Influence of parity on first trimester endovascular trophoblast invasion

The smaller firstborn: exploring the association of parity and fetal growth

PURPOSE

To investigate the association of parity with a range of neonatal anthropometric measurements in a cohort of uncomplicated term singleton pregnancies.

METHODS

Retrospective cohort study of patients with a singleton term birth at a single tertiary center (2014-2020) was carried out. The primary exposure was parity. The following neonatal anthropometric measures were considered: birthweight, head circumference, length, ponderal index, and neonatal body mass index (BMI).

RESULTS

A total of 8134 patients met the study criteria, 1949 (24.0%) of whom were nulliparous. Compared with multiparous patients, infants of nulliparous patients had a lower mean percentile for birthweight (43.1 ± 26.4 vs. 48.3 ± 26.8 percentile, p < 0.001), head circumference (44.3 ± 26.4 vs. 48.1 ± 25.5 percentile, p < 0.001), length (52.6 ± 25.1 vs. 55.5 ± 24.6 percentile, p < 0.001), ponderal index (34.4 ± 24.0 vs. 37.6 ± 24.2 percentile, p < 0.001), and BMI (39.1 ± 27.1 vs. 43.9 ± 27.3 percentile, p < 0.001). In addition, infants of nulliparous patients had higher odds of having a small (< 10th percentile for gestational age) birthweight (aOR 1.32 [95% CI 1.12-1.56]), head circumference (aOR 1.54 [95% CI 1.29-1.84]), length (aOR 1.50 [95% CI 1.16-1.94]), ponderal index (aOR 1.30 [95% CI 1.12-1.51]), and body mass index (aOR 1.42 [95% CI 1.22-1.65]). Most neonatal anthropometric measures increased with parity until a parity of 2, where it seemed to reach a plateau.

CONCLUSION

Parity has an independent impact on a wide range of neonatal anthropometric measures, suggesting that parity is associated with both fetal skeletal growth and body composition. In addition, the association of parity with fetal growth does not follow a continuous relationship but instead reaches a plateau after the second pregnancy.

Clinical factors associated with subsequent surgical intervention in women undergoing early medical termination of viable or non-viable pregnancies

Introduction

Mifepristone-misoprostol treatment for medical abortion and miscarriage are safe and effective. This study aimed to assess clinical factors associated with subsequent surgical intervention after medical termination of early viable or non-viable pregnancy.

Methods

This retrospective, single-center study included women who underwent medical abortion at Taipei Medical University between January 2010 and December 2019. A total of 1,561 subjects, with 1,080 viable and 481 non-viable pregnancies, who were treated with oral mifepristone 600 mg followed by misoprostol 600 mg 48 h later were included. Data of all pregnancies and medical termination of pregnancy were evaluated using regression analysis. The main outcome was successful termination of pregnancy.

Results

The success rate of medical abortion was comparable in women with viable and non-viable (92.13% vs. 92.93%) pregnancies. Besides retained tissue, more existing pregnancies with ultrasonographic findings were found in the non-viable pregnancy group than in the viable pregnancy group (29.4% vs. 14.1%, p = 0.011). Multivariate analysis showed that previous delivery was an independent risk factor for failed medical abortion among all included cases. In women with viable pregnancy, longer gestational age [adjusted odds ratio (aOR): 1.483, 95% confidence interval (CI): 1.224-1.797, p < 0.001] and previous Cesarean delivery (aOR: 2.177, 95% CI: 1.167-40.62, p = 0.014) were independent risk factors for failed medical abortion. Number of Cesarean deliveries (aOR: 1.448, 95% CI: 1.029-2.039, p = 0.034) was an independent risk factor for failed medication abortion in women with non-viable pregnancies.

Conclusion

This is the first cohort study to identify risk factors for subsequent surgical intervention in women with viable or non-viable pregnancies who had undergone early medically induced abortions. The success rate of medical abortion is comparable in women with viable and non-viable pregnancies. Previous delivery is an independent risk factor for failed medical abortion. Clinical follow-up may be necessary for women who are at risk of subsequent surgical intervention.

Pregnancy trained decidual NK cells protect pregnancies from harmful Fusobacterium nucleatum infection

Natural killer cells (NKs) found during pregnancy at the maternal-fetal interface named decidual (d)NKs, show signs of education following first pregnancy, resulting in better placentation and fetus-growth, hence termed pregnancy trained dNKs (PTdNKs). Here we show that PTdNKs provide increased protection of the fetus from Fusobacterium nucleatum (FN) infection. We demonstrate that PTdNKs secrete elevated amounts of the bacteriocidal protein granulysin (GNLY) upon incubation with FN compared to dNKs derived from first pregnancies, which leads to increased killing of FN. Furthermore, we showed mechanistically that the GNLY secretion is mediated through the interaction of the FN's Fap2 protein with Gal-GalNAc present on PTdNKs. Finally, we show in vivo, using GNLY-tg mice that enhanced protection of the fetuses from FN infection is observed, as compared to wild type and that this enhance protection is NK cell dependent. Altogether, we show a new function for PTdNKs as protectors of the fetus from bacterial infection.

