Postpartum abdominal laxity is a growing concern for women. Noninvasive options like microwave technology and fractional carbon dioxide (CO2) laser show promise, but their combined efficacy and safety require further investigation.

To compare the efficacy and safety of microwaves versus combined microwaves and fractional CO2 laser in the treatment of postpartum abdominal laxity among Filipino patients.

Thirty-two patients with Fitzpatrick skin type III-V and postpartum abdominal laxity received three microwaves sessions, with one side randomly assigned an additional fractional carbon dioxide laser session (designated as side B, while the other as side A). Global aesthetic improvement scale (GAIS) scores and patient satisfaction (PS) scores were determined at every follow-up. Baseline and completion body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) were taken, and adverse effects were recorded.

Significant improvements in GAIS and PS scores were noted for both sides across all sessions, with side B showing superior scores post-CO2 laser. These improvements were attributed to epidermal thickening and dermal collagen and elastin remodeling, the latter seen histologically in a representative patient. Adverse effects were mild and noted only with CO2 laser.

The combined use of the microwaves system and fractional CO2 laser is safe and well-tolerated and is superior to microwaves alone in the treatment of postpartum abdominal laxity.