How long does it take to get pregnant? For most couples, less than a year. NICE's fertility guideline, NG257, says over 80% of heterosexual couples in the general population, where the woman is under 40, will conceive within 1 year of regular unprotected vaginal sex, and over 90% within 2 years.
The NHS puts it plainly: "More than 8 out of 10 couples, where the woman is under 40, will conceive naturally within a year if they have regular unprotected sex (every 2 or 3 days)."
To be honest, that is where most pages stop. This is the data page: by month, by age, and with insemination, which is the section to use if that is how you are conceiving. The human side lives in our story of starting out trying to conceive.
How Long Does It Take to Get Pregnant on Average? (The Headline Numbers)
Over 80% of heterosexual couples in the general population conceive within 1 year and over 90% within 2 years, where the woman is under 40 and they are having regular unprotected vaginal sex. That is recommendation 1.4.1 of NICE guideline NG257.
The second year matters more than most people expect. NICE's own wording: "Of those who do not conceive in the first year, about half will do so in the second year (cumulative pregnancy rate over 90%)."
One bit of housekeeping: NG257 was published on 31 March 2026 and updated and replaced the older NICE guideline, CG156, which a lot of pages still cite. The figures for conceiving through sex did not change, but the recommendation numbers did, and the insemination figures were updated: CG156 said over 50% of women under 40 would conceive within 6 cycles of IUI and over 75% within 12, where NG257 gives 47% to 57% and 72% to 81%, depending on age.
What Are the Chances of Getting Pregnant Each Month? (The Month by Month Table)
Your chance is highest in the first few cycles, at roughly 30% to 38% per cycle when sex is well timed, and it falls after that. In a US study of 200 couples (Zinaman, Fertility and Sterility, 1996), the rate peaked at approximately 30% per cycle in the first two cycles and then tapered, with 82% conceiving over 12 cycles.
The most detailed month by month figures come from a German study of 340 women (Gnoth, Human Reproduction, 2003) who used natural family planning methods to time sex, followed from their very first cycle. It found 38% had conceived after 1 cycle, 68% after 3, 81% after 6 and 92% after 12.
Those couples were timing sex well, so I would treat that as the upper end rather than the average. In the table, "cycle" means one menstrual cycle, which the studies treat as roughly one month.
| Time trying | Cumulative chance of pregnancy | Who and how it was measured | Source |
|---|---|---|---|
| 1 cycle | 38% | 340 German women timing sex with fertility awareness | Gnoth 2003 |
| 1 cycle | About 30% (maximal per-cycle rate) | 200 US couples, sex centred on predicted ovulation | Zinaman 1996 |
| 3 cycles | 68% | same German cohort | Gnoth 2003 |
| 6 cycles | 81% | same German cohort | Gnoth 2003 |
| 6 cycles | 56% to 62% (ages 21 to 36) | 2,962 North American couples, no timing instruction | Wesselink 2017 |
| 12 cycles or 1 year | Over 80% (heterosexual couples, woman under 40, regular unprotected vaginal sex) | NICE recommendation to clinicians | NICE NG257 rec 1.4.1 |
| 12 cycles | 92% | same German cohort | Gnoth 2003 |
| 24 cycles or 2 years | Over 90% | NICE | NICE NG257 rec 1.4.1 |
Table: cumulative chance of conceiving by time spent trying. Sources: Gnoth 2003, Zinaman 1996, Wesselink 2017 and NICE guideline NG257 (2026). The studies measured different couples in different ways, which is why the figures differ.
The chance is not a steady 25% every month. The most fertile couples conceive first and leave the pool, so the average among everyone still trying drops, which is why the German figures reach 81% by cycle 6 and then only 92% by cycle 12.
The UK figures point the same way. In 8,515 planned pregnancies in the Bristol area (Ford, Human Reproduction, 2000), 74% were conceived in 6 months or less, 14% in the second 6 months and 12% after more than a year. That study only counted women who did become pregnant.
