Couples trying to have a baby have sex an average of 78 times before they become pregnant, a new study finds.
Typically, it takes a total of 185 days from deciding to conceive to getting a positive pregnancy test - the equivalent of six months and three days.
It has also emerged that couples have sex 13 times a month while trying to have a baby, according to parenting site ChannelMum.com.
The most popular position to conceive is the missionary, which is used by three-quarters of couples.
The second best position for making a baby is doggy style, adopted by 36% of people, and the eagle - where the woman is lying flat while the man kneels down and holds his legs high - came in third.
The study of 1 parents showed that half of couples admitted that they had sex much more often than usual in their attempt to have a baby.
An energetic 10 percent couple is comfortable up to 15-20 times per month, while one in 20 couples struggled almost every day - managing 21 to 25 times.
Another 5 percent said they had sex only once a month, but still managed to get pregnant.
And while more than a third of women and 51% of men said they “liked” having more sex, 18% said sex for the purpose of conceiving became a chore rather than a pleasure.
Another 43 percent felt pressured in case they didn't get pregnant.
The survey found that it's women who take the lead in the bedroom when trying to conceive, with two in five admitting that they've started having sex more frequently and 13% investing in sexy lingerie to get their partner in the mood.
One in 16 women even booked a “baby-making vacation” or a weekend.
Half of the women tried timing sex on fertile days, while 39% improved their diet and took extra vitamins.
But 5% used more unorthodox methods, including periods of fertility and sex prediction calendars.
The study also showed that just under a third of couples got pregnant in the very first month, and a fifth took between one and three years.
Siobhan Freegard, Founder of ChannelMum.com, said, “Far from being an unlucky number, 13 seems like the lucky number couples need each month to get pregnant.
"But while trying to conceive can be fun, it is also hard, stressful work and not all couples have the chance to conceive, so while you are focused on the baby, try to remember one of the other.
We previously revealed the date most couples conceive during the year.
And a couple who spent 17 years trying to start a family recently were thrilled to welcome a brood of sextuplets.
