Natural birth control
Natural birth control is a loose term which refers to methods of birth control that are considered "natural"; though what is considered "natural" varies widely. Generally, natural birth control does not involve hormonal contraception, nor synthetic chemicals including synthetic spermicide. Other methods may also be excluded, depending on how the term "natural" is defined.
Some definitions of "natural" are more lenient and include barrier contraception used without synthetic spermicide, and occasionally the copper IUD, which contains no hormones. Some definitions exclude the use of devices, but include the use of herbs, natural substances, and behavioral methods. Natural family planning is the most exclusive in its definition of what is "natural".

# Methods
The following is a list of methods which may be considered "natural birth control". The definition of "natural" varies widely among individuals, and may exclude any of these methods.

## Fertility tracking
Fertility tracking methods such as fertility awareness and the Rhythm method may be considered natural birth control. Fertility awareness involves paying attention to biological signs of fertility, while the Rhythm method involves statistical estimation of the likelihood of fertility, based on the length of past cycles.

## Herbs and natural substances
Naturally occurring substances are chemicals, but some distinguish them from synthetic substances and consider them "natural". Herbs and substances may be ingested, to interfere with ovulation or implantation. Some are used to encourage menstruation.
Other substances are inserted vaginally, for use as natural spermicides. Examples of these include lemon juice, wild yam, Queen Anne's Lace (wild carrot), and neem). A website called Sister Zeus describes many of these methods in detail.

## Sexual activity
Sexual activities which have no or a low risk of conception may also be considered natural birth control. One of the best-known methods is the withdrawal method, which involves pulling the penis out of the vagina before ejaculation. Anal sex may be used as a substitute for vaginal intercourse.
Various forms of non-penetrative sex may be used as natural birth control. These do not involve penile penetration, and include:
- various forms of oral sex
- masturbation
- erotic massage
- use of sex toys
- frottage

## Barrier methods without synthetic spermicide
Some consider barrier methods to be natural, as they do not involve hormones or affect systemic health. Their effectiveness is based on physically blocking sperm from entering the uterus. These methods include the condom, the female condom, the diaphragm, the cervical cap, and the Lea's shield. These may be combined with the use of natural substances, including natural spermicides.

## Miscellaneous
- Heat-based contraception is an experimental method that involves heating the testicles in order to kill sperm and temporarily inhibit sperm production.
- The copper IUD is sometimes considered to be natural birth control, as it has no systemic effect on the body and contains no hormones.
- The lactational amenorrhea method involves extending the natural period of postpartum infertility through breastfeeding. Frequent feedings maintain an elevated level of the hormone prolactin, which can inhibit ovulation.
- Inasmuch as pregnancy does not occur without sexual activity, total sexual abstinence is sometimes considered a form of natural birth control.

# Natural family planning
Proponents of the Catholic concept of natural family planning define 'natural' somewhat differently. The Catholic church approves only of total or periodic abstinence and temporary infertility caused by breastfeeding as methods of family planning. NFP prohibits all orgasmic acts other than those achieved through unprotected vaginal intercourse with one's spouse, in accordance with Catholic religious beliefs. Periodic abstinence involves avoiding sexual intercourse during the period of fertility surrounding ovulation. Fertile times may be identified by methods of fertility awareness, particularly through observing changes in cervical mucus and/or fluctuations in basal body temperature, or approximated by statistical methods such as the Rhythm method. Extending the natural period of breastfeeding infertility through particular breastfeeding practices (LAM) is also permitted.