NB: I am not a medical doctor and am not making any recommendations for your personal caffeine consumption. If you have a health problem, of course, consult your doctor for advice. This is just how I’ve handled my personal caffeine consumption.
As I announced yesterday on my YouTube channel, there’s a reason I’ve been quiet on this blog and on social media: I am pregnant again. Now, I don’t want this to turn into a pregnancy blog — I’ve even created a separate blog for those who want to more closely follow my pregnancy and parenting updates — but I thought I’d talk about a pregnancy-related topic that is near and dear to my heart: how I’ve handled drinking tea while watching my caffeine intake.
Monitoring caffeine is not actually a new thing for me. I have another (minor) health issue that gets exacerbated when I have too much caffeine. But since it’s more uncomfortable than dangerous, I mostly just wing it, assuming I’m taking in less caffeine drinking tea regularly than when I was drinking coffee regularly. When I started trying for a baby, I realized that I should probably figure out how to keep a closer eye on things.
Of course, when you look up “caffeine in tea,” you generally get the information back that an 8-oz. cup of tea has 26 mg of caffeine (or maybe it’s 50 mg, depending on your source). And that green tea and white tea have less caffeine than black tea. But then, sometimes you can find sources claiming that green or white tea have more caffeine than black tea. And few sources mention oolong, but mostly assume it’s somewhere between black and green tea. And finally, most of these sources assume that you make a cup of tea by taking a tea bag and putting it in a mug of hot water for 2-5 minutes.
So what if you don’t make tea like that? What if you re-steep your leaves? What if you use more leaf than they put in the average tea bag? And what is the actual variation among different tea types? Well, it’s unclear. Oh, and to get this out of the way: You cannot “decaffeinate” tea at home by steeping it for thirty seconds and discarding the first steeping. There’s more information about it here, but suffice to say that caffeine is released at a relatively even rate for at least the first 10-20 minutes of steeping, so you’d have to throw away all the enjoyable tea to get “decaffeinated” tea from this method.
The first thing I did was to try to get some information about how tea is handled during pregnancy in countries where tea is consumed more widely than coffee. Generally, in the US, tea is lumped together with coffee and is consumed mostly as a drug, for the caffeine. Caffeine is considered a vice, and therefore something that might be dangerous in pregnancy. In other countries, tea is considered a healthy drink, consumed for its benefits rather than as a vice. I did find a few blog posts and articles about women’s experiences with recommendations from doctors in Japan, and this video from Mei Leaf, but there’s not a lot of reliable information about how tea-loving countries handle advising pregnant women on drinking tea.
But I do know that the American College of Obstetricians and Gynecologists considered “moderate caffeine intake” below 200 mg per day to not increase risk of miscarriage or preterm birth. Most doctors stick to this number and say that it’s safe to have up to 200 mg of caffeine per day in pregnancy. So, armed with this number, I set out in search of a more accurate way to figure out how much caffeine I was getting from my tea.
From here, I decided I should probably consider how I brew tea. Since I generally tend to weigh my loose tea leaves, rather than using a tea bag, I knew I tended to use 3-6 grams of leaf per session. I’ll sometimes go as high as 8 g if I’m doing a flash-steeped gaiwan session. I also knew that brewing time was a factor, so I looked at the various ways I steep teas. Generally, I like to steep for 30 seconds to maybe a minute or two for each steeping, and I usually do maybe four steepings over the course of a day, so that’s definitely under five minutes of total steeping time. If I look at the white2tea steeping guidelines for a flash-steeping session, those times add up to 275 seconds for ten steepings, or just under five minutes. So I decided I would consider my brewing parameters to be somewhere between 3-5 g of tea steeped for five minutes.
Now, let’s talk about assumptions. I’m definitely making some assumptions here. First of all, I’m assuming that water quantity doesn’t really effect caffeine release. I mean, this may not be the best assumption, but at the very least, brewing more tea in the same amount of water shouldn’t make caffeine release more efficient, right? So at worst, my assumption is leading me to overestimate caffeine. Same with water temperature. The studies I found assume water temperature of 100 C, and I often use cooler water. There are studies of water temperature and caffeine release, though I didn’t look them up specifically for this project, but again, I’m assuming that, again, I’m likely overestimating caffeine by disregarding the effects of water temperature.
Okay, on to the studies. The first one looks at caffeine and theanine in standardized brews of 39 different teas, with the standard brewing method being to steep 1 g of tea in 100 ml of water for three minutes. For my purposes, I multiplied their caffeine numbers by two to account for my longer brewing time and then by 3-5 to account for my increased tea quantity. So if I wanted to steep 5 grams of tea, I assumed I would need to stick to teas with fewer than 20 mg of caffeine, as reported in Table 2. For 3 g of tea, I could go up to teas with about 30 mg of caffeine. Almost every tea in the study would fall under this amount.
I also looked at this post, which got some caffeine information from a couple studies, and expanded the range of tea types I for which I had data. The table in the post considers teas that are brewed with 1 g of tea in 100 ml of water for 30 minutes, which is pretty close to full extraction. So all I did in this case was to multiply the reported number by the amount of tea I would use, which is pretty convenient (and almost certainly exaggerating my caffeine consumption). I especially like this resource for when I want to do a special session with 8 g of a nice pu-erh and want to see just how excessive the caffeine would be.
Now, one more note about caffeine in pregnancy: One of the books I got to prepare for pregnancy was called The Panic-Free Pregnancy, which specifically addresses concerns about caffeine in pregnancy. First of all, the author of that book looks at studies of pregnant women consuming caffeine and concludes that 200 mg per day is too conservative and it’s likely that up to 300 mg per day is probably safe. He also points out that, this is meant to be a limit on average consumption, so if you go nuts and have several espressos one day, you’re probably safe if you limit yourself to decaf the next day (fun fact: decaf coffee has a small amount of caffeine and I personally find that it’s enough to ward off the headaches I get when I have no caffeine at all). So I took this as permission to occasionally indulge in a long tea session, without worrying too much, as long as I was careful for a couple days after that. I particularly like Pique Tea tea crystals for the “careful” days because I can be more certain of how much caffeine I’m getting, and one serving of Pique Tea doesn’t seem to ever have more than 50 mg of caffeine. In addition to all of this, Emily Oster, author of Expecting Better, points out that there doesn’t seem to be the correlation between tea consumption and miscarriage the way that there seems to be a correlation between coffee consumption and miscarriage, which suggests that perhaps there is something else at work here besides caffeine affecting things. Take that as you will.
One last thing: there is another concern with tea in pregnancy. Apparently catechins, which are found in the highest levels in green tea, can bind with folate, which could potentially increase the risk of folate-related birth defects. While this study did conclude that high consumption of green tea did correlate with lower folate levels, this study concluded that, for women who were taking supplemental folate, increased tea consumption was not associated with an increased risk of spina bifida. Personally, I chose to deal with this by making sure to take a prenatal vitamin (which I started months before becoming pregnant anyway) and also to offset my tea consumption and my vitamin consumption. That is, I drink tea in the morning and take my vitamins in the evening. That way, the vitamins and the tea aren’t in my digestive system at the same time.
All in all, you can tell I’ve put a lot of thought into how my tea-drinking could affect my pregnancy. Possibly too much thought (after all, people have been drinking tea for centuries and we’ve managed to keep having babies). But it helped give me peace of mind, and I hope that aggregating some of the information I found helpful might help someone else, too. I’ll close by pointing out that a lot of this research ended up being moot, as my first trimester nausea ended up limiting the amount of tea I drank anyway, mostly because I felt too sick to really enjoy the good stuff.