Menstruation forms part of the female reproductive cycle and happens every 28 days. During a woman's menstrual period she bleeds from the womb or uterus via the vagina and this can last anything between three to seven days. Menstruation usually only occurs if a women hasn't fallen pregnant during her 28 day menstruation cycle.
Menstruation, also known as a women’s period, happens as a result of hormonal changes during a women’s menstruation cycle. These hormones can affect both your sex organs such as the ovaries, fallopian tubes, uterus and vagina as well as the brain.
The ovaries contain a set number of eggs that are the same at the point of birth as they are later in life. During each menstruation cycle, one egg ripens as a result of the release of particular hormones and will be released from the ovaries and drift via the fallopian tubes to the uterus.
In preparation to receive a fertilised egg the womb lining (endometrium) will normally thicken. This action is also regulated by hormones in the blood stream. If fertilisation does take place the egg will attach itself to the endometrium, but if fertilisation doesn’t take place, the thickened endometrium is shed and this is when menstruation starts.
Hormonal treatments such as Norethisterone can push your period back by hormonally altering your menstruation cycle. This is really helpful if it's inconvenient for you to have your period because of an important exam, a special occasion or holiday.
Norethisterone is able to delay your period because it's a type of progestogen, a hormone that is naturally produced during your menstruation cycle. If you take Norethisterone it urges your body to hold on to your womb lining for a bit longer, because it keeps on stimulating it to grow. As soon as you stop taking the treatment, your hormone levels return to normal and then your period is able to start like it normally would.
Delaying the point your period starts in your menstruation cycle isn't likely to be dangerous as long as it's not attempted over a long period of time.
The pill or mini-pill can prevent pregnancy because they contain hormones that can alter your menstruation cycle. The pill contains progestogen as well as oestrogen, and these hormones work together to prevent ovulation, which means that an egg doesn't get released to get fertilised. They also make it so that the womb lining doesn't grow right before an egg is released, so even if an egg is released and fertilised the endometrium is unable to sustain it. The pill also has an influence on cervical mucus, so that it doesn't allow sperm to reach the womb.
The mini-pill works in a very similar way to the pill, but it only works with progestogen, which means that it's slightly less effective, because it's not likely to stop ovulation, however it does influence the womb lining and cervical fluids.
Other than the pill and the mini pill there are also other methods of hormonal contraception that work in a similar way to alter the menstrual cycle, such as the contraceptive injections, patches or rings. It's unlikely that altering the menstruation cycle in this way can cause health problems later in life as many women are able to use the pill for many years without it influencing their health, however it's important that you do go to your doctor for check-ups when you take the pill or mini pill.