Male and Female Fertility Factors
Current Guidance Update
Updated Semen Reference Values
The latest WHO semen analysis reference ranges use updated 5th centile values, reflecting current global fertility data and replacing previous reference standards.
Male Factor Infertility
Male factor contributes to approximately 40–50% of infertile couples, making semen analysis a mandatory first-line investigation for every fertility assessment.
Female Age & IVF Success
Female age remains the single most important predictor of IVF success, with ovarian reserve and pregnancy rates declining significantly after 35 years of age.
Comprehensive Evaluation
Both partners should undergo fertility assessment simultaneously to identify male and female factors early and ensure the most appropriate treatment pathway.
Introduction
Factors Affecting Fertility
Key Female Factors
- Ovarian reserve declines with age, accelerating after 35 years.
- Ovulation disorders, especially PCOS, are the leading cause of anovulation.
- Tubal disease accounts for approximately 20–25% of female infertility.
- Submucosal fibroids and endometrial polyps reduce implantation rates.
- Endometriosis impairs fertility through multiple mechanisms.
Key Male Factors
- Azoospermia – obstructive or non-obstructive
- Oligospermia, asthenospermia, and teratospermia
- Elevated sperm DNA fragmentation
- Varicocele present in approximately 40% of male factor infertility
- Smoking, alcohol, recreational drugs, and heat exposure
Impact of Female Age
Both oocyte quality and quantity decline with age. The proportion of chromosomally abnormal eggs increases significantly, reaching approximately 30% at age 30, 50% at 35, 75% at 40, and over 90% at 43 years and above.
Investigation Approach
- Evaluate both partners simultaneously.
- Female assessment: AMH, FSH, LH, antral follicle count, and tubal patency.
- Male assessment: Semen analysis according to WHO 2021 criteria, repeated if results are abnormal.
Frequently Asked Questions
If my semen analysis is normal, do I need further male fertility tests?
DNA fragmentation testing may provide additional information in cases of recurrent implantation failure despite normal semen parameters.
Does female age matter if eggs from a donor are used?
Donor egg success rates are largely independent of recipient age, reflecting that uterine receptivity is maintained well into the mid-40s.
Conclusion
Understanding the contribution of both partners to fertility is the essential starting point for effective infertility management — simultaneous investigation and open communication form the foundation of a productive evaluation.
Sources & References
This article draws on guidance current at the time of writing from the following bodies and publications:
- WHO (2021 Semen Analysis Reference Values)
- ESHRE (2023)
- ACOG (2022)
General reference bodies for women's health guidance:
RCOG
rcog.org.ukACOG
acog.orgFIGO
figo.orgWHO
who.intNICE
nice.org.uk⚠ IMPORTANT DISCLAIMER
This article is provided for general knowledge and reference purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. No medication, treatment, or change to your healthcare should be undertaken based on this content without first consulting a qualified doctor. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition.