Endometrial small extracellular vesicles regulate human trophectodermal cell invasion by reprogramming the phosphoproteome landscape

A series of cyclical events within the uterus are crucial for pregnancy establishment. These include endometrial regeneration following menses, under the influence of estrogen (proliferative phase), then endometrial differentiation driven by estrogen/progesterone (secretory phase), to provide a microenvironment enabling attachment of embryo (as a hatched blastocyst) to the endometrial epithelium. This is followed by invasion of trophectodermal cells (the outer layer of the blastocyst) into the endometrium tissue to facilitate intrauterine development. Small extracellular vesicles (sEVs) released by endometrial epithelial cells during the secretory phase have been shown to facilitate trophoblast invasion; however, the molecular mechanisms that underline this process remain poorly understood. Here, we show that density gradient purified sEVs (1.06-1.11 g/ml, Alix⁺ and TSG101⁺, ∼180 nm) from human endometrial epithelial cells (hormonally primed with estrogen and progesterone vs. estrogen alone) are readily internalized by a human trophectodermal stem cell line and promote their invasion into Matrigel matrix. Mass spectrometry-based proteome analysis revealed that sEVs reprogrammed trophectoderm cell proteome and their cell surface proteome (surfaceome) to support this invasive phenotype through upregulation of pro-invasive regulators associated with focal adhesions (NRP1, PTPRK, ROCK2, TEK), embryo implantation (FBLN1, NIBAN2, BSG), and kinase receptors (EPHB4/B2, ERBB2, STRAP). Kinase substrate prediction highlighted a central role of MAPK3 as an upstream kinase regulating target cell proteome reprogramming. Phosphoproteome analysis pinpointed upregulation of MAPK3 T204/T202 phosphosites in hTSCs following sEV delivery, and that their pharmacological inhibition significantly abrogated invasion. This study provides novel molecular insights into endometrial sEVs orchestrating trophoblast invasion, highlighting the microenvironmental regulation of hTSCs during embryo implantation.

Association between placenta accreta spectrum and third-trimester serum levels of vascular endothelial growth factor, placental growth factor, and soluble Fms-like tyrosine kinase-1: A meta-analysis

AIM

Antenatal suspicion of placenta accreta spectrum (PAS) currently relies on ultrasonographic findings, color doppler, and MRI, which have rendered it operator and expertise-dependent. No serum markers for PAS have been integrated into clinical practice yet. The aim of this meta-analysis was to identify potential serum markers for PAS by investigating third-trimester serum levels of vascular endothelial growth factor (VEFG), placental growth factor (PIGF), and soluble Fms-like tyrosine kinase-1 (sFlt-1) among PAS-cases and controls.

METHODS

PubMed, Scopus, EBSCO, Web of Science, and CNKI databases were systematically searched for relevant articles. Random-effects model was applied to calculate the overall standardized mean difference (SMD) for each marker. Subgroup analysis and meta-regression were performed to assess for potential covariates.

RESULTS

Eight studies involving 366 PAS-cases and 518 controls were included. Third trimester sFlt-1 levels were significantly lower in PAS-cases when compared to controls (SMD = -7.76, 95%CI = -10.42 to -5.10). This was, to a certain extent, consistent among studies though they differed in their extent of significance. Levels of VEGF (SMD = 1.59, 95%CI = -0.07 to 3.25) and PlGF (SMD = -0.49, 95%CI = -1.66 to 0.67) were not significantly different between PAS cases and controls, in which studies demonstrated conflicting results.

CONCLUSIONS

Third trimester sFlt-1 levels may be useful to predict PAS. Nonetheless, further studies are recommended to better understand conflicting results before adopting either VEGF or PlGF.

Emerging Concepts in Innate Lymphoid Cells, Memory, and Reproduction

Members of the innate immune system, innate lymphoid cells (ILCs), encompass five major populations (Natural Killer (NK) cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer cells) whose functions include defense against pathogens, surveillance of tumorigenesis, and regulation of tissue homeostasis and remodeling. ILCs are present in the uterine environment of humans and mice and are dynamically regulated during the reproductive cycle and pregnancy. These cells have been repurposed to support pregnancy promoting maternal immune tolerance and placental development. To accomplish their tasks, immune cells employ several cellular and molecular mechanisms. They have the capacity to remember a previously encountered antigen and mount a more effective response to succeeding events. Memory responses are not an exclusive feature of the adaptive immune system, but also occur in innate immune cells. Innate immune memory has already been demonstrated in monocytes/macrophages, neutrophils, dendritic cells, and ILCs. A population of decidual NK cells characterized by elevated expression of NKG2C and LILRB1 as well as a distinctive transcriptional and epigenetic profile was found to expand during subsequent pregnancies in humans. These cells secrete high amounts of interferon-γ and vascular endothelial growth factor likely favoring placentation. Similarly, uterine ILC1s in mice upregulate CXCR6 and expand in second pregnancies. These data provide evidence on the development of immunological memory of pregnancy. In this article, the characteristics, functions, and localization of ILCs are reviewed, emphasizing available data on the uterine environment. Following, the concept of innate immune memory and its mechanisms, which include epigenetic changes and metabolic rewiring, are presented. Finally, the emerging role of innate immune memory on reproduction is discussed. Advances in the comprehension of ILC functions and innate immune memory may contribute to uncovering the immunological mechanisms underlying female fertility/infertility, placental development, and distinct outcomes in second pregnancies related to higher birth weight and lower incidence of complications.

