Ovarian Reserve: Understanding Egg Quantity and quality for Fertility

Ovarian reserve, the number and quality of a woman’s eggs, naturally declines with age, significantly impacting her fertility potential. The American Society for reproductive Medicine (ASRM) emphasizes that ovarian reserve reflects a woman’s reproductive lifespan, decreasing progressively from birth and accelerating after her mid-30s. Biomarkers like Anti-Müllerian Hormone (AMH) levels, antral follicle count (AFC), and follicle-stimulating hormone (FSH) levels are crucial in assessing ovarian reserve. Diminished ovarian reserve (DOR) is a significant factor contributing to infertility, which the World Health Association (WHO) estimates affects 15% of reproductive-age couples globally. Understanding ovarian reserve is vital for women planning their reproductive future.

This article explores the factors influencing ovarian reserve, its connection to conditions like endometriosis and polycystic ovary syndrome (PCOS), and the available options for fertility preservation and treatment. Early detection and proactive management are key to navigating reproductive health effectively.

What is Ovarian Reserve?

Ovarian reserve refers to the number and quality of eggs a woman has in her ovaries,directly influencing her fertility potential. The World Health Organization (WHO) reports that women are born with approximately 1 to 2 million eggs, a number that dwindles to around 300,000 to 500,000 by puberty. The American College of Obstetricians and Gynecologists (ACOG) emphasizes that fertility begins to decline significantly after age 35 due to the natural decrease in both egg quantity and quality. Throughout a woman’s reproductive years, only about 300 to 500 eggs will be ovulated, with the remainder lost naturally.

Egg loss occurs naturally through ovulation and atresia, a process where multiple eggs begin to develop each month, but only one matures and is released while the rest break down and are absorbed by the body. External factors such as ovarian surgery, chemotherapy, and smoking can accelerate this decline, as highlighted by the Centers for Disease Control and Prevention (CDC). Certain medical conditions like endometriosis, genetic disorders, and autoimmune diseases can also reduce ovarian reserve more quickly.

Factors Influencing Ovarian Reserve

Several factors can influence a woman’s ovarian reserve.prof. Engin Oral, a leading expert in reproductive medicine, emphasizes the importance of understanding these factors for effective reproductive planning. These include:

• Natural aging
• Genetics
• Heavy smoking
• Early menopause
• Childhood ovarian issues
• Reproductive conditions such as ovarian endometriosis and polycystic ovary syndrome (PCOS)
• Surgical procedures like endometrioma surgery

Prof. Oral notes that surgical procedures, while sometimes necessary, can inadvertently impact ovarian reserve.
“If not performed carefully, surgical excision can remove healthy ovarian tissue along with the cyst, further reducing egg count,” he warned.

The Link Between Endometriosis and Ovarian Reserve

Endometriosis,a chronic condition affecting millions of women globally,has a well-established link to infertility.Ovarian endometriosis,also known as an endometrioma or ‘chocolate cyst,’ occurs when endometrial-like tissue grows inside or on the ovaries,forming cysts filled with thick,dark brown fluid. According to the Journal of Ovarian Research, ovarian endometriosis accounts for 17–44% of endometriosis cases, depending on the population studied and the diagnostic methods used.

endometriosis creates a chronic inflammatory habitat in the pelvis, leading to oxidative stress that damages ovarian tissue and reduces the pool of healthy eggs.
“Endometriosis contributes to ovarian damage in multiple ways, significantly impacting ovarian reserve,” Prof. Oral explained.

Dr. Ezekiel Mecha, a lecturer at the Department of Biochemistry, University of Nairobi, and an endometriosis expert, clarifies that
“Not all women with endometriosis experience diminished ovarian reserve. The risk is mainly in those with ovarian or bilateral endometriosis.” A study in Fertility and Sterility found that women with ovarian endometriomas experience a 30–40% decline in ovarian reserve, highlighting the need for early diagnosis and treatment.

Detecting and Managing Diminished Ovarian reserve

Doctors assess ovarian reserve using various tests.Sonographic antral follicle count examines the number of follicles in both ovaries, while hormonal tests measuring FSH, luteinising hormone (LH), oestradiol, and AMH provide further insights into ovarian function. A lower-than-normal follicle count may indicate diminished ovarian reserve, while a higher count coudl signal PCOS.

It’s significant to note that these tests are not absolute predictors of fertility. Dr. Mecha emphasizes that
“A single test may not provide a complete picture,” as AMH levels, as an example, can fluctuate due to individual health factors and laboratory conditions, making repeated testing necessary for accuracy.

Prof. Oral also cautions that
“Ovarian reserve tests help estimate egg quantity but do not reveal egg quality, which is critical for accomplished conception.”

Options for Women with Diminished Ovarian Reserve

For women with diminished ovarian reserve, fertility treatment and preservation options exist. In vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) improve pregnancy chances, while egg freezing allows women to preserve fertility for the future.
“Early diagnosis and intervention empower women to take control of their reproductive future,” Prof. Oral said.

For those trying to conceive, assisted reproductive technologies (ART) such as IVF offer a viable option. Even though endometriosis can reduce the quantity and quality of eggs,IVF success rates remain comparable between women with and without the condition. A study in Human Reproduction found no significant differences in fertilisation rates or live birth outcomes between both groups. Prof. Oral confirmed that IVF remains an effective treatment option, with frozen embryo transfer showing slightly improved success rates for endometriosis patients.

The Importance of Early Detection and Proactive Management

despite its impact, ovarian reserve decline often goes unnoticed until fertility problems arise.
“By the time many women recieve a diagnosis, their ovarian reserve may already be significantly diminished. We need to shift towards proactive fertility management,” Oral says.

Women should monitor their ovarian reserve early and seek medical advice if they experience irregular cycles, painful periods, or fertility concerns. Regular screenings, consultations with fertility specialists, and personalised treatment plans can help them navigate their reproductive journey more effectively.

Conclusion

The link between ovarian reserve, reproductive conditions like endometriosis, and infertility underscores the need for a proactive approach to reproductive health. With expert insights, women can make informed decisions about their fertility before time becomes a limiting factor. Early diagnosis, careful management, and timely intervention can make a significant difference in preserving fertility and improving the chances of conception for women affected by endometriosis.