Birth weight percentiles by sex and gestational age for twins born in southern China

Huazhang Miao,Qingguo Zhao,Rubi He,Xiu Zhang,Yuntao Wu,Fei Yao,Bing Li

doi:10.1038/s41598-018-36758-6

Abstract

Mean birth weight of twins is known to be lower than that of singletons, however, southern China lacks a twin-specific birth weight reference. In this paper, we use data from the Birth Certificate System in southern China, collected between January 1st 2014 and December 31st 2017 and including 161,076 twins, to calculate sex- and gestational week-specific birth weight percentiles (the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th). We applied generalized additive models for location, scale and shape (GAMLSS) when calculating the birth weight percentiles, and calculated percentiles for monochorionic and dichorionic twins separately. We next used data collected between Jan 1st 2018 and Apr 30th 2018, encompassing 12,371 live births, to calculate the SGA and LGA ratios using birth weight references in Australia, South Korea and China (based on birth defects surveillance system) and birth weight percentiles calculated in this study. Compared to dichorionic twins, monochorionic twins had lower birth weights at 25 to 42 weeks of gestation. The calculated SGA and LGA ratios were relatively stable compared to the other references.

Highlights

Mean birth weight of twins is known to be lower than that of singletons, southern China lacks a twin-specific birth weight reference
We used data collected between Jan 1st 2018 and Apr 30th 2018, encompassing 12,371 live births, to calculate the SGA and LGA ratios using birth weight references in Australia, South Korea and China and birth weight percentiles calculated in this study
The current study aims to construct the sex- and gestational age-specific birth weight reference percentiles for twins born in southern China, stratified by placental chorionicity

Summary

Introduction

Mean birth weight of twins is known to be lower than that of singletons, southern China lacks a twin-specific birth weight reference. We use data from the Birth Certificate System in southern China, collected between January 1st 2014 and December 31st 2017 and including 161,076 twins, to calculate sex- and gestational week-specific birth weight percentiles (the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th). Monochorionic twins had lower birth weights at 25 to 42 weeks of gestation. Infants are commonly defined as SGA or LGA if their birth weight percentile falls below the 10th percentile or above the 90th percentile of the reference standard[5,6]. SGA and LGA are associated with increased perinatal and infant mortality and morbidity, as well as long-term health problems. Proper use of birth weights reference percentiles to classify birth weight is of great significance for clinical work and research

Methods

Results

Conclusion