The reasons for unwelcomed childlessness are manifold. Quite often, more than just a single factor come into play.
The highest natural fecundity in females is between the ages of 15 and 25, and diminishes unremittingly afterwards. With the beginning of the climacteric stage, natural fertility ceases.
The most common reasons for female infertility are:
Hormonal Imbalances can lead to non-existent or delayed oocyte maturation, the absence of ovulation, insufficient formation of the corpus luteum, and problems with intrauterine embryo nidation.
Anatomical Malformations or Changes of the Uterus, Ovaries or Tubes
In rare cases, congenital malformations of reproductive organs are responsible for unwelcomed childlessness.
Impaired Fallopian Tube Function (patency)
Reasons therefore can be infections, adhesions, previous tubal pregnancies or surgeries.
Endometriosis is present - in case you find endometrial tissue outside of the uterus - in places such as the Fallopian tubes, ovaries, or even the intestines and the bladder. These lesions are ‘active’ in parallel to the menstrual cycle, and are capable of growth. This is a common cause of infertility.
Polycystic Ovarian Syndrome (PCOS)
With PCO Syndrome, a great number of ovarian cysts (follicles) are present. In most cases, there is no normal oocyte maturation. This is commonly accompanied by an increased concentration of male sex hormones, an increased body weight and also intensified pelage (hairiness).
Uterine fibroids are benign tumours, ensuing histologically from uterine smooth muscle cells. These muscular nodules may impair fertility, but it depends on their number, size and localisation.
Congenital genetic disorders are also quite rare causes of infertility, which can include variations of chromosomal numbers, structures or genomic alterations..