Medical School · Year 2 · Reproductive · includes a quiz and discussion video

Lecture 11: Infertility

Unit 2.4: Reproductive System

Learning Objectives

By the end of this lecture, students will be able to:

1. Define infertility and describe its epidemiology
2. Explain the evaluation of female infertility factors
3. Describe the evaluation of male factor infertility
4. Explain ovulation induction methods
5. Describe assisted reproductive technologies (ART)
6. Explain the management of specific causes of infertility

Section 1: Definitions, Epidemiology, and Initial Approach

Infertility is defined as the failure to achieve pregnancy after 12 months of regular, unprotected intercourse. For women over 35 years of age, evaluation is recommended after 6 months given the time-sensitive nature of declining fertility. Primary infertility refers to couples who have never achieved pregnancy, while secondary infertility describes couples with prior pregnancy regardless of outcome.

Infertility affects approximately 10-15% of reproductive-age couples, representing a significant public health concern. The distribution of causes is roughly equal between partners: female factors account for approximately 35%, male factors for approximately 35%, combined factors for approximately 20%, and unexplained infertility for approximately 10%. This distribution underscores the importance of evaluating both partners simultaneously.

Fecundability, the probability of achieving pregnancy in a single menstrual cycle, is approximately 20-25% for healthy couples with optimal timing of intercourse. Cumulative probability reaches approximately 85% by 12 months, which forms the basis for the standard infertility definition. Understanding these baseline statistics helps frame patient counseling.

Age represents the most significant factor affecting fertility, particularly for women. Female fertility peaks between ages 20-24 and begins to decline around age 32, with accelerated decline after age 37. By age 40, fertility is substantially reduced, and by age 45, natural conception is rare. This decline reflects both decreasing oocyte quantity (diminishing ovarian reserve) and decreasing oocyte quality (increased aneuploidy rates). Male fertility also declines with age, though less dramatically; older paternal age is associated with decreased semen parameters and increased rates of genetic abnormalities in offspring.

The initial evaluation should be efficient and thorough, recognizing that couples presenting with infertility are often anxious and have already been trying to conceive for a significant period. Both partners should be evaluated concurrently. A comprehensive history addresses duration of infertility, prior pregnancies for each partner, frequency and timing of intercourse, menstrual regularity, medical and surgical history, medications, and lifestyle factors including smoking, alcohol, drug use, and occupational exposures.

<image>Panel A: Infertility definition with 12-month timeline for women under 35 and 6-month timeline for women over 35, with cause distribution pie chart showing female factor (35%), male factor (35%), combined (20%), and unexplained (10%). Panel B: Fecundability graph showing monthly pregnancy probability (20-25%) with cumulative probability curve reaching 85% by 12 months, forming the basis for the standard infertility definition. Panel C: Age-fertility relationship showing female fertility curve peaking at 20-24, declining from 32, accelerating after 37, and near-zero by 45, overlaid with increasing oocyte aneuploidy rate, plus male fertility curve showing more gradual decline. Panel D: Initial evaluation checklist showing both-partner simultaneous approach with history elements including duration, prior pregnancies, intercourse timing, menstrual regularity, medical/surgical history, medications, and lifestyle factors.</image>

Section 2: Female Infertility Evaluation - Ovulatory Function and Ovarian Reserve

The female evaluation systematically assesses the four requirements for conception: ovulation, tubal patency, uterine receptivity, and cervical function. Ovulatory dysfunction accounts for approximately 25% of female factor infertility.

Assessment of ovulation begins with menstrual history. Regular, predictable cycles of 24-35 days with consistent premenstrual symptoms (breast tenderness, mood changes) strongly suggest ovulatory function. Irregular or absent menses indicates anovulation or oligoovulation, warranting further evaluation. Several methods confirm ovulation. Basal body temperature charting demonstrates a biphasic pattern with a 0.2-0.5°C rise after ovulation due to progesterone's thermogenic effect; however, this method is retrospective and has limited utility. Urinary LH detection kits identify the LH surge, predicting ovulation within 24-36 hours. Mid-luteal serum progesterone, measured approximately 7 days after expected ovulation (typically day 21 of a 28-day cycle), confirms ovulation if greater than 3 ng/mL. Ultrasound tracking of follicular development and documentation of follicular collapse provides direct evidence.

