How to... perform an examination of the placenta

Midwives magazine: Issue 7 :: 2011

University of Chester’s deputy head of midwifery and reproductive health Jane Harris outlines the key points of this procedure.

The midwife should ensure that the woman is comfortable following birth and that she has monitored the blood loss and checked the uterus is well contracted. The examination of the placenta and membranes should take place as soon as possible following this; in order to ensure that they are complete and that no further actions are required before the woman is discharged or transferred to the ward (McDonald, 2009).

The placenta
The structure of the placenta is disc-shaped with both maternal
and fetal surfaces. At term the placenta weighs approximately 500g to 600g and has a diameter of 15cm to 20cm (Johnson and Taylor, 2010). The fetal surface is made up of cotyledons, which are further divided into lobules. The outer appearance is white and shiny in nature due to chorionic plate and the amnion covering.

The cord is usually inserted in the centre of the fetal surface with blood vessels branching outwards. The umbilical cord contains two umbilical arteries and one vein; they are surrounded by Wharton’s jelly and covered by the amnion (Johnson and Taylor, 2010). The cord is twisted spirally in order to protect the vessels and it is approximately 40cm to 50cm in length.

The maternal surface is dark red in colour and is made up of 15 to 20 cotyledons, which are divided by septa. Insignificant changes can occur such as infarctions due to the depositing of fibrin, and the surface can appear gritty due to lime salt deposits (Vance, 2009).

Examination of the placenta
✲ Explain the procedure to the parents and ask if they want to observe
✲ Wash hands; wear an apron and gloves (Stables and Rankin, 2010)
✲ The delivery trolley is a good surface to use
✲ Lay out the placenta with the fetal surface uppermost – noting shape, size, colour and smell
✲ The cord is then examined noting the length, the point of insertion and the presence of any knots
✲ Count the vessels in the cut end of the cord; the absence of one of the arteries can be associated with renal agenesis (McDonald, 2009)
✲ Observe the fetal surface for irregularities
✲ By lifting the cord and holding the placenta up, you can then observe the membranes and inspect for completeness. There should be a single hole present
✲ The placenta is returned to the surface and the membranes are spread out in order to look for extra vessels, lobes, or holes in the surface
✲ The amnion is then pulled back towards the cord, thereby separating the membranes to ensure that they are both present
✲ The placenta is turned over to inspect the maternal side
✲ The cotyledons are examined to ensure that they are all present, noting any areas of infarction or blood clots
✲ Estimate blood loss
✲ Take cord blood samples
✲ Weigh or swab the placenta if indicated
✲ Dispose of the placenta as per trust guidelines
✲ Clean away equipment
✲ Wash hands
✲ Discuss the findings with the parents.

Some women may wish to take their placenta home with them, so it is important that the midwife double bags it and places it in a suitable container (Blackburn, 2008).

The midwife should document all of the findings and act accordingly (NMC, 2004). 


References

Blackburn S. (2008) Physiological third stage of labour and birth at home: In: Edwins J. (Ed.). Community midwifery practice. Blackwell: Oxford.

Johnson R, Taylor W. (2010) Skills for midwifery practice (third edition). Churchill Livingstone Elsevier: Edinburgh.

McDonald S. (2009) Physiology and management of the third stage of labour: In: Fraser D, Cooper M. (Eds.) Myles textbook for midwives (15th edition). Churchill Livingstone Elsevier: Edinburgh.

NMC. (2004) Midwives rules and standards. NMC: London.

Stables D, Rankin J. (2010) Physiology in childbearing with anatomy and related biosciences (third edition). Elsevier: Edinburgh.

Vance M. (2009) The placenta: In: Fraser D, Cooper M. (Eds.). Myles textbook for midwives (15th edition). Churchill Livingstone Elsevier: Edinburgh.