GDM pathophysiology. Low SHBG levels are associated with insulin resistance and hyperinsulinemia, while also predicting a predisposition to GDM. Other relevant agents are placental hormones such as kisspeptin and CRH, playing also an important role beyond pregnancy, but which are synthesized here in smaller amounts in the hypothalamus. These hormones affect both the course of pregnancy as well as the synthesis of pregnancy steroids and may also be involved in the GDM pathophysiology. Steroids, whose biosynthesis is mainly provided by the fetal adrenal glands, placenta, maternal adrenal glands, and both maternal and fetal livers, are also synthesized in limited amounts directly in the pancreas and may influence the development of GDM. These substances involve the sulfated ?5 steroids primarily acting via modulating different ion channels and influencing the development of GDM in different directions, mostly diabetogenic progesterone and predominantly anti-diabetic estradiol acting both in genomic and non-genomic way, androgens associated with IR and hyperinsulinemia, neuroactive steroids affecting the pituitary functioning, and cortisol whose production is stimulated by CRH but which suppresses its pro-inflammatory effects. Due to the complex actions of steroids, studies assessing their predominant effect and studies assessing their predictive values for estimating predisposition to GDM are needed.

Inflammatory bowel diseases in pregnancy.

OBJECTIVE: To bring actual summary of pre and perinatal care of women with Crohn's disease and ulcerative colitis. DESIGN: Review. SETTING: Department of Gynaecology and Obstetrics, General Faculty Hospital and 1st Faculty of Medicine, Prague. METHODS: Review of articles. CONCLUSION: Care of women with inflammatory bowel diseases should be placed in a specialised centre and management of pregnancy should be discussed by a multidisciplinary team included obstetrician, gastroenterologist, surgeon and nutritional specialist. All the possibilities in treatment of these women (except a few of them) are safe during the pregnancy and in the puerperium both for mother and fetus.

Thrombotic microangiopathy and pregnancy.

OBJECTIVE: The aim of this study is to draw attention to a nosological unit called thrombotic microangiopathy (TMA). This syndrome represents a serious pathological condition characterized by microangiopathic haemolytic anemia (MAHA), thrombocytopenia and various organ dysfunction. Patients are most often presented with symptoms of the HELLP syndrome but if the clinical picture is not restituted within 48-72 hours after delivery, other TMAs should be considered. SETTING: Department of Obstetrics and Gynecology, 1st Medical Faculty and General Teaching Hospital Prague; Clinic of Nephrology, 1st Medical Faculty and General Teaching Hospital Prague; Department of Obstetrics and Gynecology, Regional Hospital Kolín. DESIGN: Review article and case reports. METHODS: Review of the literature and description of two cases of TMA. CONCLUSION: The authors present a basic overview of the issue of TMA, which requires interdisciplinary cooperation of obstetricians, anesthesiologists, nephrologists and hematologists. In the second part of the article, we present two TMA case reports and finally show the differential diagnostic and therapeutic scheme as agreed by the authorities in the field.

Prenatal care for woman after fertility-sparing surgery for cervical cancer.

AIM: To summarize the current knowledge about the care of pregnant women after fertility-preserving operations for cervical cancer. STUDY TYPE: Review article. SETTING: Department of Gynecology and Obstetrics, 1st Faculty of Medicine, Charles University and General University Hospital, Prague. METHODOLOGY: Search of published literature on a given topic using the PubMed database. RESULTS: Pregnant women after fertility-sparing surgery for cervical cancer can benefit from screening and treatment for asymptomatic bacteriuria, cervical incompetence screening, and progressive cervical shortening by transvaginal ultrasonography. Tests to determine the presence of biomarkers of preterm birth in cervicovaginal fluid improve the prediction of preterm birth. Vaginal progesterone supplementation should be the primary prevention of preterm birth in all women after trachelectomy. Women with a history of preterm birth or late abortion may benefit from cerclage. The preferred mode of delivery is the cesarean section after 37 weeks of gestation. CONCLUSION: Due to the lack of data, pregnancy management in women who have undergone fertility-sparing surgery for early cervical cancer is inconsistent. An increasing number of pregnancies after fertility-sparing surgery will likely prompt clinical research in this field.

