Secondary infertility: What is it and what’s the difference between infertility and secondary infertility?

For couples who conceived easily and spontaneously and had a healthy birth for their first, or even second and third, children, secondary infertility (SI) can be a huge shock. But the truth is that secondary infertility occurs approximately as often as primary infertility.

Secondary infertility means that a couple was unable to conceive after 12 months of unprotected sex, after having previously had one or more healthy pregnancies and births. Some couples with secondary infertility are able to conceive, but experience miscarriages and/or stillbirth that prevents them from reaching a live birth.

Some couples have secondary infertility after multiple previous healthy births.

Note that it’s only called secondary infertility if your first birth occurred spontaneously. If you used fertility treatment like IVF to get pregnant the first time round, then any struggles to get pregnant a second time are considered part of your primary infertility.

How common is secondary infertility?

It’s generally thought that secondary infertility affects about as many couples as primary infertility. One study from 2006 reported that 3.3 million women suffered from secondary infertility, and that secondary infertility now accounts for 60% of all cases of infertility.

Another study revealed that among women aged 20-44, 10.5% experienced secondary infertility, while a report from the CDC calculated that 39% of women with fertility issues were suffering from secondary infertility.

It’s clear from these figures that a significant number of couples experience secondary infertility, but it goes under the radar of society far more than primary infertility.

What are the causes of secondary infertility?

Secondary infertility can originate in either the woman or the man. It’s estimated that SI cases are divided roughly equally between male-caused infertility, female-caused infertility, and secondary infertility due to unknown causes.

When secondary infertility originates in the woman, it can be caused by:

  • Low quantity and/or quality of eggs. This could be due to age, or as a result of an autoimmune disorder or radiation therapy. One study found that prevalence of secondary infertility jumped from approximately 2.6% in women aged 20-24 to 27.1% in women aged 40-44.
  • Blockages in the fallopian tubes. The fallopian tubes carry eggs from the ovaries to the uterus, but pelvic infections like chlamydia and gonorrhoea can cause blockages, preventing eggs from reaching the uterus.
  • Problems with the uterus. Uterine issues can include scarring from a previous dilatation and curettage procedure or caesarean delivery; fibroids or polyps, which are benign growths inside the uterus; or infection and secondary scarring from a retained placenta. All of these can create adhesions inside the uterus that interfere with future pregnancies.
  • Endometriosis can likewise cause scarring and adhesions within the uterus.
  • Polycystic ovary syndromes (PCOS). PCOS is a hormonal disorder that prevents the ovaries from releasing eggs regularly. Women with PCOS may get pregnant the first time round, but then struggle to conceive a second time.
  • Breastfeeding can prevent your body from ovulating or releasing eggs into the uterus.
  • Hypothyroidism. The thyroid controls the release of hormones that affect fertility, so women with low thyroid (hypothyroidism) can struggle to conceive and carry to term. Giving birth can affect thyroid function, causing secondary infertility.
  • Lifestyle changes. Weight gain can lower your fertility, and there are some medications and diet choices that can also affect your ability to become pregnant.

Secondary infertility that originates in men can be caused by:

  • Reduced testosterone levels. Low testosterone can be caused by a number of factors, and it in turn can cause low sperm count, abnormal sperm shape, and poor sperm motility.
  • Testicular varicocele. This is when the veins in the testes become enlarged, causing low sperm production. Around 30% of infertile men suffer from testicular varicocele.
  • Poor quality semen. Although men don’t experience a menopause, semen quality declines after around age 40, which can both hinder conception and cause a rise in miscarriages. Certain medications can also affect sperm count and quality.
  • Prostate issues. Men with an enlarged prostate generally have a lower sperm count and can have trouble ejaculating, while prostate removal can make semen flow backwards.
  • Environmental issues. Exposure to extreme heat, certain chemicals, and/or marijuana usage can all damage sperm production.

Excessive weight gain can also affect both the libido, and healthy sperm production.

How do you treat secondary infertility?

The good news is that treatment for secondary infertility can have higher success rates than those for primary infertility. That’s because it’s usually possible to identify a specific cause for SI, and once the cause has been dealt with, fertility levels return.

In general, treatments for secondary infertility are similar to those for primary infertility.


When secondary infertility is caused by adhesions in the uterus or testicular varicocele, surgery to remove the scar tissue, fibroids, or other blockages, and to fix enlarged veins in men, can be very successful.


When secondary infertility originates in the woman, they are often given medications such as clomiphene and letrozole to increase and speed up ovulation and overcome ovulatory disorders.

When SI originates in men, they may be given antioxidants and anti-aging medication to improve sperm quality.

Lifestyle changes

Depending on the cause of the SI, couples might be counselled about changing their diet to lose weight, reducing their caffeine and/or alcohol intake, and/or avoiding certain pollutants.

Timed intercourse together with ovulation monitoring can also help couples with secondary infertility to conceive.

IUI (intrauterine insemination)

Intrauterine insemination, or IUI, is when sperm is surgically placed within the fallopian tubes to increase the chances of fertilization. It’s been found to be very successful among couples with unexplained secondary infertility, with one study reporting IUI success rates of 47.4% among couples with SI, in contrast with 8.4% among those with primary infertility.


If other approaches don’t result in a healthy pregnancy, couples with secondary infertility are often advised to try IVF. IVF can be more successful among couples with SI than those with primary infertility. Secondary infertility might be less talked about than primary infertility, but it can be just as upsetting for couples trying for another baby. If you’re struggling to conceive after one or more healthy births, take heart from knowing there are many successful treatment options which can help you build the family you dream of. Whatever path you take to adding to your family, we hope it’s as smooth as possible.

This article has been brought to you with the support of Gedeon Richter.

Posted in Fertility awareness, male fertility, patients, secondary infertility and tagged , .