Fitness blogger and trainer Kayla Itsines has been forced to issue a response after people questioned whether her pregnancy workouts are safe.

Itsines, who is 24 weeks pregnant, has continued to share exercise videos on Instagram, modifying the moves for pregnancy – yet she’s still been shamed online.

“I do not lift heavy weights, in fact I’ve cut the weight in half that I usually use,” she wrote on Instagram. “So in answer to your questions on my videos… no, the weight is not too heavy, it actually feels too light for me. No, I am not hurting the baby. No, my heart rate is not over 150 (for the ladies asking) and yes, you can use weights while pregnant.”

She’s not alone, as women have previously told HuffPost UK they’ve been shamed for working out while pregnant. So what’s safe and what isn’t?

Can I Exercise During Pregnancy?

Exercise is not dangerous for a foetus – in fact, the NHS says it could be beneficial more than anything, as there’s evidence that active women are less likely to experience problems in later pregnancy and labour.

Clare Livingstone, professional policy advisor at the Royal College of Midwives (RCM), told HuffPost UK: “It’s important to keep physically active during pregnancy – moderate exercise will not harm a woman or her baby, recreational exercise such as swimming or brisk walking is known to be beneficial.”

[Read more: Stop shaming mums who work out during pregnancy]

Consultant surgeon Dr Sally Norton said there are more benefits to exercising during pregnancy than people realise, including improved heart health, reduced urinary incontinence and back pain, and preventing pregnancy diabetes. It can also help with issues like constipation, and boosts mood and mental wellbeing. 

Keeping up fitness can also help the foetus – a study from Michigan State University found it can reduce the chances of your child suffering high blood pressure later in life, and a separate study by Kansas City found it benefits mum and baby’s heart. 

How To Exercise Safely During Pregnancy

The general advice is to keep up your normal daily physical activity or exercise – whether that’s sport, running, yoga, dancing, or even walking to the shops and back – for as long as you feel comfortable. 

Aerobic, strengthening and pelvic floor exercises, and Pilates are recommended for pregnant women. Dede Efueye, midwife at Private Midwives, said these exercises can help manage aches and pains as well as develop the muscles that help to support the growing bump. “Women should always inform their instructors that they are pregnant and how far along they are so that exercises can be altered to suit them,” she advised.

Swimming and aqua aerobics are also a good option. “The buoyancy feels great and it can be varied to suit any level of fitness whilst helping to keep you active.”

“The exercise pregnant women take should reflect their previous exercise regime,” said Livingstone. “So for example, it would not be appropriate for a woman who has done no exercise for many years to suddenly start running long distances in pregnancy. If women exercised regularly before pregnancy, they should be able to continue with no adverse effects.”

If a woman has not exercised routinely up to their pregnancy they should begin with no more than 15 minutes of continuous exercise, three times per week.  This can then increase gradually to daily 30-minute sessions and will help them meet the Chief Medical Officer’s recommended exercise level of 150 minutes a week.

“The RCM advises that sporting activities and exercise are approached with some caution and if women have any concerns they should speak with their midwife or GP,” Livingstone added.

What Not To Do While Exercising During Pregnancy

Women are advised not to lie flat on their back for prolonged periods, particularly after the 16-week mark. This is because the weight of their bump presses on the main blood vessel bringing blood back to the heart which can make them feel faint.

Mums-to-be should also avoid contact sports where there’s a risk of being hit, such as kickboxing, judo or squash. And for those who love adventure, avoid scuba diving because the baby has no protection against decompression sickness and gas embolism (gas bubbles in the bloodstream).

The NHS advises against exercising at heights over 2,500m above sea level until you have acclimatised, as you and your baby are at risk of altitude sickness.

Women should also be very cautious with any exercises that may increase their risk of falling such as horse riding, gymnastics or outdoor cycling, added Efueye.