Improvements in Embryo Culture

A major improvement in embryo culture was realizing that the oxygen content in the air we breathe is much too high for eggs and embryos. In fact, most cells in the body are exposed to a much lower concentration than the air we breathe. Too much oxygen delivered to these cells can, in a sense, overheat the cell. So it is much better to culture the embryos, not only in 5% CO2, but also in only 5% oxygen (not the 20% that is in air). This is difficult to do. Large amounts of pure nitrogen gas have to be blown constantly through the incubator at a carefully controlled rate to lower the oxygen concentration in the incubator. But it is worth that extra effort to get higher pregnancy rates.

Classically, most IVF labs have cultured embryos at a pH of 7.4 (the normal acid-base of blood concentration), and at an oxygen concentration of 20% (the same as in the air we breathe). However, these are not the acid or oxygen concentrations that are most favorable for embryo growth and development. In fact, the acid concentration inside the embryo is normally much greater than that, and the oxygen concentration is much lower. Conventional IVF culturing conditions, therefore, are too alkaline and too oxygen-rich. In fact, oxygen concentration in the Fallopian tube is only about 8% (not 20% as in air), and in the uterus, it is as low as 2%.

This type of optimal culturing of embryos requires a lot of extra attention. To reduce the oxygen concentration in the incubator from 20% to 5% requires blowing through a huge amount of nitrogen (95%), and to keep the pH acid at 7.2 (but not too acid below 7.2), requires careful monitoring of the acidity of the media. This represents a lot of extra work, but it is well worth the effort. The better your pregnancy rate per cycle, the less is your eventual cost.

In a high quality referral hospital setting such as ours, the most rigid air quality system is in place, preventing particles of volatile organic compounds from entering the environment where your embryos are growing in culture. The air around all of us is filled with these toxic compounds in low concentrations that don't seem to affect your body's overall health in any obvious way, but do seriously affect the growth and development of your eggs and your embryos in culture. We can see the obvious negative effect of non-perfect air quality in an IVF lab on the evolution of poor quality embryos that give lower pregnancy rates than the good quality egg and embryo growth from those same women whose embryos are cultured in high air quality environments.

Only large IVF centers in high quality hospitals that invest many millions of dollars into "clean room" air quality, can insure the proper environment for the growth in vitro of your eggs and embryos. Even older women in their late 30's and 40's, whose embryos cannot tolerate the slightest stress, develop good quality embryos in a laboratory environment like ours that is free of these common toxins in the air that pervade most office based settings.