Current options of prediction of preterm labour.

OBJECTIVE: A summary of current possibilities to adequately determine spontaneous preterm labour. DESIGN: Review. SETTING: Department of Obstetrics and Gynecology, 1st Faculty of Medicine and General Teaching Hospital, Charles University in Prague. METHODS: Research of literature and current studies. CONCLUSION: Based on the combination of personal medical history, clinical signs, biomarkers and transvaginal ultrasonographic measurement of cervical length, it is possible to predict preterm labour. To avoid a major prediction miscalculation, it is necessary to understand and correctly evaluate certain clinical findings. This approach decreases redundant medical intervention and therefore leads to amelioration of perinatal outcome.

Insulin-like growth factor axis in pregnancy and gestational diabetes mellitus.

The insulin-like growth factor (IGF) is involved in the regulation of growth and metabolism. The aim of this study was to determine selected parameters of IGF system at systemic and local levels [subcutaneous (SAT) and visceral adipose tissue (VAT)] to assess its possible role in gestational diabetes mellitus (GDM). 37 pregnant women (21 with GDM and 16 without GDM) and 15 age-matched non-pregnant females were included in the study. Blood samples were taken in 28-32 and 36-38 weeks of gestation and 6-12 months after delivery. SAT and VAT samples were obtained during delivery or surgery. Compared with non-pregnant women, serum IGF-1 and IGFBP-3 were increased in both groups of pregnant women. IGF-2 was elevated only in GDM women from 36 weeks of gestation culminating 6 months after delivery (p=0.003). Serum IGFBP-3 was increased and IGFBP-4 decreased in GDM women vs. pregnant women without GDM during the whole study (IGFBP-3: p?0.001 for GDM vs. non-GDM; IGFBP-4: p=0.004 for GDM vs. non-GDM). Pregnant women with GDM had decreased mRNA expression of IGF-1, IGF-1R and IGF-2R and IGFBP-4 in VAT and IGF-1R in SAT compared to pregnant women without GDM. Changes in local activity of IGF are associated with the development of GDM.

Cervical cerclage - history and contemporary use.

OBJECTIVE: Contemporary role of cerclage as a preterm birth treatment. DESIGN: Review article. SETTING: Department of Obstetrics and Gynecology of the First Faculty of Medicine and General Teaching Hospital in Prague. METHODS: Research of existing literature, predominantly foreign journal articles, but also Czech literature and personal experience with the method. RESULTS: Cerclage is one of the well-known surgical procedures carried out during pregnancy. Its aim is to provide a mechanical support to the cervical canal and to keep the cervix closed. The cervical mucous plug serves as a mechanical barrier between the vagina and the uterine cavity, but it also contains many immune components which protect the fetal compartment from ascendent infections. Application of a cervical stitch can help to retain the mucous plug and thus increases the immunity of the cervical canal. Results of 15 randomised studies (Cochraine Database of Systematic R) suggest that in women with increased risk of preterm birth, cerclage decreases the occurrence of preterm birth relative to the expectant management. CONCLUSIONS: Despite the decreasing numbers of cerclage surgeries, it is still a useful method of preterm birth prevention for a specific group of women. More recently, a progesterone treatment has gained popularity. Its application, however, must begin before the 16th week of pregnancy.

A method for determination of one hundred endogenous steroids in human serum by gas chromatography-tandem mass spectrometry.