Parity-Adjusted Term Neonatal Growth Chart Modifies Neonatal Morbidity and Mortality Risk Stratification

Objective: To investigate the impact of parity-customized versus population-based birth weight charts on the identification of neonatal risk for adverse outcomes in small (SGA) or large for gestational age (LGA) infants compared to appropriate for gestational age (AGA) infants. Study design: Observational, retrospective, cohort study based on electronic medical birth records at a single center between 2006 and 2017. Neonates were categorized by birth weight (BW) as SGA, LGA, or AGA, with the 10th and 90th centiles as boundaries for AGA in a standard population-based model adjusted for gestational age and gender only (POP) and a customized model adjusted for gestational age, gender, and parity (CUST). Neonates defined as SGA or LGA by one standard and not overlapping the other, are SGA/LGA CUST/POP ONLY. Analyses used a reference group of BW between the 25th and 75th centile for the population. Results: Overall 132,815 singleton, live, term neonates born to mothers with uncomplicated pregnancies were included. The customized model identified 53% more neonates as SGA-CUST ONLY who had significantly higher rates of morbidity and mortality compared to the reference group (OR = 1.33 95% CI [1.16−1.53]; p < 0.0001). Neonates defined as LGA by the customized model (LGA-CUST) and AGA by the population-based model LGA-CUST ONLY had a significantly higher risk for morbidity compared to the reference (OR = 1.36 95% CI [1.09−1.71]; p = 0.007) or the LGA POP group. Neonatal mortality only occurred in the SGA and AGA groups. Conclusions: The application of a parity-customized only birth weight chart in a population of singleton, term neonates is a simple platform to better identify birth weight related neonatal risk for morbidity and mortality.

Uterine NK cell functions at maternal-fetal interface

During pregnancy, maternal decidual tissue interacts with fetal trophoblasts. They constitute the maternal-fetal interface responsible for supplying nutrition to the fetus. Uterine natural killer (uNK) cells are the most abundant immune cells at the maternal-fetal interface during early pregnancy and play critical roles throughout pregnancy. This review provides current knowledge about the functions of uNK cells. uNK cells have been shown to facilitate remodeling of the spiral artery, control the invasion of extravillous trophoblast (EVT) cells, contribute to the induction and maintenance of immune tolerance, protect against pathogen infection, and promote fetal development. Pregnancy-trained memory of uNK cells improves subsequent pregnancy outcomes. In addition, this review describes the distinct functions of three uNK cell subsets: CD27-CD11b-, CD27+ and CD27-CD11b+ uNK cells.

[Evaluation of the success of medical abortion by a plasma hCG control threshold]

OBJECTIVES

In France, monitoring of the success of medical abortion is recommended 2 to 3 weeks after the procedure. However, there is no clear consensus on the modalities of this monitoring. The main objective of this study is to identify a threshold of serum hCG (human chorionic gonadotropin) control for medical abortions ≤7 weeks of gestation below which success can be confirmed without recourse to pelvic ultrasound.

METHODS

This is a retrospective multicenter study conducted over a 14-month period. The serum hCG level, measured between the 15th and 25th day following the abortion, was compared with the results of the pelvic ultrasound performed at the follow-up visit. Ultrasound failure was defined as retention or persistent pregnancy.

RESULTS

Among the 624 women included, the failure rate was 22.3%, including 86.3% of retentions, 8.6% of pregnancies stopped and 5% of pregnancies progressed. Using a ROC curve, the threshold value of hCG found to exclude failure at 95% was 253 IU/l (AUC=0.9202, sensitivity=84.17%, specificity=85.95% and positive predictive value [PPV]=63%).

CONCLUSIONS

A serum hCG level ≤253 IU/l is sufficient to affirm the efficacy of medical abortion. However, since PPV is only 63% for this threshold, ultrasound should be reserved for women with high hCG levels.

Relationship between weight retention at 6 weeks postpartum and the risk of large-for-gestational age birth in a second pregnancy in China: a retrospective cohort study

OBJECTIVE

We aimed to investigate the association between weight retention at 6 weeks postpartum after the first pregnancy and large-for-gestational age (LGA) risk in a subsequent pregnancy.

STUDY DESIGN

A retrospective cohort study.

SETTING

A tertiary hospital of China.

PARTICIPANTS

5950 Chinese singleton pregnancies that delivered their second singletons between 28 and 42 weeks of gestation.

OUTCOMES MEASURES

We calculated the weight retention at 6 weeks postpartum after the first pregnancy (the body mass index (BMI) at 6 weeks after the first birth minus the prepregnant BMI of the first pregnancy) and the gestational weight gain in the second pregnancy. We used the logistic regression to obtain adjusted OR. We determined the relationship between maternal BMI change at 6 weeks after the first pregnancy and LGA risk in the second pregnancy.

