How long it takes for the average couple to conceive
There is an African proverb saying to the effect that sex is for pleasure and it's God who decides when to give a child! At the outset, it may sound quite funny, but in reality, it is not. Ask any husband and wife who are declared normal by doctors but have not been able to conceive a child. They will vouch for the truth behind the African proverb.
Where the couple is quite healthy, the woman is less than 35 years old and has normal menstrual cycles and the man is virile, the monthly average chance of getting pregnant is reported to be 20% plus or minus 5%.
In a woman of normal menstrual cycle (28 days), the most conducive time when the ovum is ready and waiting for the arrival of the sperm inside the woman's womb falls between 13th day to 15th day after the previous beginning date of menstrual discharge. Here again take 2 to 3 days plus/ minus in the beginning and the end for the possible advancements or delays in ovulation. For conceiving to take place, a healthy intercourse should take place in this period. The sperm should have enough mobility to navigate into the womb and mate with the ovum within this critical period.
Thus it is obvious that the available days for pregnancy to take place in a menstrual cycle are limited. Inability to have intercourse in this period, possible lack of sperm count (a less number reduces the probability of a live sperm to fight its way through the passage) or sperm mobility to reach up to the ovum, psychological factors like stress and worry, health problems during this time - there could be several such factors that may contribute in preventing fertilization in this short period.
When such is the case for a woman having normal and predictable menstrual cycle, the possibilities get more complicated if the woman has irregular menstrual cycle. The time of ovulation cannot be predicted easily if a woman has a menstrual cycle lasting, say 45 days once, 30 days next time, 22 days another time and so on. Statistically, the probability of getting conceived becomes much narrower in such cases.
Thus statistically, it can be said that about 20% of normal and healthy couples have a chance to succeed in getting the women pregnant in the first month. Based on statistical distribution curves, it can be premised that out of the balance couples, another 50% have every chance to succeed in a 3 months period. In the remaining balance, another half of them may succeed in a 6-month period and so on.
Doctors normally say that where everything else in the couple is normal, up to 1 year can be considered as a "normal" period for pregnancy to take place. Beyond this period, if success is elusive, then a visit to the doctor would be in order.