Generation of a malaria negative Ugandan birth weight standard for the diagnosis of small for gestational age.

Arthurine K Zakama,Stephanie L Gaw,Moses Kamya,Mary K Muhindo,Terik Weekes,Richard Kajubi,Grant Dorsey,John Ategeka,Abel Kakuru,Diane Havlir,Prasanna Jagannathan,Clive J Petry

doi:10.1371/journal.pone.0240157

Abstract

ObjectivePlacental malaria is a known risk factor for small for gestational age (SGA) neonates. However, currently utilized international and African birthweight standards have not controlled for placental malaria and/or lack obstetrical ultrasound dating. We developed a neonatal birthweight standard based on obstetrically dated pregnancies that excluded individuals with clinical malaria, asymptomatic parasitemia, and placental malaria infection. We hypothesized that current curves underestimate true ideal birthweight and the prevalence of SGA.Study designParticipants were pooled from two double-blind randomized control trials of intermittent preventive therapy during pregnancy in Uganda. HIV-negative women without comorbidities were enrolled from 12–20 weeks gestation. Gestational age was confirmed by ultrasound dating. Women were followed through pregnancy and delivery for clinical malaria, asymptomatic parasitemia, and placental malaria. Women without malaria, asymptomatic parasitemia, or placental malaria formed the malaria negative cohort and generated the Ugandan birthweight standard. The Ugandan standard was then used to estimate the prevalence of SGA neonates in the malaria positive cohort. These findings were compared to international (Williams, World Health Organization (WHO), and INTERGROWTH-21st) and regional standards (Tanzanian and Malawi).Results926 women had complete delivery data; 393 (42.4%) met criteria for the malaria negative cohort and 533 (57.6%) were malaria positive. The Ugandan standard diagnosed SGA in 17.1% of malaria positive neonates; similar to the INTERGROWTH-21st and Schmiegelow curves. The WHO curve diagnosed SGA in significantly more neonates (32.1%, p = <0.001), and the Malawi curve diagnosed SGA in significantly fewer neonates (8.3%, p <0.001).ConclusionExclusion of women with subclinical placental malaria in malaria-endemic areas created birth weight norms at higher values and increased the detection of SGA. Birth weight standards that fail to account for endemic illness may underestimate the true growth potential of healthy neonates.

Highlights

Small for gestational age (SGA) is defined as neonates weighing less than the 10th percentile of birth weight for a specific completed gestational age of a given reference population [1]
We created a malaria negative birth weight standard based on longitudinally assessed maternal malaria status and histopathologic placental evaluation for assessing clinical malaria, placental malaria, and asymptomatic parasitemia
We found that our malaria negative Ugandan standard tended to diagnose more SGA neonates than WHO Uganda and Schmiegelow’s Tanzanian curve in women with malaria infection

Summary

Introduction

Small for gestational age (SGA) is defined as neonates weighing less than the 10th percentile of birth weight for a specific completed gestational age of a given reference population [1]. Research has found that the prevalence of SGA in a given population can vary significantly based on the reference cohort utilized [2]. Even within a given country, there can be significant differences between racial and ethnic groups in relation to the prevalence of SGA [5]. This point of ethnic variation in growth is contested by the INTERGROWTH-21st project that created an international fetal and neonatal growth standard based on the assumption of no difference in global fetal growth development [5,6]

Methods

Results

Discussion

Conclusion