Fertile couples have about a 25% chance of conceiving any given month. If you don't become pregnant during the first month of trying, you may wish to learn more about how conception works. Having a good understanding of your menstrual cycle can help you time intercourse to increase your chances of becoming pregnant.

The Female Reproductive System

• Vagina: a muscular passage connecting the cervix with the external genitals
• Cervix: the lower part of the uterus that connects to the vagina
• Uterus: a hollow, muscular structure in which the fertilized egg implants and the fetus grows during pregnancy
• Ovaries: the glands that produce eggs and the female hormones estrogen and progesterone
• Fallopian tubes: tubes connecting the ovaries with the uterus

The Male Reproductive System

• Testicles, or testes: oval-shaped organs that produce sperm cells and male hormones, including testosterone

• Epididymis: coiled tubes connecting each testicle to the vas deferens, where sperm cells mature and are stored
• Scrotum: a pouch of skin that hangs outside the pelvis to hold and regulate the temperature of the testes
• Vas deferens: a muscular tube that transports sperm from the testes
  
• Seminal gland and prostate gland: glands that produce seminal fluid
• Urethra: the tube that passes urine and semen out of the body
• Penis: the organ in which muscular contractions force sperm-containing semen out of the urethra

Your Menstrual Cycle

A woman’s menstrual cycle prepares her body for the possibility of a pregnancy. An average cyucle lasts 28 days, but all women are different and your cycle may be as few as 17 days or as many as 43.

Estrogen levels rise in the first half of the menstrual cycle, causing the lining of the uterus to thicken. At the same time, an egg begins to mature in one of the ovaries.

Around the midpoint of the menstrual cycle (day 14 of an average cycle), a surge of luteinizing hormone (LH), which is produced by the pituitary gland in the brain, causes ovulation, a process in which the mature egg leaves the ovary.

In the second half of the menstrual cycle, finger-like projections located at the opening of the fallopian tubes sweep the released egg into the tube toward the uterus. At the same time, rising levels of progesterone help prepare the lining of the uterus for pregnancy.

How Pregnancy Occurs

Pregnancy is most likely the day that you ovulate, but may happen at any time of the month.

If sperm cells are present, they are guided toward the egg by the cervical mucus and the egg may become fertilized.

If no sperm cells are present, no pregnancy occurs. The egg dissolves and is absorbed into the body, hormone levels drop, and the thickened lining of the uterus is shed during the menstrual period.

An egg that has been fertilized divides and grows in a woman’s uterus (womb) throughout pregnancy until childbirth. The resulting child’s genetic makeup comes from the sperm and egg cells produced by the father and mother.

See also:

• Fertility Issues & Solutions