Is a man's metabolic syndrome a threat to his wife's pregnancy?

Metabolic Syndrome Explained:

The so-called metabolic syndrome is not a disease in its own right, but a combination of different diseases and signs. Today, it is considered the most significant risk factor for cardiovascular disease - the most common cause of death in industrialized countries. Thereby, the syndrome summarizes the different aspects which often leads to cardiovascular disease. These would be: Obesity (i.e. overweight), disturbed fat and cholesterol balance, arterial hypertension (i.e. high blood pressure) and elevated blood sugar levels. The combination of these four sub-diseases is also called deadly quartet in the Anglo-American language. Experts estimate that one in four people in Germany will develop metabolic syndrome in the course of their lives. There is also a possibility that this will multiply the likelihood of dying from the consequences of a heart attack or stroke. The chance of a person with the syndrome developing a diabetes such as type-2 diabetes mellitus may be about five times higher.

According to study results, even a woman's pregnancy is at risk due to the combination of such diseases in men.

Nearly one million pregnancies studied:

In the analysis, published in December 2020, by Oxford University Press, the researchers examined data from U.S. insurance claims for 958,804 pregnancies. These insurance claims included data between 2007 and 2016.

In addition to metabolic syndrome, information was also collected on various conditions such as chronic obstructive pulmonary disease, depression and heart disease. The burden of chronic diseases for all patients, including age and medical history (heart failure, myocardial infarction, vascular disease, renal disease, liver disease, cancer, etc.) was also analyzed. These were adjusted to take into account other pregnancy-influencing factors - particularly age, health, maternal weight, and whether the father or mother smoked.

4.6% of the men participating in the study were over 45 years old and 23.3% had at least one aspect of metabolic syndrome before conception. During the duration of the study, 22% (172,995) pregnancies were lost to ectopic pregnancy, miscarriage, or stillbirth. As maternal age and the number of other medical conditions increased, pregnancy losses also increased, although the association between paternal health and pregnancy loss remained. Increased risk of pregnancy loss also increased with father age. However, the exact mechanisms by which father health influences the risk of pregnancy loss are not known. According to the study, one plausible explanation could be epigenetic damage to male sperm DNA. Consequently, not all the necessary genes that originate in the embryo or fertilized egg could be activated.

According to research leader Prof. Michael Eisenberg of Stanford University School of Medicine, this is the first study to suggest that pregnancy risks show an association with increasing numbers of diseases in men.

Unambiguous findings:

At least one aspect of metabolic syndrome was present in 25% of 958,804 men (mean age of 35.3 years) from the US pregnancy cohort. Compared with men who did not exhibit any aspects of metabolic syndrome, the risk of pregnancy loss increased by 10% in men with one syndrome component-with two, three, or more components, by 15% and 19%, respectively. Consequently, fathers without metabolic syndrome experienced ectopic pregnancies, miscarriage, or stillbirth in 17% of pregnancies. With one aspect of the syndrome, the risk increased to 21%, with two aspects to 23%, and with three or more to as much as 27%.

Study limitations:

There were limitations to the study - these included:

• potential lack of detail and accurate diagnoses associated with retrieving information from US databases.
• Pregnancy losses that were not part of an insurance claim - these included, for example, premature birth
• The results included only privately insured and working parents, which may make the study results inapplicable to other populations.
• Incomplete information on important factors such as sociodemographic status, ethnic background, and substance abuse.

Conclusion:

According to study findings, non-beneficial father health is associated with higher risk of pregnancy loss. While the study cannot prove definite causality, i.e., that adverse father health is a cause of pregnancy loss, it does show that an association exists. The study results imply that pre-conception counseling of the father should not be forgotten as his health could potentially have an important impact on the pregnancy.

According to Prof. Eisenberg, confirmatory studies are now needed to better understand the links found between pregnancy complications and the father's health in the near future.