Is PMD related to twins?

PMD can occur in twin pregnancies, although it is rare. The findings and monitoring may differ depending on whether one or both placentas are affected.

Can PMD affect the umbilical cord?

PMD mainly involves placental tissue and its vessels. It does not necessarily cause abnormalities of the umbilical cord.

Can PMD cause too much amniotic fluid?

Some reported pregnancies with PMD have had increased amniotic fluid, but this is not a defining feature and does not occur in every pregnancy.

Abnormal Placenta During Pregnancy: What Does It Mean?

The placenta plays an important role in pregnancy by supplying oxygen and nutrients to your growing baby. Sometimes, changes in its size or appearance may be noticed during a routine ultrasound. Placental mesenchymal dysplasia (PMD) is a rare placental condition that can make these findings look unusual. Although it does not always cause problems, some pregnancies may need closer observation.

What Is Placental Mesenchymal Dysplasia?

Placental mesenchymal dysplasia is a rare developmental disorder involving the placental tissue and its blood vessels. In this condition, some of the placental villi become unusually enlarged and swollen, while the placenta may also contain enlarged or abnormal blood vessels.

The placenta may become larger than expected and develop several fluid-filled, cyst-like spaces. These changes can give it a grape-like appearance when examined after delivery.

PMD is considered benign, meaning it is not itself a cancerous condition. However, its presence can sometimes be linked with pregnancy complications, so it should not simply be ignored.

How Rare Is Placental Mesenchymal Dysplasia?

A large single-centre study examined more than 95,000 deliveries and identified only 2 cases of placental mesenchymal dysplasia, giving an incidence of 0.002% (0.02 per 1,000 deliveries).

Because so few cases are diagnosed, doctors may initially consider more common conditions when they see a multicystic placenta during an ultrasound.

What Causes Placental Mesenchymal Dysplasia?

The exact cause of PMD is not fully understood. Researchers believe that unusual genetic or epigenetic changes involving placental cells may contribute to its development.

One theory involves androgenetic biparental mosaicism, a genetic pattern in which different groups of cells carry distinct parental genetic contributions. This may help explain why PMD can occur even when the baby's chromosomes are otherwise normal.

Importantly, PMD is not known to be caused by something you ate, did, or failed to do during pregnancy.

Is Placental Mesenchymal Dysplasia the Same as a Molar Pregnancy?

No. PMD and molar pregnancy are different conditions, even though they can look alike on an ultrasound.

One important feature is that PMD can coexist with a viable fetus, unlike a complete molar pregnancy, where there is no normal developing foetus.Dr Monica Aggarwal, Associate Director, Department of Fertility, Cloudnine Group of Hospitals, Chandigarh

A molar pregnancy involves abnormal growth of placental tissue and can carry a risk of gestational trophoblastic disease. PMD, by contrast, does not involve the same abnormal overgrowth of trophoblastic cells.

What Problems Can Placental Mesenchymal Dysplasia Cause?

Not every pregnancy affected by PMD develops complications. Some babies are born healthy, particularly when there are no associated fetal abnormalities or growth problems.

However, doctors may watch for:

Fetal growth restriction
Preterm birth
Fetal distress
Low blood cell or platelet counts in the newborn
Stillbirth in severe cases
High blood pressure or preeclampsia in the mother

PMD has also been associated with Beckwith-Wiedemann syndrome (BWS), a genetic condition linked with childhood overgrowth and an increased risk of certain embryonal tumours. This does not mean that every baby with PMD has BWS.

How Is Placental Mesenchymal Dysplasia Diagnosed?

There is no single test that confirms PMD during pregnancy.

Your doctor may recommend:

Ultrasound: Checks for an enlarged placenta and cystic spaces.
Doppler study: Assesses placental and fetal blood flow.

Fetal assessment: Looks for structural or genetic abnormalities.

Genetic testing: May be recommended based on the findings.

Placental examination: Examines the placenta after delivery to help confirm PMD.

How Is Placental Mesenchymal Dysplasia Managed During Pregnancy?

There is no specific treatment to remove PMD. Management focuses on close monitoring of the mother and baby through regular ultrasounds, Doppler studies, and fetal assessments. If complications develop, doctors may increase monitoring or consider early delivery when necessary.

Can You Have a Healthy Baby With Placental Mesenchymal Dysplasia?

Yes. PMD does not always lead to pregnancy complications. Some pregnancies, especially those without fetal abnormalities or growth problems, can result in a healthy baby. Regular specialist monitoring can help identify and manage any concerns early.

When to Seek Medical Attention?

If you have been diagnosed with or are being evaluated for PMD, contact your doctor if you notice:

Reduced or absent baby movements
Vaginal bleeding or fluid leakage
Regular contractions or pelvic pressure
Severe abdominal or pelvic pain
Sudden swelling, headache, or vision changes
An ultrasound showing poor fetal growth or abnormal blood flow
Any new concern following a placental abnormality on your scan

Placental mesenchymal dysplasia can be concerning at first identification, especially because its imaging appearance may resemble other placental conditions. However, each pregnancy is different. Regular antenatal visits and appropriate testing allow your healthcare team to assess your baby’s wellbeing and respond promptly if concerns arise, helping you navigate pregnancy with greater confidence.

FAQs on Abnormal Placenta During Pregnancy: What Does It Mean?

Is PMD related to twins?
PMD can occur in twin pregnancies, although it is rare. The findings and monitoring may differ depending on whether one or both placentas are affected.
Can PMD affect the umbilical cord?
PMD mainly involves placental tissue and its vessels. It does not necessarily cause abnormalities of the umbilical cord.
Can PMD cause too much amniotic fluid?
Some reported pregnancies with PMD have had increased amniotic fluid, but this is not a defining feature and does not occur in every pregnancy.