Women are most fertile in their 20s, with fertility declining over time. Each month, a healthy woman’s chance of pregnancy is:
Although conception may be more difficult with age, pregnancy is still possible for many women. Understanding how the fertility cycle works can help improve your chances of becoming pregnant. Read on for a refresher on the female reproductive system, menstrual cycle, and the male’s role in conception.
Understanding the female reproductive system
The menstrual cycle, explained
The female menstrual cycle typically lasts between 28 to 32 days and can be divided into 3 phases. Each phase helps prepare a woman’s body for possible pregnancy.
- The endometrium starts to shed and a period begins
- A gland inside the head, called the hypothalamus, releases gonadotropin-releasing hormone (GnRH)
- The ovaries mature 10 to 20 eggs inside their follicles with the help of 2 other hormones: follicle stimulating hormone (FSH) and lutenizing hormone (LH)
- Ovulation varies from person to person, but happens at or around day 14
- When it occurs, the brain releases a large amount of LH at once
- This causes the fastest-growing follicle to rupture and release a mature egg into the fallopian tube
- The mature egg can potentially be fertilized during this stage as it moves through the fallopian tube
- While this happens, the empty follicle left behind in the ovary starts to release the hormone progesterone
- This helps nourish and thicken the endometrium to prepare it should an embryo implant
- If implantation happens, the body produces human chorionic gonadotropin, or hCG, which tells the body it’s pregnant
- If fertilization does not happen, a period will start
5 facts about the male reproductive system
Fact #1: Sperm are the male reproductive sex cells
Sperm are produced in the testes and mature throughout the reproductive tract for around 74 days.
Fact #2: Sperm store DNA in structures called chromosomes
Sperm are shaped like tadpoles. The head of the sperm stores the DNA and the tail helps it reach the woman’s egg.
Fact #3: The seminal vesicles also help
They produce a sugar-rich fluid that gives the sperm energy to swim. This fluid makes up much of the semen.
Fact #4: Only one sperm is needed for fertilization
There are millions of sperm inside every ejaculate, although only one is needed for fertilization. Ejaculated sperm can survive for 3 to 5 days inside a woman’s uterus.
Fact #5: The sperm and egg each contain their own set of 23 chromosomes
When the sperm fertilizes the egg and conception happens, these 46 chromosomes combine to form 23 pairs of unique chromosomes that are made up of each parent’s genetic information. This is called an embryo.