RESULTS

Relative to other categories of BMI change at 6 weeks postpartum, women who gained ≥3 kg/m² compared with the prepregnancy BMI were at increased LGA risk. The stratified analysis showed that LGA risk was increased in the second pregnancy in underweight and normal weight women who gained ≥3 kg/m² when using remain stable women as the reference group (OR=3.35, 95% CI 1.11 to 10.12 for underweight women; OR=2.23, 95% CI 1.43 to 3.45 for normal weight women) at 6 weeks postpartum. For the women who gained ≥3 kg/m² at 6 weeks postpartum, LGA risk was increased in normal weight women with an adequate (OR=3.21, 95% CI 1.10 to 9.33) and excessive (OR=2.62, 95% CI 1.02 to 6.76) gestational weight in the second pregnancy when using obese women as the reference.

CONCLUSION

Postpartum weight retention at 6 weeks after the first pregnancy provides us a new early window to identify LGA risk in a subsequent pregnancy and allows us to implement primary preventative strategies.

Natural killer cells: functional differences in recurrent spontaneous abortion†

Recurrent spontaneous abortion (RSA) is one of the major pregnancy disorders and poses a serious risk to both the mother and the fetus. Although a number of research efforts have been conducted, therapeutic advances for treating RSA have not lived up to their expectations. Hence, other treatments should be explored. The important role of natural killer (NK) cells in immunotherapy is attracting increasing attention, both as a pharmaceutical target and for cell therapies. NK cells are abundant in the endometrium and play a role in implantation and placentation in normal pregnancy. As research progresses, NK cells are increasingly regarded as playing essential roles in the emergence and development of RSA. In this article, I review recent findings on the role of uterine NK cells in the pathophysiology of RSA. These cells may become therapeutic NK cell-related targets. In conclusion, although several issues regarding NK cells in RSA remain unresolved and require further investigation, extensive evidence is available for the treatment of RSA.

How Do Uterine Natural Killer and Innate Lymphoid Cells Contribute to Successful Pregnancy?

Innate lymphoid cells (ILCs) are the most abundant immune cells in the uterine mucosa both before and during pregnancy. Circumstantial evidence suggests they play important roles in regulating placental development but exactly how they contribute to the successful outcome of pregnancy is still unclear. Uterine ILCs (uILCs) include subsets of tissue-resident natural killer (NK) cells and ILCs, and until recently the phenotype and functions of uILCs were poorly defined. Determining the specific roles of each subset is intrinsically challenging because of the rapidly changing nature of the tissue both during the menstrual cycle and pregnancy. Single-cell RNA sequencing (scRNAseq) and high dimensional flow and mass cytometry approaches have recently been used to analyse uILC populations in the uterus in both humans and mice. This detailed characterisation has significantly changed our understanding of the heterogeneity within the uILC compartment. It will also enable key clinical questions to be addressed including whether specific uILC subsets are altered in infertility, miscarriage and pregnancy disorders such as foetal growth restriction and pre-eclampsia. Here, we summarise recent advances in our understanding of the phenotypic and functional diversity of uILCs in non-pregnant endometrium and first trimester decidua, and review how these cells may contribute to successful placental development.

Learning from experience: cellular and molecular bases for improved outcome in subsequent pregnancies

The frequencies of preeclampsia, fetal growth restriction, fetal demise, and low birthweight are lower in subsequent pregnancies. Enhanced maternal cardiovascular adaptation, shorter first and second stages of labor, and more robust lactation also have been observed in subsequent as compared with first pregnancies. We sought to investigate the cellular and molecular bases for better outcomes in subsequent pregnancies. Based on the knowledge that specialized immune cells at the maternal-fetal interface, decidual natural killer cells, promote development of the placental bed and conversion of the spiral arteries by secreting a myriad of angiogenic and growth factors, we asked whether decidual natural killer cells differ in subsequent as compared with first pregnancies. This idea stemmed from recent studies suggesting that natural killer cells, although part of the innate immune system, possess some features of adaptive immunity, including a certain type of immune cell memory, termed trained immunity. We found that decidual natural killer cells from parous women "remember pregnancy" and differ from decidual natural killer cells of primigravidae. Compared with the decidual natural killer cells of first pregnancy, these cells, that we termed pregnancy-trained decidual natural killer cells, express greater levels of the natural killer receptors NKG2C and leukocyte immunoglobulin-like receptor B1, which interact with ligands expressed on invasive trophoblasts. Furthermore, they secrete greater levels of several growth factors, including vascular endothelial growth factor α as well as interferon-γ, augmenting remodeling of the placental bed. We propose that this pregnancy-trained memory dwells in the epigenome, where memory of stimuli is known to persist even when the stimulus is no longer present. This epigenetic memory apparently resides in endometrial natural killer cells between pregnancies. We suggest that this trained memory, which we coined pregnancy-trained decidual natural killer cells, may be the missing link in the immune basis for enhanced subsequent pregnancy. Epigenetic memory (chromatin modification) also may afford a global explanation for additional findings of enhanced maternal cardiovascular adaptation, shorter first and second stages of labor, and more robust lactation. Understanding the molecular and cellular bases of improved outcomes of subsequent pregnancy may lead to the development of treatment modalities designed for women at high risk for pregnancy disorders originating at the maternal-fetal interface.

