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
• Main Authors: George Mtove, Daniel T. R. Minja, Omari Abdul, Samwel Gesase, Kenneth Maleta, Titus H. Divala, Noel Patson, Ulla Ashorn, Miriam K. Laufer, Mwayiwawo Madanitsa, Per Ashorn, Don Mathanga, Jobiba Chinkhumba, Julie R. Gutman, Feiko O. ter Kuile, Sofie Lykke Møller, Ib C. Bygbjerg, Michael Alifrangis, Thor Theander, John P. A. Lusingu, Christentze Schmiegelow
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Malaria in pregnancy; Birthweight; Reference chart; Individual participant data meta-analysis; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-022-04307-2; https://doaj.org/article/4dedc147282f44089be3e048f6378425

Abstract Background 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. Methods 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. Results The 10th percentile for birthweights-for-gestational age was lower for STOPPAM than for Intergrowth-21, leading to a prevalence of SGASTOPPAM of 14.2% and SGAIG21 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 (SGASTOPPAM aOR 1.36 [1.09–1.71], p < 0.01 vs SGAIG21 aOR 1.21 [0.97–1.50], p = 0.08). Conclusions 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.