Hormonal methods

Combined contraceptive pill

The pill is very effective. It contains two hormones, an oestrogen and a progestogen, which if taken correctly stops the ovaries from releasing an egg.

Most women find the pill the most convenient method but some people find it hard to take a pill at the same time every day, or get side effects. Occasionally there may be more severe problems such as a blood clot in the veins. Some women cannot take the pill because of a medical problem and that's why it is not available over the counter but must be prescribed by a doctor.

One of the benefits of the pill is that menstruation is controlled by the pill and therefore very regular (every fourth week) and usually lighter and less painful.

Most pill failures are due to women forgetting pills or not realising they are less safe if they have a stomach upset. The failure rate with the pill depends on how reliably it is taken. In studies where women are usually taking it more reliably the range is from 2 in 1000 to 3 in 100 for women using it over a year.

Progestogen-only pill (POP)

Sometimes called the "minipill", this pill has only one hormone, a progestogen. It's taken every day, 365 days a year, without a break between hormone pills as in the combined pill.

Because it's taken continuously, the minipill can upset the normal menstrual cycle but as it only has a low dose of progestogen, it's uncommon to have other side effects. It's often suitable for women with medical problems who cannot take the combined pill, such as breastfeeding mothers.

If not taken correctly the progestogen-only pill may be less effective than the combined pill. Women need to be even more careful in taking this pill and keep to a three hour safety margin. The newest progestogen-only pill is 'Cerazette' which has a 12 hour safety margin but it is not subsidised so the cost of prescription can be a limiting factor.

For reliable users the failure rate is from 3 in 1000 to 4 in 100 for women using it over a year.

Depo-Provera injection

This is an injectable hormone method given every three months. The injection isn't painful, just a quick jab.

Depo-Provera releases a progestogen, a hormone which acts to stop the release of an egg form the ovary. It's a very effective, long-acting method. It's particularly suitable for people who find it difficult to remember taking a contraceptive pill each and every day.

It can be used by women who cannot take oestrogens, for example those with a tendency to blood clots or high blood pressure or focal migraine. Some women lose their periods but this isn't harmful. Some women experience side effects such as weight gain or irregular bleeding.

The Depo-Provera injection is one of the most reliable methods and failures are extremely rare if it is given at the correct time.


Since 2010 two implants are available in New Zealand. These are usually inserted above the elbow on the inner aspect of the upper arm. When they're no longer needed or they've expired, the implants are removed through a small incision.

  • 'Jadelle' consists of two small rods and releases a progestogen, called levonorgestrel. It can remain in place for five years. Jadelle is subsidised by the New Zealand government, which means it is low cost.
  • 'Implanon' consists of one rod and releases a different progestogen, called 3-keto-desogestrel. It can remain in place for three years. It is not subsidised so is more expensive than the Jadelle implant.

The main side effect with implants is irregular or unpredictable bleeding which may settle somewhat with time. Sometimes it is combined with a contraceptive pill to give better bleeding control.

Hormone Releasing IUDs

See Mirena, under IUDs (intrauterine devices).