Did you eat seaweed salad during pregnancy? Was your baby okay?

[Solomum2023]

I'm not sure this is the right place to post, but here goes.

I am 22 weeks pregnant and have been sick with worry since week 10, when I ate a large bowl of wakame seaweed salad. At the time, I didn't know how much iodine it contained, as I had only read about nori seaweed which is fine. But a more thorough Google search has since informed me that the amount I ate contained a minimum of 4x the safe daily upper limit of what your body can handle. Once I had looked into it properly, I felt SO terrible about not researching it more thoroughly beforehand. I am so good with my diet otherwise and haven't made any other "mistakes"... I just can't believe I stumbled upon what is apparently one of the very worst things to eat during pregnancy and I didn't have the presence of mind to look it up! More than anything, I wish I could go back and undo it. Clearly I haven't touched seaweed since, but the irreversible damage might already be done.

As far as I can tell based on Google research, one of two things could have happened (because my baby's own thyroid wasn't developed yet, so its iodine intake would still be entirely regulated by my own thyroid function): either my body simply discarded the excess iodine and there was no harm done, or else I had a legitimate overdose and my body's iodine production shut down as a response to the excess, meaning there was a period of time of critical brain development where my baby did not receive the iodine he needed, and his brain in those stages failed to develop properly.

Most studies indicate that excess iodine (leading to iodine deficiency) in developing fetus brains can cause congenital hypothyroidism, which can be diagnosed and treated at birth, so while it would be heartbreaking, there would be a way to handle it. But a few studies also suggest that iodine excess during pregnancy can cause mental retardation in the child, which is irreversible. (Note: if I had a child born with mental retardation, I would deal with it, and it would be okay - it would be the knowledge that I was the direct cause of it, by doing something so easily avoidable as eating a bowl of seaweed, that would absolutely destroy me.) The studies mostly say that these damages are caused after a prolonged intake of excess iodine, but one study in rats said that even a single overdose could lead to this.

Even three months after it happened, I just can't let it go. I tried talking to both my GP and midwife but they were no help, they both just say not to worry, but I honestly don't think they really heard what I was trying to say. They just hear the word "seaweed" and thought I was being silly and overly worried about everything. I needed a legitimate professional to weigh in on my situation and I honestly just felt ridiculed. And it certainly didn't help ease my anxiety about the situation.

So mumsnet, I am turning to you. If you ate seaweed salad during pregnancy, or have heard of anyone who did, did it have any consequences for the baby?

Love, a very worried and guilt-ridden mum to be 😥

Yes, I ate it three or four times when pregnant with DD1. We used to go to a fab Asian restaurant. Did not realise it was a thing not to eat it!

DD is fine btw.

I ate this repeatedly during my pregnancy, no idea I wasn’t meant to. My son is happy and healthy (3 now!)
I honestly wouldn’t worry.

That is a relief to hear, thank you for sharing. (And yeah, I had no idea it was a thing at all and wouldn't have been worried if I hadn't specifically looked it up.)

I also feel like excessive iodine would be a lot more than a one of time that you ate 4x the daily amount. This is why your GP & midwife are not concerned. If it were that huge of an issue the nhs website would advise pregnant women to avoid.

I think you'd have to eat a wheelbarrow's worth in one sitting for it to have any effect OP.

I know it's easy to say "don't worry" so instead please consider how amazing women's bodies are and how your body, without any conscious input from you, is working to protect your baby by regulating and filtering everything that enters your body, from the air you breathe to the food you eat. Your body is a host, and will create the optimum conditions for your baby.

Pregnancy is a weird and crazy time, it's easy to become fixated on the smallest things. In a world where we are so used to instant results and constant data, pregnancy throws us off-balance. It's the ultimate trust exercise. Trust your body.

Oh well, I pretty much lived off (non raw fish) sushi when I was pregnant with my DS. Totally craved it, and seaweed. Yum.

My DS9 is ridiculously clever tbh!! He's v bright kid, it'll be fine!

I don't mean to sound dismissive of this specific worry but it does sound like health anxiety - there's no way going above the RDA with a single bowl of seaweed at 10 weeks has done anything, and worrying about it for this long won't help or change anything, anyway.

Maybe you could book an appt with a private OB to discuss this and hopefully assuage the anxiety?

