Aim: We aimed to investigate if the risk of fetal distress during term labor is related to the intrapartum maternal hemoglobin (Hb) level. Second, we investigated the relation between mode of delivery, reason for instrumental delivery and short-term neonatal outcome and maternal Hb. Third, we aimed to identify factors influencing intrapartum maternal Hb level.Methods: A retrospective cohort study was performed in a tertiary hospital in The Netherlands, including data from women who gave birth between 2009 and 2016. To determine whether the likelihood of fetal distress to occur was dependent on intrapartum Hb, multivariate regression models were run with intrapartum Hb as the main independent variable of interest. Hb was used as a continuous value. We repeated this procedure for the likelihood of instrumental vaginal delivery (IVD), cesarean section (CS), 5-min Apgar score < 7, and umbilical cord arterial pH ≤ 7.05 to occur. Also, we identified factors influencing intrapartum Hb level using linear regression analysis.Results: Data of 9144 patients were analyzed. Intrapartum Hb did not contribute to the prediction of the likelihood of fetal distress, IVD for nonprogressive labor, CS for fetal condition, 5-min Apgar score < 7, and pHa ≤ 7.05. However, there was a unique statistically significant contribution of Hb to the prediction of the likelihood of IVD for any reason and IVD for fetal distress and CS for any reason and CS for nonprogressive labor. IVD for fetal distress was related to a higher intrapartum Hb level, whereas CS for nonprogressive labor was related to a lower intrapartum Hb level. Intrapartum Hb level was influenced by maternal age, ethnicity, parity, fetal sex, and birth weight.Conclusions: The risk of fetal distress and adverse neonatal outcome is not related to intrapartum Hb levels. However, our data suggest that mode of delivery is dependent on intrapartum Hb, as shown in a large tertiary population. We recommend further investigating this relation in a large prospective study.
Keywords: Fetal distress; instrumental delivery; maternal hemoglobin; neonatal outcome; obstetric labor.