Extreme exercise
You don't need to be a rocket scientist to know that mums-to-be need to take serious care of themselves. But some pregnant stars are so obsessed with looking good on the red carpet, they'll go to extreme lengths to stave off as much of their essential baby weight as possible.

Since ballooning by more than 19 kilos, J-Lo has admitted she's thrown herself into a gruelling fitness regime in the run-up to the birth of her twins, next month. Waking at 4am every morning to work out with her trainer, the star desperately hopes it will make it easier to snap back into shape once her babies are born. Call us old-fashioned, but does anyone else think this is nuts?

Baby comes first
Conversely, 40-year-old Nicole Kidman is taking no chances when it comes to her little one. As an older mum, who's suffered two previous miscarriages, she's determined to keep her baby - and her body - in the best condition. Three months pregnant, she proudly showed off her baby bump whilst on a session with her trainer.

But instead of following a super-strict fitness plan like J-Lo, she's taking it easy, opting for gentler exercise to ensure she puts her baby in no danger. And unlike Jen, Nicole's loving her newly blossoming figure, "I have a boy's body," she once said. "I would prefer to have more curves, because I think that's more beautiful."

Dangerous diets
A balanced diet during pregnancy is vital for the health of the unborn baby - but some stars are more worried about carrying extra weight than boosting their babys' wellbeing, restricting their intake of food in favour of a regimented diet.

Jessica Alba, whose gorgeous Latina bod has long been the envy of women worldwide, is said to be terrified about losing her slim-line figure.

"I try to eat as healthy as possible and exercise. As long as I don't gain too much weight too fast - I think that's the key," says the slender star. Jess was even spotted at the Sundance Film Festival picking up Reebok fitness equipment, sparking speculation that she's taking her exercise regime too far.

Owing to certain health conditions, some expectant mums need to take even more care of their bodies. Iron-deficient Nicole Richie, who gave birth in January, made sure she upped her intake of iron-rich green veg like broccoli and spinach during her pregnancy, whilst Halle Berry, whose baby is due next month, is taking no chances.

A diabetic, Halle has sought out the advice of top nutritionalists to make sure her condition causes no complications to her pregnancy.

How much is too much?
A flat tum should be the last thing on any new mum's mind, but many stars lose their baby weight within weeks of giving birth, throwing themselves into crash diets and vigorous exercise regimes to swap their swollen tummies for six-packs. But from a health perspective, jumping from the delivery room to the red carpet can be seriously dangerous.

It's been just over a month since the birth of their babies, but Nicole Richie's already shrunk back to her pre-pregnancy shape, whilst Christina Aguilera is happily flaunting her post-pregnancy curves. With so many new deliveries on the way, including more bambinos to come from Gwen, Cate and Ange, what's the bet that once their babies arrive, they'll be back their super-svelte selves faster than you can say post-natal pilates?

Celeb secrets to snapping back into shape
1 Salma Hayek dropped her baby weight through breast-feeding - a fantastic calorie burner.

2 Milla Jovovich piled on a whopping 31 kilos when she was pregnant, but regained her super-slim figure slowly by following a healthy diet of fruit, veg, omega-3 fatty acids and vitamin C supplements - without starving herself.

3 Emma Bunton, who also gave birth last year, is in the best shape of her life thanks to the Spice Girls reunion tour - which forced her to exercise five times per week.