Primary vs. secondary
Couples with primary infertility have never been able to conceive, while, on the other hand, secondary infertility is difficulty conceiving after already having conceived and carried a normal pregnancy. Apart from various medical conditions (e.g. hormonal), this may come as a result of age and stress felt to provide a sibling for their first child. Technically, secondary infertility is not present if there has been a change of partners.Some women are infertile because their ovaries do not mature and release eggs. In this case synthetic FSH can be given as injections to stimulate eggs to mature in the ovaries.
Causes in either sex
Factors that can cause male as well as female infertility are:- Genetic
- A Robertsonian translocation in either partner may cause recurrent abortions or complete infertility.
- General factors
- Diabetes mellitus, thyroid disorders, adrenal disease
- Hypothalamic-pituitary factors:
- Kallmann syndrome
- Hyperprolactinemia
- Hypopituitarism
Female infertility
Factors relating only to female infertility are:- General factors
- Significant liver, kidney disease
- Thrombophilia
- Hypothalamic-pituitary factors:
- Hypothalamic dysfunction
- Ovarian factors
- Polycystic ovarian syndrome
- Anovulation
- Diminished ovarian reserve (usually means high FSH), also see Poor Ovarian Reserve
- Luteal dysfunction
- Premature menopause
- Gonadal dysgenesis (Turner syndrome)
- Ovarian neoplasm
- Tubal/peritoneal factors
- Endometriosis
- Pelvic adhesions
- Pelvic inflammatory disease (PID, usually due to chlamydia)
- Tubal occlusion
- Tubal dysfunction
- Uterine factors
- Uterine malformations
- Uterine fibroids (leiomyoma)
- Asherman's Syndrome
- Cervical factors
- Cervical stenosis
- Antisperm antibodies
- Insufficient cervical mucus (for the travel and survival of sperm)
- Vaginal factors
- Vaginismus
- Vaginal obstruction
- Genetic factors
- Various intersexed conditions, such as androgen insensitivity syndrome
Male infertility
Factors relating only to male infertility include:- Pretesticular causes
- Hypogonadism due to various causes
- Drugs, alcohol
- Testicular factors
- Bad semen quality
- Genetic defects on the Y chromosome
- Y chromosome microdeletions
- Abnormal set of chromosomes
- Klinefelter syndrome
- Neoplasm, e.g. seminoma
- Idiopathic failure
- Cryptorchidism
- Varicocele
- Trauma
- Hydrocele
- Mumps
- Testicular dysgenesis syndrome
- Posttesticular causes
- Vas deferens obstruction
- Infection, e.g. prostatitis
- Retrograde ejaculation
- Hypospadias
- Impotence
- Acrosomal defect/egg penetration defect
Combined infertility
In some cases, both the man and woman may be infertile or sub-fertile, and the couple's infertility arises from the combination of these conditions. In other cases, the cause is suspected to be immunological or genetic; it may be that each partner is independently fertile but the couple cannot conceive together without assistance.Unexplained infertility
In about 15% of cases the infertility investigation will show no abnormalities. In these cases abnormalities are likely to be present but not detected by current methods. Possible problems could be that the egg is not released at the optimum time for fertilization, that it may not enter the fallopian tube, sperm may not be able to reach the egg, fertilization may fail to occur, transport of the zygote may be disturbed, or implantation fails.It is increasingly recognized that egg quality is of critical importance and women of advanced maternal age have eggs of reduced capacity for normal and successful fertilization.