Features of Human Decidual NK Cells in Healthy Pregnancy and During Viral Infection

The hallmark of human early pregnancy is the accumulation of a unique population of Natural Killer (dNK) cells at the main maternal-fetal interface, the decidua basalis. dNK cells play a crucial role in successful placentation probably by orchestrating the invasion of trophoblast cells deep into the decidua basalis and remodeling of the maternal spiral arteries. Recent advances in the field emphasize the importance of the local microenvironment in shaping both the phenotype and the effector functions of these innate lymphoid cells. Despite slow progress in the field, ex vivo studies revealed that dNK cells sense and destroy infected cells in order to protect the fetus from invading pathogens. In this review, we will discuss key features of dNK cells during healthy pregnancy as well as their functional adaptations in limiting pathogen dissemination to the growing conceptus. The challenge is to better understand the plasticity of dNK cells in the maternal-fetal interface. Such insights would enable greater understanding of the pathogenesis in congenital infections and pregnancy disorders.

Uterine Natural Killer Cells

Natural killer (NK) cells are members of a rapidly expanding family of innate lymphoid cells (ILCs). While most previously studied NK cells were derived from the mouse spleen and circulate in the blood, recently others and we found tissue-resident NK (trNK) cells in many tissues that resemble group 1 ILCs (ILC1s). During pregnancy, NK cells are the most abundant lymphocytes in the uterus at the maternal-fetal interface and are involved in placental vascular remodeling. Prior studies suggested that these uterine NK (uNK) cells are mostly derived from circulating NK cells. However, the murine virgin uterus contains mostly trNK cells and it has been challenging to determine their contribution to uNK cells in pregnancy as well as other potential function(s) of uNK cells due to the dynamic microenvironment in the pregnant uterus. This review focuses on the origins and functions of the heterogeneous populations of uNK cells during the course of murine pregnancy.

Effect of nutritional status of pregnant women on birth weight of newborns at Butajira Referral Hospital, Butajira, Ethiopia

Back ground:

Maternal nutritional status influences the developmental environment of the fetus which consequently affects the birth weight of the newborn. However, the association between maternal nutritional factors and birth weight is complex and is not well characterized in Ethiopia.

Objective:

To assess the effect of maternal anthropometry and biochemical profile on birth weight of babies at Butajira Referral Hospital, Butajira, Ethiopia.

Methods and materials:

Laboratory-based cross-sectional study was conducted among 337 pregnant women at the hospital. Socio-demographic and obstetric characteristics were collected using pre-tested questionnaires. Blood sample was collected from each pregnant women for determination of total serum protein, total serum cholesterol and hemoglobin level. However, maternal dietary habits were not assessed in this study.

Results:

A total of 337 pregnant women were involved in the study. The mean (standard deviation) birth weight of the newborns was 3.14 ± 0.46 kg. After adjusting for different maternal factors, parity (p = 0.013), hemoglobin level (p = 0.046), pre-pregnancy body mass index (p < 0.001) and weight gain during pregnancy (p < 0.001) were positively associated with birth weight of the newborns, while the associations with total protein (p = 0.822) and total cholesterol (p = 0.423) were not significant.

Conclusion:

This study has shown that nutritional status of pregnant women as indicated by maternal anthropometry and hemoglobin level was associated with birth weight of the baby. Therefore, nutritional status of the pregnant women should be improved to reduce the risk of low birth weight.

Trained Memory of Human Uterine NK Cells Enhances Their Function in Subsequent Pregnancies

Natural killer cells (NKs) are abundant in the human decidua, regulating trophoblast invasion and angiogenesis. Several diseases of poor placental development are associated with first pregnancies, so we thus looked to characterize differences in decidual NKs (dNKs) in first versus repeated pregnancies. We discovered a population found in repeated pregnancies, which has a unique transcriptome and epigenetic signature, and is characterized by high expression of the receptors NKG2C and LILRB1. We named these cells Pregnancy Trained decidual NK cells (PTdNKs). PTdNKs have open chromatin around the enhancers of IFNG and VEGFA. Activation of PTdNKs led to increased production and secretion of IFN-γ and VEGFα, with the latter supporting vascular sprouting and tumor growth. The precursors of PTdNKs seem to be found in the endometrium. Because repeated pregnancies are associated with improved placentation, we propose that PTdNKs, which are present primarily in repeated pregnancies, might be involved in proper placentation.

Immune responses at the maternal-fetal interface

Pregnancy poses an immunological challenge because a genetically distinct (nonself) fetus must be supported within the pregnant female for the required gestational period. Placentation, or the establishment of the fetally derived placenta, is a common strategy used by eutherian mammals to protect the fetus and promote its growth. However, the substantial morphological differences of the placental architecture among species suggest that the process of placentation results from convergent evolution. Although there are considerable similarities in placental function across placental mammals, there are important differences that arise owing to species-specific immunological (and other biological) constraints. This Review focuses on the immunological similarities and differences that occur at the maternal-fetal interface in the context of human and mouse pregnancies. We discuss how the decidua and placenta of these different species form key immunological barriers that sustain maternal tolerance yet generate innate immune responses that prevent microbial infections.

