Causes of secondary infertility

If couple who are fertile once
(having first child or children or with previous miscarriage), not able to conceive again for one year with regular unprotected intercourse history, that is called secondary infertility.

The possible causes of secondary infertility are:
Gonadal hormonal imbalance which can cause irregular menstrual cycles, anovulation etc
Fallopian tubal block
Uterine causes like endometrial abnormalities, fibroids, adhesions etc.
Thyroid hormonal or prolactin level abnormalities giving rise to irregular periods etc.

Male factors can also lead to secondary infertility like:
Abnormal seminal parameters like low sperm count, decreased motility etc.
Genital abnormalities like varicocele, ejaculatory duct obstruction etc.
 By examination and by investigations like ultrasound, hysterosalpingography, gonadal hormonal analysis, thyroid profile, prolactin levels estimation for female partner and by physical examination and semen  analysis for male partner the possible cause of the problem can be identified and treated.