The choice of reference chart affects the strength of the association between malaria in pregnancy and small for gestational age: an individual participant data meta-analysis comparing the Intergrowth-21 with a Tanzanian birthweight chart

• Published in: Malaria journal Vol. 21; no. 1; p. 292
• Main Authors: Mtove, George, Minja, Daniel T R, Abdul, Omari, Gesase, Samwel, Maleta, Kenneth, Divala, Titus H, Patson, Noel, Ashorn, Ulla, Laufer, Miriam K, Madanitsa, Mwayiwawo, Ashorn, Per, Mathanga, Don, Chinkhumba, Jobiba, Gutman, Julie R, Ter Kuile, Feiko O, Møller, Sofie Lykke, Bygbjerg, Ib C, Alifrangis, Michael, Theander, Thor, Lusingu, John P A, Schmiegelow, Christentze
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 12.10.2022; BioMed Central; BMC
• Subjects: Age; Bias; Birth size; Birth Weight; Birthweight; Care and treatment; Clinical trials; Complications and side effects; Consortia; Female; Fetal Growth Retardation; Gestational Age; Health aspects; Histology; HIV; Human diseases; Human immunodeficiency virus; Humans; Individual participant data meta-analysis; Infant, Newborn; Infant, Small for Gestational Age; Malaria; Malaria - epidemiology; Malaria in pregnancy; Meta-analysis; Microscopy; Neonates; Physiological aspects; Pregnancy; Pregnant women; Reference chart; Regression analysis; Small for gestational age; Stillbirth; Tanzania - epidemiology; Ultrasonic imaging; Vector-borne diseases; Womens health; Tanzania; Africa; Individual participant data meta-analysis; Malaria in pregnancy; Reference chart; Birthweight
• ISSN: 1475-2875; 1475-2875
• DOI: 10.1186/s12936-022-04307-2

The prevalence of small for gestational age (SGA) may vary depending on the chosen weight-for-gestational-age reference chart. An individual participant data meta-analysis was conducted to assess the implications of using a local reference (STOPPAM) instead of a universal reference (Intergrowth-21) on the association between malaria in pregnancy and SGA. Individual participant data of 6,236 newborns were pooled from seven conveniently identified studies conducted in Tanzania and Malawi from 2003-2018 with data on malaria in pregnancy, birthweight, and ultrasound estimated gestational age. Mixed-effects regression models were used to compare the association between malaria in pregnancy and SGA when using the STOPPAM and the Intergrowth-21 references, respectively. The 10th percentile for birthweights-for-gestational age was lower for STOPPAM than for Intergrowth-21, leading to a prevalence of SGA of 14.2% and SGA of 18.0%, p < 0.001. The association between malaria in pregnancy and SGA was stronger for STOPPAM (adjusted odds ratio (aOR) 1.30 [1.09-1.56], p < 0.01) than for Intergrowth-21 (aOR 1.19 [1.00-1.40], p = 0.04), particularly among paucigravidae (SGA aOR 1.36 [1.09-1.71], p < 0.01 vs SGA aOR 1.21 [0.97-1.50], p = 0.08). The prevalence of SGA may be overestimated and the impact of malaria in pregnancy underestimated when using Intergrowth-21. Comparing local reference charts to global references when assessing and interpreting the impact of malaria in pregnancy may be appropriate.