Ovarian reserve testing estimates the remaining oocyte pool, which predicts the potential for response to ovarian stimulation and, to some extent, reproductive lifespan. Anti-Müllerian hormone (AMH), produced by granulosa cells of small antral follicles, is the most useful single marker. AMH can be measured on any cycle day and is relatively stable. Low AMH (generally <1.0 ng/mL, though thresholds vary by laboratory) suggests diminished ovarian reserve. Day 3 FSH and estradiol provide additional information: elevated FSH (>10-15 mIU/mL) indicates the pituitary is working harder to stimulate the ovaries, suggesting diminished reserve; elevated day 3 estradiol (>80 pg/mL) may falsely suppress FSH and indicates accelerated follicular recruitment. Antral follicle count (AFC), determined by transvaginal ultrasound early in the menstrual cycle, counts follicles 2-10 mm in diameter; a total count less than 5-7 suggests diminished reserve.

It is important to counsel patients that ovarian reserve testing predicts response to stimulation and quantity of eggs, but does not reliably predict oocyte quality or natural conception probability, particularly in younger women with diminished reserve.

<image>Panel A: Ovulation confirmation methods including menstrual calendar with regular 24-35 day cycles, basal body temperature chart showing biphasic pattern with 0.2-0.5 degree C post-ovulation rise, and urinary LH surge detection kit predicting ovulation within 24-36 hours. Panel B: Mid-luteal serum progesterone blood draw with greater than 3 ng/mL confirming ovulation, and ultrasound images showing dominant follicle before and collapsed follicle after ovulation as direct evidence. Panel C: Ovarian reserve tests showing AMH blood draw with interpretation scale (normal, low, very low at less than 1.0 ng/mL), day 3 FSH and estradiol with concerning values (FSH greater than 10-15, estradiol greater than 80 pg/mL), and transvaginal ultrasound antral follicle count (less than 5-7 suggests diminished reserve). Panel D: Age-reserve correlation graph showing declining AFC and AMH with advancing age, with counseling note that reserve predicts quantity and stimulation response but not oocyte quality or natural conception probability.</image>

Section 3: Female Infertility Evaluation - Tubal and Uterine Factors

Tubal factor infertility, accounting for approximately 25% of female causes, results from fallopian tube damage that impairs oocyte transport, sperm transport, or fertilization. The most common cause is pelvic inflammatory disease from ascending sexually transmitted infections, particularly Chlamydia trachomatis. Other causes include prior ectopic pregnancy (especially if treated surgically), pelvic surgery with adhesion formation, endometriosis, and congenital abnormalities.

Hysterosalpingography (HSG) is the first-line test for tubal evaluation. This fluoroscopic procedure involves injecting radiopaque contrast through the cervix, opacifying the uterine cavity and fallopian tubes. Bilateral free spill of contrast into the peritoneal cavity indicates tubal patency. HSG also provides information about uterine cavity contour. Advantages include relatively low cost, ability to evaluate both tubes simultaneously, and a potential therapeutic effect (pregnancy rates are slightly higher in the months following HSG, possibly due to flushing of debris). Limitations include false-positive results from tubal spasm and inability to assess peritubal adhesions. Water-based contrast is preferred for diagnostic purposes as it is associated with fewer complications, though oil-based contrast may have greater fertility-enhancing effects.

Laparoscopy remains the gold standard for tubal assessment, allowing direct visualization of the tubes, ovaries, and peritoneal surfaces. It enables diagnosis and treatment of endometriosis, lysis of adhesions, and definitive assessment of tubal anatomy. However, laparoscopy is invasive and not required for all infertility evaluations. It is typically reserved for cases with HSG abnormalities, suspected endometriosis, or pelvic pathology.

Uterine factors affect implantation and early pregnancy maintenance. Intracavitary lesions, including submucosal fibroids and endometrial polyps, can interfere with implantation. Intrauterine adhesions (Asherman syndrome), typically from intrauterine procedures such as dilation and curettage, create scarring that distorts the cavity. Congenital uterine anomalies, particularly a uterine septum, are associated with recurrent pregnancy loss. Saline infusion sonohysterography (SIS) distends the uterine cavity with saline during transvaginal ultrasound, providing excellent visualization of intracavitary pathology. Hysteroscopy allows direct visualization and concurrent treatment of abnormalities.

