Approximately one in eight couples fail to conceive after one year
of trying and seek medical treatment for infertility, researchers
note in European Urology. Although male infertility is the cause
roughly half the time, research to date hasn't provided a clear
picture of which drugs and supplements may be able to improve sperm
quality and quantity.
For the current analysis, researchers examined data from 61
experiments that tested the effectiveness of a wide range of drugs
and supplements for improving semen parameters and the odds of a
live birth.
They looked for improvements in three things that can make
conception more likely: sperm concentration, or the amount of sperm
released when men ejaculate; sperm morphology, or the number of
sperm in the ideal size and shape with an oval head and a long tail;
and motility, or the ability of sperm to move through the female
reproductive tract to reach an egg.
"This systematic review has identified several medical and
nutritional treatments options that appear to improve semen
parameters," said senior study author Dr. Muhammad Imran Omar of the
University of Aberdeen in the UK.
"In spite of this, there are limited data suggesting pregnancy and
live birth rates are increased," Omar said by email.
Only four of the studies in the analysis reported birth rates, and
there were too few births across all of the studies to assess what
interventions might work best, the study authors note.
Roughly half of the studies looked at pregnancy rates, but here too,
the total number of pregnancies was too low to draw firm conclusions
about whether or how specific drugs or supplements might help.
Coenzyme Q10, a nutritional supplement that acts as an antioxidant
and is commonly taken for a variety of heart conditions, was tied to
gains in sperm count, motility and shape in three of four studies
lasting three to six months. But the quality of the evidence was
deemed "low," researchers point out.
Six studies examined nutritional supplements with L-carnitine, an
amino acid that can help the body burn fat for energy. Sperm count
and motility appeared to improve with L-carnitine, but not the size
and shape of sperm. These results were also rated "very low
certainty."
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Follicle-stimulating hormone (FSH) used by men, a prescription drug
that can stimulate the production of sperm in men and eggs in women,
was tied to higher pregnancy rates in five studies, but the evidence
was also of low certainty. FSH also appeared to improve sperm count
and shape but not motility, again, with very low certainty.
Tamoxifen, a cancer drug that is also prescribed to improve sperm
quality, was tied to better sperm count, motility and shape but not
to improved pregnancy rates. This evidence was "low" or "very low"
quality.
Pentoxifylline, a drug typically prescribed to improve blood flow in
people with artery disease, appeared to improve sperm count,
motility and shape in three studies lasting three to six months. But
researchers considered the evidence low-certainty.
Kallikrein, an enzyme that improves blood flow, didn't look like it
improved pregnancy rates but it was tied to improved sperm count and
motility.
Wide variation in the size, duration and design of the smaller
studies in the analysis make it hard to draw firm conclusions about
which drugs or supplements might be best for men to take when they
have infertility, the researchers conclude.
"Most of the studies have only investigated changes to sperm quality
and not whether men who are given these interventions are more
likely to get their partner pregnant," said Dr. Allan Pacey, an
andrology researcher at the University of Sheffield in the UK, who
wasn't involved in the study.
"It is a logical assumption that if sperm quality is improved that
more babies will follow," Pacey said by email. "But it is just that:
an assumption."
SOURCE: https://bit.ly/2ttyxMx European Urology, online January 9,
2019.
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