Steroid profiling helps various pathologies to be rapidly diagnosed. Results from analyses investigating steroidogenic pathways may be used as a tool for uncovering pathology causations and proposals of new therapeutic approaches. The purpose of this study was to address still underutilized application of the advanced GC-MS/MS platform for the multicomponent quantification of endogenous steroids. We developed and validated a GC-MS/MS method for the quantification of 58 unconjugated steroids and 42 polar conjugates of steroids (after hydrolysis) in human blood. The present method was validated not only for blood of men and non-pregnant women but also for blood of pregnant women and for mixed umbilical cord blood. The spectrum of analytes includes common hormones operating via nuclear receptors as well as other bioactive substances like immunomodulatory and neuroactive steroids. Our present results are comparable with those from our previously published GC-MS method as well as the results of others. The present method was extended for corticoids and 17alpha-hydroxylated 5alpha/ß-reduced pregnanes, which are useful for the investigation of alternative "backdoor" pathway. When comparing the analytical characteristics of the present and previous method, the first exhibit by far higher selectivity, and generally higher sensitivity and better precision particularly for 17alpha-hydroxysteroids.

The incidence of gestational diabetes mellitus before and after the introduction of HAPO diagnostic criteria.

INTRODUCTION: During the years 2014-2015 new diagnostic criteria for gestational diabetes mellitus (GDM) were gradually adopted by the Czech professional societies, which emerged from the results of the large prospective multicenter HAPO study (The Hyperglycemia and Adverse Pregnancy Outcome). The adoption of the new criteria was accompanied by concerns about the increase in the number of women with GDM. The paper deals with epidemiological results of GDM incidence in the first three years since the introduction of new criteria. METHODS AND RESULTS: In the years 2013-2014 GDM screening was performed at 1,594 pregnant woman at the General Teaching Hospital in Prague. According to that time valid diagnostic criteria (fasting glucose 5.6 mmol/g and/or 8.9 mmol/l in 60 min and/or 7.7 mmol/l in 120 min 75 g OGTT) GDM was found in 324, i.e. 20 % of women. In the years 2016-2018 were 2,629 pregnant women examined. GDM based on the new criteria (fasting blood glucose 5.1 mmol/l and/or 10 mmol/l in 60 min and/or 8.5 mmol/l in 120 min OGTT) was diagnosed in significantly less women - in 375, i.e. 14.3% (p < 0.0001). Overt diabetes, i.e. fasting glucose 7.0 mmol/l and/or 11.1 mmol/l in 120 min OGTT, was newly detected in 6 pregnant women, i.e. 0.2 %. Gestational diabetes was found in 62% cases based on repeated fasting fasting blood glucose and in 38% on the basis of higher blood glucose at 60 min and/or 120 min OGTT. GDM was significantly more prevalent in the age category over 30 years. Among women aged under 25 years GDM was present at 9.9%, aged 25-29.9 years at 9.6%, aged 30-34.9 years at 14.2% and aged 35 years at 18.6 %. Hypoglycaemia < 3.5 mmol/l experienced 2.9% of women during OGTT. When the screening in 2016-2018 was evaluated according to the previous diagnostic criteria, diabetes would be diagnosed in 16.2% of pregnant women. The result of the test would be falsely negative in 6% of all pregnant women, i.e. these women have repeatedly higher fasting glucose (5.1-5.5 mmol/l) according to the current criteria which was evaluated as physiological according to the previous criteria. However, in the HAPO, these values were already associated with a significant increase of complications. A total of 50% of women with GDM diagnosed according to the previous criteria would have a false positive result of OGTT (8.9-9.9 mmol/l in 60 min and/or 7.7-8.4 mmol/l in 120 min OGTT). These values are not considered to be significantly at risk under the new criteria. CONCLUSION: Our data do not confirm the increase in GDM incidence following the introduction of new diagnostic criteria which, according to current knowledge, better reflect the real risks of complications for the child and the mother. Applying the previous criteria has led to a number of false negative and positive results, so we consider the adoption of better-funded new criteria a step in the right direction. The incidence of diabetes was significant in all age categories and significantly increased in women over 30 years of age.

Phthalate metabolites in maternal and cord plasma and their relations to other selected endocrine disruptors and steroids.

