Information about Natural Methods of Birth Control

Coitus Interruptus (Withdrawal Method)

In coitus interruptus, the penis is withdrawn from the vagina prior to ejaculation. The Bible and the Koran make reference to coitus interruptus, suggesting that it has been practiced for thousands of years.

In the United States, coitus interruptus is considered ineffective and is not a common means of contraception, but it is a common method of birth control in many developing nations. When done correctly, coitus interruptus has a failure rate of about 6.7 percent (6.7 out of every 100 women become pregnant while using this birth control method).

Advantages are that it is immediately available and it is free. Disadvantages are that neither the woman nor the man can be sure that he will be able to withdraw before ejaculating and pre-ejaculatory fluids may contain viable sperm.

Natural Family Planning (Rhythm Method)

The rhythm method (preventing pregnancy by avoiding intercourse during a woman's fertile period) is also called natural family planning (NFP). The fertile period lasts about 4 days following ovulation, when the mature ovum travels through the fallopian tubes to the uterus and can be fertilized. There are three ways to predict the fertile period:

  • The calendar method requires the woman to observe and take note of the length of her menstrual cycle for 6 to 12 months. She can estimate the first and last days of the fertile period by subtracting 18 from the length of the shortest cycle and 11 from the length of the longest cycle. If the shortest cycle is 28 days and her longest cycle is 32 days, the first and last days of the fertile period should be days 10 and 21. The first day of bleeding is considered day 1. So, in this example, the woman should abstain from sexual intercourse for 12 days, starting on the 10th day after the beginning of her menstrual cycle. The failure rate for this method is 40 percent (40 out of 100 women become pregnant).
  • The cervical mucus method, also known as the ovulation or Billing method, is an attempt to predict the fertile period by feeling and observing the cervical mucus in the vagina. Women using this method note the production of clear, watery mucus in the days immediately before ovulation. To avoid pregnancy, intercourse is avoided for several days following change in the color and consistency of cervical mucus.
  • The symptothermal method uses a combination of the calendar and cervical mucus methods and the woman's basal body temperature (BBT) to estimate the beginning and end of the fertile period. The first day is estimated by subracting 21 from the shortest menstrual cycle (the calendar method) or noting the first day of cervical mucus associated with ovulation (the cervical mucus method), whichever comes first. BBT is used to predict the end of the fertile period. The woman takes her temperature every morning and notes when body temperature rises, indicating that the corpus luteum is producing progesterone and ovulation has occurred. She can resume sexual intercourse 3 days after this so-called thermal shift. Devices that combine an electronic thermometer with a small computer are being tested in an effort to improve the accuracy of BBT as a predictor of the fertile phase.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 31 Oct 2000

Last Modified: 08 Sep 2015