It started with raw fish. I was ten weeks pregnant and riddled with low-lying nausea that reared up at the very thought of vegetables — any vegetable, though the leafy green ones were especially noxious. After a lifetime of balanced eating, it was hard, mentally, to recast mac&cheese and buttered pasta as daily staples. No, I needed to eat something healthy, or at least healthy-ish, and the first thing that came to mind was raw fish. Salmon, specifically, served in slashes over white rice and virulently green seaweed and a scatter of edamame. Wasabi, the Japanese sushi chain, calls it “poke;” I call it “the best $10 you can spend in the Fulton Street Subway Station.”

I bought the poke; it stayed down; I bought it again, and again. It was only after it had become a bi-weekly staple that I happened to glance at the “Nutrition in Pregnancy” handout my doctor had given very early on. “Sushi,” it said, under the list of foods to avoid. The panic I felt was both diluted and confounded when, continuing to read, I learned that fish was an excellent source of protein and Omega 3 fatty acids, and should be consumed at least twice a week.

Evidently, I concluded, it was the rawness that was the problem, not the fish. But what about countries like Japan, where raw fish is a daily staple? Are Japanese women also told to abstain from raw fish throughout their pregnancies? And what’s so harmful about raw fish, anyways?

The answer to the first question, as it turns out, is no. Not only is it culturally acceptable for pregnant Japanese to continue eating raw fish; they are encouraged to do so by the Japanese Ministry of Health. The answer to the second question is: not much — most of the time.

For pregnant women, seafood can pose two health risks. The first is mercury exposure — which can have small — but not immeasurable — impacts on fetal health. Levels of mercury are species-, not temperature-, specific. It’s also not really something most Americans — or most Japanese — need to worry about (the Japanese government did a bunch of research around mercury consumption and found that the average Japanese citizen consumes 60% of the daily mercury allowance). Save for swordfish, bluefin tuna, and tilefish, most fish with high mercury levels are not even consumed in America. And even the big-guns like shark are fine in small quantities. Here’s a handy mercury-based frequency guideline, if you’re curious about how often you can eat bluefin tuna (weekly), or, um, bottlenose dolphin (bimonthly).

The second health risk — and this is temperature-specific — is seafood-related illness, aka food-poisoning. This can come from eating shellfish harvested from contaminated waters, or from eating any raw fish that has been kept in non-sterile/cross-contamination-prone conditions. Instances of the latter are very rare (around 1 in 2 million, per this New York Times article) — so, TLDR: as long as the raw fish comes from a sanitary source, it’s fine for pregnant-lady consumption.

But just because raw fish is, mostly, good for pregnant ladies doesn’t mean most governments endorse it. 8 of the 14 countries I looked at, including the US, advise against it, 4 (the Scandinavian countries and Japan) give it the thumbs up, and the UK and Ireland make the distinction between shellfish (no-go) and finfish (fine).

The consensus on smoked fish, meanwhile, was clearer: 10 of the 14 were against it, and the remaining four lacked a stance at all. As far as mercury was concerned, most countries were okay with some amount of tuna, but half were against any consumption of higher mercury fish, while the remainder was split between limiting consumption and no policy. Here’s how it all breaks out (click the image to view the spreadsheet): 

But Wait, There’s More

Finding out that raw fish was not a blanket pregnancy “don’t” here or in Japan got me wondering about other common pregnancy “don’ts,” and how the US policies on them compared with those other developed nations. All told, I looked at 19 countries’ official guidelines and recommendations on 6 don’t-ridden topics: seafood,  alcohol, caffeine, cheese, meat, and weight gain. Note that the official guidelines might differ from what is culturally acceptable (for example, while studies have shown that the majority of pregnant Italian women do continue to drink wine in moderation, the official policy is to avoid it altogether).

The full dataset, with sources, is available here.

Alcohol

In recent years, there has been a lot of research on alcohol and pregnancy (much of which is cohesively distilled in Emily Oster’s book, Expecting Better). The general scientific consensus seems to be that babies born to pregnant women who consumed 1-2 drinks a week had no adverse effects — but because all of the data is based on surveys, rather than supervised studies, it makes sense that governments would be loathe to use this finding prescriptively. And, indeed, most do not. 15 of the 18 countries I looked at endorsed complete abstention, and only one doesn’t call for abstention for at least part of the pregnancy. The below chart shows each country’s position, where 1 denotes complete abstention, 2 is try to abstain but if not, keep it to 1-2 drinks/week, 3 is abstain for the first three months and do not drink/binge drink thereafter, and 4 is 1-2 drinks a week.

I was surprised that Singapore, which is not exactly known for being footloose and fancy-free, had the most moderate position on drinking I could find. Singapore’s healthcare system, I should note, is considered by the World Health Organization to be one of the most efficient in the world, so this is not a case of outdated recommendations. If any Singaporeans or expats living in Singapore want to shed some light on this, please do!

Coffee

When it comes to coffee — and caffeinated beverages in general, some countries dole out recommendations in milligrams, others in cups. The latter tended to be from countries with strong cafe/coffee break cultures. Anyways, the average 12oz cup of coffee has around 120 milligrams of caffeine, so I used that as the multiplier for the cup-based recommendations. All but one of the countries surveyed allowed for prenatal caffeine consumption; where they diverged was in whether 200mg or 300mg a day was acceptable, with most falling into the higher end of the spectrum. In the chart below, 1 means avoid, 2 is avoid in first trimester and keep to 200mg/day thereafter, 3 is up to 200mg/day, and 4 is up to 300mg/day/3 cups of coffee.

