I love simplicity – especially when it comes to using fertility awareness as contraception - but sometimes things can be made too simple.
For example, some will say that the risk of pregnancy at the beginning of the menstrual cycle is the same as the risk at the end of your cycle.
It's safer to think of the early days (which start with day one of your period) as low fertility or relatively infertile, at least while you're learning.
John Guillebaud (contraception guru) says to think of the early days as "amber" and only the late postovulatory days as "green for go".
So if you're using fertility awareness as contraception, each menstrual cycle starts with amber days, moves on to red days and ends with green days.
The main reason for caution during those amber early days is that it can be hard to predict exactly when the red (fertile) days are going to start.
There are things you can do, but it's basically educated guesswork based on your cycle history, evidence about sperm survival*, and whether or not you can identify the first traces of fertile cervical fluid.
The benefits of hindsight
In contrast, it's much easier to tell when your fertile time has passed for that cycle - when your red "danger zone" days are over and you're in the "green for go" days and so safe to have unprotected sex**.
The main signs that your fertile time is over for this cycle are waking temperature and cervical (vaginal) fluid.
Your waking temperature rises after your fertile time is over for that cycle and stays high until your period starts. This is a nice established biological fact which is down to the rise in progesterone levels after ovulation. It takes a bit of learning but it isn't rocket science.
Your cervical fluid becomes plentiful and like raw egg white for a few days per cycle around the time you are most fertile, and then changes to sticky or dry once your fertile time is over. The most fertile cervical fluid is much easier to notice than the more scarce potentially fertile cervical fluid.
It's safest to check both waking temperature and cervical fluid – and then to wait a few days to make sure that you’re safe.
If you're not sure about checking cervical fluid you could use ovulation tests (pee sticks) to double-check your signs, at least to start with.
That sounds like lots of hassle, can’t I just guess?
Some will simply guess that their period is due in the next few days and assume that they’re safe to have unprotected sex. If they're tracking their cycles accurately and have regular periods they might be fine, but it's not the safest option.
The problem with just relying on the calendar is that you might have a random long cycle and so be having unprotected sex during your fertile time. Or you might be too cautious, or have a random short cycle, and end up with only a few safe days per cycle, which isn't great either.
The best option is to do a bit of learning, take your temperature and check your cervical fluid – neither of which has to be a major hassle.
OK, so if I check my signs how many safe days can I expect per cycle?
The number of safe days will usually be somewhere between 7 and 12 days – so long as your fertility signs are clear. Sometimes you might get an unclear cycle with no safe days – one where the signs are too hard to read or you’ve not ovulated. That means no safe days at all.
Sounds harsh, doesn’t it.
It doesn’t have to be so bad. All that means is no sex without a condom, or at least no sexual activity that could get you pregnant. Some couples welcome the variety, and not taking hormones can have a positive effect on a woman's libido...
If that isn’t for you and your partner then fair enough, but you’re going to need another method of contraception – or patience and support while you work out which early days are safe.
What else can I do to reduce the risk of pregnancy?
Most sexual health experts, and most fertility apps, recommend that you get support before relying on fertility awareness as contraception.
You can get this from the NHS and from independents like me, or you can learn on your own.
Probably the most important thing is to be honest with yourself and your partner about your contraception.
Much as I love fertility awareness, I don’t want anyone to feel like it is their only option. You might become a massive fan who would never dream of using anything else, or you might find that it works for a few years but then you fancy a change. Your body, your choice.
More information and support
- Getting specialist support from me and from the NHS
- Fpa (sexual health charity) leaflet - great summary of fertility awareness/natural family planning
- Toni Weschler. Taking Charge of Your Fertility. Long but very readable book about fertility awareness
* NICE Fertility Guidance says that sperm can survive for up to 7 days in the vagina. Most will be dead after 2-3 days but it only takes one...
** So long as you're not at risk of a sexually transmitted infection.