Changes in intrapartum maternal placental growth factor levels in pregnancies complicated by fetal compromise at term

BACKGROUND

Intrapartum fetal compromise (IFC) may result from the gradual decline in placental function during labour and can precipitate adverse neonatal outcomes. Placental growth factor (PlGF) is a biomarker of placental function. This study aims to investigate maternal PlGF levels and adverse perinatal outcomes in term labour.

METHODS

Prospective observational study (Mater Mothers' Hospital, Brisbane). Eligibility: 37⁺⁰- 42⁺⁰ weeks gestation, singleton, cephalic, non-anomalous pregnancies. Cases of pre-eclampsia and fetal growth restriction were excluded. Maternal PlGF was sampled at the onset of the first stage of labour (1st PlGF) and again at the second stage (2nd PlGF).

RESULTS

Sixty-three participants met inclusion criteria. Women requiring operative delivery (n = 11) for IFC had lower 1st PlGF (90.8 vs. 111.8 pg/ml) and 2nd PlGF (65.8 vs. 83.7 pg/ml) compared to the no-IFC cohort (n = 52). PlGF levels decreased significantly during labour in both the IFC (90.8 vs. 65.8 pg/ml, p = 0.021) and no-IFC (111.8 v 83.7, p < 0.001) cohorts, although the decline in PlGF levels was greater in the IFC cohort (-41.8% vs. -23.4%, p = 0.385). Maternal PlGF levels were significantly lower in those with an abnormal fetal heart rate pattern, cord arterial pH < 7.2, nursery admission and composite adverse neonatal outcome (CANO). PlGF decline was not correlated to duration of labour but was influenced by nulliparity and induced labour.

CONCLUSIONS

Maternal PlGF levels are lower in pregnancies complicated by IFC and CANO, and declines more sharply during labour compared to the no-IFC cohort. The utility of PlGF as a predictor of IFC should be further investigated with clinical trials.

A low fetal cerebroplacental ratio confers a greater risk of intrapartum fetal compromise and adverse neonatal outcomes in low risk multiparous women at term

BACKGROUND

A low fetal cerebroplacental ratio (CPR) and nulliparity have independently been shown to be associated with adverse obstetric and perinatal outcomes.

OBJECTIVES

To assess the effect of parity on the CPR and investigate the utility of a CPR threshold of <10^th centile for predicting adverse outcomes. We hypothesised that nulliparous women would have a lower CPR than multiparous women, impacting the diagnostic performance of the <10^th centile threshold. This is an important consideration for interpretation of a low CPR in clinical practice.

STUDY DESIGN

This was a retrospective cohort study of low risk, singleton pregnancies delivering at term in Australia's largest maternity hospital. The primary outcome was emergency caesarean section for intrapartum fetal compromise (EmCS IFC). Data was dichotomised according to parity and further by CPR <10^th centile. Multiple logistic regression was performed.

RESULTS

4737 women were included for analysis, 2333 were nulliparous and 2404 were multiparous. Overall the z-score (mean [SD])(CPR standardised for gestation) was lower in nulliparous compared to multiparous women (-0.16 [-1.73 - 1.42] vs 0.04 [-1.63 - 1.69], p < 0.001). Multiparous women had a non-significantly lower mean z-score for those who delivered by EmCS IFC than nulliparous women (-0.52 [-2.23 - 2.02] vs -0.45 [-2.22 - 1.1]). Nulliparous women had greater odds of having a CPR <10^th centile compared to the multiparous cohort (OR 1.24, 95% CI 1.02-1.5 vs. OR 0.81, 95% CI 0.7-0.98, p < 0.001). A CPR thresholdd <10^th centile in nulliparous women was associated with increased odds of intrapartum fetal compromise (IFC), EmCS IFC (aOR 1.72, 95CI 1.2-2.6, p < 0.05) and birthweight <10^th centile. A low CPR in multiparous women was associated with increased odds of all adverse perinatal outcomes measured: IFC, meconium stained liquor, EmCS IFC (aOR 4.99, 95%CI 2.5-9.9, p < 0.001), birthweight <10^th centile, acidosis, neonatal intensive care admission and severe composite neonatal outcome. These aORs were associated with specificities of >90% and false positive rates of <10% for all outcomes in multiparous women.

CONCLUSIONS

A CPR <10^th centile in multiparous women confers greater odds of adverse perinatal outcomes and as such of the influence of parity should be taken into account when decisions regarding clinical management are made because of a low CPR.

Postponing parenthood to advanced age

The aim of the Postponing Parenthood project was to investigate several aspects of the delaying of childbearing phenomenon in Sweden and Norway, such as medical risks and parental experiences. Data were retrieved from the Swedish and Norwegian Medical Birth Registers and three different cohorts: the Swedish Young Adult Panel Study, the Norwegian Mother and Child Cohort, and the Swedish Women's Experiences of Childbirth cohort. Postponing childbirth to age 35 years and later increased the risk of rare but serious pregnancy outcomes, such as stillbirth and very preterm birth. Older first-time parents were slightly more anxious during pregnancy, and childbirth overall was experienced as more difficult, compared with younger age groups. First-time mothers' satisfaction with life decreased from about age 28 years, both when measured during pregnancy and early parenthood. Delaying parenthood to mid-30 or later was more related to lifestyle than socioeconomic factors, suggesting that much could be done in terms of informing young persons about the limitations of fertility and assisted reproductive techniques, and the risks associated with advanced parental age.

