A concern commonly expressed about using water during labor is that immersion in a tub of warm, soothing water has the potential to slow down or even stop labor, particularly in the early stage. For many women, this is not a desirable effect!

The Waterbirth International website (www.waterbirth.org) shares this information about choosing when to get into the water:

A woman should be encouraged to use the labor pool whenever she wants. However, if a mother chooses to get into the water in early labor, before her contractions are strong and close together, the water may relax her enough to slow or stop labor altogether.  That is why some practitioners limit the use of the pool until labor patterns are established and the cervix is dilated to at least 5 centimeters.

There is some physiological data that supports this rule, but each and every situation must be evaluated on its own.

Some mothers find a bath in early labor useful for its calming effect and to determine if labor has actually started. If contractions are strong and regular, no matter how dilated the cervix is, a bath might be in order to help the mother to relax enough to facilitate dilation.

Therefore, it has been suggested that the bath be used in a ‘trial of water’ for at least one hour and allow the mother to judge its effectiveness. Midwives report that some women can go from 1 cm to complete dilation within the first hour or two of immersion.  The first hour of relaxation in the pool is usually the best and can often help a woman achieve complete dilation quickly.

In the book, Birth Day: A Pediatrician Explores the Science, Mystery, and Wonder of Childbirth, Dr. Mark Sloan explores the biochemical reason why water immersion can slow down labor. I found the explanation interesting as well as logical:

When a laboring woman climbs into a bath, the refreshing buoyancy she feels sets off a chain of physical and hormonal events. As her muscles relax, her catecholamine levels—the ‘fight or flight’ hormones that rise in labor—decrease. This can actually help her labor progress, as excessive levels of catecholamines are known to slow down uterine contractions.

But countering that lowered-catecholamine labor boost is the effect that water pressure has on other maternal hormones. When a mother sinks deep into a tub, the weight of the water on her body forces fluid contained in her tissues into her bloodstream, thus increasing her blood volume. Sounds like a good idea—increased blood volume means increased cardiac output and oxygen-carrying capacity, and oxygen is a good thing to have coursing through your arteries when you’re trying to have a baby.

But the weight of the water on a woman’s body also causes a ‘pooling’ effect in the blood vessels inside her chest, because the rib cage protects the lungs from the water-pressure squeeze exerted on the softer tissues of the limbs and abdomen. Over time this leads to a complicated hormonal chain reaction that results in decreased secretion of oxytocin, the uterine-contraction hormone, from the pituitary gland within the brain. With less oxytocin circulating than before she climbed in the tub, a woman’s labor can slow down significantly.

The labor-slowing effect of taking a bath seems to be a problem only if the bath is taken early in labor, though. Once a woman is in active labor, the oxytocin surges are strong enough that no bath in the world can derail them.

The author goes on to explain that current research isn’t clear on when exactly oxytocin levels are high enough to prevent labor from slowing down, but suggests that it is “prudent to hold off on baths until the cervix has dilated to about five centimeters.” He also notes that water immersion during labor does not increase the infection risk for either mother or baby, and that as long as water is kept at body temperature, there is no risk to either of overheating.

I also decided to ask the real experts—birthing women—what their experiences were with water in labor. I posted the question to my Facebook Talk Birth “fan” page and received a few responses:

“I feel like it definitely helped me. I couldn’t find a comfortable position, but when I got out of the water it was definitely worse. It didn’t seem to slow anything down; C was born a few hours after I got in. I plan to blow the ol’ gal up again for the next baby.”–SE

“I have such fast, easy labor that I only get in the water for transition and delivery. I will not do it any other way and kick myself for not doing it with all my births!!! It definitely takes the edge off for me (and no ring of fire either). I think it actually does slow me down a bit, but my births are crazy fast, so that is a good thing.”–NA

“I feel like for first time moms it’s hard to know how to push when you don’t have all of the pressure. I labored in the water with Ashton but delivered him out of the water when things just weren’t finishing. With Brice I knew what I was doing so had no problems pushing Brice out in the water. I really liked the water but haven’t labored without it for transition. My [midwife] also has found that first time moms many times need to get out of the water to deliver and that it can slow down labor.”–RK

“I had a waterbirth with my 2nd, and due to her malpositioning it was by far my most painful birth. Most people say the water really relaxes them and eases pain, but that was not the case with me. Also, one thing I did not realize about water birth babies is that often they are not full of color when they are born. Some people say this is because they have an easier transition into the air. I’m not sure of the reason, but this was very startling for my husband. I just talked to her and rubbed her vigorously, and she pinked up soon after.”–GC

Personally, think the laboring woman should be the guide. If she feels like getting into the water, then it seems like the right time to me! With my second baby, I had a birth pool on hand thinking I may like to try it, but my labor progressed so rapidly that there was no time to blow up the pool, let alone fill it up or deliberate about when to get into it. As midwife Judy Edmunds says, “Waterbirth is one of many lovely ways to enter the world.”

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Originally written for the FoMM newsletter.

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