Ageing or calcification of the placenta (2023)

What does an 'ageing placenta' or 'calcification of the placenta' mean?

Placental calcification is the medical term for some of the changes that happen to the placenta, as pregnancy progresses.

Many researchers regard placental calcification as a normal ageing process, rather than a change related to a disease or ailment.

The placenta is usually described as going through four grades, from 0 (most immature) to III (most mature).

All placentas start at grade zero in early pregnancy. Changes can be seen from 12 weeks onwards. As pregnancy progresses, the placenta matures and calcifies.

It is classified into the following grades at different stages in pregnancy, at approximately the following times:

• Grade 0. Before 18 weeks of pregnancy.
• Grade I. Around 18 to 29 weeks of pregnancy.
• Grade II. Around 30 to 38 weeks of pregnancy.
• Grade III. Around 39 weeks of pregnancy. It is usually not seen before 38 weeks. A grade III placenta is known as a severely calcified placenta. At this stage, a formation of indentations or ring-like structures can be seen within the placenta.

How is the calcification or age of the placenta measured?

There is some uncertainty about whether changes in the placenta can be measured accurately as it can be difficult to grade the placenta objectively.

A lot depends on the interpretation of the ultrasound images by the ultrasound doctor. Some differences may also arise as it depends on how a doctor interprets the result.

How will an ageing or calcified placenta affect my delivery?

The effect of an ageing placenta on labour and delivery is difficult to say. Experts seem to have different opinions on the significance of a calcified placenta on delivery due to the lack of conclusive evidence.

Some placental changes during late pregnancy are considered a normal part of pregnancy and not thought to be of concern. However, in cases where changes occur earlier than expected, there is some disagreement regarding their significance.

Some risks that are known to be associated with placental calcification at each stage of pregnancy are listed below.

Changes between 28 and 36 weeks
One study suggests that women in high-risk pregnancies who develop a calcified placenta between 28 and 34 weeks need closer monitoring. Some examples of high-risk pregnancies include pregnancies complicated by placenta praevia, diabetes, high blood pressure or severe anaemia.

Calcification of placenta before 32 weeks of pregnancy is called an "early preterm placental calcification". It is known to be associated with a higher risk of pregnancy and birth complications, such as

• heavy bleeding after birth or postpartum haemorrhage
• placental abruption
• premature baby
• having a baby with a low Apgar score
• stillbirth

Changes from 36 weeks
One study has suggested that having a grade III placenta at 36 weeks is associated with an increased risk of pregnancy-related high blood pressure and having a low-birth-weight baby.

Hence, ultrasound scans that show placental calcification at 36 weeks may help in identifying high-risk pregnancies.

Changes from 37 to 42 weeks
A grade III calcified placenta from 37 weeks onwards is found in about 20 to 40 per cent of normal pregnancies. However, it is thought to of little clinical significance.

The effects of calcified placenta probably need to be evaluated on a case-to-case basis, depending on:

• how early the changes are seen
• how severe they are
• whether it is a high-risk pregnancy or not
• your doctor's opinion

Is it harmful to my baby if my placenta calcifies or ages too soon?

Preterm calcification of the placenta can be harmful to a baby in the womb, but it also depends on the grade and stage of pregnancy.

Some studies suggest that placental calcification before 32 weeks of pregnancy can result in low birth weight babies, babies with a low Apgar score and even stillbirth.

Some studies have shown that having a grade II placenta between 30 and 34 weeks can predict a low birth weight baby. But this is only among women who smoke during pregnancy.

Is there anything I can do to prevent early calcification or ageing of the placenta?

The exact causes of an ageing placenta are still not very clear, so it is difficult to say what would prevent it. However, some research suggests that placental calcification is more likely in:

• younger women
• first-time pregnancies
• women who smoke during their pregnancy
  

Your doctor will be monitoring your health throughout your pregnancy. So, make sure you don’t miss any antenatal check-ups and your ultrasound scan appointments.

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