Ethnic differences in age-related changes of postpartum hemoglobin levels

Objective: Postpartum hemoglobin (Hb) levels may impact maternal and breast-fed newborn well being and health. Yet, the sources of variation in maternal postpartum Hb levels are poorly understood. We set to investigate whether age has an effect on postpartum Hb levels, and if this effect is similar in different ethnic groups. Study design: The birth records of over 200,000 births in a tertiary medical center were scanned for the first and second births to Jewish and Bedouin mothers in Israel. Age trends in Hb levels were analyzed using linear and bi-linear models. Confounding factors were eliminated by testing the significance of the preferred model in homogenous sub-populations. Results: In Jewish Israeli mothers, postpartum hemoglobin level follow a bi-linear trend, peaking at the age of 27-31 years, both during the first and second births. In Israeli Bedouin mothers, a linear decline is observed through all ages. Conclusion: These results suggest an ethnic difference in the age trends of postpartum Hb levels. Clinically, significant changes may occur between the ages of 27 and 30 years.