Infertility and Contraception¶
Chapter 408 | Part 12: Endocrinology and Metabolism
KEY CLINICAL POINTS¶
- Infertility is defined as the inability to achieve pregnancy after 12 months of unprotected intercourse, affecting ~17.5% of couples globally.
- Hormonal therapies for menopause management carry risks of cardiovascular disease, breast cancer, and osteoporosis, requiring careful risk-benefit evaluation.
- Contraceptive effectiveness varies widely, with long-acting reversible methods (LARC) like IUDs and implants having the lowest failure rates (<1%).
- The US Medical Eligibility Criteria (USMEC) guide contraceptive selection based on medical conditions and risks.
- Assisted reproductive technologies (ART) such as IVF and ICSI are critical for severe male or female infertility, with success rates influenced by age and ovarian reserve.
1. DEFINITION & OVERVIEW¶
Infertility is a disease of the reproductive system, defined as the inability to achieve pregnancy after 12 months of unprotected intercourse. The fecundability rate peaks in the first 3 months of attempting pregnancy and declines over the next 9 months. Approximately 85% of couples achieve pregnancy within 12 months, and 95% within 24 months. Age-related decline in fecundability is significant: 14% reduction at 34–35 years, 19% at 36–37 years, 53% at 40–41 years, and 59% at 42–44 years.
Table 408-1: Assisted Reproductive Technologies¶
| Method | Theoretical Efficacy (%) | Actual Efficacy (%) | Continued Use at 1 Year (%) | U.S. Use (%) |
|---|---|---|---|---|
| Ovulation induction | 99.7 | 91 | 67 | 14 |
| Injectable hormones | 99.7 | 91 | 67 | 0.5 |
| Intrauterine device (IUD) | 99.4 | 99.8 | 85 | 10.4 |
| Progestin-containing IUD | 99.8 | 99.8 | 88 | 1.8 |
| Implant | 99.5 | 99.5 | 84 | 3.1 |
| Depo-Provera | 99.8 | 94 | 56 | 5.6 |
| Emergency contraception | 95 | - | - | 11 |
1.1 WHO Classification¶
The World Health Organization (WHO) categorizes infertility as a disease of the reproductive system. It is the third most common disease globally, affecting ~48–72 million couples.
1.2 Primary vs. Secondary Infertility¶
Primary infertility refers to couples who have never achieved a pregnancy, while secondary infertility occurs after at least one successful pregnancy.
2. EPIDEMIOLOGY¶
Infertility affects ~17.5% of couples globally, with stable prevalence over decades. Primary infertility accounts for 30–40%, secondary for 40–50%, and unexplained for 15–30%. Female factors (30–40%), male factors (40–50%), and combined factors (20–30%) are the main causes. Age-related fecundability decline is significant: 14% reduction at 34–35 years, 19% at 36–37 years, 53% at 40–41 years, and 59% at 42–44 years.
Table 408-2: U.S. Medical Eligibility Criteria (USMEC) for Contraceptive Use¶
| USMEC Category | Conditions |
|---|---|
| Category 4 (Unacceptable Health Risk) | Smoking ‡15 cigarettes/day ‡35 years, known ischemic heart disease, acute DVT, previous thromboembolic events, stroke, hypertension ‡160/100 mmHg, systemic lupus, cirrhosis, pregnancy <21 days, breastfeeding <21 days, breast cancer, diabetes complications, migraines with aura |
| Category 3 (Theoretical/Proven Risks Outweigh Benefits) | Smoking <15 cigarettes/day ‡35 years, previous thromboembolic events with lower risk, superficial thrombosis, past breast cancer (no evidence for 5 years), hypertension 140–159/90–99 mmHg, anticonvulsants, rifampin, antiretrovirals, bariatric surgery, breastfeeding 21–42 days with VTE risk factors |
2.1 Global Prevalence¶
Approximately 48–72 million couples globally experience infertility, with ~17.5% prevalence. The fecundability rate declines with age, particularly in women over 35.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
Infertility is classified as female, male, or unexplained factors. Female causes include tubal (PID, endometriosis), uterine (fibroids), ovulatory (PCOS, diminished ovarian reserve), and endocrine (hypothyroidism, hyperprolactinemia). Male causes include anatomic (vasectomy), endocrine (hypogonadism), sexual dysfunction, and genetic (Klinefelter, Y deletions). Unexplained infertility accounts for 15–30% of cases.
3.1 Female Factors¶
Tubal factors (PID, endometriosis), uterine etiology (fibroids, congenital malformations), ovulatory dysfunction (PCOS, diminished ovarian reserve), and endocrine disorders (hypothyroidism, hyperprolactinism).
3.2 Male Factors¶
Anatomic (vasectomy, infection), endocrine (hypogonadism, hypothyroidism), sexual dysfunction (erectile/ejaculatory issues), and genetic (Klinefelter, Y chromosome microdeletions).
