# Trends of Large for Gestational Age and Macrosomia and Their Mediating Effect on the Association Between Diabetes Mellitus and Obstetric Hemorrhage

## TL;DR

This study examines how large for gestational age (LGA) and macrosomia rates in China changed from 2012 to 2021 and how they link diabetes in pregnancy to obstetric hemorrhage.

## Contribution

The study identifies LGA and macrosomia as mediators between diabetes in pregnancy and obstetric hemorrhage, with regional disparities in their impact.

## Key findings

- The nationwide prevalence of LGA and macrosomia was 15.8% and 6.8%, respectively.
- LGA and macrosomia each mediated about 12% of the risk of obstetric hemorrhage from diabetes in pregnancy.
- LGA rates increased in rural and western China, while macrosomia rates declined.

## Abstract

This study aimed to determine the prevalence of large for gestational age (LGA) and macrosomia in China from 2012 to 2021 and explore if LGA and macrosomia mediate the relationship between diabetes mellitus in pregnancy (DIP) and obstetric haemorrhage. The overall annual change rate (ACR) was calculated, and stratification analysis was performed. Mediation analysis assessed the influence of LGA and macrosomia in the association between DIP and obstetric haemorrhage. The nationwide prevalence of LGA and macrosomia was 15.8% and 6.8%, respectively. The ACR for LGA was 0.71% (95% CI, 0.66%–0.76%); pre‐2016, −0.44% (95% CI, −0.63% to −0.25%); post‐2016, −0.29% (95% CI, −0.39% to −0.19%). The ACR for macrosomia was −1.17% (95% CI, −1.24% to −1.09%); pre‐2016, −0.73% (95% CI, −1.03% to −0.43%); post‐2016, −2.42% (95% CI, −2.59% to −2.26%). In western and rural area, the ACR for LGA was 1.94% (95% CI, 1.84%–2.05%) and 1.81% (95% CI, 1.73%–1.89%), and LGA was increasing among these women in the post‐2016 period. About 7.0% of pregnant women had DIP, and the LGA and macrosomia prevalences among women with DIP were 23.7% and 10.0%, respectively. In the mediation analysis, the total excess risk associated with DIP on obstetric haemorrhage was approximately 0.21 and the proportion mediated by LGA and macrosomia was 12.10% and 11.81%, respectively. In rural areas, the proportion mediated by LGA and macrosomia was amplified to 18.34% and 16.40%. Macrosomia rates declined steadily, but LGA rates increased slightly in disadvantaged areas. LGA and macrosomia mediated the association between DIP and obstetric haemorrhage, and the mediating effect intensified in rural regions. Addressing LGA warrants management for at‐risk fetuses.

LGA and macrosomia are in different decreasing rates in China. Both LGA and macrosomia can work as the mediator in the association between diabetes mellitus in pregnancy and obstetric haemorrhage, and the mediating effects are similar.

The nationwide prevalence of macrosomia in China has declined in recent years.Controlling fetal weight at the threshold of LGA remained a challenge, particularly for women from disadvantaged regions.Macrosomia or LGA may mediate the association between diabetes mellitus and obstetric haemorrhage.

The nationwide prevalence of macrosomia in China has declined in recent years.

Controlling fetal weight at the threshold of LGA remained a challenge, particularly for women from disadvantaged regions.

Macrosomia or LGA may mediate the association between diabetes mellitus and obstetric haemorrhage.