<image>Panel A: HSG procedure showing speculum and catheter placement, fluoroscopic images with contrast opacifying uterus and tubes, bilateral free spill indicating patency, unilateral blockage example, and hydrosalpinx appearance, with potential therapeutic fertility-enhancing effect noted. Panel B: Laparoscopy showing trocar placement and direct visualization of normal tubes, peritubal adhesions, fimbrial phimosis, and endometriosis, as the gold standard for tubal assessment. Panel C: Uterine assessment with saline infusion sonohysterography showing normal cavity, submucosal fibroid, and polyp, plus hysteroscopy views of normal cavity, intrauterine adhesions (Asherman syndrome), and uterine septum. Panel D: Causes of tubal damage listed with PID (Chlamydia emphasis as most common cause, often subclinical), prior ectopic pregnancy, endometriosis with adhesion formation, and prior pelvic surgery.</image>

Section 4: Male Factor Evaluation

Male factor contributes to infertility in approximately 50% of couples (as sole factor or in combination). Evaluation begins with a thorough history addressing prior paternity, childhood development (cryptorchidism, delayed puberty), mumps orchitis, varicocele, testicular trauma or surgery, sexually transmitted infections, and exposures (heat, toxins, radiation, chemotherapy). Medications affecting spermatogenesis include testosterone, anabolic steroids, sulfasalazine, calcium channel blockers, and many chemotherapeutic agents. Sexual function history addresses erectile dysfunction, ejaculatory problems, and frequency of intercourse.

Physical examination assesses secondary sexual characteristics, body habitus (obesity can affect testosterone), gynecomastia, penis examination, and testicular examination (size, consistency, masses). Normal testicular volume is 15-25 mL; small, soft testes suggest primary testicular failure. Varicocele, a dilation of the pampiniform venous plexus, is the most common surgically correctable cause of male infertility; it is identified as a "bag of worms" on palpation, most prominent when standing and with Valsalva. Vas deferens should be palpated bilaterally, as congenital bilateral absence of the vas deferens (CBAVD) occurs in cystic fibrosis carriers.

Semen analysis is the cornerstone of male evaluation. Proper collection requires 2-5 days of abstinence, collection by masturbation into a sterile container, and analysis within 60 minutes of collection. The World Health Organization (2010) reference values define normal parameters: volume ≥1.5 mL, concentration ≥15 million/mL, total count ≥39 million, progressive motility ≥32%, total motility ≥40%, and normal morphology ≥4% (by strict criteria). Abnormalities are termed oligozoospermia (low count), asthenozoospermia (poor motility), teratozoospermia (abnormal morphology), and combinations thereof. Azoospermia (complete absence of sperm) requires differentiation between obstructive causes (normal FSH, often palpable abnormality) and non-obstructive/testicular failure (elevated FSH, small testes).

If the initial semen analysis is abnormal, it should be repeated after 2-3 months given the variability of semen parameters and the 74-day duration of spermatogenesis. Hormonal evaluation (FSH, testosterone, and possibly LH and prolactin) is indicated for abnormal semen analysis. Genetic testing (karyotype, Y-chromosome microdeletion) is indicated for severe oligospermia or azoospermia.

<image>Panel A: Male history elements including prior paternity, cryptorchidism (undescended testis), mumps orchitis, varicocele, medications affecting spermatogenesis (testosterone, anabolic steroids, chemotherapy), and sexual function assessment. Panel B: Physical examination showing testicular examination with orchidometer for volume measurement (normal 15-25 mL), varicocele appearance ("bag of worms") with grading, and vas deferens palpation for congenital bilateral absence (CBAVD in cystic fibrosis carriers). Panel C: Semen analysis showing specimen cup with collection requirements (2-5 days abstinence, analysis within 60 minutes), WHO reference values table (volume 1.5+ mL, concentration 15+ million/mL, motility 40%+, morphology 4%+), and terminology (oligozoospermia, asthenozoospermia, teratozoospermia). Panel D: Azoospermia workup flowchart branching to obstructive (normal FSH, palpable abnormality) versus non-obstructive (elevated FSH, small testes, testicular failure), with hormonal evaluation and genetic testing (karyotype, Y-chromosome microdeletion) indications.</image>

