Population-based reference for birth weight for gestational age in northern China

Altered distribution of fatty acid exerting lipid metabolism and transport at the maternal-fetal interface in fetal growth restriction

INTRODUCTION

Fetal growth restriction (FGR) is a common complication of pregnancy. Lipid metabolism and distribution may contribute to the progression of FGR. However, the metabolism-related mechanisms of FGR remain unclear. The aim of this study was to identify metabolic profiles associated with FGR, as well as probable genes and signaling pathways.

METHODS

Metabolomic profiles at the maternal-fetal interface (including the placenta, maternal and fetal serum) from pregnant women with (n = 35) and without (n = 35) FGR were analyzed by gas chromatography-mass spectrometry (GC-MS). Combined with differentially expressed genes (DEGs) from the GSE35574 dataset, analysis was performed for differential metabolites, and identified by the Metabo Analyst dataset. Finally, the pathology and screened DEGs were further identified.

RESULTS

The results showed that fatty acids (FAs) accumulated in the placenta and decreased in fetal blood in FGR cases compared to controls. The linoleic acid metabolism was the focus of placental differential metabolites and genes enrichment analysis. In this pathway, phosphatidylcholine can interact with PLA2G2A and PLA2G4C, and 12(13)-EpOME can interact with CYP2J2. PLA2G2A and CYP2J2 were elevated, and PLA2G4C was decreased in the FGR placenta.

DISCUSSION

In conclusion, accumulation of FAs in the placental ischemic environments, may involve linoleic acid metabolism, which may be regulated by PLA2G2A, CYP2J2, and PLA2G4C. This study may contribute to understanding the underlying metabolic and molecular mechanisms of FGR.

Maturation of the gut metabolome during the first year of life in humans

The gut microbiota is involved in the production of numerous metabolites that maintain host wellbeing. The assembly of the gut microbiome is highly dynamic, and influenced by many postnatal factors, moreover, little is known about the development of the gut metabolome. We showed that geography has an important influence on the microbiome dynamics in the first year of life based on two independent cohorts from China and Sweden. Major compositional differences since birth were the high relative abundance of Bacteroides in the Swedish cohort and Streptococcus in the Chinese cohort. We analyzed the development of the fecal metabolome in the first year of life in the Chinese cohort. Lipid metabolism, especially acylcarnitines and bile acids, was the most abundant metabolic pathway in the newborn gut. Delivery mode and feeding induced particular differences in the gut metabolome since birth. In contrast to C-section newborns, medium- and long-chain acylcarnitines were abundant at newborn age only in vaginally delivered infants, associated by the presence of bacteria such as Bacteroides vulgatus and Parabacteroides merdae. Our data provide a basis for understanding the maturation of the fecal metabolome and the metabolic role of gut microbiota in infancy.

A New Birthweight Reference by Gestational Age: A Population Study Based on the Generalized Additive Model for Location, Scale, and Shape Method

BACKGROUND

It is important to choose a suitable birthweight reference to assess newborns, especially those that are small for gestational age (SGA). Currently, there is no regional standard reference for the north of China or for Shandong province.

METHODS

A total of 130,911 data records of singleton, live neonates born at 24-42 weeks of gestation were collected from 2016 to 2018 in Shandong province. A new birthweight-for-gestational age percentile reference was constructed based on the Generalized Additive Model for Location, Scale and Shape (GAMLSS) package in R version 3.5. The established gestational age weight curve was compared separately with the Fenton curve, INTERGROWTH-21st curve, and the Chinese Neonatal Network Standard curve of 2015.

RESULTS

We established the reference values of birthweight by gestational age at the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles. Newborns had much heavier birthweights than those in the INTERGROWTH-21st and Fenton curves at most gestational ages. Although the newborns' birthweight references were closer to the Chinese Neonatal Network Standard except a few for gestational age, this study and INTERGROWTH-21st had similar birthweight curve shapes.

CONCLUSIONS

There are obvious differences among the criteria for newborn birthweights. Therefore, it is more accurate to assess newborns using the local birthweight reference.

"Double Frozen Transfer" Could Influence the Perinatal and Children's Growth: A Nested Case-Control Study of 6705 Live Birth Cycles

OBJECTIVE

This study aims to evaluate neonatal and children growth outcomes of cryotransfer of embryos developed from frozen gametes [double frozen transfer (DFT)].

METHODS

This nested case-control study included 6,705 women who had a singleton live birth after embryo transfer at the Center for Reproductive Medicine, Shandong University, from 2008 to 2020. Of these, 745 women underwent frozen embryo transfer (FET) using embryos developed from frozen gametes (DFT). Propensity score methodology was used to balance the two groups by maternal age and body mass index (BMI) before evaluating outcomes. After age and BMI were matched using the propensity score methodology in a ratio of 1:4, the control groups enrolled 2,980 women who underwent fresh embryo transfer (ET) and 2,980 women underwent FET from fresh gametes. The children born were followed to at least 5 years of age, and some were followed up to 10 years. Neonatal outcomes and childhood growth measurements were compared among the three groups.

RESULTS

The average birth weight of the DFT group (3,462 g) was significantly higher than the FET group (3,458 g) and ET group (3,412 g). The rate of large for gestational age (LGA) babies in the DFT and FET group was higher than that for the ET group (30.9% vs. 24.8%; 29.4% vs. 24.8%, respectively). After adjusting for different confounder combinations in the three models, the birth weight and risk of LGA in the DFT and FET groups were still higher than in the ET group, and the values group of P for trend in the models were significant. In multiple linear regression analysis of the children's development, the height Z-score of children born from the DFT and FET group was higher than that for children from the ET group (β = 0.21, 95% CI 0.07-0.35; b = 0.17, 95% CI 0.05-0.28, respectively). However, childhood growth measurements including body weight Z-score and BMI Z-score were not significantly different among the three groups. In addition, the proportion of male children born from DET was higher than that from ET.

