Secondary infertility: when conceiving again is difficult, causes and options in the UK

Infertility is when a couple cannot get pregnant despite having regular unprotected sex. The NHS describes two types: primary infertility, where someone who has never conceived has difficulty, and secondary infertility, where someone has had 1 or more pregnancies, whether they ended in a birth, a miscarriage or otherwise, but is having difficulty conceiving again.

Having conceived before does not guarantee that it will be easy again. Fertility changes over time with age, health, medical treatment and, where partners differ, with the other person's fertility. People with secondary infertility often feel confused or guilty, particularly if the first pregnancy was easy, but the causes are the same set of factors that affect anyone.

The NHS says that infertility is usually diagnosed and treated only when a couple have not managed to conceive after 2 years of trying through regular unprotected sex, although it advises seeing a GP after 1 year, and sooner in certain circumstances.

The NHS says some people get pregnant quickly but for others it can take longer, and that for couples who have been trying for more than 3 years without success the likelihood of getting pregnant naturally within the next year is 1 in 4 or less. It is a good idea to see a GP if you have not conceived after a year of trying. Women aged 36 and over, and anyone who is already aware they may have fertility problems, should see their GP sooner.

A GP can check for common causes of fertility problems and suggest treatments that could help. Mention any previous problems after childbirth or surgery, pelvic infections, irregular or absent periods, previous treatment such as chemotherapy, and any change of partner.

The NHS says there are many possible causes, that problems can affect either partner, and that in about a quarter of cases no cause can be identified. The common causes include lack of regular ovulation, poor quality semen, blocked or damaged fallopian tubes and endometriosis.

The NHS lists factors that affect fertility, several of which can change over the years between a first pregnancy and the next attempt: age, since fertility declines with age; weight, since being overweight or obese reduces fertility and being severely underweight can affect ovulation; sexually transmitted infections such as chlamydia; smoking, including passive smoking; alcohol; exposure to certain pesticides, solvents and metals, particularly in men; and stress.

The NHS notes that the chief medical officers recommend adults drink no more than 14 units of alcohol a week, and that the safest approach during pregnancy is not to drink alcohol at all. Surgery between pregnancies, new medicines and new health conditions are further reasons why circumstances may differ.

A GP will usually ask about your history and may arrange initial tests, for example blood tests and a semen analysis for a male partner, before referral to a fertility clinic.

Further investigations in specialist clinics may include assessment of the fallopian tubes and womb. For unexplained infertility, the NHS says NICE recommends that women who have not conceived after 2 years of regular unprotected sex should be offered IVF treatment.

The NHS says treatment offered will depend on what is causing the problem and what is available from your local integrated care board (ICB). Options include medical treatment for lack of regular ovulation, surgical procedures such as treatment for endometriosis, repair of the fallopian tubes or removal of scarring within the womb or abdomen, and assisted conception such as intrauterine insemination (IUI) or IVF.

The NHS warns that some treatments such as IVF can cause complications. Placing more than one embryo increases the chance of twins, which significantly increases the risk of complications for you and your babies, and the risk of ectopic pregnancy is slightly increased with IVF. Lifestyle steps, such as stopping smoking, reaching a healthy weight and limiting alcohol, are advised alongside treatment.

The NHS says the treatment offered depends on what is causing the problem and what is available from your local integrated care board (ICB), so access to NHS fertility treatment varies by area. Ask your GP what applies where you live.

The NHS says private treatment is also available, but it can be expensive and there is no guarantee it will be successful, so it is important to choose a private clinic carefully. You can ask a GP for advice and should make sure you choose a clinic licensed by the Human Fertilisation and Embryology Authority (HFEA).