Section 5: Causes of Female Infertility - Detailed Review

Ovulatory disorders are classified by the World Health Organization into three groups. WHO Class I (hypogonadotropic hypogonadism) involves deficient GnRH or gonadotropin secretion, resulting in low FSH and estrogen. Causes include hypothalamic amenorrhea from stress, excessive exercise, or eating disorders, as well as Kallmann syndrome (congenital GnRH deficiency with anosmia) and pituitary tumors or destruction. WHO Class II (eugonadotropic anovulation) is characterized by normal FSH levels with disordered follicular development. Polycystic ovary syndrome (PCOS) accounts for the vast majority of cases. Other causes include hyperprolactinemia and thyroid dysfunction. WHO Class III (hypergonadotropic hypogonadism) represents ovarian failure with elevated FSH. Primary ovarian insufficiency (POI) may be idiopathic, autoimmune, iatrogenic (chemotherapy, radiation), or genetic (Turner syndrome, fragile X premutation).

Tubal factor infertility is most commonly caused by pelvic inflammatory disease, particularly from Chlamydia, which may cause subclinical salpingitis leading to tubal damage without overt symptoms. Hydrosalpinx, fluid-filled blocked tubes, is particularly detrimental to fertility and should be addressed before IVF, as the fluid is toxic to embryos.

Endometriosis causes infertility through multiple mechanisms: anatomic distortion from adhesions, endometriomas affecting ovarian reserve, altered peritoneal environment with inflammatory cytokines affecting oocyte and sperm function, and possibly impaired endometrial receptivity. The relationship between minimal/mild endometriosis and infertility is less clear but treatment may still improve outcomes.

Uterine factors including submucosal fibroids and intracavitary lesions physically disrupt implantation. Müllerian anomalies vary in their impact; a uterine septum is associated with recurrent pregnancy loss while a bicornuate uterus has better outcomes.

Unexplained infertility, diagnosed when all testing is normal, likely represents subtle abnormalities in oocyte quality, sperm function, fertilization, or implantation not detected by standard testing. It is a diagnosis of exclusion and still warrants empiric treatment.

<image>Panel A: WHO Class I (hypogonadotropic hypogonadism) with low FSH/estrogen, causes including functional hypothalamic amenorrhea (stress, exercise, eating disorders), Kallmann syndrome (anosmia), and pituitary tumors, with treatment via pulsatile GnRH or gonadotropins. Panel B: WHO Class II (eugonadotropic anovulation) with normal FSH and abnormal ovulation, dominated by PCOS (polycystic ovary ultrasound), plus hyperprolactinemia (prolactinoma MRI) and thyroid dysfunction, and WHO Class III (ovarian failure) with elevated FSH from POI, Turner syndrome (45,X), or chemotherapy. Panel C: Tubal factor showing PID inflammation (Chlamydia emphasis), hydrosalpinx on ultrasound, and endometriosis (adhesions, endometrioma, peritoneal implants) with multiple infertility mechanisms. Panel D: Uterine factor showing submucosal fibroid and uterine septum disrupting implantation, and unexplained infertility (diagnosis of exclusion with normal tests) still warranting empiric treatment.</image>

Section 6: Ovulation Induction

Ovulation induction restores ovulation in anovulatory women or superovulates (produces multiple follicles) for fertility treatments. Agent selection depends on the underlying cause.

Letrozole, an aromatase inhibitor, has emerged as first-line therapy for ovulation induction in PCOS based on superior live birth rates compared to clomiphene in randomized trials. By inhibiting estrogen synthesis, letrozole releases the hypothalamic-pituitary axis from negative feedback, increasing endogenous FSH secretion. Typical dosing is 2.5-7.5 mg daily on cycle days 3-7. Advantages include a lower multiple pregnancy rate than clomiphene and favorable endometrial effects. The main side effect is hot flashes.

