SARAH MCCAMMON, HOST:
Hundreds of patients at the Pacific Fertility Clinic in San Francisco received phone calls this weekend with some unfortunate news. A piece of equipment that was keeping thousands of eggs and embryos frozen for future use malfunctioned. This could potentially jeopardize these patients' plans for making or expanding their families, though at this point it's unclear how the eggs and embryos have been affected.
Joining me now to talk about this is Dr. Richard Paulson. He directs the fertility program at the University of Southern California, and he joins me from California. Hello.
RICHARD PAULSON: Hi. Nice to be with you.
MCCAMMON: So first, for our listeners who may not be that familiar with egg or embryo freezing, can you explain why women and their partners would do this, what kind of circumstances?
PAULSON: Well, so there's a wide variety of patients, though still the vast majority are couples who would like to have a family and who find when they try at home that they are unable to do so. It is not uncommon nowadays for women to come in and store their eggs to allow for fertility in the future and in that way sort of circumvent the biological clock. There's lots and lots of other stories, too.
MCCAMMON: Tell us more about how exactly these eggs and embryos are preserved.
PAULSON: So in order to preserve biological tissue, you need to take it down to a temperature at which there is no biological activity. And we can do that by lowering the temperature to minus 196 degrees Celsius. And then they are placed in very tiny, little containers. And those are then placed in the liquid nitrogen. That keeps them cold. And as long as they stay submerged in that liquid nitrogen, they can be essentially kept indefinitely. There's no biological activity, and there does not appear to be any deterioration.
MCCAMMON: And, Dr. Paulson, what's your understanding about what happened to cause this storage failure at the Pacific Fertility Clinic earlier this month?
PAULSON: We do not know very much. We don't even know whether the temperature in the tank actually went up or if this was perhaps just a mistake on the part of the recording apparatus, right? So the first thing for us to understand is what these cryotanks or freezers - however you want to call them - what they look like. The cryotanks are best thought of as giant thermoses. So for example, the tank that we have where we keep our embryos is about 3 feet across and about 3 feet high. It looks like a large R2-D2 unit. It's filled with liquid nitrogen.
And it's very well insulated. In order for the temperature to go up, that liquid nitrogen would have to be gone. Tanks don't have a drainage port at the bottom, so the only way for the liquid nitrogen to go out is to evaporate. So you have to ask yourself whether there was a breach in the wall of the container or if the lid was left open or how it happened that the liquid nitrogen disappeared.
MCCAMMON: And what happens now? How does the clinic figure out whether these eggs and embryos are still viable?
PAULSON: So that, unfortunately, is very difficult. The only way to know whether the tissue that's in there has retained its viability of course would be to actually thaw it and try to use it. That's the only way.
MCCAMMON: Dr. Paulson, you've been with patients who are struggling with fertility. What do you think these conversations with their doctors are going to be like?
PAULSON: Oh, I can't imagine it. You have to understand that fertility is a very personal and very intimate thing. And I think it's very fair to say that fertility doctors are very emotionally involved with their patients. My mind flashes through the stories of patients that I've heard over the various years. And imagining them coming back and my telling them that something went wrong in the laboratory and that I'm not sure whether their eggs are going to be usable or not, I - it boggles the mind.
MCCAMMON: That's Dr. Richard Paulson, the director of USC Fertility. Thank you so much.
PAULSON: My pleasure. Transcript provided by NPR, Copyright NPR.