< link rel="DCTERMS.isreplacedby" href="http://caltechgirlsworld.mu.nu/" /> Not Exactly Rocket Science: Prenatal Paranoia -- a science post

Monday, November 01, 2004

Prenatal Paranoia -- a science post

From time to time I have been planning on writing a bit about my science issues, and after reading this post from Shrinkette, I was motivated. If an MD is confused about the relationship between laboratory research and what it means in the clinic, a lot other people must be too.

Today's topic: Prenatal Paranoia

We study neural development in my lab, both in utero and neonatally in rodents. In fact, the first week of a rodent's life corresponds to parts of the third trimester of the human's gestation. The rat's brain finishes developing, the ears open, etc. We are part of a research center dedicated to studying the links between brain development and Schizophrenia, and as such we are often the recipients of presentations on what different things that can happen during pregnancy(stress, infection, etc) mean for brain development. You'll forgive me if I don't give link references for some of the examples, but I will be sceptical of some of them, and I don't think they or the powers that be would appreciate my naming them. Some clever googling should suffice for verification.

There are a lot of things that pregnant and pre-pregnant women think they need to do these days in order to improve their baby's health. Things like prenatal care, special multivitamins, folic acid, excercise, and staying off of certain medications are all good things for babies. These things have been demonstrated both preclinically (in animal studies) and epidemiologically (prospective and retrospective studies that use patient and case information to assess risk/reward statistically). We know these things to be true, but there are a number of other things rumbling about in the popular press that haven't been verified that are being bandied about as scare tactics to guilt new moms into using products they don't need or into stopping the use of things they do need.

Yes, we know some medications don't mix with babies. For example, methotrexate(Rheumatrex, etc.), an anti-cancer drug that is prescribed in low doses for autoimmune diseases like rheumatoid arthritis, eczema, lupus, etc. is an abortifacient. That's a bad idea if you wnat to maintain a pregnancy. Exposure to benzodiazepines (valium, etc.) can lead to learning disabilities and perhaps hyperactivity. Accutane (isoretinoin, retinoic acid) exposure leads to heart and craniofacial defects and an increased risk of becoming schizophrenic. The most familiar example of this is probably the consequences of thalidomide exposure.

But in other cases the evidence is not clear. The article Shrinkette references refers to SSRIs, the class of drugs that includes Prozac. We've thought that SSRIs are probably safe, although this research seems to indicate otherwise. But there's a big caveat here. A number of them, as a matter of fact. First of all, these are rodents, not people, and let's face it, drugs can act differently in mice and men. Second, just because these animals react "badly" in a difficult and stressful situation doesn't mean that humans exposed to Prozac or Paxil in utero will grow up to be depressed or have PTSD. Increased "fearfulness" in mice (which is the proper interpretation of the data, anything else is an overinterpretation) has no clear-cut partner in the human emotional spectrum; you could call it depression, anxiety, or even increased emotional sensitivity. Yet MDs and patients will read this article, or the popular press blurbs about it and the upshot is that patients will be afraid to use the meds they need to function. Self-medication is dangerous, but self-non-medication can be worse. Withdrawal is a bitch, but aside from that, cutting off some meds cold turkey can have dangerous side effects, like heart attack or seizures.

The one that gets my goat, though is research presented at the meeting I just attended, the same meeting referenced by Shrinkette. A well-respected, eminent researcher presented evidence (without clarifying his methods) that ultrasound may actually disrupt brain development. I mean COME ON PEOPLE. Ultrasound has repeatedly been shown to be safe, and is practically de rigeur for expectant parents these days. At-risk pregnancies even get multiple ultrasounds, and many parents opt for a 3-D or 4-D ultrasound, which require long term and/or multiple scans. I don't see any of these kids with the extreme brain abnormalities his monkeys seem to show.

One guy (also well respected and the director of a center) told our seminar group that ANY prenatal stress to mom could disrupt fetal development, and that asking Mom to do mental arithmetic (counting backwards from 100 by 7s: 100, 93, 86, etc.) for 10 seconds was enough to stimulate the fetal stress response, as demonstrated by elevated fetal heart rate. By that logic, we should all just be born C-section since birth is a hell of a lot more stressful on a baby than MATH. This dude also said that the steroids commonly given to babies to develop and help open their lungs cause developmental delays and activate the stress response. I gotta ask, what's worse, a kid who needs help in school or a dead baby who couldn't breathe?

People please, a grain of salt, ok? Scientists and especially doctors aren't gods. Yes, we probably know more than you about what we do. But you know more than I do about what you do, so why is it that because I can put Dr. in front of my name that people assume I' m nearly infallible and I have great pronouncements to make about health? I play with rats. A monkey can do some parts of my job. Most researchers are the same, whether they like it or not.

Furthermore, humans are complex creatures. No two people will have the same reaction to medications or treatments. Not even twins. Identical twins that develop in the same placenta only have a 50% chance of becoming schizophrenic if their twin is schizophrenic. The interaction between genes and the environment is not clear in this, or many other conditions.

Common sense seems to go out the window where our babies are concerned. Maybe that's why our kids must have bike helmets and sit in booster seats until they're 8 and can't take metal lunch boxes to school anymore, even though we all survived without these necessities. Don't let a bad interpretation guilt you into a bad medical choice, be informed and don't be afraid to ask your doctor or get a second opinion if you don't like the answers.

Update: Just wanted to clarify that the Science paper in question (mice and SSRIs) is about neonatal exposure as well as prenatal exposure. This means it also applies to babies who are exposed to SSRIs via breast milk, kids who may, in some cases, owe their continued existence to mom's anti-depressant prescription for her post-partum depression or post-partum psychosis. Again, the choice is almost a no brainer here.


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