What is perimenopause?
Perimenopause, also known as the transition to menopause, is the time leading up to menopause when ovarian function gradually declines and hormone levels begin to fluctuate. This stage can last anywhere from 4 to 10 years, typically starting in the 40s, though it can begin as early as the 30s or even earlier.
A key factor affecting fertility during perimenopause is the decline in the number of viable eggs (also known as ovarian reserve). As the number of eggs decreases, it becomes more challenging to conceive naturally. In addition to fewer eggs, the remaining eggs may be of lower quality, increasing the risk of chromosomal abnormalities and miscarriage. During perimenopause, people may also experience irregular periods, making it harder to predict ovulation and plan conception attempts.
Fortunately, advancements in fertility treatments offer pathways to parenthood for individuals going through perimenopause.
Understanding Perimenopause and Its Impact on Fertility
1. Hormonal Changes During Perimenopause
Perimenopause brings hormonal shifts that directly affect fertility, largely due to the natural decline in ovarian function.
- Ovarian Function Decline: Over time, the number of follicles (which contain eggs) in the ovaries decreases. Most are lost during fetal development, and the remaining supply drops more rapidly as menopause approaches. This leads to irregular periods and changes in follicle growth, making ovulation less predictable. The brain’s signals that trigger ovulation, especially those from luteinising hormone (LH), also become less reliable.
Oestrogen’s Role in Perimenopause:
- Fluctuating Oestrogen Levels: During perimenopause, oestrogen levels can fluctuate unpredictably, leading to symptoms like irregular periods, hot flushes, and mood swings. Even though periods may continue, it’s common to experience anovulatory cycles (cycles where no egg is released), which lowers the chances of conception.
- Elevated Oestradiol (E2) Levels: As the ovarian reserve diminishes, the follicles in the ovaries become less responsive to signals from the brain, particularly follicle-stimulating hormone (FSH). In response, the brain releases higher levels of FSH to stimulate the ovaries. However, the remaining follicles (often of lower quality) may release surges of oestradiol early in the cycle, causing higher-than-expected oestradiol levels when they should typically be low. These elevated levels may falsely suggest healthy ovarian function, when in reality, they reflect a compensatory mechanism.
- Erratic Follicle Development: Perimenopause can cause unpredictable recruitment and overstimulation of follicles, which may temporarily increase oestrogen production and further disrupt the hormonal balance.
Progesterone’s Role in Perimenopause:
- Decreased Progesterone Production: With fewer ovulatory cycles, progesterone production declines. This can lead to shorter luteal phases (the second half of the menstrual cycle) or luteal phase defects, making it harder for the uterus to support embryo implantation. Low progesterone can negatively affect conception efforts.
- Progesterone Fluctuations and Anovulation: Progesterone levels become unpredictable during perimenopause, contributing to irregular periods and anovulatory cycles. These fluctuations further reduce fertility during this time.
Elevated Luteinising Hormone (LH) Levels:
- Rising LH Levels: LH plays a key role in regulating the menstrual cycle and ovulation. During perimenopause, LH levels often rise as a compensatory response to declining ovarian function. As the ovaries become less responsive to FSH, the brain increases the production of both FSH and LH to try to stimulate follicle development and trigger ovulation. Unfortunately, despite higher LH levels, ovulation often fails because of the diminished ovarian response.
- Impact on Androgens: Increased LH levels during perimenopause can also cause the ovaries and adrenal glands to produce more androgens (male hormones), leading to symptoms such as acne, excess hair growth (hirsutism), and weight gain. This is because LH promotes the production of androgens, which are normally converted to oestrogen. However, as fewer follicles develop, these androgens may not be fully converted, resulting in higher circulating androgen levels.
Elevated Follicle-Stimulating Hormone (FSH) Levels:
- Declining Ovarian Response: As the ovaries become less responsive to FSH, fewer follicles mature, and the feedback loop to the brain weakens. To compensate, the brain produces more FSH to try to stimulate the ovaries. Elevated FSH levels (>10-12 IU/L) are often a sign of diminished ovarian reserve (DOR), which directly impacts fertility.
