Water & Pregnancy

If you’re pregnant, you’ve probably already noticed that you’re thirstier than usual. You may have also heard that you’re supposed to drink a certain amount of water every day. While most people don’t need to actually measure their water intake (unless there is a particular concern and your doctor or midwife advises you to), one does need to drink more than usual to stay sufficiently hydrated. There are a few reasons for this, for why we need more water during pregnancy, and some of them might surprise you. This list is not at all exhaustive–there are many more reasons than this!--but here are a few of them.

We Have More Blood

During pregnancy, our blood volume increases. This usually ranges from a 40% - 50% increase for a singleton, and 65% or more for twins. This process helps ensure that both we and our baby get enough nutrients and oxygen. Our blood is the conveyance through which nutrients, hormones, and air travel to the placenta, so the additional blood is necessary to make sure we have enough of these resources to share with our growing baby. Producing so much extra blood can make us feel more tired, more easily out of breath, and also much thirstier. We need to hydrate more than usual to support the production of all this additional blood.

Circulation

We also need to drink more to support the circulation of all this additional blood. If we are dehydrated, it can lead to sludgier fluids with poor venous return in our extremities. Several common pregnancy discomforts are caused or exacerbated by this, including oedema (swollen ankles), leg cramps, sore wrists, restless ankles, and puffy hands. Drinking more water can help all that blood move through our body more fluidly which can relieve some of these symptoms.

Baby’s blood

As well as more of our own blood, we also have to provide enough liquid to support our baby’s blood. At term, foetuses have about 400 mL of blood, some of which is in the placenta. Being enclosed within the maternal body, foetuses can’t independently intake their own liquids, and therefore rely on us to hydrate for two. This makes us thirsty for two.

Amniotic fluid

Your baby gestates in your body in an amniotic bath, which contains many nutrients, minerals, hormones, and other good stuff, but its main ingredient is, of course, water. While pregnant, we are constantly flushing and cleansing baby’s amniotic fluids, refreshing the used water with brand new clean water. This requires a lot of water intake on our part, since we completely cycle through amniotic fluid approximately every two hours. No wonder you’re so thirsty!

Detoxing

When we’re pregnant, our body is not only intaking for two, but outputting for two as well. You may have noticed you have to urinate a lot more frequently. This is not just because your growing baby is putting increasing pressure on your bladder–although that sure doesn’t help matters–it is mostly because we have to excrete all of our baby’s waste as well as our own, because again, baby is within the confines of our body and has nowhere to expel their waste except through us. Our liver and skin take on extra detoxing duties, and so do our kidneys. The baby urinates into the amniotic fluid, and as we refresh it with new liquid, we also have to expel the old liquid. Hence, we pee a lot more often when we’re pregnant.

UTI’s

One of the downsides of having to drink so much more water is that if we don’t, it can make our fluids thicker and slower. I already mentioned swelling and puffiness, but another related pregnancy annoyance is an increased risk of urinary tract infections. If we get too dehydrated it can be more common to get bacterial build-up around the urethra and develop a UTI. The best defense against this is just to stay hydrated (along with proper hand-washing and toilet hygiene, of course), which includes staying hydrated overnight. You might have heard that you should avoid drinking water before bed so you won’t have to get up and pee in the night? I’m afraid that doesn’t work. You will still have to get up and pee because a lot of what we’re needing to eliminate is amniotic fluid which is already there. You will simply risk getting dehydrated with an increased likelihood of developing a urinary tract infection. So keep drinking water, even before bed.

Hot & Sweaty

Another way we detox is through our skin. We flush out some of those used fluids by sweating more. Have you noticed you’re warmer? More prone to feeling over heated? It’s partly because of our size, and how much harder our circulation system has to work, and it’s also because our skin is flushing out waste. Some people experience acne and skin challenges during pregnancy, and some experience a rosy glow. No doubt this extra flushing contributes to both, as well as making us more thirsty.

Salt

You may have come across some outdated advice to avoid salt, or to limit your salt intake, to lower the chance of puffy ankles or leg cramps. This is incorrect. We actually need lots of salt when we’re pregnant because of all the water. We need electrolytes. You may have noticed you crave salty foods? Go ahead and trust this instinct–eat salt to taste. We require a lot more during pregnancy to support all these extra fluids in our body, so don’t be afraid to indulge. Some people even sprinkle a pinch of sea salt in their water to help maximize absorption.

Sugar

Another effect of good hydration is that it helps flush excess sugars out of our body as well. This is important for anyone, but especially if you have gestational diabetes. While drinking water won’t directly lower your blood sugar levels, it does help stabilize them, by making it easier for your body to expel extra sugars.

Barfing

Drinking water also relates to pregnancy nausea. Throwing up is extremely dehydrating so it is very important to rehydrate after vomiting. In fact, most people instinctively drink water right afterwards. But hydration can also help stabilize your nausea, and has been found to slightly help reduce mild feelings of low-grade seasickness during pregnancy. If you have severe nausea and vomiting, hyperemesis gravidarum, I’m afraid drinking water won’t eliminate the symptoms, but it will reduce the risk of dehydration.

Timing

Here’s a thought you may not have heard before. Some pregnancy dieticians recommend drinking most of your water between meals, rather than during. This might improve digestion as well as hydration, and as Lily Nichols says, lead to a “happier tummy”. However, regardless of when you drink, it is always important to stay hydrated during pregnancy.

Labour

Finally, labour. As important as it is to stay hydrated during pregnancy, it is just as vital during labour, when you are, after all, still pregnant. Check out this article on drinking in labour to find out why.

The bottom line, though, is to listen to your body. Drink whenever you are thirsty. Prioritize water. Drink as much and as often as you want to, even if it’s at night or right before bed. And don’t hold back on salt. Unless your care provider specifically advises it, there is usually no need to count or track water (or salt) intake. Just do what feels right because most of the time, your body speaks to you quite loudly when you are pregnant. Most of the time, you can let your own thirst be your guide.

-Stephanie Ondrack is a retired birth doula (or maybe on an extended sabbatical) and has been with The Childbearing Society since 2003.

She lives in East Van with her partner, kids, chickens, and cats