Low-intensity focused ultrasound to support early lactation after caesarean birth: a randomised, double-blind,...

The primary aim of this study was to evaluate the effect of low-intensity focused ultrasound (LIFU) on lactation outcomes in primiparous women after caesarean birth, specifically initial lactation time, prolactin levels, and milk production. The secondary aim was to assess its effects on the degree of breast engorgement, breast pain visual analogue scale (VAS) score, exclusive breastfeeding at 42 days postpartum, and short-term safety.

This prospective randomised, double-blind, sham-controlled trial enrolled and randomised 132 eligible term singleton primiparous women who underwent caesarean birth at a tertiary hospital in Nanchong, China, between December 2022 and June 2023. Of these, 10 participants were not included in the final analysis because of withdrawal after randomisation, postpartum mother-infant separation, or incomplete follow-up after discharge, and 122 women were ultimately included in the final analysis. Participants were allocated in a 1:1 ratio to an ultrasound group or a control group using block randomisation. Both groups received standard postpartum breastfeeding support. In addition, the ultrasound group received adjunctive LIFU once daily for 3 consecutive days. The primary outcomes were initial lactation time, serum prolactin levels, and milk production. Secondary outcomes were the degree of breast engorgement, breast pain VAS score, exclusive breastfeeding at 42 days postpartum, and safety.

Compared with the control group, the ultrasound group had a shorter initial lactation time, higher prolactin levels, and better milk production status on postpartum days 2 and 3. Mixed-model analysis showed that LIFU was associated with higher postpartum prolactin levels and a steeper early rise from 24 h to 72 h postpartum. The ultrasound group also had less severe breast engorgement on postpartum day 3, lower breast pain VAS scores across treatment sessions, and a higher exclusive breastfeeding rate at 42 days postpartum (all P < 0.05). No intervention-related adverse events or serious adverse events were observed during the study period.

On top of standard breastfeeding support, LIFU may help improve early lactation outcomes and reduce breast discomfort in primiparous women after caesarean birth. LIFU was also associated with a higher exclusive breastfeeding rate at 42 days postpartum within the follow-up period of this study. Because this was a single-centre study with limited follow-up, these findings should be interpreted cautiously and confirmed in larger, multicentre studies with longer follow-up.

This RCT was registered with Chinese Clinical Trial Registry (ChiCTR2200063204) on September 1, 2022. The trial protocol has been published: http://www.chictr.org.cn/edit.aspx?pid=176070&htm=4.