Female Infertility

Female Infertility

Inability of a couple to conceive because of some abnormality/ cause in the female partner is called as female infertility.

It is important to understand both the structure (anatomy) and the normal functioning (physiology) of female reproductive system in order to understand why some women find it difficult to conceive a baby and how the real issue can be addressed. The female reproductive system consists of external and internal organs.

External organs include the labia majora, labia minora, clitoris, and glands like the Bartholin’s glands. The external structures facilitate coitus, provide passage to the sperm and also protect the internal organs from infections. Internal organs include uterus, fallopian tubes and ovaries. These organs play a central role in the hormonal regulation and ability of a woman to reproduce.

Ovaries are a pair of small oval glands located on either side of the uterus and are the reservoir of millions of eggs that a female foetus acquires in her mother’s womb. Ovaries become functional at puberty and start producing sex hormones and mature eggs. Uterus (also known as womb) is another important internal organ. The foetus develops inside the uterus. The lower part of uterus forms the cervix which acts as an entry point to uterus, allowing the sperms to swim into the uterus and the menstrual blood to flow out of uterus. Fallopian tubes are narrow tubes, one on either side of uterus, which are attached to the upper part of the uterus and serve as pathways for the ova (eggs) to travel from the ovaries to the uterus. Fertilization of an egg by a sperm normally occurs in the fallopian tubes. The fertilized egg then moves to the uterus, where it gets implanted in the lining of uterus.

Physiology of female reproductive system

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The physiology of female reproductive system revolves around the monthly cycle of hormonal activity, which results in a series of physiological changes in the female reproductive organs, thus preparing her body for pregnancy. This cycle is known as menstrual cycle – the term “menstru” meaning “monthly”.

Menstrual cycle begins in girls at puberty and continues until menopause. The entire cycle is governed by hormones FSH and LH secreted by the pituitary gland (located in brain) and can be divided into 3 phases based on the activity in the ovary (ovarian cycle) and in the uterus (uterine cycle). The ovarian cycle can be divided into follicular phase, ovulation and luteal phase. Similarly, the uterine cycle can be divided into menstruation, proliferative phase and secretory phase.

Follicular phase

The follicular phase of the ovarian cycle corresponds to the proliferative phase of the uterine cycle and is marked by the beginning of menstruation, which signals the beginning of a new menstrual cycle. Pituitary gland in the brain secrets Follicle Stimulating Hormone (FSH) to stimulate the ovaries, as a result of which, a number of eggs start growing in the ovaries. One of these eggs becomes dominant and suppresses all other eggs, which eventually undergo atresia over a period of next 10- 14 days. Each egg is contained in a bag of fluid, called as follicle, during its development. At the end of the follicular phase, a single dominant follicle is ready for ovulation to release the egg.

Ovulatory phase

Ovulation is triggered by release of another hormone, Luteinising Hormone (LH), from the pituitary gland. This surge in level of LH causes a series of changes in the follicle and eventually leads to the release of egg from the follicle – a process known as ovulation. The egg, thus released, is captured by the fimbriae of the fallopian tubes and is than pushed gently towards the endometrial cavity.

Luteal phase

The luteal phase of the ovary corresponds to the secretory phase of the uterus and begins right after ovulation. The shell of the follicle remaining after the ovulation develops into a corpus luteum, which acts like a gland and secrets hormones progesterone and oestrogen.

Progesterone is essential to support pregnancy, as it brings about the secretory changes in the uterine lining to enable the fertilised egg to implant. Simultaneously the egg, during its passage through the fallopian tube should meet the sperm (which travels from the vagina, through uterus, to the tube if intercourse has taken place). The sperm fertilises the egg in the fallopian tube and later the fertilised egg reaches the uterus and gets implanted there resulting in pregnancy. The corpus luteum continues to secrete hormones and support pregnancy. In case there is no pregnancy, the corpus luteum dissolves and as soon as the hormone secretion stops the uterine lining sheds off leading to menstruation and initiation of a new menstrual cycle.

The major causes of female infertility can be categorized as follows-

 

Age related infertility
Ovulatory disorders like Poly Cystic Ovarian Syndrome (PCOS)
Tubal disorders
Fibroids
Endometriosis
Uterine causes
Hormonal causes of female infertility
Thyroid gland dysfunction
Hyperprolactinemia
Abnormal Follicle Stimulating Hormone (FSH) secretion
Other hormonal causes
Unexplained Infertility
Primary ovarian insufficiency (POI)

Female infertility has many causes including hormonal imbalance, structural abnormalities in uterus of the fallopian tubes, ovulatory disorders, endometriosis and psychological problems. The evaluation of the female partner begins with detailed history, physical examination and hormonal assessment. Investigations required for assessment of an infertile woman typically include-

 

Hormonal assessment
Ultrasound Scan
Test for Tubal Patency
Hysteroscopy