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

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.

Should singleton birth weight standards be applied to identify small-for-gestational age twins?: analysis of a retrospective cohort study

“…The prevalence of SGA twins depends on the definition used. Due to the lack of reference, growth standards for singletons are commonly used to assess twin growth in clinical practice [ 23 , 33 ]. Previous studies showed that the growth trajectory of twins diverges from the one of singletons in the third trimester [ 13 , 19 , 34 , 35 ].…”

“…Despite several birth weight standards for twin gestations has been published in recent years in China [ 15 , 33 , 38 ], these standards seem not promoted. We undertook a local validation to assess the appropriateness of the chosen standards.…”

Reference values for babies' pulse oximetry recordings, highlighting the impact of cesarean sections and COVID-19 pandemic

“…The conventional values of low birth weight (2,500 gm) are determined by uterine growth expressed as the gestational age-specific birth-weight percentile. 9 Preterm birth (less than 37 weeks of gestation). 10 All of the children in the sample had physical exams, medical records reviewed, and tests performed in the lab, including measurements of arterial blood gas, serum hemoglobin, and chest X-rays to rule out diseases not identified during clinical evaluation.…”