This leaflet is to help you understand what placental mesenchymal dysplasia is, what tests you need, and the implication of being diagnosed for your baby.

What is a Placental mesenchymal dysplasia?

Placental mesenchymal dysplasia (PMD) is a rare placental disorder reported to be 0.02% of all pregnancies.

How does a Placental mesenchymal dysplasia happen?

The underlying cause of PMD is currently unknown. Approximately 25% of cases of PMD are associated with Beckwith-Wiedemann syndrome (macrosomia, exomphalos, visceromegaly, macroglossia, omphalocele, hemihypertrophy, placentomegaly and increased susceptibility to childhood tumors). 

Other syndromes can be associated with this placental pathology although it can occur with normal fetuses as well. 

Should I have more tests done?

The prenatal diagnosis consists of an ultrasound, performed for the evaluation of the placenta and the fetus. In case of fetal abnormality, an amniocentesis is indicated to look for a genetic anomaly (ex: Beckwith-Wiedemann syndrome).   

What are the things to watch for during the pregnancy?

The common fetal complications reported with PMD are preterm delivery (52%), fetal growth restriction (33%), genetic syndromes such as the Beckwith-Wiedemann syndrome (28%) and fetal death (13%).  Maternal hypertensive disease can also be evident in this condition. Due to potential complications, close prenatal surveillance is recommended to prevent foetal demise.

What are the risks for me at delivery?

There may be no clinical consequences at delivery.  If impaired fetal growth is present, babies may not tolerate labour well and mothers may require Caesearean delivery.  

What does it mean for my baby after it is born?

In the absence of associated syndromes, PMD is a condition that does not affect the structural anatomy of the fetus. The only consequences for your baby are related to prematurity and fetal growth restriction. Babies who also have a problem within the chromosomes may have even more problems after being born. 

Will it happen again?

The risk of this happening again is equal to the general population (0.02% of all pregnancies).

What other questions should I ask?

  • How often will I have ultrasound examinations done during the pregnancy?
  • Where should I deliver?
  • Do I need a Caesarean Section for delivery?


Last updated May 2023