Pregnancy and chemical lab safety
Jun25

Pregnancy and chemical lab safety

A query from my inbox last week: Are there any safety resources for women scientists who are pregnant, other than MSDSs? The short answer to this question is that your best resources is likely to be the safety office at your school or workplace. Otherwise, the National Institute for Occupational Safety & Health has a page with information on reproductive health and the workplace, as does the University of California, Davis. Yale University says in its Chemical Hygiene Plan: Exposure to certain chemicals may adversely affect the fertility of the parents and may affect the developing fetus during pregnancy. Therefore, anyone working with reproductive toxins or teratogenic agents and planning to conceive a child or are pregnant should consult their Principal Investigator, the Chemical Hygiene Officer, and/or the Department of Employee Health or Student Health as appropriate for opinions regarding risks of exposure and potential exposure control options. The Chemical Hygiene Officer can assess potential exposures and work with the individual and with the Principal Investigator or laboratory supervisor as appropriate, to adjust work practices to minimize any potential risk. The Employee Health or Student Health Physician can discuss the potential risks of exposure as they apply to each particular situation. A list of suspected reproductive toxins and teratogenic agents can be obtained from Yale Environmental Health and Safety. I checked for information at a few additional schools and didn't find much else. If anyone knows of additional resources, please feel free to post them in the comments or email them to...

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On Birth Control,“Plan B,” and…Batman
Dec09

On Birth Control,“Plan B,” and…Batman

The “morning-after” pill, used to prevent conception when other planning methods fail, became a political lightning rod this week. Reports by Pharmalot, NPR, Reuters, and many others relate how the Secretary of the U.S. Department of Health and Human Services blocked an FDA recommendation to provide over-the-counter access to this treatment to a wider range of patients (currently, women under the age of 17 must have a prescription to obtain Plan B). After the uproar generated by the announcement, I wondered what, exactly, was this contentious molecule, and what did it do? In the US, hospitals administer Plan B as two small pills, each with a 750 μg dose of the synthetic hormone levonorgestrel. First approved by the FDA in 1999, levonorgestrel prompted several companies, among them generic manufacturers Barr, Watson, and Teva, to jump in as suppliers in the ensuing decade. According to a 2011 Teva patent, Plan B is most effective when taken within 72 hours of when a person’s first-line contraceptive fails. The FDA estimates its success rate at 80-90%. Levonorgestrel binds to the same receptors as other sex hormones (think estradiol or progesterone), and prevents ovulation or impairs fertilization of egg cells. Some researchers believe that Plan B prohibits already-fertilized eggs from adhering to the endometrium (uterine inner wall), which might prevent further embryonic development leading to pregnancy. In fact, a large dose of 17-α-ethinylestradiol (EE) – the main ingredient in most birth control pills – can sometimes be used “off-label” to achieve the same effect. The uncertainty over whether Plan B actually terminates pregnancies brings it onto similar ground with mifepristone (RU-486) and diethylstilbestrol (DES). These two drugs, previously popular options for emergency contraception, have mixed public perception today; many associate RU-486 with abortion, and DES with endocrine disorders and tumor formation in offspring. Chemistry Note: It’s humbling to watch Mother Nature re-use the same chemical templates over and over, and that small changes in the overall steroid structure lead to huge biochemical consequences. Like Batman, with his never-ending supply of utility-belt gadgets, the steroid core structure can be tweaked in seemingly endless ways to produce biologically active molecules. I would have to devote (several) more posts to just how many modifications, but think about the effects simple oxidation (bile acids), ring expansion (cortistatins), or conjugation (sulfonated sterols) have on biological processes. The sex hormones have been puzzling synthetic chemists for nearly 100 years; in fact, two prominent chemists spent large portions of their careers perfecting the introduction of a single methyl group into the steroid core! Levonorgestrel claims “second-generation” hormone status; next-gen progestins, such as desogestrel, do away completely with C-3 oxygenation, and sport...

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