Pregnancy summary:
My original query was:
Dear Flowers, this one caught me completely unprepared:
A colleague is asking if anybody is aware of potential risk of Flow cytometric work (including sample preparation) specific for pregnant women. I remember when I was pregnant I had back problems when I sat too long in front of the machine, but that was easily solved taking a walk. Thanks a lot for the information, Mara
Answers:
1) I guess lifting the sheath fluid boxes might prove difficult later on.
And, in response to this:
2) I would recommend the Streck Cytometry Concentrate cat#280097. It would solve the heavy lifting problem.
3) For flow, the major concerns we have had are reagent based. Our concerns a) Sodium Azide (in the antibodies) b) 7-aminoactinomycin D (causes "heritable genetic mutations") c) Ethidium bromide/ Acridine Orange (and any other dye that readily enters cells)
Universal precautions regarding handling of blood should be adequate to protect the fetus.
We discourage the pregnant from preparing solutions or handing the chemicals in their raw form. Our pregnant techs (including myself, in the past) have generally been willing to run prepared samples.
4) There are biosafety concerns unique to pregnancy that primarily relate to exposure to human viruses contained in clinical samples or human cell lines. These should be covered by the blood borne pathogen act. Viruses of primary concern are cytomegalovirus (CMV) and EBV, hepatitis B and C, HIV-1, and measles. Some human pathogens used in mouse experiments are also of concern. Lymphocytic choriomeningitis virus (LCMV) is infectious for humans and a danger to the fetus. Pregnancy involves a state of mild immunosuppression, and pregnant women should either be prevented from working with human samples or counselled on the risk of exposure. Hepatitis B immunisation is a requirement, but it will not be protective against infection unless there is a strong antibody response. Up to 30% of vaccinated adults are non-responders to the current recombinant HBV vaccine, so antibody titers need to be checked.
5) I went through a safety assessment of my work for the same reason last year. I was told not to handle many of the fluorescent dyes routinely used in flow cytometry. The hazardous chemicals are labelled R40 / R45 / R46 and R47 in some catalogues (e.g. Sigma) however many suppliers just state "no toxicity data" or "not tested".
The assessment took weeks to do because of the lack of information and the fact that none had asked our safety officer to do one before so they had to do some research on what was required before they could do the assessment. I'd be interested to hear of any other responses you get to your question - if only to find out what I shouldn't have done!
6) Yes, heavy lifting is one of the major risks of miscarriage. One should probably also practise really good hygiene when working with DNA binding dyes, BrdU and other mutagens. The issue of electromagnetic fields has recently been raised - women exposed to intense electromagnetic fields have a slight to moderate increased risk of miscarriage but this issue is still controversial.
Also, keep the risks in perspective; if your friend smokes, drinks, does not eat a balanced diet, is over 35 years old and/or is not getting good prenatal care the risks due to these factors probably render any discussions of occupational risks specific to flowcytometry work irrelevant to the baby's health.
7) The first thing that comes to mind is that sample prep can involve mutagenic and/or teratogenic reagents (for example, formaldehyde, ethidium bromide, BrdU). Clearly one would want to be careful here and check the MSDSs.
8) There are no specific risk factors associated with pregnancy for general cytometry work that I am aware of. In most cases, standard safety precautions (e.g. protective gloves, no ingestion in the lab, hand washing, etc) should suffice. However, as a precaution, it may be advisable to assess potential workplace exposures by category.
a) Chemicals: Make a list of every chemical handled. Are there any teratogenic agents used? Lead?
b) Biological: Probably not a major concern if all cells are fixed. Consider whether cells could harbour infectious agents that are potentially teratogenic (e.g. rubella virus, Toxoplasma Gondii, etc)
c) Physical: Is there any exposure to ionising radiation? In the U.S., exposure limits for pregnant women are generally 10% of the allowable dose for adults.
d) Mechanical: This is primarily a concern to the mother, not the baby. Assess ergonomic features of the workstation design. Is the chair comfortable? Does she need to overextend to reach the controls? Excessive twisting or bending? Frequent work breaks (as you mentioned) are advisable to reduce operator fatigue. There are a number of stretches that might also alleviate discomfort associated with extended work while seated.
Here's a good place to identify agents that might be harmful during pregnancy:
9) I just joined the mailing list, but I thought this might be helpful. The MSDS sheet for Hoechst 33342 reference beads indicates it may alter genetic material. Propidium Iodide is also listed as mutagenic. If you are using a dye laser with Rhodamine 590 Chloride, the dye is considered carcinogenic but non-mutagenic. I would recommend checking the MSDS Safety sheets for any chemicals being used. A good internet link for free MSDS information is
10) Nearly all nucleic acid dyes intercalate, and so are always a risk; especially so in rapidly dividing cells. I'd be unhappy about letting any pregnant worker handle powders of these things, and warn them to be extra careful of stock solutions (same would go for acrylamide
and possibly some membrane potential dyes like rhodamine 123).
Obviously all procedures should be safe for routine workers, and thus safe for pregnant workers... but I understand your concern.
11) The machine itself should be safe of course. However from the theoretical point of view pregnant colleagues should not work with DNA intercalating substances as PI, LDS, TOPRo3 etc.. At least in Germany work with these substances for pregnant women is forbidden.
12) My biggest risks were fixation of the cells in paraformaldehyde, so I was careful to always glove and not breathe!
13) Tell your pregnant co-worker to stay away from colcemid (demecolcine) which is used in some chromosome sample preparations for flow cytometry. Colcemid arrests cells in metaphase and is a teratogen.
14) The only thing I can think of would be the DNA-intercalating dyes. They might be something a pregnant woman would want to be especially careful to protect herself from.
15) The only thing I can think of is reagent exposure, such as formaldehyde fixative and sodium azide. The laser exposure isn't any different than non-pregnant conditions.
16) I am sure you are aware of the mutagenic affects of various DNA stains (PI, EB, etc.). I would think that so long as appropriate precautions are followed (gloves, lab coats, etc), there should be limited risk. I do not believe that the radiation from the various gas lasers and diode lasers pose any serious risk.
And, finally, according to Paul, if you want to avoid pregnancies in the lab, just check the water.
17) Well, this is an interesting question - - in the past 5 years of so we have had about 6-7 babies in this flow lab.....we think that it has something to do with the water since that is the only thing we figure is in common....we are still trying to work it out...but thinking about it they do all sit for long periods of time too......
Thanks to everyone for your answers
Mara