Cruel internet trolls have "bump shamed" the Duchess of Cambridge for her lack of pregnancy curves after her first public appearance since announcing her pregnancy.

Kate, 35, attended a reception at Buckingham Palace for World Mental Health Day on Tuesday, after taking six weeks off while she battled hyperemesis gravidarum - a severe form of morning sickness - revealing just a hint of a baby bump.

While many commenters on Kensington Palace's Instagram account complimented Kate on how well she looked, others were eager to point out her tiny stomach with one saying: "I can't believe she's pregnant, she looks too thin."

Kate showed off her tiny baby bump in a Temperley London dress. Photo / Getty Images
Kate showed off her tiny baby bump in a Temperley London dress. Photo / Getty Images

Others even claimed that they look more pregnant than the Duchess does, questioning how she can still look so slim.

Advertisement

However, experts hit back at the comments saying that 'bump shaming' can cause unnecessary anxiety for mothers-to-be.

Lesley Gilchrist, practising midwife and co-founder of My Expert Midwife, said: "Bump shaming can really damage a woman's body confidence and cause needless worry and anxiety over the health of their baby.

It's important to remember that the bump size is just the size of the baby's 'packaging' and has no bearing on the size of their baby."

Peggy Osborne, a midwife at The Women's Health Clinic who also teaches NHS antenatal classes added: "There is a lot of pressure on new mothers to have the perfect bump, especially when you have had to announce it perhaps before you were ready.

Prince William, Catherine and Prince Harry attend a reception on World Mental Health Day to celebrate the contribution of those working in the mental health sector. Photo / Getty Images
Prince William, Catherine and Prince Harry attend a reception on World Mental Health Day to celebrate the contribution of those working in the mental health sector. Photo / Getty Images

"But there is no real use comparing one pregnancy to a previous one, as the embryo could implant differently or eating habits may have changed - especially with hyperemesis."

Kate is estimated to be less than 20 weeks into her pregnancy, which was announced in August before she reached the crucial 12 week stage.

Peggy added: "At this stage in the pregnancy the uterus is being pushed higher in to the abdomen but baby is yet to cause any real 'bump', typically any additional roundness is just fluid."

Unlike regular morning sickness, it doesn't fade away with time and can leave some women bedbound as they are unable to keep food or drink down.

It is also considered to be the second leading cause of hospitalisation during pregnancy and can lead to dehydration - dangerous to both the mother and child.