Clomiphene citrate, a selective estrogen receptor modulator (SERM), acts as an estrogen antagonist at the hypothalamus, blocking negative feedback and increasing GnRH and FSH secretion. It is administered as 50-150 mg daily on cycle days 5-9 (or 3-7). Approximately 80% of women with PCOS ovulate with clomiphene, and 40-50% conceive within six cycles. Side effects include hot flashes, mood changes, visual disturbances (rare, mandating discontinuation), and anti-estrogenic effects on cervical mucus and endometrium. The multiple pregnancy rate is 5-10%, primarily twins.

Gonadotropins (FSH preparations such as Gonal-F, Follistim, or human menopausal gonadotropin containing FSH and LH) directly stimulate the ovaries and are used when clomiphene/letrozole fail or for IVF protocols. They require daily injections and close monitoring with serial transvaginal ultrasound and serum estradiol to assess follicular response. Risks include ovarian hyperstimulation syndrome (OHSS) and high multiple pregnancy rates (20-30%) with ovulation induction protocols; these risks are managed through careful dose titration and cycle cancellation if too many follicles develop.

Human chorionic gonadotropin (hCG), which mimics the LH surge, is administered as a "trigger shot" to induce final oocyte maturation and ovulation when follicles reach mature size (approximately 18-20 mm).

For hypothalamic amenorrhea (WHO Class I), pulsatile GnRH administration via a programmable pump mimics physiologic GnRH secretion and can restore normal ovulation with minimal multiple pregnancy risk.

<image>Panel A: Letrozole as aromatase inhibitor showing mechanism (blocks estrogen synthesis, FSH rises via released negative feedback), dosing (2.5-7.5 mg days 3-7), superior live birth rates in PCOS compared to clomiphene, and lower multiple pregnancy rate. Panel B: Clomiphene citrate as SERM showing hypothalamic mechanism (blocks estrogen receptor, GnRH/FSH rise), dosing (50-150 mg days 5-9), 80% ovulation rate, 40-50% pregnancy rate in 6 cycles, side effects (hot flashes, visual disturbances requiring discontinuation), and 5-10% multiple rate. Panel C: Gonadotropins showing direct FSH/LH ovarian stimulation by daily injection, monitoring protocol (serial ultrasound plus estradiol), OHSS risk (enlarged ovaries, ascites), and high multiple pregnancy rate (20-30%), with hCG trigger when follicles reach 18-20 mm. Panel D: Pulsatile GnRH showing pump device for hypothalamic amenorrhea (WHO Class I), mimicking physiologic GnRH secretion to restore normal ovulation with minimal multiple pregnancy risk.</image>

Section 7: Intrauterine Insemination and In Vitro Fertilization

Intrauterine insemination (IUI) involves placing washed, concentrated sperm directly into the uterine cavity around the time of ovulation, bypassing the cervix. The sperm preparation ("washing") removes seminal plasma and selects for motile sperm. IUI is commonly combined with ovarian stimulation to produce 2-3 mature follicles, improving success rates.

Indications for IUI include unexplained infertility (empiric treatment), mild male factor infertility (total motile count after preparation >5-10 million), cervical factor (poor mucus, cervical stenosis), use of donor sperm, and ovulatory dysfunction when combined with ovulation induction. Success rates are approximately 10-20% per cycle with stimulation; rates are lower with unstimulated cycles and lower still with significant male factor. IUI is less effective than IVF but is less invasive and less expensive, making it a reasonable first-line treatment for appropriate indications. Most pregnancies occur within 3-4 cycles; beyond this, success rates diminish and IVF is typically recommended.

In vitro fertilization (IVF) involves fertilization of oocytes outside the body with subsequent embryo transfer to the uterus. IVF is the most effective fertility treatment and is indicated for tubal factor, severe male factor, failed other treatments, advanced maternal age, endometriosis, and elective fertility preservation.