NICE recommends sex every 2 to 3 days, and our guide to the best time to get pregnant covers the fertile window.
👉 If you are in month four or five and nothing has happened yet, you are still well inside the normal range.
How Does Age Change How Long It Takes to Get Pregnant? (The By Age Table)
The chance of conceiving within a year goes from 92% at ages 19 to 26 down to 82% at ages 35 to 39, according to the age table NICE prints in guideline NG257. That table comes from a European model built on 782 couples (Dunson, Baird and Colombo, Obstetrics and Gynecology, 2004). It assumes sex twice a week and only covers women aged 19 to 39. The drop before 40 is smaller than most people assume: given two years, the same table shows 98% at 19 to 26 and still 90% at 35 to 39.
For detail from 30 onwards, NICE bases its own figure on age on Steiner and Jukic (Fertility and Sterility, 2016): 960 US women aged 30 to 44 with no known fertility problems. In that study, 87% of women aged 30 to 31 were pregnant within 12 cycles, against 76% at 36 to 37 and 71% at 38 to 39. The median time to pregnancy was 3 months for women under 38.
| Female age | Pregnant within 12 cycles (1 year) | Pregnant within 24 cycles (2 years) |
|---|---|---|
| 19 to 26 | 92% | 98% |
| 27 to 29 | 87% | 95% |
| 30 to 34 | 86% | 94% |
| 35 to 39 | 82% | 90% |
Table: Dunson, Baird and Colombo 2004, as reproduced in NICE guideline NG257 (2026), Table 1.
| Female age | Per-cycle chance | Pregnant within 6 cycles | Pregnant within 12 cycles |
|---|---|---|---|
| 30 to 31 | 19.5% average | 77% | 87% |
| 32 to 33 | 20.9% | 76% | 88% |
| 34 to 35 | 16.2% | 71% | 82% |
| 36 to 37 | 14.5% | 69% | 76% |
| 38 to 39 | 13.2% | 62% | 71% |
| 40 to 41 (only 37 women) | 8.6% | 47% | 54% |
| 42 to 44 (only 14 women) | 6.6% | 29% | 48% (95% CI 24% to 80%) |
Table: Steiner and Jukic 2016, Table 2. The study reports no figures beyond 12 cycles.
What about getting pregnant at 40 and over?
Roughly half of women conceive within a year at 40 to 41, with wide uncertainty, because every study has small numbers at this age. Steiner and Jukic found 54% pregnant within 12 cycles at 40 to 41 and 48% at 42 to 44, with a median time to pregnancy of 8 months at 40 to 41. NICE's own age table stops at 39, and this is the age where waiting a year before asking for help is the wrong plan.
The man's age matters too, but less: NICE's summary (recommendation 1.4.3) is that female fertility and, to a lesser extent, male fertility decline with age.
If you would rather hear the studies talked through, Dr Lora Shahine, a double board-certified OB-GYN and reproductive endocrinologist, walks through the same North American and Steiner and Jukic figures in this video, including why the first few cycles count for so much. She practises in the US, so her closing advice on when to get checked is her own view rather than UK guidance. The UK thresholds are in the GP section below.
How Long Does It Take With Insemination or Donor Sperm? (The Figures Most Pages Skip)
With intrauterine insemination (IUI), NICE expects 47% to 57% of women under 40 to conceive within 6 cycles, depending on age, and about half of the rest to conceive with a further 6 cycles, which takes the cumulative figure to 72% to 81%. That is recommendation 1.4.2 of NICE NG257, based on HFEA donor insemination data from 1991 to 2023.
Most pages assume regular unprotected sex, and plenty of people are not conceiving that way. The NHS page on trying to get pregnant now says that if you are 39 or under and using artificial insemination where sperm is put directly in the womb, it may take 6 to 12 rounds of treatment.
