The effect of maternal pushing on fetal cerebral oxygenation and blood volume during the second stage of labour

Br J Obstet Gynaecol. 1995 Jun;102(6):448-53. doi: 10.1111/j.1471-0528.1995.tb11316.x.


Objective: To measure the effect of maternal pushing during the second stage of labour on fetal cerebral oxygenation and blood volume.

Design: A prospective study comparing changes in the fetal cerebral concentrations of oxyhaemoglobin, deoxyhaemoglobin and cerebral blood volume, before and during maternal pushing in the second stage of labour.

Setting: Teaching hospital obstetric unit.

Subjects: Ten term fetuses during labour.

Results: Following the onset of maternal pushing, mean cerebral deoxyhaemoglobin concentration increased by a mean of 0.79 (SD 0.59) mumol.100 g-1, (P < 0.01) without any consistent change in the oxyhaemoglobin concentration. These changes were associated with a significant decrease in the calculated mean cerebral oxygen saturation from a mean of 46.8% (SD 8.6) to 38.1% (SD 5.2) (P < 0.01). Pushing was also associated with a significant increase in the mean cerebral blood volume, which rose by a mean of 0.33 ml.100 g-1 (SD 0.37) (P < 0.05).

Conclusion: Maternal pushing during the second stage of labour leads to a significant decrease in fetal cerebral oxygenation, together with an increase in cerebral blood volume.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Volume
  • Brain Chemistry*
  • Cerebrovascular Circulation*
  • Female
  • Fetal Blood / chemistry*
  • Heart Rate, Fetal / physiology*
  • Hemoglobins / analysis*
  • Humans
  • Labor Stage, Second*
  • Pregnancy
  • Pressure
  • Prospective Studies


  • Hemoglobins
  • deoxyhemoglobin