To understand this awe-inspiring process which converts a single cell into a small baby kicking away with life, you must understand a bit about your body.
Your reproductive system
The womb is the compartment of your body in which the foetus forms and grows till the birth of your child. In medical terms, it is knows as the uterus. The uterus is a pear-shaped muscular organ situated deep in the lower abdomen. In the non-pregnant stage, it is only 3 inches x 2 inches x 1 inch in size, but the same uterus stretches gradually in size to accommodate a fully formed baby.
The lower part of the uterus is narrow and is called the cervix. This part has an opening at its tip called the external os. The cervix protrudes into a long stretchable passage, which opens outside. During sexual intercourse, seminal fluid containing sperm flows though this passage called vagina.
The upper broad end of the uterus opens on either side into two long tubes called the fallopian tubes. Each tube ends in a funnel-shaped opening guarded by five finger-like protections called fibres. This funnel-shaped opening lies close to ovary on either side. The ovary is a spherical, walnut-sized organ responsible for producing female hormones and the eggs which are called ova.
At birth, each ovary has thousands of eggs. During a woman’s reproductive life, only 400 ova are shed. The shedding of ova does not begin until after puberty. Each month, an ovum is shed through a rupture in the outer wall of the ovary. This process is called ovulation. This ovum is picked up by the funnel-shaped end of the fallopian tube, and it gradually travels down the fallopian tube towards the uterine cavity. Ovulation occurs somewhere in the middle of a menstrual cycle. This is, the middle of the interval between two consecutive periods (menses), or roughly fourteen days before every period.
Menstruation, of menses, is a cyclic process occurring every 28-30 days. The onset of the first menstrual period most commonly occurs between the age of 11 and 15 years. The menstrual cycle then continues, unless interrupted by pregnancy, till menopause.
Menstruation is a flow of dark, red blood arriving every month at a predictable time, and lasting for 3 to 8 days. During the first half of this 28 cycle, as the ovum gets ready to be shed, the ovaries produce oestrogen hormones. Under the influence of these hormones, the tissues lining the uterine cavity thicken and form a cushion as a preparation of for pregnancy.
In the middle of the cycle, the ovum is shed and the empty follicular bed of the ovum produces the hormone progesterone. This further helps in preparing the uterine lining for pregnancy. In case the shed ovum is not fertilized and no pregnancy results, the levels of both oestrogen and progesterone hormones fall and the preparatory cushion of tissues is shed off together with blood. This is called menstruation.
Fertilization is the union of a mature ovum with a sperm. If sexual intercourse has taken place within about 12-24 hours of ovulation, then one of the thousands of sperms deposited in the vagina, having traveled up through the os and uterine cavity as it descends towards the uterine cavity.
This fertilized ovum enters the uterine cavity and gets embedded inside the thickened lining of the uterus. Once the pregnancy is established, the production of oestrogen and progesterone continues, the inner lining of the uterus is sustained and there is no shedding of eggs, as a result of which the menstruation stops. [an error occurred while processing this directive]