Anaemia in the first trimester and poor physiological plasma expansion during pregnancy negatively impact foetal weight and newborn anthropometrics: An observational cohort study in Tanzania

• Published in: Tropical medicine & international health 2024-03, Vol.29 (3), p.243-255
• Main Authors: Schmiegelow, Christentze, Møller, Sofie Lykke, Yde, Anna Mathilde, Nielsen, Birgitte Bruun, Hjort, Line, Theander, Thor Grundtvig, Lusingu, John Peter Andrea, Minja, Daniel Thomas Remias, Bygbjerg, Ib Christian
• Format: Article
• Language: English
• Subjects: anaemia; Anemia; anthropometry; Birth weight; birthweight; Blood flow; Circumferences; Clinical outcomes; Cohort analysis; foetal weight; Hemoglobin; Medical imaging; Neonates; Observational studies; Placenta; plasma expansion; Pregnancy; Regression models; uterine and umbilical blood flow; Weight reduction
• ISSN: 1360-2276; 1365-3156
• DOI: 10.1111/tmi.13967

Objectives Anaemia during pregnancy is a major health challenge affecting pregnancy outcome worldwide. The objectives of this study were to investigate the impact of severe–moderate anaemia in the first trimester, as well as changes in haemoglobin during pregnancy among non‐anaemic women, on foetal weight, placental blood flow and newborn anthropometrics. Methods In a prospective cohort study, 346 women residing in rural Tanzania were followed throughout pregnancy with serial ultrasound and newborn anthropometrics assessed within 24 h of delivery. Associations between placental blood flow, foetal weight and newborn anthropometrics with either first trimester severe–moderate anaemia (haemoglobin≤9.5 g/dL) or changes in haemoglobin from the first to the third trimester among non‐anaemic women, were assessed by mixed model regression and multiple linear regression, adjusting for maternal and foetal co‐variables. Foetal weights and birthweight were converted to z‐scores using a population based sex‐specific weight reference. Results Severe–moderate anaemia in the first trimester was associated with significantly reduced foetal weight z‐scores (adjusted mean difference (aMD) −0.44 (95% CI −0.81, −0.07)) and newborn anthropometric indices (birth weight z‐score aMD −0.55 (−0.9, −0.13), abdominal circumference aMD −11 mm (95% CI −20, −3)). There were no association between first trimester severe–moderate anaemia and placental blood flow. Among women who were non‐anaemic in the first trimester, women with the least reduction in haemoglobin (Δ ≥ −0.3 g/dL) delivered significantly smaller newborns (birthweight z‐score aMD −0.55 (−0.91, −0.20), abdominal circumference aMD −10 mm (95% CI −17, −3), compared to women with the greatest reduction (Δ haemoglobin ≤ −1.4 g/dL)). Conclusions Severe–moderate anaemia in early pregnancy was associated with smaller newborn anthropometrics which was reflected in smaller mean foetal weights in the second and third trimester. Furthermore, among women who were non‐anaemic in the first trimester, there was an association between smaller newborn anthropometrics and limited haemoglobin decrease during pregnancy, possibly reflecting insufficient plasma expansion.