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 four times a year and the digital edition monthly.

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

CRISPR epigenome editor offers potential gene therapies
News

CRISPR epigenome editor offers potential gene therapies

April 25, 2025

Scientists from the University of California, Berkeley, created a system to modify the methylation patterns in neurons. They presented their findings at ASBMB 2025.

Finding a symphony among complex molecules
Profile

Finding a symphony among complex molecules

April 23, 2025

MOSAIC scholar Stanna Dorn uses total synthesis to recreate rare bacterial natural products with potential therapeutic applications.

E-cigarettes drive irreversible lung damage via free radicals
Journal News

E-cigarettes drive irreversible lung damage via free radicals

April 17, 2025

E-cigarettes are often thought to be safer because they lack many of the carcinogens found in tobacco cigarettes. However, scientists recently found that exposure to e-cigarette vapor can cause severe, irreversible lung damage.

Using DNA barcodes to capture local biodiversity
ASBMB Annual Meeting

Using DNA barcodes to capture local biodiversity

April 15, 2025

Undergraduate at the University of California, Santa Barbara, leads citizen science initiative to engage the public in DNA barcoding to catalog local biodiversity, fostering community involvement in science.

Targeting Toxoplasma parasites and their protein accomplices
Journal News

Targeting Toxoplasma parasites and their protein accomplices

April 11, 2025

Researchers identify that a Toxoplasma gondii enzyme drives parasite's survival. Read more about this recent study from the Journal of Lipid Research.

Scavenger protein receptor aids the transport of lipoproteins
Journal News

Scavenger protein receptor aids the transport of lipoproteins

April 11, 2025

Scientists elucidated how two major splice variants of scavenger receptors affect cellular localization in endothelial cells. Read more about this recent study from the Journal of Lipid Research.