The condition can lead to problems both for mother and baby. It's linked to pre-eclampsia and placental abruption, when the placenta peels away from the wall of the uterus.

It can also prevent the baby from growing at a normal rate in the womb, known as intrauterine growth restriction (IUGR). There can be serious complications for the baby, including lack of oxygen during the birth, premature labour, low blood sugar, too little calcium in the blood, or too many red blood cells and sometimes even stillbirth.

What causes placental insufficiency?

Placental insufficiency occurs either because the placenta doesn’t grow properly, or because it’s damaged.

Sometimes the placenta may not grow to be big enough — for example, if you are carrying twins or more. Sometimes it has an abnormal shape or it doesn’t attach properly to the wall of the uterus.

Your lifestyle can also damage the placenta. Placental insufficiency can occur if you smoke or take some kinds of illegal drugs while you’re pregnant. Medical conditions such as diabetes, pre-eclampsia and blood clotting conditions also increase your risk.

What are the symptoms of placental insufficiency?

Placental insufficiency has no symptoms. Sometimes it’s diagnosed when women realise their baby isn’t moving as much. Other signs the baby may not be developing properly are that your abdomen is smaller than in previous pregnancies.

The condition may be picked up during your routine antenatal tests, which measure the growth of your uterus and the baby. Sometimes it’s noticed during a routine ultrasound.

How is placental insufficiency treated?

If your doctor suspects placental insufficiency, they will keep a close eye on your baby's growth. You will be asked to keep a record of the baby's movements and let your medical team know if you notice any changes.

Treatment will depend on the stage of the pregnancy. If you’re under 37 weeks, your doctor may decide to wait for as long as possible and keep a close eye on the baby. But if you are full term or there are signs that your baby is under stress, they may decide to induce labour or deliver the baby with a caesarean.