People who want a baby and struggle to conceive often resort to in vitro fertilisation (IVF). While IVF has helped countless people have children, it’s expensive and comes with some risks.
But research shows some people with so-called “unexplained infertility” have a 30-40% chance of conceiving without treatment if they just keep trying for a bit longer.
So, how long should you wait before starting fertility treatment? This depends on a range of factors that might increase or decrease your chance of conceiving naturally, as well as your personal preferences for seeking treatment or not.
A new online guide can estimate your chance of conceiving with and without treatment. The free tool collects information based on what we understand to be the main factors affecting a woman’s chance of falling pregnant, with a view to informing decisions around fertility treatment.
Sometimes there’s no clear explanation
It’s recommended women who have tried unsuccessfully for a baby for 12 months, or six months if they’re over 35, seek medical advice. This is so the doctor can arrange for tests to determine whether there’s a reason for infertility.
If these tests show the woman’s fallopian tubes are blocked, or that the male partner has a very low sperm count, it’s best to go straight to IVF. In most cases, that’s the only way the couple will be able to get pregnant.
If your doctor finds no obvious problem, you have what’s called “unexplained” or “idiopathic” infertility.Shutterstock
Weighing up your options
It can be very frustrating to be told there’s nothing wrong, when month after month goes by without pregnancy happening.
If your tests come back normal, it might be worth considering giving nature a bit more time, or trying a simpler form of infertility treatment, such as intrauterine insemination (IUI). IUI involves insertion of the male partner’s (or a donor’s) sperm into a woman’s uterus at or just before ovulation.
So which path is right for you? This is where the new online guide can help.
It’s built on evidence
Research tracking thousands of people with unexplained infertility has found many go on to have healthy babies naturally, or with the help of simple fertility treatment. In one study of more than 1,200 couples with unexplained infertility, 25% conceived naturally within 12 months.
Of course, for some women conception will be more likely, and for some women it will be less likely.
Experts used the data from this research to develop the online guide. The personalised calculations are based on four factors that evidence indicates are most likely to affect the chance of pregnancy.
The most important factor that affects a woman’s chance of having a baby — naturally or with IVF — is her age. So what’s labelled unexplained infertility may in fact be age-related. While pregnancy can still happen, by age 40 a woman’s fertility is about half the level it was when she was 30.
Other factors include how long she has been trying for a baby (the likelihood of conception decreases with the duration of trying), whether she’s been pregnant before (women who have never conceived before have a lower probability of achieving a pregnancy), and what proportion of the male partner’s sperm move normally (called “progressive motility” on a semen analysis report).
How does it work?
The guide is designed for heterosexual couples and for women who are trying to get pregnant with a known sperm donor, where:
the woman has regular menstrual cycles
the woman has at least one open fallopian tube
the woman is 42 or younger
the man has had a sperm test.
Four questions ask about the four factors most likely to affect a woman’s chance of conception, described above.
The responses are then fed into the algorithm, which estimates the chance of pregnancy over the next 12 months in three different scenarios:
This information can help people consider their options and decide about next steps.
If your estimated chance of spontaneous pregnancy in the next 12 months is 30% or more, you have a good chance of avoiding the need for expensive fertility treatments. But if you’re not pregnant after six months, the guide suggests seeking advice from a fertility specialist about the next steps.
If your estimated chance without treatment is less than 30%, it’s best to see a fertility specialist as soon as possible.
A word of caution
While the guide can help you explore your options and consider next steps, the estimates it gives are based on averages of data from large studies of people with unexplained infertility.
This means it shouldn’t replace advice from a fertility specialist, who will hopefully use the available evidence to recommend the best way forward for you, considering your personal circumstances and preferences.
Authors: Karin Hammarberg, Senior Research Fellow, Global and Women's Health, School of Public Health & Preventive Medicine, Monash University