Hi! It does sound health anxiety doesn't it? The thing is, I don't have health anxiety about anything else (that sounds wrong - I mean I am reasonable about guidelines and don't overthink things as long as I feel fine). The thing that has stuck with me about this particular worry is that one simple google search will tell you that as much as a spoonful of seaweed exceeds your daily RDA, and a bowlful is at minimum 4x recommended safe daily upper limit, not RDA. And that overdosing on iodine - and the amount I ate could be considered an overdose - can cause your body's thyroid to shut down its own production of iodine (the Wolff-Chalkov effect). This wouldn't be a longterm issue for a non-pregnant body, but your fetus is unable to escape this effect once it has been activated, so essentially your fetus' thyroid will be unable to develop properly for the rest of the pregnancy, leading to potential harm to brain development.
This is all something that one single google search (bringing up medical studies) can tell me, so I think my actual anxiety about this issue actually stems from the fact that I get such dismissive responses when I try to ask about it (I am thinking about my healthcare providers, not your specific comment), and I can't understand why, when there are all these studies so readily available that all say the same thing.

I have considered booking a private appointment but I need to find someone who will actually take the time to do the research and take my question seriously, does that make sense? I really think my concern is being dismissed because "a bowl of seaweed" sounds ridiculous. But the amount of iodine in this particular seaweed isn't ridiculous - there really is that much, much more than the human body can handle, in that amount. (And when they say "a portion," they mean a spoonful. It is incredibly misleading.) Honestly I think seaweed is such a niche food in the west, and very rarely does anyone go into a sushi restaurant and order a huge bowl of it - though clearly it does happen, as this thread is proof - that most healthcare providers just don't know much about it. And that does worry me.

Having said ALL of that above, I also posted on this forum because I was seeking the reassurance of other pregnant women previously having eaten the amount of seaweed I did without it causing an issue, which seems to be the case from the other comments on this thread. Posting this and getting responses fro has made me more calm about the potential repercussions than I have been all pregnancy, so thank you to everyone who took the time to write.

There's a big difference between exceeding the rda and toxicity. You would likely have to exceed the rda for many many days at a time to have toxicity and then you'd probably have symptoms. Think of it as averaging out your iodine consumption over a week period.. Really, a 24 hour day in terms of the human metabolism is relatively arbitrary. Iodine quantities in water around the world vary greatly as well.
OP, do not worry. The stress you are causing yourself is far more likely to be damaging for your pregnancy than this one off incident. Take a look at this (I just found off a Google search)
www.ncbi.nlm.nih.gov/books/NBK560770/

Stop googling OP. A little knowledge is a dangerous thing.

I really think you’ve done no harm, looks online like an overdose would be from having too much over a long period of time, not just on one occasion. That would probably refer to people taking it as a supplement and taking too much, consistently, over a long period x

You had ONE iodine-rich meal. One. How do you think humans would ever have survived, particularly in seashore communities where eating seaweed was routine, if you could OD yourself and damage a pregnancy with one seaweed salad? Apply some critical thinking.

Your fixation on this has honestly tipped over the line into a mental health issue, or at least the foundations of one. If you really can't let this go, you need to start seeking out some help.

I didn’t even know this was a thing. I ate seaweed all throughout pregnancy and none of my children have mental retardation, that’s for sure. In Japan they are eating seaweed all the time and no one cautions them about it afaik so 🤷‍♀️ Please relax the baby will be ok

I was pregnant with DC1 in Japan. I ate sushi, seaweed, eggs, and took regular trips to the onsen (hot baths). None of these things are contraindicated in Japan.
DC1 is fine.

My child is feral as fuck, but I don't blame the 40 plates of seaweed I ate. Love seaweed.

I’m a complete nutrition freak and I’ve honestly never heard of any issues with eating seaweed in pregnancy. I’m also hypothyroid so am very aware of iodine intake and have had iodine testing done. I have had advice in the past from this lady and I’m sure she’d take you seriously if you were to consult her: melaniebrownnutrition.com/pregnancy

Put Google down OP!

I was sooooo wary of everything during my pregnancy. Learning not to Google things was the best thing I did. My baby is 1 now and doing really well, despite my having done dreadful things (according to Google) and experienced terrible symptoms of terrible things (according to Google) near enough every day of the first couple of weeks.

As kindly as I can say it, you don’t really know what you’re reading about or understand pregnancy anywhere near well enough to come to conclusions about iodine and brain development so don’t trouble yourself with it.