The IVF process follows defined steps. Controlled ovarian hyperstimulation uses gonadotropins to develop multiple follicles, monitored by ultrasound and estradiol levels. A GnRH agonist or antagonist protocol prevents premature ovulation. When follicles reach maturity, an hCG trigger (or GnRH agonist trigger in high-risk patients) induces final maturation. Oocyte retrieval, performed transvaginally under ultrasound guidance approximately 36 hours after trigger, aspirates follicular fluid containing oocytes. Fertilization occurs in the laboratory, either by conventional insemination (surrounding the oocyte with sperm) or intracytoplasmic sperm injection (ICSI). Embryo culture proceeds for 3-5 days, with blastocyst transfer (day 5) increasingly preferred. Embryo transfer uses a thin catheter to place embryos transcervically into the uterus under ultrasound guidance. Luteal phase support with progesterone (vaginal, intramuscular, or both) maintains the endometrium until placental production takes over.

Success rates vary primarily with maternal age. For women under 35 using their own eggs, live birth rates are approximately 40% per fresh transfer; rates decline to approximately 30% at 35-37, 20% at 38-40, and 10% at >40. These statistics inform counseling about realistic expectations.

<image>Panel A: IUI procedure showing sperm washing (centrifuge, concentration), timing relative to LH surge or trigger shot, catheter insertion through cervix with sperm injection into uterus, 10-20% per cycle success rate, and indications (unexplained, mild male factor, cervical factor, donor sperm). Panel B: IVF controlled ovarian stimulation with daily gonadotropin injections and monitoring ultrasounds showing multiple follicles, trigger shot timing, and transvaginal oocyte retrieval with needle aspiration under ultrasound guidance approximately 36 hours after trigger. Panel C: Laboratory phase showing conventional fertilization (surrounding oocyte with sperm) versus ICSI (microinjection needle), embryo development from zygote to blastocyst over 5 days, and embryo transfer with catheter under ultrasound guidance. Panel D: Luteal phase support with progesterone (vaginal, intramuscular, or both), and success rate table by age group (under 35: approximately 40%, 35-37: approximately 30%, 38-40: approximately 20%, over 40: approximately 10% live birth rate per fresh transfer).</image>

Section 8: ICSI, Preimplantation Genetic Testing, and Cryopreservation

Intracytoplasmic sperm injection (ICSI) involves directly injecting a single sperm into the oocyte cytoplasm, bypassing the natural fertilization process. This technique revolutionized treatment of severe male factor infertility.

Indications for ICSI include severe oligozoospermia, asthenozoospermia, or teratozoospermia where standard insemination is unlikely to succeed; previous fertilization failure with conventional IVF; surgically retrieved sperm from the epididymis (MESA, PESA) or testis (TESE, micro-TESE); and use of cryopreserved sperm with poor post-thaw parameters. ICSI is also required when preimplantation genetic testing is performed to prevent contamination from extraneous sperm. ICSI achieves fertilization rates comparable to conventional IVF (approximately 70-80%) even with severely abnormal sperm parameters.

Preimplantation genetic testing (PGT) allows embryo analysis before transfer. A biopsy is performed, typically at the blastocyst stage by removing several trophectoderm cells (the precursor to the placenta, sparing the inner cell mass that becomes the fetus). PGT-A (aneuploidy screening) tests for whole chromosome gains or losses, aiming to improve implantation rates and reduce miscarriage by selecting euploid embryos. Its routine use remains debated, but it is commonly employed in advanced maternal age and recurrent pregnancy loss. PGT-M (monogenic disorder testing) screens for specific genetic conditions when one or both parents are carriers (cystic fibrosis, sickle cell disease, Huntington disease). PGT-SR tests for structural rearrangements in carriers of balanced translocations to select embryos with normal chromosome complement.

Embryo cryopreservation using vitrification (rapid freezing) allows storage of excess embryos for future use. Frozen embryo transfer (FET) success rates now equal or exceed fresh transfer rates, likely due to the more physiologic endometrial environment in unstimulated cycles. "Freeze-all" strategies, where all embryos are frozen and transferred in subsequent cycles, are employed in high OHSS risk patients and when PGT is performed.

Oocyte cryopreservation enables fertility preservation for women facing gonadotoxic therapy or those electing to delay childbearing. Survival and pregnancy rates have improved dramatically with vitrification.