Fertility Treatment Options During Perimenopause
1. Natural Conception and Monitoring
If ovulation is still occurring, natural conception may be possible during perimenopause, though timing is critical due to fluctuating hormone levels. Healthcare providers can monitor the cycle using hormone tracking, ultrasounds, or ovulation kits to identify the optimal time for conception.
- Timed Sexual Intercourse: Once ovulation is detected, individuals can time sexual intercourse with their partner or use donor sperm during the fertile window to increase the chances of conception.
- Intrauterine Insemination (IUI): For those with healthy sperm (or using donor sperm), IUI involves placing sperm directly into the uterus during the most fertile time in the cycle, bypassing some barriers to conception.
These methods can help those who want to conceive naturally or with minimal intervention.
2. Fertility Preservation: Egg and Embryo Freezing
People in the early stages of perimenopause who are not ready to conceive but wish to preserve their fertility can consider egg or embryo freezing. The success of these techniques depends largely on ovarian reserve at the time of freezing, so it’s important to discuss realistic expectations with a fertility specialist.
3. In Vitro Fertilisation (IVF)
IVF is one of the most effective fertility treatments for individuals experiencing perimenopause. However, success rates depend on the quality and quantity of eggs, both of which decline with age. IVF protocols are personalised based on factors like hormone levels and Anti-Müllerian Hormone (AMH), which helps estimate ovarian reserve.
- Luteal Phase Support: Many people experiencing perimenopause have luteal phase defects due to erratic progesterone production. IVF cycles often include luteal phase support with progesterone to ensure the uterine lining is prepared for embryo implantation.
- Ovarian Stimulation Protocols: IVF stimulation protocols are often customised based on factors such as age and ovarian reserve. Some clinics may use higher dose protocols for those with diminished ovarian reserve, while others may take a more conservative approach. It depends on their previous experience and patient demographic.
Importance of Blood Tests Before IVF
Before starting IVF during perimenopause, blood tests for progesterone, FSH, LH, oestradiol (E2) and AMH are essential. These tests give insight into hormone levels, ovarian function, and the state of the menstrual cycle. This information helps fertility specialists adjust treatment timing and stimulation protocols to improve outcomes.
Egg Quality and Preimplantation Genetic Testing (PGT-A)
As eggs from individuals in perimenopause are more likely to have chromosomal abnormalities, preimplantation genetic testing for aneuploidy (PGT-A) may be recommended. PGT-A helps identify chromosomally normal embryos, reducing the risk of miscarriage or implantation failure.
4. Egg Donation
For individuals with diminished ovarian reserve or poor egg quality, egg donation is a highly effective fertility option. Eggs donated by younger individuals tend to have better quality and higher success rates than using one’s own eggs in IVF.
Emotional and Psychological Considerations
Perimenopause, combined with fertility challenges, can be emotionally taxing. Individuals may experience feelings of grief, frustration, or anxiety about their reduced fertility potential. Fertility clinics often offer counselling to help manage these emotions and cope with the uncertainty of treatment outcomes.
Patient Education and Informed Consent
Clear communication is key when discussing fertility treatments during perimenopause. Healthcare providers should explain the risks, benefits, and success rates associated with treatments at this stage. Providers should also discuss alternative options, such as egg donation or adoption, to help individuals make informed decisions aligned with their family-building goals.
Summary
Perimenopause is a transitional phase marked by hormonal fluctuations and a natural decline in fertility. While it may be more difficult to conceive during this time, treatments like IVF, egg donation, and natural conception with careful monitoring offer potential pathways to parenthood. Regular hormone testing, personalised treatment plans, and emotional support are essential in navigating fertility challenges during perimenopause. As more individuals seek fertility treatments later in life, healthcare providers must stay up to date with the latest advancements to provide the best possible care.