NICE's table also covers intracervical insemination (ICI), where sperm is placed at the cervix. With fresh semen it gives 58% pregnant at 6 cycles and 76% at 12 for women under 31, falling to 39% and 55% for women over 35.
| Maternal age | 6 cycles | 12 cycles | Method and data |
|---|---|---|---|
| Under 30 | 50% | 70% | ICI, thawed semen |
| 30 to 34 | 43% | 62% | same |
| Over 34 | 33% | 54% | same |
| Under 31 | 58% | 76% | ICI, fresh semen |
| 31 to 35 | 50% | 71% | same |
| Over 35 | 39% | 55% | same |
| 18 to 34 | 57% | 81% | IUI with donor sperm, theoretical cumulative rate from HFEA data 1991 to 2023 |
| 35 to 37 | 54% | 78% | same |
| 38 to 39 | 47% | 72% | same |
| 40 to 42 | 31% | 52% | same |
Table: cumulative chance of pregnancy with insemination. Source: NICE guideline NG257 (2026), Table 2, figures exactly as NICE prints them. NICE's table continues with lower IUI figures for ages 43 and over.
- The IUI rows are donor insemination data, and NICE notes that pregnancy rates for IUI in health-related fertility problems may be lower. They include both unstimulated and stimulated IUI, the 2020 to 2023 data is preliminary, and the percentages are life table estimates.
- The ICI rows come from clinic donor insemination in France and the Netherlands in the 1970s and 1980s, in women who had never had a baby and whose husbands had no sperm in their semen. They are the closest published figures to home insemination, but they are not home insemination data.
NICE's threshold for asking for help is 6 cycles of insemination, not a year.
One of our real stories is about exactly this: two mums, third try.
When Should You See a GP? (The UK Rules, Not the American Ones)
See a GP after 1 year of trying, after 6 cycles of insemination, or straight away if you are 36 or over or either of you has a known or suspected cause of infertility. Those thresholds come from recommendations 1.16.2 to 1.16.8 of NICE NG257, and the NHS gives the same advice: a year, or sooner for women aged 36 and over and anyone who already knows they may have fertility problems.
| Your situation | When to ask for help | Source |
|---|---|---|
| Trying through sex, woman under 36, no known cause | After 1 year, both partners assessed | NICE NG257 rec 1.16.5 |
| Using artificial insemination, with partner or donor sperm | After 6 cycles of insemination | NICE NG257 rec 1.16.6 |
| Woman aged 36 or over, or a known or suspected cause in either partner | Straight away (referral at presentation) | NICE NG257 rec 1.16.8 |
| Unable to have vaginal intercourse, or would find it very difficult | At the outset, for a consultation about conception options | NICE NG257 rec 1.16.2 |
| A miscarriage or ectopic pregnancy while you are counting | The clock does not restart | NICE NG257 rec 1.16.7 |
Table: when to seek help in the UK. Source: NICE guideline NG257 (2026), recommendations 1.16.2 to 1.16.8.
The rule you often read, 6 months once you are 35 or over, is American: ASRM recommends evaluation at 6 months when the female partner is 35 years of age or older. In the UK the age is 36, and NICE says to offer referral at presentation.
The miscarriage rule is new in the 2026 guideline: if you have a miscarriage or an ectopic pregnancy along the way, NICE says to continue following the timeframe and not to restart it afterwards.
NICE's list of suspected or known causes, any one of which means you should not wait:
- Periods, pelvis and past surgery: irregular or absent periods, significant pelvic pain, a gynaecological condition such as endometriosis or chronic pelvic inflammatory disease, or a history of ectopic pregnancy, recurrent ovarian cystectomies or multiple abdominopelvic surgeries.
- Testicles and ejaculation: a history of undescended testes, testicular cancer, inguinal or scrotal surgery with an atrophic testicle, a clinically significant varicocele, orchitis (including mumps orchitis after puberty), or any condition with loss of ejaculation.
- Cancer treatment: a history of chemotherapy or pelvic radiotherapy. If treatment that may affect fertility is planned, NICE says referral should be expedited.