<image>Panel A: ICSI showing micromanipulation setup with holding pipette and injection pipette, close-up of single sperm injection into oocyte, and indications (severe male factor, surgically retrieved sperm, prior fertilization failure, PGT requirement). Panel B: Preimplantation genetic testing with trophectoderm biopsy at blastocyst stage, comparing PGT-A (aneuploidy screening with chromosome array), PGT-M (monogenic disorder testing with family pedigree and mutation detection), and PGT-SR (structural rearrangement testing for translocation carriers). Panel C: Cryopreservation showing vitrification process (rapid cooling curve versus slow freezing), embryo storage in liquid nitrogen, and frozen embryo transfer cycle with programmed endometrial preparation, noting FET success rates now equaling or exceeding fresh transfers. Panel D: Fertility preservation showing oocyte cryopreservation with improved vitrification outcomes, common indications (gonadotoxic therapy, elective delay of childbearing), and freeze-all strategies for OHSS risk or PGT cases.</image>

Section 9: Treatment by Diagnosis

The management approach is tailored to the identified cause of infertility.

For PCOS, treatment progresses stepwise. Lifestyle modification, particularly weight loss of 5-10% in overweight women, can restore ovulation. First-line ovulation induction uses letrozole (preferred) or clomiphene. If unsuccessful, gonadotropins are used with careful monitoring given the high multiple follicle risk in PCOS. IVF with or without single embryo transfer is employed for resistant cases. Ovarian drilling (laparoscopic electrocautery) is rarely used today given effective medical options.

Tubal factor treatment depends on severity. Mild distal tubal disease may be amenable to laparoscopic fimbrioplasty or salpingostomy with reasonable pregnancy rates. Severe tubal damage, including hydrosalpinx, is best treated with IVF after salpingectomy. Hydrosalpinx removal before IVF improves implantation rates by eliminating the toxic effect of tubal fluid. Proximal tubal obstruction may be treated with hysteroscopic tubal cannulation or IVF.

Endometriosis-associated infertility management depends on stage. For minimal to mild endometriosis, laparoscopic excision or ablation may improve natural conception rates. For moderate to severe disease with significant anatomic distortion, IVF is often the most efficient treatment. Endometriomas greater than 4 cm may warrant surgical excision before IVF, though this must be balanced against the loss of ovarian reserve from surgery.

Male factor treatment is guided by severity. Mild male factor may respond to IUI with ovarian stimulation (total motile count after washing >5-10 million). Moderate male factor warrants IVF. Severe male factor or azoospermia requires ICSI. For obstructive azoospermia, surgical sperm retrieval (MESA, TESE) combined with ICSI achieves excellent results. For non-obstructive azoospermia, micro-TESE may identify pockets of spermatogenesis.

Unexplained infertility is treated empirically. A typical progression is 3 cycles of ovarian stimulation with IUI followed by IVF if unsuccessful. The FASTT trial demonstrated that proceeding directly to IVF after failed clomiphene-IUI achieved pregnancy faster and more cost-effectively than additional IUI cycles.

<image>Panel A: PCOS treatment stepwise ladder from lifestyle modification (5-10% weight loss) to letrozole (preferred) or clomiphene, then gonadotropins with careful monitoring, then IVF with or without single embryo transfer for resistant cases. Panel B: Tubal factor decision tree showing mild distal disease (laparoscopic fimbrioplasty or salpingostomy), severe damage or hydrosalpinx (salpingectomy followed by IVF, emphasizing removal improves implantation rates), and proximal obstruction (hysteroscopic cannulation or IVF). Panel C: Endometriosis treatment showing minimal-mild disease (laparoscopic excision may improve natural conception), moderate-severe (IVF most efficient), and endometrioma greater than 4 cm (surgical excision before IVF balanced against ovarian reserve loss). Panel D: Male factor treatment by severity (mild with IUI and TMC greater than 5-10 million, moderate with IVF, severe with ICSI, azoospermia with surgical retrieval plus ICSI), and unexplained infertility (3 cycles stimulated IUI then IVF per FASTT trial).</image>