Endocrine disruptors (EDs) are known to have harmful effects on the human endocrine system; special effort is actually given to the exposure during pregnancy. Humans are usually exposed to a mixture of EDs, which may potentiate or antagonize each other, and the combined effect may be difficult to estimate. The main phthalate monoesters monoethyl-, mono-n-butyl-, monoisobutyl-, monobenzyl-, mono-(2-ethylhexyl)-, mono-(2-ethyl-5-hydroxyhexyl)- and mono-(2-ethyl-5-oxohexyl) phthalate were determined in 18 maternal (37th week of pregnancy) and cord plasma samples using liquid chromatography-tandem mass spectrometry. Previously determined levels of selected bisphenols, parabens and steroids were also considered in this study. In cord blood, there were significantly higher mono-n-butyl phthalate levels than in maternal blood (p=0.043). The results of multiple regression models showed that maternal plasma phthalates were negatively associated with cord plasma androstenedione, testosterone and dehydroepiandrosterone and positively associated with estradiol and estriol. For estriol, a cumulative association was also observed for sumabisphenols. To the best of our knowledge, this is the first pilot study evaluating the effect of prenatal exposure by multiple EDs on newborn steroidogenesis. Our results confirmed phthalate accumulation in the fetal area and disruption of fetal steroidogenesis. This preliminary study highlights the negative impacts of in utero EDs exposure on fetal steroidogenesis.

Steroid hormone levels in the peripartum period - differences caused by fetal sex and delivery type.

Progesterone, estrogens, androgens and glucocorticoids all play important roles during pregnancy, from implantation to delivery. Focusing on selected steroid hormones in the peripartum period, we defined reference ranges measured using LS-MS/MS, and assessed relationships with maternal age, pregnancy weight gain, delivery type, and fetal sex. Samples were taken from 142 healthy women with physiological gravidity at the 37th week, during the first period of labor, and from newborn mixed cord blood. We found higher cortisol and 17-OH-pregnenolone plasma levels in mothers at the 37th week that carried male fetuses (p=0.03), but no significant differences in any studied hormones in newborns of different sex. Neither maternal age nor weight gain nor newborn birth weight had any relationships to any of the studied hormones. However, there were differences depending on vaginal versus planned cesarean section deliveries. In women carrying a male fetus we found significantly higher levels of 17-OH-pregnenolone, progesterone, cortisol, corticosterone and significantly lower levels of estradiol in those undergoing spontaneous vaginal delivery. However, we found no significant differences in the cord blood of newborn males from either delivery type. We established reference ranges for our analysis methods, which should be useful for further studies as well as in standard clinical practice.

May circulating steroids reveal a predisposition to intrahepatic cholestasis of pregnancy in non-pregnant women?

Intrahepatic cholestasis of pregnancy (ICP) is a frequent liver disorder, mostly occurring in the third trimester. ICP is not harmful to the mothers but threatens the fetus. The authors evaluated steroid alterations in maternal and mixed umbilical blood to elucidate their role in the ICP development. Ten women with ICP were included in the study. Steroids in the maternal blood were measured by Gas Chromatography-Mass Spectrometry (GC-MS) (n=58) and RIA (n=5) at the diagnosis of ICP, labor, day 5 postpartum, week 3 postpartum and week 6 postpartum. The results were evaluated by ANOVA consisting of the subject factor, between subject factors ICP, gestational age at the diagnosis of ICP and gestational age at labor, within-subject factor Stage and ICP × Stage interaction. The 17 controls were firstly examined in the week 36 of gestation. ICP patients showed reduced CYP17A1 activity in the C17,20 lyase step thus shifting the balance between the toxic conjugated pregnanediols and harmless sulfated 5alpha/beta-reduced-17-oxo C19 steroids. Hence, more toxic metabolites originating in maternal liver from the placental pregnanes may penetrate backward to the fetal circulation. As these alterations persist in puerperium, the circulating steroids could be potentially used for predicting the predisposition to ICP even before next pregnancy.