CONCLUSIONS

There is an increased risk of LGA babies associated with pregnancies conceived from DFT. Children are inclined to be taller in the future in this group than after FET. The related etiology and pathophysiology mechanisms still need to be revealed. In the future, well-designed, observational studies with in-depth collection of patients' characteristics may shed more light on this issue.

Association between endometrial thickness and birth weight in fresh IVF/ICSI embryo transfers: a retrospective cohort study of 9273 singleton births

RESEARCH QUESTION

What is the association between endometrial thickness (EMT) on HCG trigger day and outcomes related to birth weight in fresh IVF and intracytoplasmic sperm injection (ICSI) embryo transfer cycles?

DESIGN

A retrospective cohort study of 9273 singleton live births born to women undergoing fresh IVF/ICSI cycles in a single centre between January 2014 and December 2018. Multivariable logistic regression was used to investigate the associations between EMT, low birth weight (LBW) and small for gestational age (SGA). Multivariable-adjusted linear regression models incorporating restricted cubic splines were used to investigate the dose-response relationship between EMT, birth weight and birth weight z-score, respectively. An EMT of 8 mm was set as a reference value.

RESULTS

Compared with women with an EMT of 8.0 to < 14.0 mm the risk of delivering a SGA infant was increased with EMT < 8.0 mm (adjusted odds ratio [aOR] 1.78, 95% confidence interval [CI] 1.09 to 2.90) and decreased with EMT ≥ 14.0 mm (aOR 0.57, 95% CI 0.35 to 0.93, respectively). Birth weights of infants born to women with an EMT of 8.0 mm compared with women with EMT of 5.0, 6.0, and 7.0 mm were lower by 120 g (95% CI -175 g to -66 g), 80 g (95% CI -116 g to -44 g), and 40 g (95% CI -58 g to -22 g) respectively; infant birth weight z-scores were also decreased by 0.19 (95% CI -0.27 to -0.10), 0.12 (95% CI -0.18 to -0.07) and 0.06 (95% CI -0.09 to -0.03), respectively.

CONCLUSIONS

A thinner endometrium was associated with lower birth weight and birth weight z-score, and higher risk of SGA. Women with a thin endometrium warrant special attention during pregnancy.

Phosphorylation of Yes-associated protein impairs trophoblast invasion and migration: implications for the pathogenesis of fetal growth restriction†

Fetal growth restriction (FGR) is a condition in which a newborn fails to achieve his or her prospective hereditary growth potential. This condition is associated with high newborn mortality, second only to that associated with premature birth. FGR is associated with maternal, fetal, and placental abnormalities. Although the placenta is considered to be an important organ for supplying nutrition for fetal growth, research on FGR is limited, and treatment through the placenta remains challenging, as neither proper uterine intervention nor its pathogenesis have been fully elucidated. Yes-associated protein (YAP), as the effector of the Hippo pathway, is widely known to regulate organ growth and cancer development. Therefore, the correlation of the placenta and YAP was investigated to elucidate the pathogenic mechanism of FGR. Placental samples from humans and mice were collected for histological and biomechanical analysis. After investigating the location and role of YAP in the placenta by immunohistochemistry, we observed that YAP and cytokeratin 7 have corresponding locations in human and mouse placentas. Moreover, phosphorylated YAP (p-YAP) was upregulated in FGR and gradually increased as gestational age increased during pregnancy. Cell function experiments and mRNA-Seq demonstrated impaired YAP activity mediated by extracellular signal-regulated kinase inhibition. Established FGR-like mice also recapitulated a number of the features of human FGR. The results of this study may help to elucidate the association of FGR development with YAP and provide an intrauterine target that may be helpful in alleviating placental dysfunction.

New birthweight charts according to parity and type of delivery for the Spanish population

OBJECTIVE

Birthweight by gestational age charts enable fetal growth to be evaluated in a specific population. Given that maternal profile and obstetric practice have undergone a remarkable change over the past few decades in Spain, this paper presents new Spanish reference percentile charts stratified by gender, parity and type of delivery. They have been prepared with data from the 2010-2014 period of the Spanish Birth Statistics Bulletin.

METHODS

Reference charts have been prepared using the LMS method, corresponding to 1,428,769 single, live births born to Spanish mothers. Percentile values and mean birth weight are compared among newborns according to gender, parity and type of delivery.

RESULTS

Newborns to primiparous mothers show significantly lower birthweight than those born to multiparous mothers (p<0.036). Caesarean section was associated with a substantially lower birthweight in preterm births (p<0.048), and with a substantially higher birthweight for full-term deliveries (p<0.030). Prevalence of small for gestational age is significantly higher in newborns born by Caesarean section, both in primiparous (p<0.08) and multiparous mothers (p<0.027) and, conversely, the prevalence of large for gestational age among full-term births is again greater both in primiparous (p<0.035) and in multiparous mothers (p<0.007).

CONCLUSIONS

Results support the consideration of establishing parity and type of delivery-specific birthweight references. These new charts enable a better evaluation of the impact of the demographic, reproductive and obstetric trends currently in Spain on fetal growth.

Systematic review of the methodological quality of studies designed to create neonatal anthropometric charts

Babies all over the world are assessed at birth using neonatal anthropometric charts as a matter of clinical routine. This systematic review evaluated the methodological quality of studies designed to create neonatal anthropometric charts and to highlight features in the charts that could affect clinical decision-making and comparisons between populations. The variety and quality of available charts could affect how newborns at risk are identified, together with the indications for treatment, especially nutritional interventions.

CONCLUSION

The studies that generated the charts currently recommended for clinical use have major methodological limitations and international and regional comparisons are very difficult.