Section 10: Complications, Success, and Psychosocial Considerations

Ovarian hyperstimulation syndrome (OHSS) is the most significant complication of fertility treatment, occurring when excessive response to gonadotropin stimulation leads to ovarian enlargement, increased vascular permeability, and third-spacing of fluid. Mild OHSS, characterized by abdominal discomfort and mild ovarian enlargement, is common and self-limiting. Moderate OHSS involves significant ascites and larger ovaries. Severe OHSS is potentially life-threatening, with massive ascites, pleural effusion, hemoconcentration, renal dysfunction, and thromboembolic risk. Prevention strategies include low-dose stimulation protocols, GnRH agonist trigger (instead of hCG) in high-risk patients, and freeze-all strategies to avoid hCG-producing pregnancy that worsens OHSS. Treatment is supportive, with fluid management guided by hemoconcentration and symptoms.

Multiple pregnancy remains a significant concern, particularly with non-IVF treatments where embryo number cannot be controlled. Multiple pregnancy carries increased risk of preterm delivery, growth restriction, and maternal complications. Prevention through careful ovulation induction monitoring, cycle cancellation if too many follicles develop, and single embryo transfer (SET) in IVF is paramount. Elective SET in good-prognosis patients achieves equivalent cumulative pregnancy rates with dramatically reduced twin rates.

Success rates must be communicated honestly. Per-cycle success with IVF varies by age and diagnosis but averages 30-40% live birth rate in women under 38 using their own eggs. Cumulative success over multiple cycles is higher. Third-party reproduction (donor eggs, gestational carriers) may be necessary for some couples.

The emotional burden of infertility is substantial. Stress, anxiety, depression, relationship strain, and financial pressure are common. Couples should be counseled that the emotional journey is normal and that support resources, including counseling and support groups, are available. The decision to stop treatment is difficult but appropriate when the emotional or financial toll becomes unsustainable.

<image>Panel A: OHSS pathophysiology showing enlarged ovaries, ascites, pleural effusion, and hemoconcentration, with severity classification (mild, moderate, severe), risk factors (PCOS, high AMH, high oocyte yield), and prevention strategies (GnRH agonist trigger, freeze-all). Panel B: Multiple pregnancy risks (preterm delivery, growth restriction, maternal complications) with prevention through careful monitoring, cycle cancellation for excessive follicles, and single embryo transfer in IVF showing equivalent cumulative rates with dramatically reduced twin rates. Panel C: Success rates showing age-specific IVF live birth curves (30-40% for women under 38), cumulative success over multiple cycles, and third-party reproduction options (donor eggs, gestational carriers) when own gametes are unsuccessful. Panel D: Psychosocial aspects showing emotional burden (stress, anxiety, depression, relationship strain, financial pressure), support resources (counseling, support groups), and acknowledging the decision to stop treatment as appropriate when toll becomes unsustainable.</image>

Summary

Infertility is defined as failure to conceive after 12 months of unprotected intercourse (6 months if age >35). Approximately 10-15% of couples are affected, with causes distributed roughly equally between female factors, male factors, combined, and unexplained.

Female evaluation assesses ovulation (menstrual history, mid-luteal progesterone), ovarian reserve (AMH, day 3 FSH, AFC), tubal patency (HSG, laparoscopy), and uterine cavity (SIS, hysteroscopy).

Male evaluation centers on semen analysis (WHO criteria: volume ≥1.5 mL, concentration ≥15 million/mL, motility ≥40%, morphology ≥4%). Azoospermia requires differentiation between obstructive and non-obstructive causes.

Ovulation induction uses letrozole (first-line for PCOS) or clomiphene, with gonadotropins for resistant cases or IVF. HCG triggers ovulation.

IUI is appropriate for unexplained infertility, mild male factor, and cervical factor. IVF is indicated for tubal factor, severe male factor, and failed other treatments.

ICSI enables fertilization with severely abnormal sperm. PGT screens embryos for aneuploidy or specific genetic conditions.

Treatment is tailored to diagnosis: lifestyle modification and letrozole for PCOS, salpingectomy and IVF for hydrosalpinx, ICSI for severe male factor, empiric treatment for unexplained.

OHSS prevention uses GnRH agonist triggers and freeze-all strategies. Multiple pregnancy prevention uses careful monitoring and single embryo transfer.

Key Terms

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