Rhythm Method
As sperm can survive for seven days, there are probably no 'safe' days between cessation of the period and ovulation (4). Fertility awareness (e.g. rhythm methods) has one of the highest failure rates of contraceptive methods (Pearl Index)but there are no side effects and the method is acceptable to some cultures more than others. If ovulation can be predicted accurately, intercourse from two days onwards would theoretically be unlikely to result in conception. Ovulation occurs 14 days before the next period. Calculation of the post ovulation 'safe' period is easier for those women with a regular cycle. Ultrasound has shown that ovulation pain (Mittelschmerz) tends to begin 24 48 hours before ovulation.
The basal temperature can be used as a guide to the timing of ovulation. Following ovulation, progesterone is produced (Fig 2. 3)
And this results in the temperature rising by 0.5 degree centigrade. The temperature should be basal rather than after activity and is generally measured in the morning on waking. If you record your temperature for a couple of months and feel confident that your chart shows clear changes this method may have advantages if you are reluctant to use other methods. From the medical point of view this method is not regarded as being effective.
Assessment of the cervical mucus provides an indication of ovulation but it is not reliable. Progesterone, which is released into the circulation after egg release and though the second half of your menstrual cycle, makes the mucus less profuse and more sticky.
The rhythm or calendar method involves calculation of the shortest and longest cycles over the last twelve cycles. The fertile phase is calculated as 20 days subtracted from the shortest cycle and 11 days from the longest cycle. If the cycle is regularly 28 days the fertile phase would be from Day 8 (28-20) until Day 17 (28-11). If the cycle varies from 21 to 35 days, the fertile phase would be from Day 1 to Day 24. For those with irregular cycles there may be few safe days.
Related Medical Abstracts - Click on the paper title:-
Please click on the required question.
- 1 How important is effective contraception for the world's population?
- 2 How long can my partner's sperm survive in me?
- 3 How long are my eggs capable of fertilisation?
- 4 How long does my fertile phase last?
- 5 What is an ideal contraceptive?
- 6 How can the effectiveness of a contraceptive method be measured?
- 7 Can knowledge of the fertile phase be used for effective contraception?
- 8 I am breast-feeding my baby. Do I need contraception?
- 9 How effective is coitus interruptus?
- 10 How effective are condoms (sheaths)
- 11 What are the advantages and disadvantages of condoms?
- 12 How long have vaginal methods of contraception been available?
- 13 How can I get a diaphragm (cap)
- 14 How can the cap be checked?
- 15 How effective are diaphragms and caps?
- 16 What are the advantages and disadvantages of vaginal methods?
- 17 What is the contraceptive sponge?
- 18 How effective is the contraceptive sponge?
- 19 What is the female condom?
- 20 What are the advantages and disadvantages of female condoms?
- 21 How effective are spermicides?
- 22 What are the advantages and disadvantages of spermicides?
- 23 Which contraceptives are appropriate for an adolescent?
- 24 Which contraceptives are appropriate for a woman in her forties?
- 25 If I am taking the combined oral contraceptive pill or cyclical HRT, how can I tell when I have reached my menopause?
- 26 How effective is the Persona Unipath Personal Contraceptive System?
- 27 Where can I obtain further information about contraception?
- 28 Support Groups.
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This is the personal website of David A Viniker MD FRCOG, Consultant Obstetrician and Gynaecologist at Whipps Cross University Hospital, London - Specialist Interests - Reproductive Medicine including Infertility, PCOS, PMS, Menopause and HRT.
I do hope that you find the answers to your women's health questions in the patient information and medical advice provided.