Can we measure the spiral and uterine artery blood flow by real-time sonography and Doppler indices to predict spontaneous miscarriage in a normal-risk population?

Introduction: The predictive value of spiral artery flow Doppler measurements of a subsequent early miscarriage in first trimester pregnancy is explored here. Objective: The aim of this study is to determine uterine and spiral artery blood flow changes in first trimester subsequent miscarriages and correlate within the mechanisms of the Doppler indicies. Study design: The uterine artery and spiral artery pulsatility and resistance indexes, systolic and diastolic ratios, acceleration times, and blood flow of both the right and left uterine arteries were obtained by trans vaginal color Doppler ultrasonography in consecutive viable pregnancies between 5 and 12 gestational week. Women were subsequently classified as having continuing pregnancies or pregnancy loss before 20 weeks gestation. To predict subsequent pregnancy loss, Doppler findings were adjusted for maternal age, history of previous abortion, presence of subchorionic hematoma, embryonic bradycardia, and gestational age by means of multivariate logistic regression analysis. The cut-off values are used for the ROC curve. Results: Twenty-five pregnancies (11.7%) were spontaneously aborted before 20 weeks of gestational age. In 29 (13.6%) cases there were previously abortion history, 30 (14%) had bradycardia, and 37 (17.3%) had subchoronic hematoma. Regarding the parameters of uterine and spiral artery pulsatility and resistive index, acceleration time, systolic/diastolic ratios and blood flows, only uterine artery S/D low values were significantly associated with pregnancy loss in the multivariate logistic regression analysis (P = 0.0001,95% CI: 4.968-55.675). Conclusion: The uterine artery systolic/diastolic ratios have a predictive value for early pregnancy loss and seem to be useful as a marker. On the other hand, spiral artery changes could be so local that they cannot be determined by the parameters of spectral Doppler techniques. This suggests that uterine vascular bed alterations should be measured to understand the prognosis of early pregnancy loss during the first trimester.

Influence of parity on fetal hemodynamics and amniotic fluid volume at term

OBJECTIVES

Pregnancy complications, particularly those associated with placental dysfunction, occur more frequently in nulliparous than in parous women. This difference may be a consequence of improved trophoblastic invasion and, as a result, improved placental function following previous pregnancy. Placental dysfunction in cases of fetal growth restriction may be identified by ultrasound assessment of fetoplacental hemodynamics and amniotic fluid volume. In this prospective observational study, we investigated whether differences in these measures of placental function exist between nulliparous and parous women, prior to active labor.

METHODS

Over a 2-year period, 456 nulliparous and 152 parous women with uncomplicated singleton pregnancies were recruited to this prospective observational study. Each participant underwent an ultrasound assessment prior to active labor, during which fetal biometry, umbilical artery, middle cerebral artery and umbilical venous Dopplers, as well as amniotic fluid volume, were assessed. All cases were followed up within 48 h of delivery. Ultrasound parameters and intrapartum outcomes were then compared between the nulliparous and parous groups.

RESULTS

Compared with nulliparous women, parous women had significantly higher fetal middle cerebral artery pulsatility index, cerebroplacental ratio and amniotic fluid volume. In nulliparous women, middle cerebral artery flow rate was also significantly higher and represented a greater percentage of umbilical venous flow than was observed in parous women.

CONCLUSION

Prior to the active phase of labor, ultrasound parameters indicative of placental function differ significantly between nulliparous and parous pregnancy, even amongst an uncomplicated, low-risk cohort.

The association between parity and birthweight in a longitudinal consecutive pregnancy cohort

BACKGROUND

Nulliparity is associated with lower birthweight, but few studies have examined how within-mother changes in risk factors impact this association.

METHODS

We used longitudinal electronic medical record data from a hospital-based cohort of consecutive singleton live births from 2002-2010 in Utah. To reduce bias from unobserved pregnancies, primary analyses were limited to 9484 women who entered nulliparous from 2002-2004, with 23,380 pregnancies up to parity 3. Unrestricted secondary analyses used 101,225 pregnancies from 45,212 women with pregnancies up to parity 7. We calculated gestational age and sex-specific birthweight z-scores with nulliparas as the reference. Using linear mixed models, we estimated birthweight z-score by parity adjusting for pregnancy-specific sociodemographics, smoking, alcohol, prepregnancy body mass index, gestational weight gain, and medical conditions.

RESULTS

Compared with nulliparas', infants of primiparas were larger by 0.20 unadjusted z-score units [95% confidence interval (CI) 0.18, 0.22]; the adjusted increase was similar at 0.18 z-score units [95% CI 0.15, 0.20]. Birthweight continued to increase up to parity 3, but with a smaller difference (parity 3 vs. 0 β = 0.27 [95% CI 0.20, 0.34]). In the unrestricted secondary sample, there was significant departure in linearity from parity 1 to 7 (P < 0.001); birthweight increased only up to parity 4 (parity 4 vs. 0 β = 0.34 [95% CI 0.31, 0.37]).

