When are women most fertile?

What's the best time of the month to have sex, if you want to get pregnant?
06 November 2018


Pregnant abdomen



When in their cycle are women most fertile?


Sophie got in touch via Facebook to ask at what point in their cycle are women most fertile. Chris Smith put this question to fertility nurse Laura Carter-Penman from Bourn Hall clinic...

Laura - Well most women average a 28 day cycle. Some ladies have slightly shorter cycles and some have slightly longer cycles, and most ladies ovulate about halfway through that cycle so around about day 14. So from a fertility perspective, we would usually recommend regular sexual intercourse from around about day 10, because sperm lasts five to seven days and an egg will only last one to two days maximum. So ladies are mainly fertile from probably about day 14 of their cycle round to about day 21 of their cycle.

Chris - So it's all to do with ovulation occurring on day 14 but what about if a person doesn't have a regular cycle? Because the data you've given us assumes that a person knows where they are in that cycle. So what happens then?

Laura - So for us we might recommend that you have some scans so you can see what's happening, to see whether the follicle production is going on within your cycle. Patients can try using luteinising hormone sticks, those sort of surge kits as they're called. You can buy them over the counter, pee on a stick and it tells you whether you're ovulating or not. Obviously for ladies then that aren't detecting that, they may need some help with something like Clomiphene - a reproduction of a follicle stimulating hormone that usually occurs naturally but isn't in those ladies.

Chris - That encourages the chemical process of ovulation?

Laura - Yep. And then obviously we would link that again with scanning so that we can see that there is a follicle production as well.

Chris - So roughly what fraction of people do have a regular cycle, and what fraction have irregular cycles?

Laura - So probably one in six ladies have an irregular cycle, so it's quite a high proportion really. I mean we keep focusing again here on sort of, “female factor” but actually 40 percent of problems are male factor problems. 40 percent female, 20 percent sometimes sits between the ‘unknown’ and also is a mixture of two. Quite often it appears that patients are drawn together if they both have an infertility issue.

Chris - Well, they say opposites attract but not in this case! James, you were going to say?

James - Yeah I was just going to wonder, you're talking about kits you can buy over the counter… would you put any stock in the smartphone apps that sort of, suggest your fertility in the cycle?

Laura - Yeah there's lots out there now which help you track your cycle. They would recommend that you track your temperature because there's supposed to be a slight temperature rise when you ovulate. There's now a bit like FitBits and things like that they're now out there for fertility as well. That is a big sort of up and coming burgeoning market within that side of things as well.

Chris - Do people say they find these things useful, or do you think it just helps to focus their mind? They get a plan in place so then they tend to stick to it which means they're more likely to be successful?

Laura - For some patients it's really helpful, it gives them a focus. For others it just absolutely adds to the stress of the situation and we would recommend that they go and seek help from a specialist and see their GP, speak to a fertility nurse. There's lots of things out there to help and actually the apps are useful but I think sometimes for patients who are really struggling it's not the best thing it really adds to their stress.

Chris - Some people use these apps because they don't want to get pregnant. Is that a risky strategy then?

Laura - I would say it's a very risky strategy!


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