When to see a doctor about fertility: 12 months, 6 or sooner

US guidance recommends an evaluation after 12 months, or 6 months from age 35

The American Society for Reproductive Medicine (ASRM) sets the timetable in its 2023 definition of infertility. For people having regular unprotected intercourse with no known cause of reduced fertility in either partner, it says an evaluation should begin at 12 months when the female partner is under 35, and at 6 months when she is 35 or older (ASRM, "Definition of infertility", 2023). The American College of Obstetricians and Gynecologists (ACOG) gives the same intervals, with its threshold worded as older than 35 (ACOG, 2020, reviewed 2026), and the Centers for Disease Control and Prevention (CDC) describes the same practice (CDC, 2024).

Over 40, ACOG recommends an evaluation before trying

For women older than 40, ACOG recommends an evaluation before trying to conceive, or a conversation with an ob-gyn about one straight away (ACOG, 2023; ACOG, 2020, reviewed 2026). The CDC says couples in which the woman is older than 40 should consider more immediate evaluation and treatment (CDC, 2024).

A known cause is a reason for an earlier evaluation at any age

ASRM's patient guidance says an evaluation should begin immediately when there is an obvious medical problem affecting conception, such as absent or irregular periods, sexual dysfunction, a history of pelvic disease or previous surgery (ASRM, "Does my age affect my fertility?", 2023). ACOG gives endometriosis as an example of a condition that makes early evaluation more important (ACOG, 2023), and names polycystic ovary syndrome in the same advice; the guide to PCOS and pregnancy covers it. In the UK, NICE recommends referral at the first appointment when either partner has a known or suspected cause of infertility or a history of factors that predispose to it (NICE, 2026).

UK guidance uses age 36 and refers at the first appointment

The National Institute for Health and Care Excellence (NICE) published a new fertility guideline in March 2026, replacing its 2013 guideline, CG156. It recommends offering both partners assessment and investigation after 1 year of unprotected vaginal intercourse without a pregnancy, where there is no known cause (NICE, 2026). From age 36, it recommends offering referral to a specialist at the first appointment, without a set period of trying first (NICE, 2026). The NHS advises seeing a GP after a year of trying, and sooner for women aged 36 and over (NHS, 2023).

For unexplained infertility, NICE advises trying for a total of 2 years before treatment (NICE, 2026), and the NHS describes infertility as usually diagnosed and treated after 2 years of trying (NHS, 2023).

Under NICE guidance, a miscarriage or ectopic pregnancy does not restart the clock

NICE's 2026 guideline says that a miscarriage or ectopic pregnancy during the year of trying does not restart the timeframe before investigations can begin (NICE, 2026). The US sources cited on this page do not address the point.

People using insemination or donor sperm follow a timetable counted in cycles

ASRM's 2023 definition counts the need for medical help to conceive, including donor sperm, eggs or embryos, as infertility, and states that the definition should not be used to deny or delay treatment on the grounds of relationship status or sexual orientation (ASRM, "Definition of infertility", 2023). NICE recommends offering assessment after 6 cycles of artificial insemination without a pregnancy (NICE, 2026).

The same timetable applies after an earlier pregnancy

Neither ASRM's definition nor NICE's guideline sets a separate timetable for people who have been pregnant before. The guide to secondary infertility covers difficulty conceiving after an earlier pregnancy.

The first appointment is usually with an ob-gyn in the US or a GP in the UK

In the US, ACOG says an ob-gyn usually does the first assessment. The specialist in infertility is a reproductive endocrinologist, an ob-gyn with further training, and men may see a urologist (ACOG, 2020, reviewed 2026). In the UK the first appointment is usually with a GP (NHS, 2023). ACOG lists what a first evaluation commonly includes:

• a medical and sexual history for both partners, including past pregnancies, medicines, and how long and how often they have been having sex
• for men, a semen analysis, and sometimes blood tests of reproductive hormones
• for women, a urine or blood test that shows whether ovulation is occurring, and blood tests of thyroid function, prolactin and ovarian reserve
• imaging such as ultrasound, or hysterosalpingography, an X-ray that shows whether the fallopian tubes are blocked

ACOG notes that most evaluations can be completed within a few menstrual cycles (ACOG, 2020, reviewed 2026). StatPearls, a peer-reviewed clinical reference, gives the reason semen analysis is part of the first assessment: a male factor is involved in about 40 in 100 infertility cases (StatPearls, 2026). The guide to the chances of getting pregnant gives the figures behind the one-year starting point.