National data linkage assessment of live births and deaths in Mexico: Estimating under-five mortality rate ratios for vulnerable newborns and trends from 2008 to 2019

Insights into the Global and Mexican Context of Placental-Derived Pregnancy Complications

Placental-derived pregnancy complications encompass a range of disorders that hinder optimal fetal development, significantly impacting maternal and neonatal health outcomes. Key conditions include placental insufficiency, preeclampsia, fetal growth restriction (FGR) or intrauterine growth restriction (IUGR), fetal overgrowth, and gestational diabetes mellitus (GDM), which together contribute to a heightened risk of preterm birth, perinatal mortality, and long-term developmental challenges in affected infants. These complications are particularly notable because they generate approximately 80% of pregnancy disorders and pose significant public health concerns across diverse global contexts. Their management continues to face challenges, including a lack of consensus on diagnostic criteria and varied implementation of care standards. While imaging techniques like magnetic resonance imaging (MRI) and Doppler ultrasound have emerged as critical tools in clinical assessment, disparities in access to such technologies exacerbate existing inequalities in maternal and fetal health outcomes. Maternal and pregnancy care is a broad range of services aimed at promoting the well-being of women throughout the perinatal period. However, access to these services is often limited by economic, geographical, and sociocultural barriers, particularly for marginalized groups and women in low- and middle-income countries (LMICs). The implementation of targeted interventions designed to address specific obstacles faced by disadvantaged populations is a crucial component of bridging the gap in health equity in maternal care. Public health authorities and policymakers strive to develop evidence-based strategies that address the interplay between healthcare access, socioeconomic factors, and effective interventions in order to mitigate the adverse effects of placental-derived pregnancy complications. Continued research and data collection are essential to inform future policies and practices to improve outcomes for mothers and infants.

Post-term births as a risk factor for small for gestational age births and infant mortality in Brazil, Mexico, and Palestinian refugees: An analysis of electronic birth records

BACKGROUND

Post-term pregnancy, defined as reaching or exceeding 42 + 0 weeks of gestation, is known to be associated with unfavourable birth outcomes. High-income countries have responded to this risk by widely adopting labour induction protocols in late-term, but many low- and middle-income countries have not. However, understanding underlying mechanisms linking post-term births to adverse newborn and infant outcomes remains limited.

OBJECTIVE

To investigate the (a) prevalence of post-term, (b) the risk factors associated with post-term (c) the association between post-term births and the risk of small-for-gestational-age (SGA) neonates and of infant mortality in middle-income settings.

METHODS

We used existing electronic datasets from the general population of Brazil, Mexico, and Palestinian refugees. Regression models were used to explore the associations between post-term birth and SGA and infant mortality.

RESULTS

We analysed 21,335,033 live births in Brazil (2011-2018), 23,416,126 in Mexico (2008-2019), and 966,102 in Palestinian refugees (2010-2020) (N = 45,717,261). Post-term deliveries accounted for 3.1% of births in Brazil, 1.2% in Mexico, and 2.1% in Palestinian refugees. Post-term births had approximately three times the risk of resulting in SGA neonates compared to term births. Additionally, post-term neonates exhibited a 15% to 40% increased risk of infant mortality compared to term infants. Notably, post-term SGA neonates faced a significantly increased risk of infant mortality compared to term appropriate for gestational age neonates.

CONCLUSIONS

These findings emphasise the critical significance of implementing induction strategies to prevent post-term pregnancies and mitigate the associated risks of SGA neonates and subsequent infant mortality. Moreover, the study highlights the importance of accurately determining gestational age and using INTERGROWTH-21st charts to improve the identification of SGA cases, enabling targeted interventions. This is especially relevant because post-term SGA neonates may not exhibit low birthweight (a commonly used risk marker) and, therefore, may miss out on required specialised attention.

Appendicular Muscle Mass Index as the Most Important Determinant of Bone Mineral Content and Density in Small for Gestational Age Children

Preterm small for gestational age (SGA) children are at increased risk for low bone mineral content later in life; however, data on SGA children born at term are scarce. We included 44 SGA and 57 adequate for gestational age (AGA) children aged 6 to 11 years to compare bone mineral density (BMD) and bone mineral content (BMC) and to identify which anthropometric and biochemical values influence bone mineralization in these children. Fat mass, appendicular skeletal muscle mass index (ASMMI), BMC, and BMD were significantly lower in SGA children than in AGA (P ≤ .005). Appendicular muscle mass index correlated with BMC(TBLH,FN,L1-L4) and BMD(TBLH,FN,L1-L4) in both groups (r2 = 0.7, P < .05). In multivariate analysis, ASMMI was strongly associated with BMC and BMD in both groups. There were no differences in clinical biomarkers, calcium intake, and physical activity between the groups. Achieving adequate muscle mass contributes to adequate bone mineralization and a lower risk for low BMC and BMD in SGA children.

Neonatal mortality risk of large-for-gestational-age and macrosomic live births in 15 countries, including 115.6 million nationwide linked records, 2000-2020

OBJECTIVE

We aimed to compare the prevalence and neonatal mortality associated with large for gestational age (LGA) and macrosomia among 115.6 million live births in 15 countries, between 2000 and 2020.

DESIGN

Population-based, multi-country study.

SETTING

National healthcare systems.

POPULATION

Liveborn infants.

METHODS

We used individual-level data identified for the Vulnerable Newborn Measurement Collaboration. We calculated the prevalence and relative risk (RR) of neonatal mortality among live births born at term + LGA (>90th centile, and also >95th and >97th centiles when the data were available) versus term + appropriate for gestational age (AGA, 10th-90th centiles) and macrosomic (≥4000, ≥4500 and ≥5000 g, regardless of gestational age) versus 2500-3999 g. INTERGROWTH 21st served as the reference population.

MAIN OUTCOME MEASURES

Prevalence and neonatal mortality risks.

RESULTS

Large for gestational age was common (median prevalence 18.2%; interquartile range, IQR, 13.5%-22.0%), and overall was associated with a lower neonatal mortality risk compared with AGA (RR 0.83, 95% CI 0.77-0.89). Around one in ten babies were ≥4000 g (median prevalence 9.6% (IQR 6.4%-13.3%), with 1.2% (IQR 0.7%-2.0%) ≥4500 g and with 0.2% (IQR 0.1%-0.2%) ≥5000 g). Overall, macrosomia of ≥4000 g was not associated with increased neonatal mortality risk (RR 0.80, 95% CI 0.69-0.94); however, a higher risk was observed for birthweights of ≥4500 g (RR 1.52, 95% CI 1.10-2.11) and ≥5000 g (RR 4.54, 95% CI 2.58-7.99), compared with birthweights of 2500-3999 g, with the highest risk observed in the first 7 days of life.

CONCLUSIONS

In this population, birthweight of ≥4500 g was the most useful marker for early mortality risk in big babies and could be used to guide clinical management decisions.