June 5, 2019&mdash;More men in the U.S. are waiting to start a family. And just as women over 35 face extra fertility and pregnancy risks, older fathers may encounter problems as well, according to a study published in the journal <a href="https://www.maturitas.org/" target="_blank">Maturitas</a>. 
Beyond fertility
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Aging can lower men's testosterone levels and reduce sperm number. It may also cause damage to the sperm and semen. And just as people may lose muscle strength and endurance with age, men's sperm also tend to lose fitness over time, researchers said. 
That can lead to difficulty conceiving. But that's not the only concern for older dads. Damaged sperm can affect a developing baby's DNA and increase the risk of pregnancy complications, birth defects and long-term health issues.
When researchers looked at more than 40 years of research on fertility, pregnancy and the health of children, they found that women who conceived with men over 45 had a higher chance of pregnancy complications, such as gestational diabetes and preeclampsia. And babies born to older dads had a higher risk of:
<ul>
 <li>Late-term stillbirth. </li>
 <li>Low birth weight. </li>
 <li>Low Apgar scores. (That's a test given to babies right after birth to assess how well they're doing outside the womb.)</li>
 <li>Newborn seizures.</li>
 <li>Birth defects. </li>
 <li>Childhood cancers, autism, and cognitive and psychiatric disorders later in life. </li>
</ul>
Because of these risks, researchers advise men who want to delay fatherhood to talk to their doctor about their fertility and about banking sperm before they turn 35&mdash;or no later than 45.

Waiting to start a family? What men need to know