Planning Pregnancy

The majority of couples conceive easily - it simply takes time and opportunities for sex. The optimum age for conception (biologically) is between 25 and 35 years. Many women have unrealistic expectations about a normal time to pregnancy and may feel pressures in view of their age. The National Institute for Health and Care Excellence (NICE) guidelines suggest that "People who are concerned about their fertility should be informed that over 80% of couples in the general population will conceive within one year if the woman is aged under 40 and they do not use contraception and have regular intercourse (every 2-3 days). Of those who do not conceive in the first year, about half will do so in the second year - that means that 90% of couples will conceive within two years. 

Preconception health and lifestyle

Women who are planning pregnancy should discuss their preconception health with their fertility awareness practitioner, GP or practice nurse. This provides an opportunity to discuss any lifestyle factors including alcohol, smoking, weight, diet and exercise, all of which can adversely affect fertility. All women should start taking 400 mcg of folic acid three months before conception (and for the first three months of pregnancy). Folic acid reduces the incidence of neural tube defects such as spina bifida. Some women may require a higher dose of folic acid.  The medical consultant may want to test vitamin D levels and advise on supplementation with vitamin D or a multivitamin supplement. A preconception consultation should also include a blood test to confirm immunity to rubella. Infection with rubella in early pregnancy has serious consequences for the unborn baby. For more information on preconception care see the NHS choices web site 

Free Digital Tool: What you need to know when planning pregnancy

Tommy’s (baby charity) have recently developed a free digital tool, in partnership with authorities including the Royal College of Obstetricians and Gynaecologists, to provide all the information you need when planning pregnancy. Try the free Planning for Pregnancy tool here

Optimising intercourse timing

NICE guidelines on the frequency and timing of intercourse recommend: "People who are concerned about their fertility should be informed that vaginal sexual intercourse every 2-3 days optimises the chance of pregnancy" (NICE 2013) This ensures that intercourse occurs frequently across the full width of the fertile time. Frequent intercourse optimises the genetic quality of sperm. This intercourse frequency may work well for some couples, but it may not be practical for others, for example where one partner has to travel for work. An understanding of fertility awareness can help to optimise intercourse timing. It may also help to identify factors which contribute to fertility delays. The diagnostic value of a fertility chart is discussed in The Complete Guide to Fertility Awareness 

Cervical secretions: the best prospective marker

The Fertility Awareness section of this site provides an overview of the menstrual cycle and the indicators of fertility - temperature, secretions, cervical changes and calculations. The following information assumes knowledge of that section.

To achieve pregnancy, the best prospective marker for timing intercourse is the cervical secretions. Figure 1 shows the effect of the ovarian hormones estrogen and progesterone on the cervical secretions demonstrating the limited number of days when secretions allow sperm penetration. For a large part of the menstrual cycle a thick mesh-type secretion  prevents sperm penetration. At the fertile time the mucin molecules are arranged like parallel swimming lanes encouraging sperm penetration through the cervical canal. The appearance of the secretions changes during the menstrual cycle from sticky white to wetter, transparent and stretchy (highly fertile secretions). The last day of this highly fertile secretion is peak day. The day after peak the secretions change back to stickiness or to dryness again. The fertile time starts as soon as there is a possibility of sperm survival - this is shown by the first sign of secretions. The fertile time ends when the egg is no longer fertilisable - that is about three days after peak day. 

Figure 1 Changes in cervical secretions demonstrating the fertile time when secretions allow sperm penetration

Copyright © Cecilia Pyper and Jane Knight in collaboration with FertilityUK and the Institute for Reproductive Health, Georgetown University 2016.

Copyright © Cecilia Pyper and Jane Knight in collaboration with FertilityUK and the Institute for Reproductive Health, Georgetown University 2016.

Cervical secretions can be recognised by their sensation, appearance and testing with the finger-tip (figure 2):

Figure 2: Characteristics of cervical secretions

Copyright © 2016 Jane Knight in collaboration with FertilityUK. Adapted from clubb & Knight, Fertiility, David & charles 1986.

Copyright © 2016 Jane Knight in collaboration with FertilityUK. Adapted from clubb & Knight, Fertiility, David & charles 1986.


Sensation: Sensation is important and often the most difficult to learn. Throughout the day the presence or absence of secretions is recognised by the sensation at the vulva (the vaginal opening), the way the beginning of a period is noticed. The sensation may be a distinct feeling of dryness, of dampness or moistness, stickiness, wetness, slipperiness or lubrication.