The big outlier here is Israel, whose government recommends total avoidance of “espresso coffees, percolator coffees, black coffee and high-caffeine content energy drinks” — though it does allow for up to three cups/day of lower-caffeinated beverages like soda or hot chocolate. The US American Pregnancy Association recommends avoidance in the first trimester, and up to 200mg after; the other 200mg countries don’t make the first trimester off-limits. The APA’s reasoning for the first-trimester ban is the increased risk of miscarriage associated with high caffeine consumption, but a) the level of “safe” caffeine consumption is actually quite a bit higher than even 300mg, and b) none of the research I found cited the first trimester as being more susceptible to caffeine than any other. That said, morning sickness might render coffee entirely unappealing (mine did from weeks 6 to about 14).

Cheese

Cheese falls into a similar pregnancy camp as raw fish, where the risk lies not in the thing itself, but in the creepy-crawlies that might glom onto it. In the case of cheese, soft, unpasteurized cheeses and mold-ripened cheeses are decently hospitable breeding grounds for listeria, a strain of bacteria that can cause miscarriage or stillbirth in infected pregnant women. Basically, listeria dig mold and moisture and low-acidity — and are vanquished by pasteurization and the higher-acidity levels that come with age. So, from a scientific perspective, preggos can hold the camambert and unpasteurized ricotta and take the chedder and the pasteurized feta and be good to go — but not all countries’ cheese guidelines line up with science. In general, the guidelines can be divided into four camps: the no mold-ripened or soft, unpasteurized camp, the no unpasteurized camp, the no soft camp, and the no soft or unpasteurized camp.

You might think that France would be among the most permissive — and anecdotally, it might be — but policy-wise, it falls into the same “no soft cheeses” camp as Argentina and Australia. The US, meanwhile, joins the cheese-loving nations of the UK and Ireland, along with Sweden and Singapore, as the most permissive.

 

Meat

Meat carries two possible health risks: bacteria contamination (toxoplasmosis and salmonella in undercooked meat; listeria in non-dried deli meat and refrigerated pates) and vitamin A. The first is dispatched with heat, the second, by avoiding liver, which is naturally high in vitamin A. But back up — what’s wrong with vitamin A? If taken in so-called “megadose” quantities, it is toxic and is associated (though not directly linked) with birth defects. The American Pregnancy Association defines the safe upper daily limit as 3000 IU, and sets the recommended limit at 770 IU. While the amount of vitamin A in liver varies, on average, a 3oz serving of beef liver will have 12,000 IU; a chicken liver, 27,000 IU — ie, 4-9 times the upper daily limit. So, yes, avoiding liver seems prudent. And yet! The majority of guidelines I read say only to cook meat thoroughly and possibly to avoid non-dried deli meats, and pates, with no mention of liver in the altogether. (Indeed, Argentina’s guidelines actually encourage consumption of liver, for its high iron content.)

Above, you can see that only the UK recommends avoidance of all three meat categories. Only 7 of the 15 surveyed countries recommend avoiding non-dried deli meats (and Denmark encourages their consumption). 8 recommend avoiding pates, and 7 recommend avoiding whole liver — but only Finland, Ireland, Singapore and the UK recommend avoiding both.

Weight Gain

Closing things out with another touchy subject! In the US, culturally, the expectation is that pregnant women can eat until the cows come home — and then pay like hell after the baby comes. I was shocked (and, not a little bummed, at least until the morning sickness hit) when my doctor told me that, rather than eating for two, I should be eating for one and one/seventh. In theory, an extra 300 calories a day plus nature doing its thing will add up to somewhere between 25-35 pounds by week forty, assuming the calorie-consumer starts out at a healthy weight (BMI of 18-24). The 25-35 recommendation was initially put forth by the Institute of Medicine in 2009; today, it’s certainly the most common recommendation, and most of the surveyed countries that do stray from it do not do so broadly.

A few countries — France, China, and Russia — gave a target weight (26lbs), rather than a range. Japan had the lowest end (15lbs) — though anecdotal evidence suggests many Japanese OBs think 15lbs is more of a high end. Of the countries with ranges, the UK’s was the narrowest (22-26lbs); Italy’s (20-35) was the widest. South Africa’s “formal recommendation is that there should be no guideline for weight gain;” Sweden also appears to be guideline-less.

 

In Conclusion: Shout Outs to Nuance, Cleanliness, and Culture

After pulling all of these guidelines together, a few themes emerged. One, I think, is that the rules are not so black and white as they may seem on a doctor’s mimeographed handout, and it’s worth finding out the reasons behind them, and the research behind those reasons. A little bit of knowledge is an empowering thing, particularly during a time as emotionally fraught as pregnancy.

A follow up to this theme is that, in the case of seafood and meat and cheese, it is not, for the most part, the foods themselves that are harmful, but the environments in which they are caught or stored or prepared. It is always a good thing, when possible, to know where your food is coming from; while pregnant, this is especially true.

And, finally, culture pervades even the sterile halls of medicine, and that this can be a beneficial thing. If fish were not a staple in the Japanese diet, if cheese was not a staple of the British diet, if coffee culture were less pervasive in Scandinavia, would their respective governments have bothered to investigate the health impacts of mercury levels and unpasturized hard cheeses and caffeine? To culture, I tip my hat.