Association between maternal haemoglobin at 27-29weeks gestation and intrauterine growth restriction.

OBJECTIVE

To examine the relationship between maternal haemoglobin concentration (Hb) at 27-29weeks' gestation and fetal growth restriction (FGR).

DESIGN

This was a retrospective, case control study.

SETTING

A University hospital in London, UK.

POPULATION

Pregnant women attending for routine antenatal care at 27-29weeks of pregnancy.

METHODS

Maternal Hb, measured routinely at 27-29weeks in pregnancies complicated by FGR (n=491) was compared to normal controls (n=491). Multiple regression analysis was used to examine the association between Hb and maternal characteristics.

MAIN OUTCOME MEASURES

Birthweight z-score, admission to the Neonatal Unit (NNU) and adverse perinatal outcome.

RESULTS

Increased Hb at 27-29weeks gestation is associated with reduced birthweight, with an inverse relationship between maternal Hb and fetal birthweight z-score (R(2)=0.10, p<0.0001). In addition, for the prediction of admission to the NNU (R(2)=0.24, p<0.0001) and serious adverse neonatal outcome (R(2)=0.10, p<0.0001), maternal Hb is an independent predictor with a linear and quadratic relationship, respectively. Therefore, both increased and decreased maternal Hb levels increase the risk of serious neonatal complications.

CONCLUSIONS

Raised Hb at 27-29weeks gestation is associated with FGR and with an increased risk of admission to the NNU and adverse fetal outcome.