Methods of relieving pain in labor - warm baths

Warm baths

Baths produce soothing, calming effect and may be useful for some patients in labor. It does not increase the risk of infection. However, the effect of bathing on labor pain is modest. Setting up and providing bathing in labor wards increases hospital costs and complexity of midwives’ work.

Many laboring women find a bath soothing and relaxing. Baths have been used for years in out of hospital birth settings for both labor and birth, and in more recent times many modern hospitals have installed bathtubs and allowed women to use them, primarily for relaxation and pain relief during labor.

At the very beginning of using baths in labor wards there were concerns regarding safety. Theoretically, bathing during labor may increase the risk of infection, both for the mother and the baby. The results of early studies indicated that bathing may cause potentially very serious complications. However latest, more rigorous studies, have shown it to be untrue. If baths are properly cleaned and other precautions against infection are taken, such as avoiding frequent vaginal examinations, the risk of infection in the mother or the baby is not increased by bathing.

Even though there are quite a few studies on the effect of bathing and labor, their conclusions are inconsistent, and the results vary. One study found that immersion in warm baths pain eased off pain in the first 30 minutes of labor, while in non-bathed women pain during this period increased. After 90 minutes, however, pain scores were similar. First stage of labor progressed somewhat faster in bathing group.

Another, similarly designed study has shown no effects of bath on pain, and the labor of those who had baths was longer. Many prospective trials are poorly designed, and their findings are therefore doubtful. The same contradiction exists in regards to the number of requests for epidurals in bathing and non-bathing patients. To add to the controversy, one large randomized trial found that baths decrease the need for epidurals, while another did not confirm this finding.

The Cochrane Database review updated in 2007 concluded that “immersion in water during the first stage of labor significantly reduces women’s perception of pain and use of epidural or spinal analgesia. Water immersion during the first stage of labor significantly reduces epidural/spinal analgesia requirements and reported maternal pain, without adversely affecting labor duration, operative delivery rates, or neonatal wellbeing. Immersion in water during the second stage of labor increased women’s reported satisfaction with pushing.”

These conclusions seem very promising. However, when we check the actual data in the review the picture becomes less impressive. The number of requests for epidural analgesia was slightly lower in those who used bathing during labor, while need for narcotics was slightly higher. Even though the conclusion stated the benefits of bathing while “not adversely affecting neonatal wellbeing”, the rate of infection in the newborns in the bathing group was double. More women in the bathing group had postpartum depression, less of them breastfed six weeks after delivery, more babies had lower Apgar scores five minutes after birth and more of them had low umbilical blood pH, the parameter that reflects inadequate oxygen delivery.

The results of literature reviews always depend on who the reviewer or reviewrs are. Some bias is unavoidable in interpreting data, no matter how objective one claims to be. Two of the reviewers in our case have been involved in conducting trials on the subject of bathing in labor, this may be the reason that their conclusion are rather more optimistic than warranted by the actual findings of the studies.

Are baths bad then? I don’t think so. It comes down to common sense. Bathing in labor may be beneficial and soothing for some women and are unlikely to harm the mother or the baby. On the other hand, I wouldn’t expect incredible results from them. As mentioned in the corresponding chapter, pain associated with childbirth is one of the most painful experiences known to humans. Is it likely that baths will have that much effect on it? Personally I doubt it. The main problem is that there is insufficient research on the subject.

Although bathing during labor does not increase the rate of complications, it increases complexity of midwives’ work. Baths must be of sufficient size. Often more than one woman is in labor at any particular moment in a labor ward of average size, therefore more than one bath must be installed. This requires space and therefore increases the cost. Bathing is not easily standardized and requires additional training of medical staff. High water temperatures may raise both the mother’s and the fetus’ temperatures, sometimes causing increased heart rate in the fetus, elevated temperature of the baby after birth, and associated clinical concerns. Because the temperature of the fetus is approximately one degree C higher than the temperature of the mother, a modest rise in maternal temperature may raise fetal temperatures to potentially dangerous levels. Because of that it is recommended that the temperature of water in the bath must be maintained between 36 and 37 degrees Celsius. This requires special equipment and extra attention. All this increases cost without bringing meaningful results. And while it may be used during labor conducted at home, its routine use in hospitals is problematic.

References:

1. Simkin PP, O’Hara M. Nonpharmacologic relief of pain during labor: Systematic reviews of five methods Am J Obstet Gynecol 2002; 186:S131-59.

2. Cluett E R, Nikodem VC, McCandlish RE, Burns EE. Immersion in water in pregnancy, labour and birth. Cochrane Database of Systematic Reviews 2002, Issue 2. Art. No.: CD000111. DOI: 10.1002/14651858.CD000111.pub2.

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Dr. Eugene Smetannikov is a practicing anesthesiologist with the interest in obstetric anesthesia. He is the author of the most comprehensive book on the subject, The Truth About Labor Epidural