Changes in plasma concentrations and mRNA expression of hepatokines fetuin A, fetuin B and FGF21 in physiological pregnancy and gestational diabetes mellitus.

We measured plasma concentrations, adipose tissue and placental mRNA expression of hepatokines fetuin A, fetuin B and fibroblast growth factor 21 (FGF21) in 12 healthy pregnant women (P group), 12 pregnant women with gestational diabetes (GDM) and 10 healthy non-pregnant women (N group) to explore their potential role in the etiopathogenesis of GDM. GDM and P group had comparable BMI, C-reactive protein (CRP) and glycated hemoglobin levels while IL-10 and TNF-alpha levels were higher in GDM group. Fetuin A and fetuin B levels were higher in pregnancy as compared to N group and decreased after delivery with no apparent influence of GDM. In contrast, the pattern of changes of circulating FGF21 levels differed between GDM and P group. Fetuin A concentrations positively correlated with CRP, TNF-alpha mRNA expression in adipose tissue and IL-6 mRNA expression in placenta. Fetuin B positively correlated with CRP. FGF21 levels correlated positively with IFN-gamma mRNA in adipose tissue and inversely with IL-8 mRNA in the placenta. Taken together, fetuin A and fetuin B levels were increased during pregnancy regardless of the presence of GDM. In contrast, FGF21 patterns differed between healthy pregnant women and GDM patients suggesting a possible role of this hepatokine in the etiopathogenesis of GDM.

Low maternal serum concentrations of mannose-binding lectin are associated with the risk of shorter duration of pregnancy and lower birthweight.

Chronic inflammation has been implicated as the underlying mechanism responsible for the pathophysiology of preterm labour. Mannose-binding lectin (MBL) plays a central role in the innate immune response and is thus an important component of the first line of defense. The aim of this study was to investigate whether serum concentrations of MBL correlated with the incidence of preterm birth and low birthweight in a cohort of women with signs of threatened preterm birth. A cohort of 60 patients who presented with regular contractions and/or short cervix (group A) between 24 and 32 weeks of gestation and 20 healthy controls (group B) who had no pregnancy complications and delivered at term were recruited into a prospective study. The following outcomes were recorded: presence of preterm labour and birthweight in all patients. MBL and high sensitivity C-reactive protein levels were measured in all serum samples. The serum concentrations of MBL were significantly reduced in patients with threatened preterm labour (Group A), compared to the control Group B. Furthermore, infants born to Group A mothers with MBL deficiency (n = 13, MBL ≤100 ng/mL) had significantly lower birthweights, compared to those born to Group A women with normal MBL serum concentrations (P < .0001). Our small cohort study demonstrated a strong association between MBL deficiency and preterm delivery, and associated low birthweight. MBL deficiency could thus be considered an important risk factor for preterm birth.

Cardiotoxicity of ß-mimetic catecholamines during ontogenetic development - possible risks of antenatal therapy.

Catecholamines are involved in the regulation of a wide variety of vital functions. The ß-adrenergic receptor (ß-AR) - adenylyl cyclase system has been identified early in embryogenesis before the heart has received adrenergic innervation. The structure of ß-receptors in the immature myocardium is similar to that in adults; there are, however, significant quantitative developmental changes in the inotropic and chronotropic responsiveness. Information on the toxic effect of the ß-AR agonists in the immature heart is surprisingly scarce, even though these agents are used in clinical practice both during pregnancy and in early postnatal development. Large doses of ß-AR agonists induce malformations of the cardiovascular system; the type of change depends upon the time at which the ß-AR agonist was administered during embryogenesis. During postnatal ontogeny, the cardiotoxicity of ß-AR agonists increased from birth to adulthood. It seems likely that despite interspecies differences, developmental changes in the cardiac sensitivity to ß-AR agonists may exist in all mammals, depending on the degree of maturation of the system involved in ß-adrenergic signaling. All the existing data draw attention to the possible harmful consequences of the clinical use of ß-AR agonists during early phases of cardiac development. Late effects of the early disturbances of the cardiac muscle cannot be excluded.