4. CLINICAL FEATURES¶
Symptoms include irregular menses, dysmenorrhea, pelvic pain, and infertility. Signs may include submucosal fibroids, endometriosis, or PCOS. Complications include ectopic pregnancy, miscarriage, and maternal/fetal complications from obesity or smoking.
4.1 Female Symptoms¶
Irregular menstrual cycles, dysmenorrhea, pelvic pain, and infertility. Submucosal fibroids and endometriosis may reduce pregnancy rates and increase miscarriage risk.
4.2 Male Symptoms¶
Abnormal semen parameters (oligoasthenozoospermia), sexual dysfunction (erectile/ejaculatory issues), and genetic abnormalities (Klinefelter syndrome).
5. DIFFERENTIAL DIAGNOSIS¶
Not explicitly detailed in the text, but includes conditions such as PCOS, endometriosis, thyroid dysfunction, and hormonal imbalances.
6. INVESTIGATIONS & DIAGNOSIS¶
Fertility evaluation begins after 1 year of unprotected intercourse. Ovulation assessment via LH strips, progesterone, or BBT. HSG, ultrasound, semen analysis, AMH, FSH, estradiol, and genetic screening are used. Endocrine tests include TSH, prolactin, and testosterone.
Table 408-3: Effectiveness of Different Forms of Contraception¶
| Method | Theoretical Efficacy (%) | Actual Efficacy (%) | Continued Use at 1 Year (%) | U.S. Use (%) |
|---|---|---|---|---|
| No method | 15 | 15 | 34.7 | |
| Fertility awareness | 96 | 76 | 47 | 1.2 |
| Withdrawal | 96 | 78 | 46 | 4.4 |
| Condoms | 98 | 82 | 43 | 8.4 |
| Diaphragm | 94 | 82 | 57 | 2 |
| Spermicides | 82 | 72 | 43 | 1 |
| Female sterilization | 99.5 | 99.5 | 100 | 18.1 |
| Male sterilization | 99.5 | 99.9 | 100 | 5.6 |
| Intrauterine device (IUD) | 99.4 | 99.8 | 85 | 10.4 |
| Progestin-containing IUD | 99.8 | 99.8 | 88 | 1.8 |
| Implant | 99.5 | 99.5 | 84 | 3.1 |
| Depo-Provera | 99.8 | 94 | 56 | 5.6 |
| Emergency contraception | 95 | - | - | 11 |
6.1 Diagnostic Tests¶
Semen analysis, HSG, ultrasound, AMH, FSH, estradiol, TSH, prolactin, and testosterone. Genetic screening for Y chromosome microdeletions or karyotype in azoospermia.
7. MANAGEMENT & TREATMENT¶
Ovulation induction with clomiphene, letrozole, or metformin. IUI for mild male factor infertility. IVF/ICSI for severe male or female infertility. Tubal repair or surgery for obstructive causes. Hormonal contraceptives (combined or progestin-only) for contraception, with LARC methods (IUD, implants) preferred for efficacy.
7.1 Ovulation Induction¶
Clomiphene citrate, letrozole, or metformin for PCOS. Low-dose gonadotropins for hypothalamic amenorrhea. IUI combined with ovulation induction for female factor infertility.
7.2 Assisted Reproductive Technologies¶
IVF for tubal infertility, ICSI for severe male factor infertility. Donor oocytes for diminished ovarian reserve. LARCs (IUD, implants) for long-term contraception.
8. PROGNOSIS & COMPLICATIONS¶
Success rates vary by age and treatment. IVF risks include multiple pregnancies and OHSS. Complications include ectopic pregnancy, miscarriage, and maternal/fetal risks from obesity or smoking. Progestin-only methods reduce endometrial and ovarian cancer risks by 50% and 40%, respectively.
8.1 IVF Risks¶
Multiple pregnancies (highest risk), OHSS, and embryo implantation failure. Success rates depend on age, ovarian reserve, and embryo quality.
9. SPECIAL CONSIDERATIONS¶
Obesity in women increases anovulatory cycles and miscarriage risk. In men, abnormal sperm parameters are linked to obesity and smoking. Counseling for smoking cessation, preconception care, and genetic screening is critical. LARC methods are preferred for long-term contraception due to high efficacy and low failure rates.
9.1 Obesity and Infertility¶
Obesity in women correlates with anovulatory cycles, miscarriage, and maternal/fetal complications. In men, it is associated with abnormal sperm parameters.
10. KEY POINTS & CLINICAL PEARLS¶
Infertility is defined as inability to achieve pregnancy after 12 months of unprotected intercourse. Hormonal therapies for menopause carry risks of cardiovascular disease, breast cancer, and osteoporosis. LARC methods (IUD, implants) are most effective for contraception. USMEC guidelines guide contraceptive selection based on medical conditions. ART (IVF, ICSI) is critical for severe infertility, with success rates influenced by age and ovarian reserve.