Low first-trimester hemoglobin and low birth weight, preterm birth and small for gestational age newborns

Int J Gynaecol Obstet. 2007 Aug;98(2):124-8. doi: 10.1016/j.ijgo.2007.05.011. Epub 2007 Jun 22.


Objective: To examine the relationship between first-trimester hemoglobin (Hb) concentration and risk of low birth weight (LBW), preterm birth and small for gestational age (SGA).

Methods: Data were obtained from a population-based prenatal care program in China. A total of 88,149 women who delivered during 1995-2000 and had their Hb measured in the first trimester were selected as study subjects.

Results: The prevalence of anemia (Hb<110 g/L) was 22.1% in the first trimester. The risk of LBW, preterm birth and SGA was increased steadily with the decrease of first-trimester Hb concentration. After controlling for confounding factors, women with Hb 80-99 g/L had significantly higher risk for LBW (OR=1.44, 95% CI 1.17-1.78), preterm birth (OR=1.34, 95% CI 1.16-1.55) and SGA (OR=1.13, 95% CI 0.98-1.31) than women with Hb 100-119 g/L. No elevated risk was noted for women with Hb> or =120 g/L.

Conclusion: Low first-trimester Hb concentration increases the risk of LBW, preterm birth and SGA.

MeSH terms

  • Adult
  • Anemia / complications*
  • Case-Control Studies
  • China
  • Cohort Studies
  • Female
  • Hemoglobins / analysis*
  • Hemoglobins / deficiency
  • Humans
  • Infant, Newborn
  • Infant, Small for Gestational Age*
  • Odds Ratio
  • Pregnancy
  • Pregnancy Complications, Hematologic*
  • Pregnancy Trimester, First
  • Premature Birth / blood*
  • Premature Birth / epidemiology
  • Risk Factors


  • Hemoglobins