If denim is a mom's best friend, then the perfect fitting pair of jeans is her Fairy Godmother. The truth is that it takes a bit of magic to find the perfect pair.

With 70's style gracing the pages of every fashion mag, denim is having a moment right now. But not all denim is created equal. The key to avoiding the “mom jean" trap is to find the right silhouette, fit, wash, and rise.

Rather than break it down for you by body type (how many times have we seen that?) I'm excited to share this denim style guide for the various phases of motherhood—from your 1st trimester to your 4th.

1st Trimester:

For first time mamas, it's likely that very little change is happening to you below the belt other than typical bloating. This is the time to focus on stretch fabrics and take advantage of trends that you may have to pass on in the coming months. It's also the time to shop your own closet. No need to buy anything to fit the bump until you need to.

Super Stretch Boyfriend Jean

These soft cotton, cropped boyfriend jeans by Goldsign are a closet staple. We love the simple pocket detailing and light distressed look.

Trend to Try Before Bump = Denim Culottes

Made of distressed denim, these over the top wide leg culottes are a fantastic addition to a mama's wardrobe. Pair yours with a classic white blouse and easy to wear loafers for a day of parent/teacher conferences and PTA meetings or add sophistication with heels and a blazer for an edgier downtown vibe. Looking for a sexy look for a night out with the hubs

2nd Trimester:

In the next 3 months, your belly will go through the “beer belly" phase. It's the most difficult to dress because it's not a fully formed bump yet. You are probably not ready for full on maternity jeans, so it's best to try elastic waist denim. No I am not referring to the “jegging" which is basically the modern version of “mom jeans." Many premium brand denim companies are making them. They're super chic and super comfy. They also offer richer and more flattering washes. As thighs expand (and they often do during pregnancy) it's best to go with a darker, less distressed wash.

Elastic Waist Worn Under Belly

These black skinny jeans can be dressed up or down easily depending on your mood and events of the day.

Trend to Try with “Beer Belly" Bump = Denim Joggers

Sometimes, comfort is key. And with these easy sweat pants by Ice Wash you can be comfortable without sacrificing style.

3rd Trimester:

The bump has popped! Time to show it off! And most likely time to buy (or borrow) legit maternity jeans. It is also a good time to bring denim into your wardrobe by way of tops, jackets, and vests. If you are now living in maxi dresses and leggings, then layering jean jackets and chambray shirts can bring new life to the maternity pieces that you are so tired of wearing.

The skinny

These sleek skinnies look perfect with pretty much anything. These should be a staple in your maternity wardrobe.

The wide leg

Thankfully, 7 For All Mankind has us covered throughout all stages of life, including pregnancy.

The boyfriend

These casual, cool boyfriend fit AG Jeans are perfect for end-of-summer-beginning-of-fall weather.

Trend to Try = The Denim Jacket

Everyone needs a solid fitting denim jacket in their closet. Rachel Comey has the answer for us with this stunner, ladies.

4th Trimester:

A lot of 1st time mamas are unfamiliar with the 4th trimester. For those of us not given the genetic make-up of Gisele or Heidi, it will take a moment (or a lot of moments) to get the baby weight off. This is a good time to go back to the styles that worked for you during your 1st and even 2nd trimesters. That said, it's also the time to invest in you. I see so many mamas that don't buy clothes until they “lose the weight." I assure you that if you invest in you and feel good about yourself, the weight will come off even faster. High-rise, soft washes are your friends. Though if you had a c-section, you may want to stick with joggers and denim styles up top. No matter how soft or stretchy, it can still aggravate your scar.

All Hail the High Rise

Post baby? High rise is the way to go. They will keep you feeling confident, comfortable, and cute.

Trend to try = Elastic Waist Novelty Denim

These daring zebra leggings are the hottest mom jeans on the market.

In many ways, denim is the easiest item in our closet. It almost goes with anything. It's most important to focus on the fit. Don't beat yourself up if you never fit into your “pre-baby" jeans, and don't force it either. If it's time to buy a fresh cut or a new chic wash, this is the time to splurge.