Cardi B isn’t listening to critics as she faces backlash for hitting the gym a mere week after giving birth to her third child … though, doctors tell us she might want to heed the warnings.

Here’s the skinny … the rapper took to Instagram Sunday, documenting herself on the StairMaster a little over a week after welcoming her third baby with Offset.

This sparked a big reaction online … with fans expressing concern for her well-being, while others slammed her for succumbing to “snap back” pressure.

Cardi B fires back at fan criticism of "insane" postpartum workout regimen

Cardi made it clear she was tuning out the peanut gallery … returning to the gym again Monday, pointing out she’s only doing 30-minute sessions, and taking it slow.

As Cardi put it, she’s using cardio to help prevent postpartum depression, noting it’s her third time going through this experience.

We spoke to a handful of OBGYNs, each offering up different opinions on the issue.

cardi b

One doctor said most docs in their profession would recommend against going to the gym right away … clarifying, however, that it’s a case-by-case basis.

Per the medical professional, if a woman gives birth naturally and has a smooth delivery, a doctor may sign off on the new mom easing back into light activity … like walking.

However, the doc urged expectant mothers to consult their personal OBGYNs before doing anything strenuous.

Another doctor expressed a slightly different sentiment … explaining they wouldn’t personally clear a patient for exercise until 2 or 3 weeks postpartum. But, they know others who might clear a patient at the 1-week mark.

A third OBGYN urged fans not to do something just because a celebrity is doing it … again, advising mothers-to-be to consult medical professionals first.

As for why the doctors voiced concern over Cardi’s decision … many said there were risks to getting back at it, as bodies need time to heal after a birth. Some possible side effects of rushing into working out postpartum include a hernia, strained muscles, a pelvic prolapse, and bladder problems, among other issues.

The warning is even more severe for women who’ve had C-sections … as an infection at the incision site, loss in abdominal strength, scar trauma, and more could all arise if they begin working out before at least 6 weeks have passed.

Here’s hoping the rapper got the all-clear from her doc before hopping on the StairMaster … though critics should really ease up, since each case is different.