Planned home births in the Czech Republic, 2018.

STUDY AIM: A summary of the current situation regarding issues of planned home births in the Czech Republic. TYPE OF STUDY: Review and summarization. Affiliations: Department of Obstetrics and Gynecology of the Liberec regional hospital, and the Department of Obstetrics and Gynecology of the First Faculty of Medicine and General Teaching Hospital in Prague. METHODS: We present a summarization of the available data on the controversial subject of planned home births in the Czech Republic. Planned home births in the Czech Republic are currently the subject of much professional, legal, and ethical discussion. This study also includes a review of the international literature, which describes the influence of planned home births on maternal and perinatal mortality and morbidity. There is as yet no professional organization or legal framework in the Czech Republic for regulating home births, and no precise and dependable data exits on the number, outcomes, or incidence of complications. However, there is an unambiguous consensus among all related specialist organizations in the Czech Medical Association of J. E. Purkyně, which does not support or recommend home births. Despite this, there is a small percentage of women that prefer to give birth at home. Through social networks and public discussion forums that deal with such issues these women find a community that supports and shares, but that also sometimes passes on half-truths and misinformation. Every initially physiological birth can without warning become complicated and require immediate medical intervention. Delays, and inadequate preparation and qualifications can fundamentally influence the further courses and outcomes, complicating the health and life of both mother and child. CONCLUSION: The aim of all specialists participating in any way with this issue should be the spread of indisputable facts based on evidence and warning of the demonstrable risks associated with planned home births.

Pitfalls in screening for gestational diabetes in the Czech Republic - patient survey.

OBJECTIVE: The aim of our survey was to investigate gestational diabetes (GDM) screening policy in the Czech Republic with regards to the correct methodology of the screening. MATERIALS AND METHODS: 1100 anonymous questionnaires were distributed among patients of a tertiary level obstetric department from July 2015 to September 2015. RESULTS: 958 (87.0%) questionnaires were found eligible for analysis. 794 (82.9%) of participants had at least one risk factor for GDM development. The oGTT was performed in 751 (94.6%) women at risk of GDM and 153 (93.3%) women at low risk of GDM. From the 904 performed oGTT, 154 (17.0%) were performed completely by recommended standards. In the remaining cases, at least one deviation from standard was noted. The results of oGTT were provided by 364 (40.3%) of respondents. In this subgroup, 71 (19.5%) matched International Association of Diabetes in Pregnancy Study Groups (IADPSG) criteria for GDM diagnosis. However, these women were often not those who were evaluated as screening positive by the office gynaecologist. CONCLUSION: The screening for GDM was frequently not performed in accordance with the national guidelines and the diagnostic criteria used were not uniform.

[The role of maternal imunity and woman´s microbiome in the pathogenesis of preterm labor]. / Úloha materské imunity a mikrobiomu zeny v patogenezi predcasného porodu.

OBJECTIVE: To summarize available data concerning the role of maternal imunity and woman´s microbiome in the pathogenesis of preterm labor and their use in clinical practice. SETTING: Department of Obstetrics and Gynecology od the First Faculty of Medicine, Charles University in Prague, and General Teaching Hospital. DESIGN: Review article. METHODS: Compilation od published data from scientific literature. CONCLUSION: Preterm labor complicates approximately 10% of all pregnancies and represents a serious medical, social and economic problem. In the past, a lot of causes of preterm labor were discussed; infection, uteroplacental ischemia, decidual hemorrhage, uterine overdistension, cervical disease and maternal-fetal tolerance disorder were considered the most common. However, chronic inflammation seems to be the common pathogenic process underlying preterm labor, irrespective of the original stimulus. Currently, impaired maternal-fetal immunological tolerance represents most discussed topic. Growing scientific evidence suggests that the immune regulation of the maternal-fetal interface is the result of the coordinated interaction among maternal microbiota, trophoblast and maternal cellular components. From this view we understand preterm labor as a result of disruption of this process.