Are pregnant women of non-Northern European descent more anaemic than women of Northern European descent? A study into the prevalence of anaemia in pregnant women in Amsterdam.

OBJECTIVES: to investigate the prevalence of anaemia in pregnancy according to the cut-off points used in the national clinical guideline 'Anaemia in Primary Care Midwifery Practice', and to investigate a possible difference in prevalence between pregnant women of Northern European descent compared with women of non-Northern European descent. The study also investigated whether any difference in prevalence resulted in a higher risk of a transferred home delivery, thus reducing the chance for women to choose the place of birth.
DESIGN: retrospective cohort study.
SETTING: primary care midwifery practices in a highly urbanised area in Amsterdam, the Netherlands. PARTICIPANTS: all patients in three midwifery practices over 1 year were selected provided that they met the inclusion and exclusion criteria. The practices were selected on the basis of urbanisation, resulting in an adequate ethnic population which was comparable with the ethnic mix in other similarly urbanised areas in the Netherlands. This resulted in a study population of 828 pregnant women of Northern European and non-Northern European descent with low-risk singleton pregnancies during 2003. ANALYSIS: mean haemoglobin level and anaemia rate were computed for the total study population as well as separate ethnic groups. Differences between groups were determined using chi(2) tests, and effect sizes were expressed in relative risks including 95% confidence intervals (CI).
FINDINGS: the prevalence of anaemia in pregnancy was 3.4% (n = 28) at booking (first visit) and 2.7% (n = 22) at approximately 30 weeks of gestation. The relative risk of anaemia at booking was 5.9 (95% CI 2.1-16.7) for pregnant women of non-Northern European descent compared with those of Northern European descent. The relative risk of anaemia at approximately 30 weeks of gestation was 22 (95% CI 3-162) for pregnant women of non-Northern European descent compared with those of Northern European descent. The incidence of transferred home delivery was 3.1% in the study population. The relative risk for transferred home delivery was 24.1 (95% CI 3.3-176.7) for pregnant women of non-Northern European descent compared with those of Northern European descent. KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: pregnant women of non-Northern European descent are a specific group in terms of anaemia and are at high risk of a low haemoglobin level for all cut-off values; they have a higher chance of becoming anaemic in pregnancy than women of Northern European descent. As a result, they have a higher risk of a transferred home delivery, taking away their opportunity to choose the place of birth. Haemoglobinopathies did not explain the higher risk of anaemia in pregnant women of non-Northern European descent. Being of non-Northern European descent should be added as a risk factor for anaemia in pregnancy until more is known about the background of this risk factor.