Parity-based assessment of anemia and iron deficiency in pregnant women

This study aimed to separately evaluate the prevalence of anemia and iron deficiency in nulliparous and multiparous women.

We retrospectively examined data of women who delivered in our clinic from January 2016 to December 2018. Inclusion criteria were delivery occurring at ≥36 weeks and singleton pregnancy. Pregnant women with severe medical disorders were excluded. We estimated complete blood count (CBC) and serum ferritin (SF) in the first trimester and only CBC in the late second trimester. Data of nulliparas and multiparas were analyzed separately. Statistically significance was set at p < 0.05.

Totally, 481 nulliparas and 603 and multiparas were enrolled. Mean hemoglobin values in the first trimester were 12.6 ± 1.0 and 12.4 ± 1.0 g/dl (p < 0.001), while median SF values were 42.7 (12.2, 108.2) and 27.7 (8.0, 72.6) ng/ml (p < 0.001) in nulliparas and multiparas, respectively. Hemoglobin in the late second trimester was 11.2 ± 0.9 and 10.7 ± 1.0 g/dl (p < 0.001) in nulliparas and multiparas, respectively. Low ferritin levels (SF < 12 ng/ml) were more frequently found in multiparas than in nulliparas (111/603 vs. 46/481, p < 0.001, Odds ratio [OR] = 2.13). Anemia in the first trimester (hemoglobin<11.0 g/dl) was found in 3.5% (17/481) and 8.8% (53/603) (p < 0.001; OR, 2.63), while that in late second trimester (hemoglobin<10.5) was observed in 21.0% (101/481) and 36.3% (219/603) (p < 0.001, OR = 2.15) nulliparas and multiparas, respectively. Non-anemic women (hemoglobin level ≥11.0) with low ferritin levels (SF < 12 ng/ml) in the first trimester showed higher rate of anemia development in the second trimester than those with both normal hemoglobin and ferritin levels, irrespective of parity (51.3% [19/37] vs. 16.2% [69/427], p < 0.001 in nulliparas and 76.9% [60/78] vs. 26.5% [125/472], p < 0.001 in multiparas].

Anemia and low SF levels occurred more commonly in multiparous than in nulliparas. Further, low SF was a risk factor for anemia development in later pregnancy.