The findings of a multicenter, randomized, sham-controlled, blinded trial supported the safety and efficiency of low-intensity focused ultrasound (LIFU) in alleviating uterine contractions and postpartum breast pain in puerperal women. Investigators carried out this study to assess the safety and effectiveness of LIFU use in aiding fundus descent and alleviating postpartum breast pain in comparison with the sham treatment.

This study incorporated pregnant females at or beyond 37 weeks of gestation, with no grave complications during prenatal check-ups, who were breastfeeding, and following specified postnatal exercise routines as advised by their doctors. Overall, 176 eligible women were randomly allocated to either the LIFU or sham group. Each volunteer was given three therapy sessions, during which the LIFU signal was used on the uterus and breast areas using coupling gel. The sham group received no ultrasound signal output. After each therapy, fundal height measurement and assessment of breast pain score were carried out.

The key endpoint, uterine involution, was indicated by estimating uterus fundal height. Visual analogue scale (VAS) score, used to examine breast pain, was analyzed alongside fundal height to examine correlation. Remarkable differences were witnessed in fundus descent rate and index following the second (rate: 1.5 (1.0, 2.0) cm/d; index: 0.15 (0.1, 0.18), P < 0.001) and third treatments (rate: 1.67 (1.33, 2.0) cm/d; index: 0.26 (0.23, 0.3), P < 0.001) in the LIFU group as opposed to the sham group.

VAS scores also illustrated pivotal differences between the two groups across therapies. Furthermore, a correlation was witnessed between VAS score reduction and fundus descent rate after the third treatment in the LIFU group, suggesting a link between pain relief and uterine involution acceleration. Furthermore, LIFU proved to be a painless therapy with no side effects, highlighting its potential for broad clinical usage in managing uterine involution and breast pain.