Overview
Infertility is defined as failure to conceive after 12 months of regular unprotected intercourse (or 6 months if the woman is over 35). It affects one in six couples. Causes are approximately equally divided between male factors, female factors, and unexplained cases. Most couples will eventually conceive with appropriate investigation and treatment.
How common is it?
About 1 in 6 couples globally experience infertility. In the UK, infertility affects approximately 3.5 million people. Male factor infertility accounts for roughly one third of cases, female factor one third, and unexplained or combined causes one third.
Causes and risk factors
Infertility reflects a problem at any stage of conception: sperm production or function, ovulation, fallopian tube patency, uterine receptivity, or fertilisation.
Common risk factors
- Female: ovulatory disorders (PCOS is most common), tubal damage from infection or endometriosis, uterine abnormalities, premature ovarian insufficiency, age-related egg quality decline
- Male: low sperm count (oligospermia), absent sperm (azoospermia), poor motility, abnormal morphology, varicocele, hormonal imbalance, previous orchitis or testicular torsion
- Combined/unexplained: account for 25 to 30% of cases
- Lifestyle: smoking, excess alcohol, obesity, anabolic steroid use, sexually transmitted infections
Symptoms
- Inability to conceive after 12 months of trying (6 months if over 35)
- Irregular or absent menstrual periods (suggesting ovulatory disorder)
- Signs of PCOS: acne, excess facial or body hair, irregular periods
- Signs of premature ovarian insufficiency: hot flushes, night sweats
- Male: no obvious symptoms in most cases; occasionally testicular pain or sexual dysfunction
When to see a doctor
See a GP after 12 months of trying (6 months if over 35, or earlier if there is a known cause such as previous infection, irregular periods, or previous cancer treatment). Both partners should be assessed simultaneously.
Diagnosis
Female: day 21 progesterone (confirms ovulation), FSH, LH, AMH and antral follicle count (ovarian reserve), pelvic ultrasound, hysterosalpingography (checks tubal patency). Male: semen analysis is the primary test. Both: STI screening.
Treatments
Ovulation induction
Clomifene citrate or letrozole stimulates ovulation in women with irregular cycles (especially PCOS). Gonadotrophin injections are used for more resistant cases.
Intrauterine insemination (IUI)
Washed sperm is placed directly into the uterus around ovulation. Used for unexplained infertility, mild male factor, or single parent and same-sex couples. Success rate approximately 10 to 15% per cycle.
In vitro fertilisation (IVF)
Eggs are retrieved after ovarian stimulation, fertilised in the laboratory, and a resulting embryo transferred to the uterus. Cumulative live birth rate 50 to 60% for women under 35 over multiple cycles.
Intracytoplasmic sperm injection (ICSI)
A single sperm is injected directly into an egg. Used for severe male factor infertility. Live birth rates comparable to IVF with normal sperm.
Surgical treatment
Laparoscopic treatment of endometriosis, hydrosalpinx, or uterine polyps. Varicocele repair in men may improve sperm parameters.
Self-care and lifestyle
- Both partners should stop smoking and reduce alcohol to improve natural conception rates and IVF success
- Maintain a healthy BMI (obesity and underweight both impair fertility)
- Take folic acid 400 micrograms daily (5mg if high risk)
- Avoid recreational drugs including anabolic steroids (devastate spermatogenesis)
Prevention
Prompt treatment of STIs prevents tubal damage. Avoiding obesity, smoking, and anabolic steroids preserves fertility. Egg freezing is an option for women who wish to delay childbearing.