You’ve got 40 weeks before your world’s turned upside down. Make the most of them.

Week 6: Your eggo is preggo, so sign up for Active Moms’ Club’s prenatal fitness classes. Six weeks of personal trainer-led sessions will have you squatting, balancing, and weightlifting to a smooth delivery. Held at I.D. Gym (2727 North Lincoln Avenue); call 773-505-3945 to register.

Week 15: Show aches and pains who’s boss with a calming lavender/rose oil rubdown at Lincoln Park Massage Spa (630 West Webster Avenue; 773-296-6300).

Week 20: You’re showing. Revamp your wardrobe at Krista K Maternity + Baby (3530 North Southport Avenue; 773-248-4477). Through March 18, the Maternity Fashion for Work event is outfitting moms-to-be in career-appropriate (and anything-but-dowdy) duds. Plus, get 20 percent off when you buy two or more items.

Week 30: Help! Time’s running out. Turn to Hip Circle Studio’s Malik Turley, a doula whose 300 Weeks program covers everything from breastfeeding basics to dance classes for those with growing bellies.

Week 35: All signs point to an impending delivery. In the meantime, head to Preggers (900 North Michigan Avenue, fifth floor; 312-943-6262) for Pour Deux horoscope candles and get a hint of what’s to come.

Week 40: The fun really starts.

WEATHER
Science Storms
What: Stand inside a tornado, digitally control a glass-enclosed fire, and turn a disc to see how avalanches happen at the huge-scale exhibit.
Why: The twenty-foot bolt of lightning crackling overhead.
When: Opens Thurs. Mon.-Sat., 9:30 a.m.-4 p.m.; Sun., 11 a.m.-4 p.m.
Where: Museum of Science and Industry, 5700 Lake Shore Dr., at 57th St. (773-684-1414).

CRACK
Eggs to Chicks
What: Fun hatches at the exhibit with a child-height egg incubator, hatchery, and pen for newborn peepers.
Why: More than 200 fuzzy ones will come out of their shells.
When: Tues.-May 10. Mon., 9:30 a.m.-noon; Tues.-Sat., 9:30 a.m.-5 p.m.; Sun., noon-5 p.m.
Where: Kohl Children’s Museum, 2100 Patriot Blvd., Glenview (847-832-6600).

SHOP
Kooky
What: The local designer-driven pop-up boutique for kiddies returns — this time in the heart of downtown.
Why: It’s your one-stop baby shower gift shop.
When: Thru Mar. 31. Mon.-Sat., 10 a.m.-8 p.m.; Sun., 11 a.m.-6 p.m.
Where: The Shops at North Bridge, 520 N. Michigan Ave., at Grand Ave. (312-343-4964).

Photo: Thinkstock