The NHS also says to speak to a GP before you start trying if either of you lives with a condition such as epilepsy, diabetes, sickle cell disease or HIV, takes any medicine or herbal remedies, has a fertility issue such as endometriosis or low sperm count, or cannot have sex or finds it difficult. Do not stop taking any prescribed medicine until you have talked to your GP or specialist.
Go together if you can, because NICE says both partners should be assessed. For the male side, see whether you should get a semen analysis.
Try It: Where Are You on the Curve? (A Quick Tool)
This puts the tables above together for your own situation. It only shows figures that have actually been published, so where NICE gives no figure it says so, and it quotes the NICE wording on when to ask for help.
Where Am I on the Curve?
Pick how you are trying, your age band and how long it has been. You get the published figures from the tables in this guide and the point where NICE says to ask for help. It is a number on a population curve, not a prediction for you, and it is not a diagnosis.
4 months
Choose your answers above to see the published figures. If the tool does not load, every number it uses is in the tables in this guide.
What If It Has Been More Than a Year? (Many Couples Still Conceive)
Many couples who have not conceived after a year still go on to conceive without treatment: between 43% and 63% of them in the following 12 cycles, depending on age, according to Dunson, Baird and Colombo (2004). The same study estimated true sterility at about 1% at every age it covered.
That is why, for people with unexplained infertility, NICE advises trying for a total of 2 years before treatment (recommendation 1.38.1).
None of this is a reason to delay the GP appointment, because the odds do fall with time. The NHS says that for couples who have been trying for more than 3 years, the chance of conceiving naturally within the next year is 1 in 4, or less.
You are also far from alone: the NHS says around 1 in 7 couples may have difficulty conceiving. We have a separate piece on trying to conceive for years.
Frequently Asked Questions
How long does it take to get pregnant your first time?
There is no separate NHS or NICE figure for a first pregnancy, so the general figure applies: over 80% of heterosexual couples where the woman is under 40, within a year. First-timers may be a little slower. In Steiner and Jukic (2016), the 12-cycle pregnancy rate at age 30 to 31 was 83% for women never previously pregnant against 92% for women with a previous pregnancy. Part of that is selection: the second group has already shown it can conceive.
Can I get pregnant after 1 week?
Yes, if that week includes your fertile window. In Wilcox's 1995 study, conception only happened when sex took place in the six days ending on the day of ovulation. What you cannot do is confirm it within a week. Implantation happens 6 to 12 days after ovulation (Wilcox, 1999), and the NHS says the pregnancy hormone hCG only starts to be produced around 6 days after fertilisation.
Can I tell I'm pregnant after 1 day?
No. One day after sex or insemination there is nothing to detect, and fertilisation may not have happened yet, because the NHS says sperm can survive in the fallopian tubes for up to 7 days. Pregnancy tests detect hCG, and the NHS says most tests work from the first day of a missed period. Our guide on when to take a pregnancy test after ovulation has the full timeline.
How fast does pregnancy develop?
Sex or insemination in the six days up to ovulation, then fertilisation, then implantation 6 to 12 days after ovulation, which was day 8, 9 or 10 for 84% of ongoing pregnancies in Wilcox's 1999 study. Pregnancy is dated from the first day of your last period, not from conception, so the count of weeks runs ahead. By week 4 on the NHS week by week guide, the embryo is about 2mm long, roughly the size of a poppy seed.
What the Tables Can't Tell You (The Human Bit)
A chart can say 81% by cycle six. It can't say what it feels like when the test is negative again. The odds stay on your side for longer than it feels like they do, and it is still hard while you wait.
So look after each other, and if you reach one of the thresholds above, book the appointment. It isn't about giving up. It's about taking the next step.
Keep Reading: Helpful TTC Guides
These go deeper on the parts of the journey around the numbers:
- The best time to get pregnant
- When to take a pregnancy test after ovulation
- Should you get a semen analysis?
- Trying to conceive for years
- Real story: two mums, third try
