Journal News

MCP: Sperm-quality study updates advice for couples

Clinical trial suggests doctors should change IVF protocol
Laurel Oldach
Nov. 1, 2018

Could doctors at fertility clinics be giving men bad advice? Two clinician–researchers at the Center for Reproductive Medicine of Shengjing Hospital in Shenyang, China, think so.

Research from Da Li and XiuXia Wang’s labs, published in the journal Molecular & Cellular Proteomics, upends conventional wisdom that abstaining between efforts to conceive can improve a couple’s chances of success. The research team worked with almost 500 couples to test whether how long a couple waits between efforts to conceive could change their success rate.

An artist’s representation of fertilization of an oocyte by a sperm cell.Courtesy of Karl-Ludwig Poggemann/Flickr

“For years, men have usually been advised to limit sexual activity to increase the chances of pregnancy,” said Li. “However, it’s time to change our minds.”

Some earlier studies had shown that semen produced shortly after a man’s most recent ejaculation — within three hours or so — had faster and more motile sperm than if the man abstained for several days before ejaculating again. But it wasn’t clear why the sperm changed or whether the changes affected fertility. So researchers set up a few side-by-side experiments.

They looked at individual subjects’ semen after they had abstained for either several days or just an hour or two, comparing the volume of semen and the mobility of sperm. As had been observed earlier, the sperm from shorter abstinence periods moved faster.

Using mass spectrometry to look at the protein makeup of the samples, the team found major molecular differences. The majority of the affected proteins were involved in cell adhesion, a function that sperm need in order to fuse with egg cells.

The team also observed changes to proteins involved in sperm motility and metabolism, especially proteins that handle reactive oxygen species, a byproduct of cellular energy production. Although reactive oxygen species are needed for some normal sperm functions, an excess can damage sperm’s genetic material.

According to Li and Wang’s results, the longer sperm exist, the more vulnerable they are to DNA damage by reactive oxygen, which could harm their ability to form a viable embryo.

To see whether the changes to sperm were affecting fertility, the research team also ran a study of about 500 couples preparing for in vitro fertilization at the fertility clinic. They asked men in the control group for semen samples after several days of abstinence, whereas men in the experimental group abstained for less than three hours before providing their samples. The IVF team proceeded as usual with the two types of sample, using them to generate and then implant embryos.

“A typical live birth rate in a cohort of this size is about 30 percent,” Li said. In the experimental cohort, live births were higher by one-third.

“Our data indicate that couples with relatively normal semen parameters should have frequent sex around the ovulation period,” Li said. “This could make all the difference to their efforts to start a family.”

Meanwhile, IVF treatments at the Center for Reproductive Medicine, which treats about 5,000 infertile couples per year, also are being updated to use semen from more closely spaced ejaculations.

The team plans to continue working with patients, Li said, and will investigate differences in post-translational modifications that his lab saw between the types of samples. “This is a very new field,” he said, noting that there are many unanswered questions about the changes the team observed.

Enjoy reading ASBMB Today?

Become a member to receive the print edition monthly and the digital edition weekly.

Learn more
Laurel Oldach

Laurel Oldach is a former science writer for the ASBMB.

Get the latest from ASBMB Today

Enter your email address, and we’ll send you a weekly email with recent articles, interviews and more.

Latest in Science

Science highlights or most popular articles

Snaking toward a universal antivenom
News

Snaking toward a universal antivenom

May 26, 2024

Scientists at Scripps Research have discovered antibodies that protect against a host of lethal snake venoms.

Cell’s 'garbage disposal' may have another role
News

Cell’s 'garbage disposal' may have another role

May 25, 2024

Researchers at Johns Hopkins University have determined that the proteasome could be helping neurons near skin sense the environment.

Clues from bird flu’s ground zero on dairy farms in the Texas panhandle
News

Clues from bird flu’s ground zero on dairy farms in the Texas panhandle

May 25, 2024

Dairy farmers and veterinarians in northern Texas furiously investigated a mysterious illness among cattle before the government got involved.

Universal tool for tracking cell-to-cell interactions
News

Universal tool for tracking cell-to-cell interactions

May 19, 2024

A team of researchers has developed LIPSTIC, which can lay the groundwork for a dynamic map tracking physical interactions between different cells — the elusive cellular interactome.

Weedy rice gets competitive boost from its wild neighbors
News

Weedy rice gets competitive boost from its wild neighbors

May 18, 2024

Rice feeds the world. But researchers have found that a look-alike weed has many ways of getting ahead.

From the journals: JLR
Journal News

From the journals: JLR

May 17, 2024

A “T” makes a difference in blood clotting. High cholesterol: two screens are better than one. Biomarkers for cardiovascular risk. Statin-induced changes to the HDL lipidome. Read about recent papers on these topics.