How long should it take to get pregnant?
Some couples are content to stop their contraception and just see what happens, no matter how long it takes; others find themselves in a monthly cycle of expectation and disappointment. Most GP’s won’t start fertility investigations or refer to a specialist until after 12 months of trying. The reason for this can be understood when we look at how efficient normal fertility actually is.
Normal conception rates
Even for a healthy, normally fertile couple, the 'per month' success rate is around 15-20%, so it is not at all uncommon for it to take some months to conceive. Overall, around 70% of couples will have conceived by 6 months, 85% by 12 months and 95% will be pregnant after 2 years of trying.
Although the normal 'per month' rate is around 20%, as you might expect for couples where there actually is a problem, the pregnancy rate is lower. When you are thinking about fertility treatments, it is useful to consider the overall background rate of pregnancy after any given period of trying, particularly to make sense of success claims of any treatment. Studies have looked at the ongoing success rates after many years and the results are summarised below:
Number of months trying |
Overall % of couples |
Monthly success rate (%) |
Proportion (%) who |
0 |
100 |
20 |
86 |
6 |
30 |
14 |
77 |
12 |
14 |
11 |
69 |
24 |
4.3 |
8 |
57 |
36 |
1.9 |
6 |
48 |
48 |
1 |
5 |
41 |
60 |
0.6 |
4 |
36 |
As you can see, 'infertility' is really the wrong term to use, because this implies that there is no chance of getting pregnant. For most couples who are referred for further investigations, it would be best described as 'subfertility', meaning reduced fertility, as there is usually a background pregnancy rate with no treatment at all - it's just taking longer than they would wish. Of course couples will want to exclude an insurmountable problem, or one which will definitely require some form of treatment to succeed.
Causes of infertility
For conception to occur, adequate numbers of actively swimming (motile) sperms need to enter the cervix, work their way up the uterus and into the fallopian tubes. At the same time, an egg must be released from the ovary and be able to make its way down the tube to meet the sperm. The egg and sperm combine at fertilisation and the dividing egg makes its way back down to the uterus to implant into the thickened lining of the womb. Any problem along the way may result in problems falling pregnant.
The causes of infertility can be considered as follows:
Ovulation problems 10-15%
Tubal blockage or endometriosis 30-40%
Male (sperm) problems 30-40%
Unexplained 15-20%
These rates are variable for any given population, and are only a guide. Each of these factors is given consideration, in the discussion before, during the examination and in the investigations subsequently arranged.