Appearance: Soft white toilet tissue is used to blot or wipe the vulva. There may be dampness only on the tissue resulting from vaginal moistness. This moistness soaks into the tissue and any cervical secretions appear raised as a blob on the tissue. The colour is noted. It may be white, creamy, opaque, or transparent (clear). Secretions observed on underclothing may have dried slightly causing some alteration in characteristics.

 Finger Testing: A finger-tip lightly applied to the secretion on the tissue and then gently pulled away tests its capacity to stretch. It may feel sticky and break easily, or it may feel smoother and slippery like raw egg white and stretch between the thumb and first finger, from a little up to several inches before it breaks. This stretchiness is known as the spinnbarkeit effect, and shows that the secretions are highly fertile.



The changes in cervical secretions are observed at intervals throughout the day and marked on the chart in the evening. Women who are planning pregnancy do not need to chart their observations, but some women like to keep a record. A series of simple charts can be recorded on one sheet. This helps to confirm a normal pattern of secretions and ensure that intercourse occurs across the entire fertile time. A series of blank charts with instructions for use can be accessed from the download area. 

Intercourse on any day of secretions could result in pregnancy. The days when the secretions are wet, slippery, transparent and stretchy carry a high chance of pregnancy with the highest chance on peak day and a very high chance the day before peak which usually coincides with the day of the most profuse secretions.

Variability in cycle length and its impact on trying to conceive

The timing of the cervical secretions will vary dependent on the length of the menstrual cycle. A very broad estimate of the likely fertile time can be made by looking back at the length of the last 12 menstrual cycles. Identify the longest and shortest cycle then use the calculations Shortest cycle (S) minus 20 = first fertile day; and Longest cycle (L) minus 10 = last fertile day. The illustration below (figure 3) shows a chart from a woman who is planning pregnancy. Her last 12 cycles have varied from 25-30 days. Using the calculations S minus 20 and L minus 10 this gives the broadest estimate of the fertile time from days 5 to 20 inclusive — so in a cycle as short as 25 days it would be possible to conceive from intercourse as early as day 5; whereas with a cycle as long as 35 days it would be possible to conceive from intercourse as late as day 20 (note the dotted vertical lines indicating the broadest target based on these calendar calculations).

In figure 3 the first five days are marked as period, then two days of dryness. Days 8, 9 and 10 are recorded as a moist sensation with white/cloudy, sticky secretions. Days 11, 12 and 13 are recorded as wet days with slippery, transparent, stretchy secretions — the highly fertile days. Day 13 is marked as peak day, recognised retrospectively the following day by a change back to sticky secretions on day 14. This is followed by dryness until the next period. The horizontal arrow shows the more precise fertile time from days 8 to 16 inclusive (from the first sign of any secretions until three days after peak). This couple are having frequent intercourse and have specifically targeted the days when the cervical secretions show the most fertile characteristics - they are optimising their chances of pregnancy. 

Figure 3: Planning pregnancy chart

What about taking temperatures when trying to conceive?

Waking temperature is of limited value for women trying to conceive. It does not give any useful information about intercourse timing, because the temperature does not go up to the higher level until after ovulation. However, recording waking temperatures for a few cycles may help to confirm the occurrence of ovulation and the length of the luteal phase. If conception occurs, there will be no period at the expected time and the temperature will remain at the higher level. Some women notice a second rise in temperature to an even higher level about a week after the ovulation rise (with temperatures often reaching around 37 degrees centigrade). A sustained high temperature for 20 days or more suggests pregnancy has occurred - a pregnancy test would confirm this.  Temperature-taking should not be allowed to intrude on the relationship. 

Ovulation predictor kits

Ovulation predictor kits do just as their name implies - they predict that ovulation is likely to occur (by detecting the surge in luteinising hormone). Some kits only identify two days of maximum fertility whilst others typically identify four days (using estrogen metabolites as well as LH).  These kits (and monitors) may be of value if women are unable to distinguish their cervical secretions, but they are costly and can place added pressure on a relationship.

Proof of ovulation

The changes in cervical secretions with an awareness of highly fertile secretions (wetter, slippery, stretchy secretions) is an encouraging sign reflecting the growing follicles and higher levels of estrogen, but these secretions do not prove the occurrence of ovulation. Similarly hormone monitoring and a rise in temperature only provide presumptive evidence. Ultrasound scans which monitor the growth of follicles and observe the corpus luteum provide strong evidence of ovulation, but the only definitive proof of ovulation is pregnancy. 

When to seek further help

A couple who have not conceived after six months of frequent "fertility-focussed" intercourse should seek medical advice with a view to referral for further investigations. Although it may take longer for women over 35 to conceive, investigations (on both partners) should normally be started after six months. NICE guidelines provide information on the diagnosis and management of fertility problems and the criteria for access to assisted fertility treatments such as IVF.