Sperm Health is Linked to Pregnancy Outcomes

As researchers discover more about the science of fertility, it’s clear that the biological role of fathers extends beyond the (important!) moment of conception. Men’s prenatal health has a deep impact on the health of pregnant partners and developing babies.

Sperm health and the risk of recurrent miscarriage

In a study that compared the sperm health of men whose partners had suffered three or more consecutive miscarriages with the sperm health of men whose partners had not suffered miscarriage, Imperial College London researchers found significantly more DNA damage in the sperm of men whose partners had suffered recurrent miscarriage.

While most prior research on recurrent miscarriage has focused on health issues in the mother, lead author Dr. Channa Jayasena designed this study to focus on the influence of sperm health, explaining that “[a] growing body of evidence that suggests sperm health dictates the health of a pregnancy. For instance, previous research suggests sperm has an important role in the formation of the placenta, which is crucial for oxygen and nutrient supply to the fetus."

The analysis showed that sperm from men with partners who had suffered recurrent miscarriage contained twice as much DNA damage compared to the control group. “It has taken medicine a long time to realize sperm health has a role to play in miscarriage and that the cause doesn’t lie solely with women,” Dr. Channa Jayasena explains. “Now we realize both partners contribute to recurrent miscarriage, we can hopefully get a clearer picture of the problem and start to look for ways of ensuring more pregnancies result in a healthy baby.”

Sperm influences formation of the placenta

Dad’s fertility health, including sperm health, is responsible for delivering the DNA blueprint that creates a placenta which nourishes his growing baby throughout pregnancy. How cool is that?

Soon after a sperm successfully fertilizes the egg, a placenta begins to develop alongside the embryo. The placenta is a temporary organ attached to the uterine wall that connects the developing fetus and mother, delivering nutrients to the growing baby and removing waste. The placenta is crucial for mother and baby, but it might come as a surprise that it is the father’s DNA, carried by sperm, that contains the blueprint for the creation of the placenta.

A 2013 study from the Cornell University College of Veterinary Medicine confirmed past research which revealed the role of mom’s DNA in spurring embryonic development, and dad’s DNA in growing a healthy placenta. Lead author Dr. Xu Wang explains these essential roles: “Mouse experiments showed that if all DNA comes from the mother, only the embryo grows, suggesting some degree of sex-based division of labor between programming the placenta and the embryo. Our results confirm what these past findings hinted at,” highlighting the essential role that male sperm have in carrying blueprints for healthy placental creation.

It turns out that pregnancy is a true co-creation by mom and dad! But when men’s fertility health declines, oxidative damage to sperm DNA can result in poor semen quality and male infertility. This lowers the chance of chances of conception, of course, but DNA damage in sperm can also impact the health of a pregnancy through its influence over placental formation and even the viability of the pregnancy.