TY - JOUR
T1 - Stillbirth risk by fetal size among 126.5 million births in 15 countries from 2000 to 2020
T2 - A fetuses-at-risk approach
AU - National Vulnerable Newborn Mortality Collaborative Group and 15 Vulnerable Newborn Measurement Core Group
AU - Okwaraji, Yemisrach B
AU - Suárez-Idueta, Lorena
AU - Ohuma, Eric O
AU - Bradley, Ellen
AU - Yargawa, Judith
AU - Pingray, Veronica
AU - Cormick, Gabriela
AU - Gordon, Adrienne
AU - Flenady, Vicki
AU - Horváth-Puhó, Erzsébet
AU - Sørensen, Henrik Toft
AU - Abuladze, Liili
AU - Heidarzadeh, Mohammed
AU - Khalili, Narjes
AU - Yunis, Khalid A
AU - Al Bizri, Ayah
AU - Barranco, Arturo
AU - van Dijk, Aimée E
AU - Broeders, Lisa
AU - Alyafei, Fawzya
AU - Olukade, Tawa O
AU - Razaz, Neda
AU - Söderling, Jonas
AU - Smith, Lucy K
AU - Matthews, Ruth J
AU - Wood, Rachael
AU - Monteath, Kirsten
AU - Pereyra, Isabel
AU - Pravia, Gabriella
AU - Lisonkova, Sarka
AU - Wen, Qi
AU - Lawn, Joy E
AU - Blencowe, Hannah
N1 - © 2024 The Author(s). BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd.
PY - 2024/7/11
Y1 - 2024/7/11
N2 - OBJECTIVE: To compare stillbirth rates and risks for small for gestational age (SGA), large for gestational age (LGA) and appropriate for gestational age (AGA) pregnancies at 24-44 completed weeks of gestation using a birth-based and fetuses-at-risk approachs.DESIGN: Population-based, multi-country study.SETTING: National data systems in 15 high- and middle-income countries.POPULATION: Live births and stillbirths.METHODS: A total of 151 country-years of data, including 126 543 070 births across 15 countries from 2000 to 2020, were compiled. Births were categorised into SGA, AGA and LGA using INTERGROWTH-21st standards. Gestation-specific stillbirth rates, with total births as the denominator, and gestation-specific stillbirth risks, with fetuses still in utero as the denominator, were calculated from 24 to 44 weeks of gestation.MAIN OUTCOME MEASURES: Gestation-specific stillbirth rates and risks according to size at birth.RESULTS: The overall stillbirth rate was 4.22 per 1000 total births (95% CI 4.22-4.23) across all gestations. Applying the birth-based approach, the stillbirth rates were highest at 24 weeks of gestation, with 621.6 per 1000 total births (95% CI 620.9-622.2) for SGA pregnancies, 298.4 per 1000 total births (95% CI 298.1-298.7) for AGA pregnancies and 338.5 per 1000 total births (95% CI 337.9-339.0) for LGA pregnancies. Applying the fetuses-at-risk approach, the gestation-specific stillbirth risk was highest for SGA pregnancies (1.3-1.4 per 1000 fetuses at risk) prior to 29 weeks of gestation. The risk remained stable between 30 and 34 weeks of gestation, and then increased gradually from 35 weeks of gestation to the highest rate of 8.4 per 1000 fetuses at risk (95% CI 8.3-8.4) at ≥42 weeks of gestation. The stillbirth risk ratio (RR) was consistently high for SGA compared with AGA pregnancies, with the highest RR observed at ≥42 weeks of gestation (RR 9.2, 95% CI 15.2-13.2), and with the lowest RR observed at 24 weeks of gestation (RR 3.1, 95% CI 1.9-4.3). The stillbirth RR was also consistently high for SGA compared with AGA pregnancies across all countries, with national variability ranging from RR 0.70 (95% CI 0.43-0.97) in Mexico to RR 8.6 (95% CI 8.1-9.1) in Uruguay. No increased risk for LGA pregnancies was observed.CONCLUSIONS: Small for gestational age (SGA) was strongly associated with stillbirth risk in this study based on high-quality data from high- and middle-income countries. The highest RRs were seen in preterm gestations, with two-thirds of the stillbirths born as preterm births. To advance our understanding of stillbirth, further analyses should be conducted using high-quality data sets from low-income settings, particularly those with relatively high rates of SGA.
AB - OBJECTIVE: To compare stillbirth rates and risks for small for gestational age (SGA), large for gestational age (LGA) and appropriate for gestational age (AGA) pregnancies at 24-44 completed weeks of gestation using a birth-based and fetuses-at-risk approachs.DESIGN: Population-based, multi-country study.SETTING: National data systems in 15 high- and middle-income countries.POPULATION: Live births and stillbirths.METHODS: A total of 151 country-years of data, including 126 543 070 births across 15 countries from 2000 to 2020, were compiled. Births were categorised into SGA, AGA and LGA using INTERGROWTH-21st standards. Gestation-specific stillbirth rates, with total births as the denominator, and gestation-specific stillbirth risks, with fetuses still in utero as the denominator, were calculated from 24 to 44 weeks of gestation.MAIN OUTCOME MEASURES: Gestation-specific stillbirth rates and risks according to size at birth.RESULTS: The overall stillbirth rate was 4.22 per 1000 total births (95% CI 4.22-4.23) across all gestations. Applying the birth-based approach, the stillbirth rates were highest at 24 weeks of gestation, with 621.6 per 1000 total births (95% CI 620.9-622.2) for SGA pregnancies, 298.4 per 1000 total births (95% CI 298.1-298.7) for AGA pregnancies and 338.5 per 1000 total births (95% CI 337.9-339.0) for LGA pregnancies. Applying the fetuses-at-risk approach, the gestation-specific stillbirth risk was highest for SGA pregnancies (1.3-1.4 per 1000 fetuses at risk) prior to 29 weeks of gestation. The risk remained stable between 30 and 34 weeks of gestation, and then increased gradually from 35 weeks of gestation to the highest rate of 8.4 per 1000 fetuses at risk (95% CI 8.3-8.4) at ≥42 weeks of gestation. The stillbirth risk ratio (RR) was consistently high for SGA compared with AGA pregnancies, with the highest RR observed at ≥42 weeks of gestation (RR 9.2, 95% CI 15.2-13.2), and with the lowest RR observed at 24 weeks of gestation (RR 3.1, 95% CI 1.9-4.3). The stillbirth RR was also consistently high for SGA compared with AGA pregnancies across all countries, with national variability ranging from RR 0.70 (95% CI 0.43-0.97) in Mexico to RR 8.6 (95% CI 8.1-9.1) in Uruguay. No increased risk for LGA pregnancies was observed.CONCLUSIONS: Small for gestational age (SGA) was strongly associated with stillbirth risk in this study based on high-quality data from high- and middle-income countries. The highest RRs were seen in preterm gestations, with two-thirds of the stillbirths born as preterm births. To advance our understanding of stillbirth, further analyses should be conducted using high-quality data sets from low-income settings, particularly those with relatively high rates of SGA.
KW - fetuses-at-risk approach
KW - gestational age
KW - preterm birth
KW - size for gestational age
KW - stillbirth
U2 - 10.1111/1471-0528.17890
DO - 10.1111/1471-0528.17890
M3 - Article
C2 - 38991996
SN - 1470-0328
JO - BJOG: An International Journal of Obstetrics and Gynaecology
JF - BJOG: An International Journal of Obstetrics and Gynaecology
ER -