CONCLUSIONS

The association between parity and birthweight was non-linear with the greatest increase observed between first- and second-born infants of the same mother. Adjustment for changes in weight or chronic diseases did not change the relationship between parity and birthweight.

Birth order progressively affects childhood height

BACKGROUND

There is evidence suggesting that first-born children and adults are anthropometrically different to later-borns. Thus, we aimed to assess whether birth order was associated with changes in growth and metabolism in childhood.

METHODS

We studied 312 healthy prepubertal children: 157 first-borns and 155 later-borns. Children were aged 3-10 years, born 37-41 weeks gestation, and of birth weight appropriate-for-gestational-age. Clinical assessments included measurement of children's height, weight, fasting lipid and hormonal profiles and DEXA-derived body composition.

RESULTS

First-borns were taller than later-borns (P < 0·0001), even when adjusted for parents' heights (0·31 vs 0·03 SDS; P = 0·001). There was an incremental height decrease with increasing birth order, so that first-borns were taller than second-borns (P < 0·001), who were in turn taller than third-borns (P = 0·007). Further, among sibling pairs both height SDS (P = 0·009) and adjusted height SDS (P < 0·0001) were lower in second- vs first-born children. Consistent with differences in stature, first- (P = 0·043) and second-borns (P = 0·003) had higher IGF-I concentrations than third-borns. Both first- (P < 0·001) and second-borns (P = 0·004) also had reduced abdominal adiposity (lower android fat to gynoid fat ratio) when compared with third-borns. Other parameters of adiposity and blood lipids were unaffected by birth order.

CONCLUSIONS

First-borns were taller than later-born children, with an incremental height reduction from first to third birth order. These differences were present after correction for genetic height, and associated to some extent with alterations in plasma IGF-I. Our findings strengthen the evidence that birth order is associated with phenotypic changes in childhood.

First-born children have reduced insulin sensitivity and higher daytime blood pressure compared to later-born children

BACKGROUND

Evidence suggests that first-born children and adults are phenotypically different to later-born children. Therefore, we aimed to assess whether birth order would be associated with changes in metabolism in childhood.

METHODS

We studied 85 healthy prepubertal children aged 4 to 11 years, born 38 to 40 weeks' gestation, and birth weight appropriate for gestational age: 32 first-born and 53 later-born children. Clinical assessments included measurement of children's height, weight, fasting lipid and hormonal profiles, and dual-energy x-ray absorptiometry-derived body composition. Children also underwent 24-hour ambulatory blood pressure monitoring, and frequently sampled intravenous glucose tests with Bergman's minimal model.

RESULTS

First-born children were approximately 3 cm taller (height SD scores 0.88 vs 0.39; P = .009) and were slimmer (body mass index SD scores -0.05 vs 0.39; P = .048) than later-born children. Consistent with their taller stature, first-born children also had a 27% increase in IGF-I concentrations (227 vs 173 ng/mL; P = .002). Insulin sensitivity was reduced by 21% among first-borns compared to later-borns (8.4 vs 10.6 × 10(-4)/min/[mU/L]; P = .019). Further, 24-hour ambulatory blood pressure monitoring showed that first-borns had higher daytime systolic (+5 mm Hg; P = .032) and diastolic (+4 mm Hg; P = .029) blood pressure. Blood lipids were unaffected by birth order.

CONCLUSIONS

Although first-borns were taller and slimmer, these children had reduced insulin sensitivity and increased daytime blood pressure compared to later-borns. Thus, first-borns may be at a greater risk of metabolic and cardiovascular diseases in adult life. This finding may have important public health implications, in light of a worldwide trend toward smaller families.

Uterine artery Doppler velocimetry at 11-14 weeks in singleton pregnancies conceived by assisted reproductive technology

OBJECTIVE

Singleton pregnancies resulting from assisted reproductive technologies (ART) have an increased risk of preterm delivery, pre-eclampsia and intrauterine growth restriction. The aim of the present study was to determine whether first-trimester trophoblastic invasion, as assessed by uterine artery Doppler velocimetry, is different in singleton pregnancies resulting from ART compared to those conceived naturally.

METHODS

Case-control study on 31 singleton ART pregnancies (26 in-vitro fertilization-embryo transfer, five intracytoplasmic sperm injection) and 62 matched pregnancies conceived spontaneously. Doppler velocimetry was performed at 11-14 weeks of gestation.

RESULTS

The mean resistance index (coefficient of variation) was 0.70 (17%) and 0.70 (18%) in ART and controls, respectively (P = 0.92). The corresponding values for mean pulsatility index were 1.40 (44%) and 1.47 (44%) in ART and controls, respectively (P = 0.58). Pregnancies with no, unilateral or bilateral diastolic notches were 48%, 26%, 26% and 36%, 37%, 27%, in ART and controls, respectively (P = 0.43).

CONCLUSION

There are no differences in uterine artery Doppler indices between pregnancies obtained by invasive ART and naturally conceived matched controls. This finding suggests that there is no major difference in trophoblastic invasion of the maternal spiral arteries between ART and spontaneous pregnancies.