Introduction to Infertility

Summary

Infertility, defined as the inability to conceive after 12 months of unprotected intercourse in women under 35 or 6 months in women 35 and older, affects about 10–15% of couples. It may be primary, secondary, subfertility, or sterility, with causes attributed to female (35–45%), male (30–35%), combined, or unexplained factors. Evaluation involves semen analysis, hormonal testing, and imaging, while management includes lifestyle optimization, medical or surgical treatments, and assisted reproductive technologies such as IVF, with counselling recommended to address psychological distress.

Definition

Infertility is defined as the inability to achieve pregnancy after 12 months of regular, unprotected sexual intercourse in women under the age of 35, or after 6 months in women aged 35 years or older. According to the British Fertility Society, infertility is considered “a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sex.”

Epidemiology and Fecundity

 Infertility affects approximately 10–15% of married couples worldwide, with estimates in the UK suggesting that 1 in 7 couples will struggle to conceive. Fecundity—the probability of achieving pregnancy in a single menstrual cycle—ranges from 20–25% in healthy couples, meaning that most couples (about 85%) will conceive naturally within one year of trying. Among those who do not conceive in the first year, approximately half will achieve pregnancy within the following year without intervention.

Types of Infertility

• Primary infertility: failure to conceive despite at least 12 months of regular unprotected intercourse, in couples with no previous pregnancies.

• Secondary infertility: difficulty conceiving despite a history of previous conception (including miscarriage or live birth).

• Subfertility: reduced fertility with a lower chance of conception, but not complete sterility.

• Sterility: complete inability to conceive due to irreversible factors such as hysterectomy, premature ovarian failure, testicular failure, or menopause.
  
  

Unexplained Infertility
This diagnosis is reserved for couples with normal semen parameters, evidence of ovulation, and patent fallopian tubes. Notably, up to 60% of couples with unexplained infertility may conceive spontaneously within three years.

Etiology

The causes of infertility are diverse and may involve one or both partners:

• Female factors (35–45%)

• Ovulatory disorders (e.g., polycystic ovary syndrome, premature ovarian insufficiency, hypothalamic dysfunction, hyperprolactinemia)

• Tubal pathology (e.g., pelvic inflammatory disease, endometriosis, tubal adhesions, congenital anomalies)

• Uterine factors (e.g., congenital malformations, fibroids, intrauterine adhesions, endometrial pathology)

• Cervical and vaginal factors (e.g., stenosis, trauma, congenital anomalies, inflammation)

• Immunological factors (antisperm antibodies)

• Male factors (30–35%)

• Abnormal semen quality or quantity (azoospermia, oligospermia, asthenospermia, teratospermia)

• Testicular failure, varicocele, cryptorchidism, genetic abnormalities, infections

• Pre-testicular causes (hypogonadotropic hypogonadism, systemic illness)

• Post-testicular causes (obstruction, ejaculatory dysfunction)

• Combined male and female factors (20%)

• Unexplained causes (10–15%)

Initial Assessment and Investigations

Infertility evaluation typically begins in primary care, with assessment of both partners.

• Male evaluation: semen analysis (first-line), with further hormonal, genetic, or imaging studies as indicated.

• Female evaluation: hormonal testing (FSH, LH, TSH, prolactin), assessment of ovulation, and imaging to evaluate tubal and uterine factors (e.g., pelvic ultrasound, hysterosalpingography, or laparoscopy if required).
  
  

Referral to specialist fertility services is indicated if conception has not occurred after 12 months of regular unprotected intercourse, or after 6 months in women aged ≥36 years or when risk factors for infertility are identified (e.g., history of pelvic inflammatory disease, endometriosis, chemotherapy, or gonadal surgery).

General Advice for Couples Trying to Conceive

• Engage in regular sexual intercourse every 2–3 days throughout the cycle.

• Preconception care: folic acid supplementation (400 mcg daily), optimization of chronic medical conditions, and up-to-date immunizations.

• Lifestyle measures:

• Maintain a healthy BMI (19–25 kg/m²).

• Cease smoking and recreational drug use.

• Avoid excessive alcohol consumption; women are advised to abstain entirely while trying to conceive.

• Minimize caffeine intake.
  
  

Management of Infertility

Treatment is tailored according to the identified cause and may include:

1. Medical management: ovulation induction (e.g., clomifene citrate, letrozole, gonadotropins).

2. Surgical management: correction of tubal pathology, removal of intrauterine adhesions or fibroids, or treatment of endometriosis.

3. Assisted reproductive technologies (ART): intrauterine insemination (IUI), in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI).
   
   

Psychological Impact

 Infertility is associated with significant emotional and psychological distress. NICE guidelines recommend that couples should be offered counselling and psychological support before, during, and after fertility investigations and treatment, irrespective of the outcome.