Maternity Nursing: Antepartum Q 31
The nurse teaches a pregnant woman to avoid lying on her back. The nurse has based this statement on the knowledge that the supine position can:
A. Unduly prolonged labor.
B. Cause decreased placental perfusion.
C. Lead to transient episodes of hypotension.
D. Interfere with free movement of the coccyx.
Correct Answer: B. Cause decreased placental perfusion.
This is because of the impedance of venous return by the gravid uterus, which causes hypotension and decreased systemic perfusion.
Option A: More recently there is emerging evidence that if the woman sleeps on her back that this puts her at increased risk of stillbirth (Stacey et al. 2011; Owusu et al. 2013; Gordon et al. 2015). This is biologically plausible because of what is already known about negative sequelae of the woman adopting this position during the day.
Option C: Maternity care provider clinicians have been aware for many decades that maternal supine position and pregnancy are not a good mix. This is probably because when the woman lies on her back the gravid uterus is known to compress the inferior vena cava (Kerr et al. 1964). This can result in a range of negative sequelae such as maternal hypotension and reduced blood flow to the fetus (Holmes, 1960).
Option D: The supine position may be disadvantageous for fetal wellbeing and in compromised pregnancies may be a sufficient stressor to contribute to fetal demise. This fits well with the triple risk model for stillbirth.