Changes in maternal hemoglobin during pregnancy and birth outcomes

Abstract

BackgroundThe relationship between maternal hemoglobin (Hb) levels during pregnancy and birth outcomes has been controversial. Changes in Hb level during pregnancy may have an impact on birth outcomes. This study aimed to investigate whether changes in Hb levels from early to mid- or late pregnancy is associated with birth outcomes.MethodsParticipants were singleton mothers who delivered at the National Center for Child Health and Development between 34 and 41 weeks of gestation in 2010 and 2011 (n = 1,986). Hb levels were measured at three time points: early (<16 weeks), mid- (16–27 weeks), and late (28–36 weeks) pregnancy. Associations between changes in Hb levels from early to mid- or late pregnancy and birth outcomes (birth weight, Z-score of birth weight, placental weight, and placental ratio) were assessed by multiple regression, adjusting for maternal and fetal covariates.ResultsA smaller reduction in Hb levels from early to mid- or late pregnancy was significantly associated with lower birth weight, Z-score of birth weight, placental weight, and placental ratio. Compared to women with an intermediate reduction from early to late pregnancy, women with the least reduction had a significantly increased risk of delivering low birth weight (LBW) (adjusted odds ratio [aOR], 2.0; 95% confidence interval [CI], 1.3-3.1) and small-for-gestational-age (SGA) (aOR, 1.6; 95% CI, 1.04-2.3) infants, while women with the greatest reduction had a significantly decreased risk of delivering SGA (aOR, 0.38; 95% CI, 0.23-0.65) infants, but an increased risk of high placental ratio (aOR, 1.7; 95% CI, 1.2-2.5).ConclusionsHb changes from early to mid- or late pregnancy were inversely associated with birth weight, placental weight, and placental ratio.

Establishment of reference intervals for complete blood count parameters during normal pregnancy in Beijing

“…Since 1968, WHO suggested that anemia in pregnancy was likely to be present when Hb was <110 g/L . In our study, we found Hb had a decline during trimester 1, reaching the lowest point at trimester 2 and began to rise again at trimester 3, which was similar with previous studies . One reason for this phenomenon may be the secondary hemodilution to an increase in plasma volume, which is known as physiologic anemia .…”

Maternal Demographic and Placental Risk Factors in Term Low Birth Weight in Ghana

“…Recent reports have compelling evidence of the role of nutritional deficiencies and inadequacies in pre-eclampsia particularly micronutrients, iron supplementation and inadequate diversity in food sources [32][33][34]. Anaemia is a common maternal nutritional disorder that has also recently been shown to lead to fetal anaemia, poor growth and LBW [35][36][37]. Interestingly, there was little evidence in our study that vascular tree structure associated with LBW suggesting that the structure may not strongly impact the volume or available surface area for nutrient exchange in the study population.…”

Maternal Anemia and Iron Deficiency Anemia: Similarities and Singularities

“…However, the prevalence of iron deficiency anemia was 3.6% and 5.6%, respectively [16]. In Japan, the frequency of maternal anemia in 2011 increased substantially between the first and second trimesters, (4.5% and 44.1%, respectively) [11].…”

“…As a result of this discussion, anemia has become a priority for many countries, with the main goal being its reduction across different population groups [3]. There are many studies with different methodological strategies focusing on anemia [4][5][6][7][8][9][10][11][12]. Such studies include distinct population subgroups and different sample sizes, producing conflicting results [12].…”