10/01/2016 7:03 PM AEDT | Updated 15/07/2016 12:51 PM AEST

The Do's And Dont's Of Training Safely While Pregnant

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Pregnant woman doing yoga

Exercising while pregnant can get controversial.

The polarising topic was back in the news last month after a mum-to-be posted a video on social media showing her doing back squats while holding a 40kg barbell at six months pregnant.

It was the latest in a number of button-pushing online posts from pregnant women who stand by rigorous workout regimes in the face of online criticism.

Aussie exercise guru Michelle Bridges has even come under fire for sending the wrong message to pregnant mums.

Given the ongoing debate, The Huffington Post Australia talked to Sydney personal trainer Simon Margheritini to get the lowdown on pre-natal exercise.

He said staying active during pregnancy was a good thing.

Health benefits could include improved circulation to help with fluid retention, decreased anxiety and increased stamina and endurance, he said.

Prudent training during pregnancy can be positive

Pre-natal exercise could also help to prevent varicose veins, hemorrhoids and lower back pain.

"As the baby gets bigger the pelvis tilts forward and with that can come a real pain in the lower back," Margheritini said.

"Pilates is definitely a great exercise that is recommended because it strengthens your abdominals and obliques."

But he said a key to working out while pregnant was not going too hard.

"In regards to aerobic workouts, the client should always be able to hold a conversation during the workout, that's very importnant," Margheritini said.

"You're looking at a heartbeat, depending on the fitness of the person, between 120 and 140 beats-per-minute. You don't want to go over that."

When it comes to weights, Margheritini's advice was not to train more than 4 times a week for about 30 minutes, and completely cut out particular exercises like the military press.

Mums-to-be should stay cool when running

"Don't lift weights above your head because that increases blood pressure," he said, adding that it was also crucial not to overheat and important to stay hydrated.

Other exercises to stay away from were deadlifts, leg presses and chin-ups.

According to one prominent physiotherapist, crunches are another no-no and doing them in the later stages of pregnancy puts women at risk of ripping abdominal wall tissue.

Margheritini said the aim should be targeting major muscle groups like the chest, back and legs.

"You should do functional exercises such as squats with a theraband or chest press with a theraband, that increases blood flow and will make you work your abdominals."

A fitball is great to workout the deep abdominals when pregnant

He said a great investment for those wanting to workout in the lead up to giving birth was a fitball -- recently showcased by a heavily pregnant Bridges.

"Everything you do on that will really help the pelvic floor muscles -- they're the ones situated right under the deep abdominal muscles," Margheritini added.