Little baby headspin

August 22, 2005 9:01 AM

Pregnancy, dental work, and nitrous oxide.

My wife is in her first trimester and needs to have some dental work done. Her dentist has told her that a local is fine, but we're wondering whether the use of nitrous oxide (to help with anxiety for the procedure) during pregnancy is okay, borderline, or a straight out bad bad thing. Questions that arise include:

- how does nitrous do its thing -- is it oxygen deprivation, or is there neurotransmitter activity there?
- Reports of chronic nitrous oxide abuse (presumably from dentists with a Problem) state that B12 deficiencies are among the problems. Wouldn't this be more of a risk for a developing fetus?
- wouldn't nitrous in the mother's bloodstream go directly across the placenta (small molecule) and into the developing fetus too?

Just to make it clear, we both come down on the "do absolutely nothing if there's any possibility of damage" side of the argument -- we're not looking for an excuse, but are genuinely curious.

posted by 5MeoCMP to health (11 comments total)

You don't mention the kind of dental work exactly so I'll just quickly note that some pregnant women avoid getting mercury amalgam fillings added or removed during pregnancy. The US FDA says the risk is low, but Canada, Germany and New Zealand recommend avoidance of such exposures during pregnancy [citation].
posted by xo at 9:28 AM on August 22, 2005

Wikipedia has a good article about the substance. Note that it is used in childbirth, when mixed with oxygen. There's a vast difference between the use of nitrous once as an anaesthetic, and chonic abuse [which is what produces the B12 deficiencies and other problems.] If your wife had a habit of going through boxes of whip-its a day, and had been doing that for weeks or months, I'd be worried, both for her and the foetus. However, as drugs and medications go, nitrous [in small or one-time doses] is probably one of the less damaging things you can put into your body. A single encounter with nitrous is not going to induce B12 deficiency, particularly if your wife takes vitamins. I'll leave the neurochemistry to people who know more about that area, but yes, nitrous interacts with cells in a way more complex than simple oxygen deprivation [as one might expect, given the difference between the sensations one gets when deprived of oxygen, and the sensations engendered by nitrous inhalation.] If your obstetrician and dentist both think it's OK, I wouldn't worry too much - but check with them, and ask them these questions, since they're more qualified to address your concerns than people on the internet.
posted by ubersturm at 9:28 AM on August 22, 2005

When a new-in-town co-worker wanted to locate a dentist which offered nitrous oxide, I asked mine about it, and now my impression is very few dentists use it any more. Based on my own one-time (non-dental) experience with the gas, I'm not surprised -- its anesthetic efficacy seemed mighty dubious, to me.
posted by Rash at 9:52 AM on August 22, 2005

A small point of advice for you and your wife... I had to have some necessary dental work done very, very early in my pregnancy (week 8 or so) that required an x-ray. They only took the x-rays that they absolutely needed and also covered me with an additional lead apron in order to be absolutely sure that I was protected from the rays. It was definite overkill but it provided me some peace of mind.
posted by Emperor Yamamoto's Eggs at 9:54 AM on August 22, 2005

I don't know whether this would be considered a potential risk to the baby, but for what it's worth many dental procedures do release trapped bacteria into the bloodstream.
posted by nakedcodemonkey at 10:00 AM on August 22, 2005

My former dentist, who was usually pretty generous when doling out the nitrous, wouldn't give it to her patients when she was pregnant. So I would imagine that if she was that concerned just about second-hand giggle-gas, huffing it straight out would probably not be a good thing for a pregnant lady to do.
posted by spilon at 10:03 AM on August 22, 2005

There is some concern about the safety of nitrous oxide during pregnancy for a couple of reasons. First of all, studies since 1975 have documented an increased incidence of miscarriage in operating room personnel exposed to waste anesthetic gasses including nitrous. Second, as mentioned above, nitrous interferes with the actions of B12 and folate in the body and both of these are important to fetal development. Additionally, the first trimester is the riskiest time for exposure to teratogens. Here is the US governments page on occupational exposure to nitrous; scroll down for the relevant part. I would be surprised if you could even find a dentist willing to give your wife nitrous until near the end of her pregnancy; while one brief exposure might not be bad why risk it? Although you didn't ask it, there is also evidence to suggest that benzodiazepines such as Valium are also unsafe during pregnancy. It might be worth considering putting off the dental work, or doing something that is less invasive, but that is for your dentist and wife to discuss.
posted by TedW at 10:06 AM on August 22, 2005

My dentist recently scheduled me with a new hygenist when I asked for nitrous, because the original hygenist was pregnant. If he's not willing to let a pregnant woman work around someone else using nitrous, I would assume it's a bad idea to have a pregnant woman directly use it.
posted by Nelson at 10:29 AM on August 22, 2005

My experience was like Nelson's - my dentist said if I wanted some nitrous during a cleaning that would be fine but to notify them ahead of time to make sure they put me with a non-pregnant/not-trying-to-get-pregnant hygenist.

So on the one hand they have a concern over repeated exposure, a la their leaving the room during an x-ray despite putting you right in the path of it. On the other there's a lot more direct intake from using the NO2 than being near someone using it.
posted by phearlez at 10:45 AM on August 22, 2005

Thanks everyone. I suspect that a lot of the dentist care over exposure comes from the NIOSH guidelines and worker protection, but those guidelines are there for a reason. Most especially the folate concerns.

We will be avoiding the "factitious air".
posted by 5MeoCMP at 12:37 PM on August 22, 2005

I was getting a crown but my dentist was pregnant and would not use gas.
posted by lois1950 at 5:44 PM on August 22, 2005