Kate Middleton's health history, from her shock cancer diagnosis to her battle with extreme morning sickness and the three-inch scar running down her head from a childhood injury

The Princess of Wales today said she was 'going to be ok' as she bravely opened up about her cancer diagnosis. 

Kate Middleton, 42, was admitted to a London hospital in January for planned surgery and returned home to Windsor to continue her recovery.

Doctors, however, discovered an unspecified form of cancer in tests taken after her operation. 

In a video message today, Kate revealed the diagnosis 'came as a huge shock' but she was now in the 'early stages' of preventative chemotherapy treatment. 

Here, MailOnline details her health history. 

Kate Middleton , 42, was admitted to a London hospital in January for planned surgery and returned home to Windsor to continue her recovery. Doctors, however, discovered an unspecified form of cancer in tests taken after her operation. In a video message today, Kate revealed the diagnosis 'came as a huge shock' but she was now in the 'early stages' of preventative chemotherapy treatment 

The Prince and Princess of Wales were seen together last week as William went to the The Commonwealth Day Service at Westminster Abbey

The Princess of Wales with her children in her Mother's Day portrait, which now has added significance given her diagnosis

Three-inch scar on head

Kate has a three-inch scar on the left side of her head from when she was a child.

It was first spotted in 2011 when the princess was conducting her first solo royal engagement at a black-tie private dinner at Clarence House.

It was confirmed to be the result of surgery carried out when she was a young child.

An official statement explained that 'the scar related to a childhood operation,' but said that details of the operation were a private matter. 

Royal sources confirmed that it had been 'a very serious operation' but declined to comment further.

However, surgeons at the time said the scar is unlikely to be the result of a tumour and may have been caused by a birth mark being removed.

Kate's scar was first spotted when she attended a dinner at Clarence House in 2011

A statement explained that the scar, normally concealed, was from a childhood operation

Morning sickness

The Princess was hospitalised for three days with severe morning sickness in 2012, while she was pregnant with Prince George.

She was admitted to King Edward VII's Hospital — a private hospital in Marylebone that has been used by the Royal Family for more than a century.

Kate went on to suffer again from hyperemesis gravidarum (HG) while pregnant with Princess Charlotte in 2014 and Prince Louis in 2018. 

The condition saw the Princess announce her later two pregnancies early, before reaching the crucial 12-week stage.

However, while carrying Princess Charlotte and Prince Louis, she was cared for at Kensington Palace rather than in hospital.

HG can lead to severe dehydration and puts both mother and baby at risk of being deprived of essential nutrients, as they are unable to keep food and drink down.

Sufferers can be left vomiting up to 30 times a day, with exhausting and hazardous consequences.

Kate revealed in 2020 that she used meditation and deep breathing to help her control her symptoms.

Abdominal surgery

The Princess had planned major abdominal surgery in January, and spent two weeks in hospital. 

Kate was admitted to The London Clinic in Marylebone and returned home to Windsor to continue her recovery with the support of her family.

At the time, it was thought her condition was non-cancerous but no other details of the surgery were given.

She was advised to recuperate for two to three months. 

Her absence from the public eye fueled a social media storm and a number of unfounded conspiracy theories. 

It was alleged at least one staff member at the London Clinic attempted to access her medical records. 

Three workers been suspended while the hospital investigates the claims.

Kensington Palace announced in January that the Princess of Wales had abdominal surgery

Police officers stand outside The London Clinic today where Kate is staying after surgery

In a video message released today, Kate said she was advised by her medical team to undergo a course of preventative chemotherapy. 'This of course came as a huge shock, and William and I have been doing everything we can to process and manage this privately for the sake of our young family,' she added

The Princess of Wales said her family (pictured together on December 25) 'need some time, space and privacy while I complete my treatment'

Cancer diagnosis 

The Princess today revealed she is in the 'early stages' of treatment for an unspecified form of cancer. 

No tests prior to her abdominal surgery had confirmed the presence of cancer.

However, doctors discovered the disease in tests taken after her operation.

In a video message released today, Kate said she was advised by her medical team to undergo a course of preventative chemotherapy. 

'This of course came as a huge shock, and William and I have been doing everything we can to process and manage this privately for the sake of our young family,' she added. 

'I am well and getting stronger every day by focusing on the things that will help me heal: in my mind, body and spirits,' she said. 

Kate also acknowledged others whose lives have been affected by cancer.  

'For everyone facing this disease, in whatever form, please do not lose faith or hope. You are not alone.' 

Kate's cancer battle in her own words: The Princess of Wales' emotional video statement in full 

I wanted to take this opportunity to say thank you, personally, for all the wonderful messages of support and for your understanding whilst I have been recovering from surgery.

It has been an incredibly tough couple of months for our entire family, but I've had a fantastic medical team who have taken great care of me, for which I am so grateful.

In January, I underwent major abdominal surgery in London and at the time, it was thought that my condition was non-cancerous. The surgery was successful. However, tests after the operation found cancer had been present. My medical team therefore advised that I should undergo a course of preventative chemotherapy and I am now in the early stages of that treatment.

This of course came as a huge shock, and William and I have been doing everything we can to process and manage this privately for the sake of our young family.

As you can imagine, this has taken time. It has taken me time to recover from major surgery in order to start my treatment. But, most importantly, it has taken us time to explain everything to

George, Charlotte and Louis in a way that is appropriate for them, and to reassure them that I am going to be ok.

As I have said to them; I am well and getting stronger every day by focusing on the things that will help me heal; in my mind, body and spirits.

Having William by my side is a great source of comfort and reassurance too. As is the love, support and kindness that has been shown by so many of you. It means so much to us both.

We hope that you will understand that, as a family, we now need some time, space and privacy while I complete my treatment. My work has always brought me a deep sense of joy and I look forward to being back when I am able, but for now I must focus on making a full recovery.

At this time, I am also thinking of all those whose lives have been affected by cancer. For everyone facing this disease, in whatever form, please do not lose faith or hope. You are not alone.