Beyoncé is certainly no stranger to breaking boundaries – she’s the most nominated woman in the history of the Grammy Awards, as well as being one of the world’s best-selling music artists of all time.

Now, she’s made waves with her September cover of Vogue. It’s rumoured she was responsible for choosing Tyler Mitchell to shoot the pictures, making it the first time in the magazine’s history that a black photographer has done the cover.

To accompany the striking photos, Beyoncé told her story in her own words, covering everything from body acceptance to her ancestry. The star rarely gives interviews, so it was surprising that she was so open about the difficulties during pregnancy.

She says: "I was 218 pounds (15.5 st) the day I gave birth to Rumi and Sir. I was swollen from toxemia and had been on bed rest for over a month. My health and my babies’ health were in danger, so I had an emergency C-section."

Toxemia is another term used for pre-eclampsia – here’s everything you need to know about the condition unique to pregnancy.

What are the symptoms?
The two earliest signs of pre-eclampsia are high blood pressure and protein in your urine. Obviously these aren’t exactly things you can diagnose on your own, but the HSE says they should be picked up during antenatal appointments.

As pre-eclampsia develops, it can cause fluid retention (oedema). This can cause sudden swelling of your feet, ankles, face and hands.

Further symptoms could include; severe headaches, excessive weight gain due to fluid retentions, pain in your upper abdomen and vomiting. 

Who is at risk?
According to the HSE, pre-eclampsia cannot happen until you are at least 20 weeks pregnant. Most cases occur in the third trimester (from week 27 to the birth of the baby).

The cause of pre-eclampsia is not fully understood. However, it is thought that a problem may develop with the blood vessels in the placenta, resulting in its underdevelopment.

Chances of developing pre-eclampsia are heightened by a number of factors; if it is your first pregnancy, if it has been at least ten years since your last pregnancy; if you have a family history of the condition; if you are a teenager or over 40-years-old; if you are obese at the start of your pregnancy; if you have an existing medical problem - for example, diabetes, kidney disease, migraines or high blood pressure.

Additionally, if you are expecting multiple babies – like Beyoncé who gave birth to twins - you have a higher chance of developing pre-eclampsia.

How is it treated?
According to the HSE, treatment tends to focus on closer monitoring and trying to lower the mother's blood pressure until delivery of the baby.

Depending on the severity of your symptoms, treatment could involve further appointments with a GP or midwife or a referral to a hospital.

For more information on pre-eclampsia, you can visit the HSE website here.