Smoking Decreases Men's Chances of Fatherhood by IVF and ICSI

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Hans van der Slikke, MD, PhD: “It’s July of 2002, we’re in Vienna at the ESHRE Conference, and next to me is Dr. Zitzmann from Munster, Germany. Welcome, Dr. Zitzmann. You presented a very striking story about the influence of the male partner smoking on fertility. We already had the idea that it was a bad thing for fertility as it is for many other things but you presented the model and you proved where it could be acting so please tell us about the model you used.”

Michael Zitzmann, MD: “It has been previously shown that smoking can cause damage to the genomic material inside the sperm and that means the DNA. It has already been shown that this damaged DNA is present in the embryo. So what we investigated was how is the rate of intracytoplasmic sperm injection and the pregnancies achieved by that are affected by male smoking. We found that the fertilization of the embryo or the egg cell and the initial steps of the development towards an embryo are not hampered by ICSI but afterwards, after transplantation of the embryo, the effect of male smoking seems to strike. This means that a chance for failure of ICSI is about two times higher when the man smokes than if he doesn’t.”

Hans van der Slikke, MD, PhD: “You had two groups and you did research in IVF cycles as well as in ICSI cycles because one could think there will be a difference between the two because of the way of fertilization. So how big were your groups, the IVF and the ICSI group, and what percentage of men smoked?”

Michael Zitzmann, MD: “The ICSI group was 153 couples and the IVF group was 148 couples; that means 301 couples undergoing altogether 415 treatment cycles. Male smokers were about 50% in each group.”

Hans van der Slikke, MD, PhD: “Yes, and what about the female smokers?”

Michael Zitzmann, MD: “Female smokers were less, they were about 25% in each group.”

Hans van der Slikke, MD, PhD: “Did you take that into account as well?”

Michael Zitzmann, MD: “Yes, that was included in the analysis as well as age of both partners, smoking status, and of course the numbers of embryos transferred.”

Hans van der Slikke, MD, PhD: “What’s your definition of smoking?”

Michael Zitzmann, MD: “Smoking means more than five cigarettes per day and we did not include men who smoke occasionally or stopped smoking just to see whether there is an effect or not. Later on we will investigate if occasional smoking has an effect or how long it takes after quitting to restore function.”

Hans van der Slikke, MD, PhD: “So you had these two groups and you compared them, what were the results in terms of fertilization in the two groups?”

Michael Zitzmann, MD: “In IVF, fertilization was reduced when the male partner smoked. The sperm has to actively penetrate the egg in this procedure and this ability is obviously hampered by smoking. Other negative factors were reduced sperm motility and female smoking. In ICSI, were the sperm is injected into the egg, the fertilization rate was not different between smokers and non-smokers. Indeed, no factor influenced fertilization in ICSI.”

Hans van der Slikke, MD, PhD: “But then you continued your research, you didn’t stop and say that’s it, and you counted the continuing of the pregnancy.”

Michael Zitzmann, MD: “Yes, we looked at the rate of clinical pregnancies and that means fetal heart beat seen by ultrasound, and there was a striking difference. The chance for failure of ICSI or IVF is both about two times higher when the man smokes. The further development of the embryo is obviously hampered when the male partner smokes. Another negative factor for embryo development was higher age of the potential mother.”

Hans van der Slikke, MD, PhD: “And this was significant results.”

Michael Zitzmann, MD: “Yes, a significant odds ratio, that means reduced chances for pregnancies in men who smoke in comparison to those who don´t, especially when the woman is older than 35 years.”

Hans van der Slikke, MD, PhD: “You had a very nice demonstration of this with the slide with the cigarettes and burning down the success rate. This is a question that’s obviously not difficult to answer - what’s your advice to men and women who want to undergo treatment in IVF or ICSI?”

Michael Zitzmann, MD: “Of course, the advice is to quit smoking and a good argument, as we say, is it costs more money for the couple because sometimes these assisted reproduction techniques are not paid for by insurance but it also means a health risk for the woman because hormonal stimulation infers a health risk for over stimulation syndrome and also the retrieval of the egg cells means puncture and a potential risk for infection so most women urge their partners to quit when they hear this.”

Hans van der Slikke, MD, PhD: “Maybe even before it could help them to prevent this costly treatment, so in a natural situation do you think it would have an effect as well?”

Michael Zitzmann, MD: “We did not investigate this but one can infer from our results, and it has been previously reported, that this should have an effect in natural conception as well, yes.”

Hans van der Slikke, MD, PhD: “So from now on - no smoking. Thank you very much, your presentation was very convincing.”

Michael Zitzmann, MD: “Thank you.”