Understanding Conception

The likelihood of pregnancy within any given month is believed to be about 25% and involves the ability to conceive or the fertility potential of both partners. This is why it is important to understand normal reproductive function in both men and women

The Female Reproductive System

The reproductive system of a woman is entirely internal.

• The vagina is the passage that leads from the outside of the body to the cervix, which is the opening to the uterus.
• The uterus or womb is a muscular organ where the fertilized egg of embryo attaches itself and develops. It is about the size and shape of a pear, and is lined with a rich and nourishing lining called the endometrium.
• From the top of the uterus extend the fallopian tubes one on either side, which lead to the ovaries.
• Ovaries are almond shaped structures which contain the eggs or oocytes. Women are born with their full quota of eggs i.e. more than 3 million. The eggs are contained in structures called the follicles. Their number falls to 450,000 by puberty. In the entire reproductive lifespan only around 400 eggs are used.
• Each month during the reproductive years i.e. from puberty to menopause, the woman goes through a menstrual cycle, which on an average is a 28-day cycle. In one cycle usually only a single egg or ovum matures inside a follicle. Halfway through the cycle, the egg is released from the follicle in a process called ovulation. Once the ovum is released, it is swept into the fallopian tube where it meets the sperm. The fertilized egg or embryo travels down the fallopian tube into the uterus where it embeds in the endometrium.
• The sequence of events is controlled by monthly changes in the levels of the hormones FSH & LH secreted by the pituitary gland and the hypothalamus.
• If fertilization does not occur the endometrium breaks down and is expelled outside the body as the menstrual flow or menses, which lasts for 3-4 days on an average.

The Male Reproductive System

The male reproductive system is both internal and external.

Sperms are produced in the testis inside the scrotum. Their production starts from puberty and is continuous. Sperm production is controlled by the hormones FSH and LH from the pituitary gland in the brain.

As sperms are produced, they pass from the testes through the epididymis of coiled tubes, that store and nourish sperms as they mature. Once sperms are completely mature, they move into another tube, the vas deferens, which connects with another structure called the seminal vesicles. Here the mature sperms are stored. The entire process of sperm formation to maturation takes approximately 72 days.

When a man ejaculates of expels the fluid from his penis, during intercourse, sperms form the seminal vesicles combine with a thick fluid from the prostate gland which is a small gland close to the urinary bladder, to create semen. The semen is deposited into the woman’s vagina.

Fertilization :

Millions of sperms are deposited into the vagina during sexual intercourse. The sperms make their way through the cervix into the uterus and then on to the fallopian tubes. Around 200 sperms make it to the fallopian tube. Most die along the way. Once inside the fallopian tube, the sperm attracts the egg by releasing a chemical. The egg is surrounded by a protective covering called the zona pellucida, which allows only one sperm to penetrate it. Once inside the egg, the head of the fertilizing sperm releases its genetic contents, which fuses with the nucleus of the egg.

Development of the fertilized egg:

The fertilized egg then undergoes several divisions to form a structure called the zygote. It moves into the uterus within a period of 5-7 days and is then termed as embryo. In the uterus, the embryo implants or attaches itself and burrows into the endometrium,. After implantation it secretes a hormone called human chorionic gonadotrophin (hCG) which helps maintain the pregnancy. This is the hormone analyzed in the blood/urine to detect or confirm a pregnancy.

This is some background information on the process of conception. If you wish to know more, kindly approach the front desk to schedule an appointment with one of our doctors. We would be happy to be of assistance.