In 98% of cases, a correct and timely diagnosis allows the cause of infertility to be treated successfully. Detecting the origin of the problem early increases the chances of bringing the baby home, because each treatment is tailored to the couple’s needs. At Ingenes, our team of specialists thoroughly investigates the causes preventing pregnancy. The causes of infertility are divided into five main factors: ovulatory, male, embryonic, tubal, and uterine. To understand them, remember that pregnancy is a multi-step process: The woman must release a healthy egg (ovulation). The egg travels from the ovary to the uterus through an unobstructed Fallopian tube. The man’s sperm must meet the egg in the tube (fertilization). The resulting embryo attaches to the endometrium of the uterus (implantation) and develops over nine months. Anything that interferes with any of these steps is considered a cause of infertility and is grouped into five sections: What is the ovulatory factor and how does it affect fertility? Ovulation is the most fertile phase of the menstrual cycle. The hypothalamus releases GnRH, which stimulates the pituitary to produce FSH (follicle growth) and LH (egg release). These same hormones cause the ovaries to produce estrogen and progesterone, essential for fertilization and pregnancy. Hormonal imbalance or an ovarian problem prevents ovulation and accounts for 25% of female infertility cases. Avoid self-medication and always consult your doctor. Main ovulatory disorders: Amenorrhea Anovulation Premature ovarian failure Hyperprolactinemia Thyroid disorders Obesity Ovarian cysts Low ovarian reserve Insulin resistance Polycystic ovary syndrome How do embryonic factors influence infertility? When egg and sperm unite, 46 chromosomes form (23 from each parent). If there are genetic alterations, the embryo may not develop or implant, increasing the risk of miscarriage. Most common embryonic disorders: Genetic alterations Implantation failure Recurrent miscarriages (more than two spontaneous losses) Why do tubal factors block conception? Twenty-five percent of female infertility is due to problems in the Fallopian tubes, where fertilization occurs and the embryo passes to the uterus. An obstruction prevents gametes from meeting and increases the risk of ectopic pregnancy. Common tubal disorders: Pelvic adhesions Chlamydia infection Hydrosalpinx Recurrent cervicovaginal infections Tubal ligation What uterine conditions interfere with implantation? The uterus hosts and nourishes the embryo during pregnancy. Between 5% and 12% of female infertility is related to uterine malformations or lesions that hinder implantation. Common uterine alterations: Adenomyosis Endometriosis Müllerian malformations Uterine fibroids Polyps Asherman’s syndrome How does the male factor affect the couple’s fertility? Today we know that one-third of infertility cases originate from the male. Semen quality is evaluated with a semen analysis: there should be more than 20 × 106 sperm/mL, at least 50% motile and 15% normal morphology (WHO). Main causes of male infertility: An ejaculatory dysfunction Asthenozoospermia (low motility) Azoospermia (absence of sperm) Diabetes mellitus Erectile dysfunction Genital tract infections Teratozoospermia (abnormal morphology) Varicocele Vasectomy Before any treatment, always consult a reproductive specialist. Why is maternal age key in fertility? Unlike men, women are born with all their eggs (1 × 106) and do not produce more. After age 35, ovarian reserve declines, and by 40 many women have a higher proportion of low-quality eggs. The natural probability of pregnancy is 20–30% per month before age 30 and drops to 5% by age 40. In men, after 40 the incidence of semen alterations can increase. Irregular menstrual cycles also influence fertility. Learn more about irregular periods and infertility and myths about male infertility. Frequently Asked Questions 1. Can lifestyle changes improve fertility? Yes. A balanced diet, a BMI between 18.5 and 24.9, regular exercise, avoiding tobacco and alcohol, and reducing stress improve hormonal balance. Each case is unique: avoid self-medication and consult a specialist. 2. What tests diagnose infertility? In women: hormonal tests (FSH, LH, AMH, prolactin), transvaginal ultrasound, and hysterosalpingography. In men: semen analysis evaluating count, motility, and morphology. Sometimes genetic tests or endometrial biopsies are recommended. An early diagnosis raises the treatment success rate up to 98%. 3. When should assisted reproductive techniques (ART) be used? They are recommended after 6–12 months of unsuccessful attempts (or sooner if the woman is over 35). Key factors: age, ovarian reserve, semen quality, and prior treatment responses. Only a specialist can define the best protocol (IUI, IVF, FSH dosing, ultrasound monitoring, and E2). 4. How does endometriosis impact fertility and what treatments are available? Endometriosis causes adhesions, alters pelvic anatomy, and creates inflammation that hinders fertilization and implantation. It affects 50% of women with infertility. Options range from pain management (NSAIDs) to laparoscopic surgery. In moderate to severe cases, combining surgery with IVF yields better results. Sources American Society for Reproductive Medicine. Diagnostic evaluation of infertility. 2023. World Health Organization. Laboratory manual for the examination and processing of human semen. 6th ed. 2021. MedlinePlus. Female infertility. 2024. National Institute of Child Health and Human Development. Endometriosis and infertility. 2022. We understand how important this journey is. You are not alone: lean on our support and always consult a fertilization specialist for proper guidance and treatment.