VIENNA, July 2 (UPI) -- Smoking may reduce the impact of fertility treatments and estrogens found in everyday environment can reduce a man's fertility, according to studies released Tuesday.
Dr. Michael Zitzmann of the Institute for Reproductive Medicine in Munster, Germany, found smoking had an impact on a test group of couples undergoing fertility therapy. Of 301 couples studied, 153 attempted intracytoplasmic sperm injection -- a process in which a single sperm is injected into a single egg in the laboratory. Another 148 couples underwent in vitro fertilization. About 70 men in each test group were habitual smokers.
For the ICSI patients, study results showed that 22 percent of the women whose partners smoked became pregnant compared to 38 percent of the women whose partners didn't smoke. The IVF group saw similar results; 18 percent of the women whose partners smoked became pregnant while 32 percent of the women with non-smoking partners conceived.
Results also showed that the chances of the fertility treatment failing completely were two to three times higher among couples where the man smoked than in non-smoking couples.
The study did not record how many cigarettes were regularly smoked by each patient.
Zitzmann said carcinogens found in tobacco, including benzopyrene and cotinine, directly impair sperm structure and the sperm's genetic material. "This is a good argument to get them to stop smoking," he said.
Some fertility clinics advise patients to quit smoking prior to beginning fertility treatments but this is not done consistently, Zitzmann said, adding that national guidelines on the issue should be investigated.
It takes a minimum of two months after smoking stops for sperm to show improvement, he added.
Zitzmann's research was echoed by other physicians. Dr. Declan Egan, a fertility specialist at the National University of Ireland in Galway, Ireland said he regularly advises patients who smoke to kick the habit before therapy begins.
"We advise everyone to stop smoking three months before starting our IVF program," Egan told United Press International. "If one partner smokes, they're 30 percent less likely to get pregnant." That figure rises to 50 percent if both the man and woman smoke, he said.
In other research presented jointly with Zitzmann's study, Professor Lynn Fraser of Kings College in London discussed evidence suggesting that environmental estrogens could reduce fertility. Both reports were presented at the 18th annual meeting of the European Society for Human Reproduction and Embryology in Vienna.
Fraser and colleagues examined three types of environmental estrogen including 8-prenylnaringenin, found in hops; nonylphenol, found in industrial products such as paint, household cleaners, pesticides and herbicides; and the form of estrogen found in soy. These three compounds and a naturally occurring estrogen, estradiol, were studied for their effects on the final stage of sperm development. The immature sperm came from mice and were studied in a laboratory test tube. Estradiol is found naturally in the human vagina.
All estrogens sped up development of the sperm, however the three environmental estrogens disarmed a mature sperm from fertilizing an egg. Fraser said this was because these three estrogens triggered the sperm to prematurely undergo a process called acrosome reaction, in which the head of the sperm ruptures to release enzymes that assist in breaking the egg membrane.
"It was quite striking," Fraser said at the conference. "The gold standard, estradiol, was very weak" compared to the environmental estrogens, she said.
How this effect could play out in humans remains to be seen, but Fraser said environmental estrogens could pose a risk for couples trying to conceive naturally. However, they could offer some benefit to sperm used in in vitro fertilization, in which the timing of fertilizing an egg extracted from a woman is critical. The long-term effects of these environmental estrogens are also unclear.
"There are many, many things in our environment we don't think about, but use routinely," she said. "Anything that we eat or anything that we touch, most of those compounds will get into the blood" and therefore into the reproductive tract.
