Clinical Health Updates

Warm packs beneficial in labor

Clinical Question:
Do warm packs prevent perineal trauma when applied to the perineum during labor?

Bottom Line:
The application of perineal warm packs in late second stage does not reduce the likelihood of nulliparous women requiring perineal suturing but significantly reduces third- and fourth-degree lacerations, pain during the birth and on days 1 and 2, and urinary incontinence. This simple, inexpensive practice should be incorporated into second stage labor care.

Dahlen HG, Homer CS, Cooke M, Upton AM, Nunn R, Brodrick B. Perineal outcomes and maternal comfort related to the application of perineal warm packs in the second stage of labor: A randomized controlled trial. Birth 2007;34(4):282-290.

Study Design:
Randomized controlled trial (nonblinded)

In this randomized controlled trial of 717 women the use of warm packs from late second-stage labor until crowning was compared with usual care that did not include warm packs. Although masking of women and their birth attendants was not possible, the outcome assessors were masked. Eligible women were nulliparous with singleton term pregnancy in cephalic presentation who anticipated a normal delivery and had not performed perineal massage. Warm packs consisted of perineal pads soaked in boiled tap water at a temperature of approximately 45 degrees centigrade. The trial was conducted in an ethnically diverse population in Australia, where 75% of women are immigrants from other countries. With a study size adequate to detect a 10% difference, there was no difference between groups for the principal outcome of need for perineal suture. However, the number of third- and fourth-degree lacerations was reduced in the wam pack group, (31/357 vs 15/360; number needed to treat [NNT] = 22; 95% CI, 12-109). Women receiving warm packs were less likely to report severe pain during birth than women who were not given warm packs (59% vs 82%, respectively). There were also modest, statistically significant reductions in mean perineal pain scores on days 1 and 2 postpartum using a 10-point visual analog scale, with less than 1-point mean differences. At 3 months postpartum women who had received warm packs were less likely to report urinary incontinence (36/276 vs 46/277; NNT = 28).