Fertility plays a vital role in overall health, and understanding how it works can help you make informed decisions about your reproductive future. Whether you are trying to conceive, exploring fertility preservation, or simply curious about how your body works, knowing the basics can be empowering. Let’s dive into key aspects of fertility, fertilization, and common causes of infertility.

What Is Fertility?

Fertility refers to the ability to conceive and have children. It naturally declines with age, but there are many factors that can influence reproductive health. You may have heard that global fertility rates are dropping, but this doesn’t mean people are becoming less fertile—rather, it reflects societal changes, such as career priorities, financial considerations, and personal choices.

For women, fertility is closely tied to both egg quantity and quality. Women are born with all the eggs they will ever have, peaking at around 6-7 million eggs as a fetus. By birth, this number drops to 1-2 million, and at puberty, about 500,000 remain. However, quality is more critical than quantity. As women age, the risk of chromosomal abnormalities (aneuploidy) increases, making conception and sustaining a healthy pregnancy more difficult. While fertility gradually declines in the early 30s, it doesn’t suddenly disappear at 35. In fact, studies show that about 78% of women aged 35-40 conceive within a year, compared to 84% of women aged 20-34.

Men also experience fertility decline. While they continue producing sperm throughout life, sperm quality—including count, motility, and morphology—decreases with age. Older fathers may also have an increased risk of passing genetic mutations to their children, which has been linked to conditions like autism and schizophrenia.

How Does Fertilization Work?

For pregnancy to occur, you need an egg, sperm, and a healthy reproductive system. The process starts in the ovaries, where an egg matures inside a follicle. Around the middle of the menstrual cycle, the egg is released (ovulation) and travels through the fallopian tube.

Sperm must be present at the right time to fertilize the egg, which is viable for less than 24 hours. Sperm can survive in the female reproductive tract for up to five days, meaning the best time to conceive is in the days leading up to ovulation. If a sperm successfully penetrates the egg, fertilization occurs, forming an embryo that implants into the uterus about 5-7 days later.

What Causes Infertility?

Infertility is defined as the inability to conceive after a year of regular, unprotected intercourse (or six months for women over 35). While many factors can contribute to infertility, the most common causes fall into the following categories:

Female Infertility

• Ovulatory Dysfunction: The most common cause, affecting egg release. Polycystic ovary syndrome (PCOS) is a leading culprit, but other issues, like hypothalamic amenorrhea (caused by stress, excessive exercise, or eating disorders) and primary ovarian insufficiency (early menopause), can also disrupt ovulation.
• Tubal Factor Infertility: Blocked or damaged fallopian tubes, often due to infections like chlamydia, gonorrhea, or pelvic inflammatory disease, prevent the egg and sperm from meeting.
• Uterine Factor Infertility: Conditions like fibroids, polyps, or congenital abnormalities (such as a uterine septum) can interfere with embryo implantation and pregnancy.

Male Infertility

• Low Sperm Count and Poor Sperm Quality: Sperm health can be affected by genetics, hormonal imbalances, lifestyle factors, and conditions like varicoceles (enlarged veins in the testicles). Taking testosterone supplements can also suppress sperm production.
• Age and Lifestyle Factors: Excessive alcohol consumption, smoking, obesity, and prolonged heat exposure (such as frequent hot tub use) can negatively impact sperm production and quality.

Can You Prevent Fertility Decline?

While aging is inevitable, some lifestyle choices can support fertility health. Here are some key tips:

• Avoid smoking, as it accelerates reproductive aging in both men and women.
• Maintain a healthy weight, as both obesity and being underweight can affect hormone levels and ovulation.
• Manage stress and avoid excessive exercise, particularly for women, as these can disrupt ovulation.
• Limit alcohol and caffeine intake, as excessive consumption may reduce fertility.
• Get regular health checkups, including STI screenings, which can prevent infections that lead to infertility.

What Are Your Options If You Struggle with Fertility?

If you are having trouble conceiving, your first step should be a consultation with a fertility specialist, also known as a reproductive endocrinologist. Your provider will go over your medical history and give you and your partner a full fertility work-up.  Depending on the results of your fertility testing, reproductive technology offers several solutions, including:

• Ovulation Induction: Medications like Clomid or letrozole can help stimulate ovulation in women with irregular cycles.
• Intrauterine Insemination (IUI): This process places sperm directly into the uterus to improve fertilization chances.
• In Vitro Fertilization (IVF): Eggs are retrieved, fertilized in a lab, and transferred back into the uterus.
• Egg Freezing (Oocyte Cryopreservation): A great option for women who want to preserve fertility for future pregnancy attempts.
• Preimplantation Genetic Testing (PGT): Used during IVF to screen embryos for genetic abnormalities before implantation.

Final Thoughts

Fertility is complex, and while some aspects are beyond our control, many factors can be managed with lifestyle choices and medical support. If you’re planning for the future or facing challenges conceiving, knowledge is your best tool. Stay informed, take care of your body, and don’t hesitate to seek professional guidance when needed!