Miscarriage, the loss of a pregnancy in the first 20 weeks, is unfortunately quite common, affecting up to 1 in 4 recognized pregnancies. Though causes are not always known, one potential contributor is poor sperm quality in the male partner.
What is considered “poor sperm quality”?
Poor sperm quality, also called male infertility, refers to sperm that are abnormally low in number, motility (ability to swim), and/or morphology (normal shape and size). The World Health Organization provides reference values for “normal” sperm:
- Sperm concentration: 15 million sperm per mL or more
- Sperm motility: 40% or more motile or 32% or more with progressive motility
- Sperm morphology: 4% or more normal forms
Falling short of any of these parameters could indicate potential fertility problems. However, it does not necessarily mean a couple cannot conceive naturally. Other factors also play a role.
How are poor sperm quality and miscarriage connected?
Research shows that poor sperm quality is associated with an increased risk of both pregnancy loss and miscarriage. Some key points of connection:
- Low sperm counts, motility, and/or morphology can make it difficult for sperm to reach and fertilize an egg, and create an embryo capable of implanting properly in the uterus.
- Abnormal sperm may carry damaged DNA that leads to abnormal embryonic or fetal development, resulting in early loss of the pregnancy.
- Miscarriage rates are higher in couples undergoing fertility treatments with intracytoplasmic sperm injection (ICSI) using the male partner’s sperm compared to donor sperm.
However, poor sperm quality alone does not definitively cause miscarriage. Other maternal health factors (like thyroid problems, hormonal imbalances, uterine abnormalities, etc.) and lifestyle factors (smoking, alcohol, medications, etc.) also influence risk.
What sperm problems are associated with miscarriage?
Here is a summary of the main sperm abnormalities linked to higher miscarriage rates:
Low sperm count (oligozoospermia)
– Having less than 15 million sperm per milliliter
– May reduce chances of fertilization occurring
Poor sperm motility (asthenozoospermia)
– Less than 32% of sperm have progressive motility (moving forward)
– Sperm may not reach/penetrate egg or support embryo development
Abnormal sperm morphology
– Less than 4% of sperm have normal size and shape
– Associated with DNA damage that can lead to genetic abnormalities
DNA fragmentation
– Chromosomal or gene defects that interfere with normal cell division
– Can cause failed implantation or developmental problems
The lower the sperm quality in these parameters, the higher the miscarriage risk appears to be.
What fertility treatments can help?
If poor sperm health is suspected as a contributor to pregnancy loss, couples do have treatment options. Some of the assisted reproductive technologies that may help include:
- ICSI – Single sperm are injected into each mature egg to achieve fertilization
- PICSI – ICSI using sperm selection to choose the best quality sperm
- IMSI – ICSI with high magnification to select optimal sperm
- Testicular sperm extraction – Sperm obtained directly from testicular tissue
- Donor sperm – Healthy donor sperm used for IUI, IVF, or ICSI
These options help compensate for low sperm count, motility, and morphology issues that may be causing miscarriage. Genetic testing of embryos before transfer may also help identify abnormalities.
What lifestyle changes help improve sperm quality?
In addition to medical therapies, men can take steps to try to optimize their natural sperm quality and potentially reduce miscarriage risk. Recommendations include:
- Stop smoking and avoid secondhand smoke
- Limit or abstain from alcohol
- Get body weight into a healthy BMI range
- Exercise moderately most days of the week
- Reduce stress using techniques like meditation, yoga
- Avoid excessively hot temperatures (hot tubs, laptops on lap)
- Wear looser fitting underwear like boxers
- Eat a nutritious, antioxidant-rich diet
- Take a fertility supplement containing zinc, selenium, vitamin C, etc.
- Get tested for any contributing health conditions
Making positive changes takes about 3 months to improve sperm parameters. Quitting smoking is particularly beneficial.
What tests help evaluate sperm for miscarriage risk?
The following are some of the key tests that provide information on sperm quality and potential miscarriage risk:
Semen analysis
– Examines semen volume, sperm concentration, motility, and morphology
Sperm DNA fragmentation test
– Measures DNA damage like breaks in genetic material
Sperm chromatin structure assay (SCSA)
– Detects abnormal packaging of DNA in sperm
Comet assay
– Quantifies single and double DNA strand breaks
Karyotype or genetic testing
– Identifies chromosomal abnormalities like deletions, extra or missing chromosomes
If any of these tests show substantial abnormalities, the risk of miscarriage may be elevated.
Conclusion
In summary, male factor infertility involving low sperm count, poor motility, and/or abnormal morphology is associated with increased miscarriage rates. The exact mechanisms connecting poor sperm quality and pregnancy loss are not fully understood, but likely involve reduced chances of fertilization and implantation, as well as DNA damage that interferes with normal embryonic development. Fortunately, assisted reproductive technologies can often help couples achieve a successful pregnancy in spite of sperm deficiencies. Additionally, men can take active steps to try to improve their natural sperm quality through positive lifestyle changes and treatment of underlying health conditions when present.