Maternal anaemia during early pregnancy and the risk of neonatal outcomes: a prospective cohort study in Central China

BACKGROUND: The purpose of this study was to explore the association between anaemia during early pregnancy and the risk of neonatal outcomes.

METHODS: We collected clinical data from pregnant women (≥18 years) who received their first antenatal care between 8 and 14 weeks of gestation in Hunan Provincial Maternal and Child Health Care Hospital.

Multiple logistic regression models and restricted cubic spline regression models were used to analyse the association between anaemia during early pregnancy and the risk of neonatal outcomes.

In addition, sensitivity analysis was further performed to assess the robustness of the results.

RESULTS: The prospective cohort study ultimately included 34 087 singleton pregnancies.

In this study, the rate of anaemia during early pregnancy was 16.3%.

Our data showed that there was a positive relationship between the rate of preterm birth, low birth weight as well as small for gestational age (SGA) and the severity of maternal anaemia (P(trend)<0.05).

After adjustment, the association of early pregnancy anaemia and haemoglobin (Hb) levels with the risk of preterm birth (mild anaemia adjusted OR (aOR) 1.37 (95% CI 1.25 to 1.52), moderate anaemia aOR 1.54 (95% CI 1.35 to 1.76) and severe anaemia aOR 4.03 (95% CI 2.67 to 6.08), respectively), low birth weight (mild anaemia aOR 1.61 (95% CI 1.44 to 1.79), moderate anaemia aOR 2.01 (95% CI 1.75 to 2.30) and severe anaemia aOR 6.11 (95% CI 3.99 to 9.36), respectively) and SGA (mild anaemia aOR 1.37 (95% CI 1.25 to 1.52), moderate anaemia aOR 1.54 (95% CI 1.35 to 1.76) and severe anaemia aOR 2.61 (95% CI 1.74 to 4.50), respectively; P(non-linear)<0.05) was observed.

However, no association was found between early pregnancy anaemia or Hb levels and the risk of congenital malformations.

Sensitivity analysis verified the stability of the results.

CONCLUSIONS: Maternal anaemia during early pregnancy was associated with an increased risk of preterm birth, low birth weight and SGA and their rates may increase with the severity of maternal anaemia.

TRIAL REGISTRATION NUMBER: ChiCTR1800016635.