Hemoglobin levels during the first trimester of pregnancy are associated with the risk of gestational diabetes mellitus, pre-eclampsia and preterm birth in Chinese women: a retrospective study

Abstract

BackgroundHemoglobin (Hb) measurement is a standard test among pregnant women during the first perinatal visit that is used to evaluate physical status and anemia. However, studies focusing on Hb levels and pregnancy outcomes are scarce. This study aimed to determine whether Hb levels in early pregnancy were associated with the risk of gestational diabetes mellitus (GDM), pre-eclampsia (PE) and preterm birth.MethodsA hospital-based retrospective study was conducted among 21,577 singleton, non-smoking pregnancies between June 2013 and January 2015. The demographic data and medical information of each participant were collected individually through questionnaires and patient medical records. Odds ratios were generated using a multivariate logistic regression analysis to evaluate the relative risk of GDM, PE and preterm birth continuously and across different hemoglobin ranges in the overall population and in women from different pre-pregnancy body mass index (BMI) categories, respectively. The level of statistical significance was set at 0.05.Results(1) For women who were underweight, normal-weight, overweight and obese, early pregnancy Hb levels were 127.8 ± 10.1 g/L, 129.6 ± 9.7 g/L, 132.2 ± 9.5 g/L and 133.4 ± 9.4 g/L, respectively. (2) Women with GDM and PE had significantly increased Hb levels during early pregnancy compared with controls, whereas women with preterm birth processed significantly decreased Hb levels. (3) After adjusting for confounders, the risks for GDM and PE increased with high maternal Hb (OR: 1.27 for Hb 130–149; OR: 2.06 for Hb ≥ 150 g/L), and the risk for preterm birth decreased with high maternal Hb (OR: 1.30 for Hb 130–149; OR: 2.38 for Hb ≥ 150 g/L) and increased with low maternal Hb (OR: 1.41 for Hb < 110 g/L). Among women whose BMI was < 24 kg/m2, high GDM (OR: 1.27 for Hb 130–149; OR: 1.84 for Hb ≥ 150 g/L) and low preterm rates (OR: 0.77 for Hb 130–149; OR: 0.23 for Hb ≥ 150 g/L) were observed with high Hb, whereas in women whose BMI was ≥24 kg/m2, only high GDM rates were observed with Hb > 150 g/L (OR: 2.33).ConclusionThese findings suggest that Hb levels during early pregnancy play a role in predicting the risk of GDM, PE and preterm birth.

Effects of hemoglobin levels during pregnancy on adverse maternal and infant outcomes: a systematic review and meta‐analysis

“…The characteristics of all 117 included studies are presented in Table S6 (online only, see this Table for Refs. 111–125) . The selected studies were published between 1977 and 2018.…”

Maternal Anemia in Various Trimesters and Related Pregnancy Outcomes: Results from a Large Cohort Study in Iran

“…But in another study carried out in China, a relationship between preterm birth and anemia in all three trimesters has been reported with an opposite trend (a strong relationship between anemia in first trimester and preterm birth, compared to anemia in third trimester) (30). This was also reported in another similar study (31). It seems that more studies are needed in this area.…”

Haemoglobin trajectories during pregnancy and associated outcomes using pooled maternity and hospitalization data from two tertiary hospitals

“…However, a number of studies have investigated point estimates of Hb and anaemia in pregnancy and outcomes. Anaemia and low Hb in the pregnancy period have been linked to a higher risk of transfusion , preterm birth , SGA and admissions to neonatal intensive care units . A meta‐analysis of cohort studies has also confirmed a significant increase in the risk of preterm birth with anaemia in the first or second trimester .…”