gms | German Medical Science

Background: During the entire pregnancy the need for iron is increased. If a sufficient amount is not ingested, iron deficiency (ID) and iron deficiency anaemia (IDA) are the consequences that affect the health of both, the mother and the unborn child. The German prenatal care program checks for haemoglobin levels at the first examination in pregnancy and in the 24^th week if levels were ≥112 g/l in the first examination. The aim of this study was to evaluate the extent of ID and IDA in pregnant women in the 24^th week and supplemental iron intake in the 24^th and 36^th week. Additionally, we intended to find risk factors for untreated ID/IDA.

Materials and methods: Our study is based on the LIFE Child study birth cohort. From May 2011 until December 2019, data about iron status and intake in the 24^th week of 820 pregnant women was obtained. Additional information on iron intake in the 36^th week was obtained from 629 of those 820 women. Iron deficiency (ID) in pregnant women was defined as serum ferritin levels <30 µg/l and normal haemoglobin (≥105 g/l, WHO reference level) and/or MCV levels (laboratory reference level). IDA in pregnant women was defined as a decrease in haemoglobin and MCV. We classified two groups of pregnant women: those with untreated ID/IDA and those without untreated ID/IDA. Women with untreated ID/IDA did not take supplemental iron in the 24^th and 36^th week. Women of the other group had either no ID/IDA in the 24^th week, or had ID/IDA in the 24^th week and took supplemental iron either at both examination dates or at least at one. Socioeconomic status was assessed with the Winkler-Stolzenberg Index. Data about health conditions were obtained from a pregnancy history questionnaire and the German maternity pass.

Results: 77.6% (636/820) of pregnant women in the 24^th week had ID or IDA: of those 636 women, 98.7% (628/636) had ID and 1.3% (8/636) had IDA. 14.3% (91/636) of the pregnant women with ID/IDA did not take supplemental iron in the 24^th and 36^th week. Haemoglobin levels <105 g/l was seen in 4 of those 91 (4.4%) women in the 24^th week. Haemoglobin levels of those 91 women were between 98 to 135 g/l in the 24^th week, with 18 (19.8%) women <112 g/l, the threshold for further evaluation for anaemia set by German maternity guidelines.

The analyses for risk factors revealed that untreated ID/IDA was less probable in pregnant women with a higher socioeconomic status (OR=0.92, CI: 0.85–0.99). Factors that pose a higher risk for ID/IDA such as rapid pregnancy sequence, twin pregnancy, increased nausea, and hemorrhages during pregnancy were not correlated with untreated ID/IDA.

Conclusion: ID was very common among pregnant women in the 24^th week. Overall, our study shows that IDA occurred only in a few pregnant women in the 24^th week. Surprisingly, almost 15% of the women with ID/IDA did not receive treatment with supplemental iron in the 24^th and 36^th week. Our study results indicate that the control of the haemoglobin level with a limit value of 112 g/l in the 24^th week is not sufficient. Screening for ID/IDA should start earlier in pregnancy and should include serum ferritin levels. This would allow to identify women with iron deficiency early in pregnancy and to initiate an appropriate treatment, thus preventing anaemia at the end of the pregnancy and in the postpartum phase.