Common Causes of Secondary Infertility

There are a lot of myths and misconceptions about infertility. Even though healthcare professionals do their best to educate the general public, misinformation is still prevalent across the web and in conversations around the globe.

These misconceptions not only cause confusion, but they can leave those struggling to conceive feeling lost and defeated when there’s still hope and a potential solution available.

In this blog, we’ll discuss one of the most commonly misunderstood fertility struggles: secondary infertility (sometimes referred to as second hand infertility). We’ll be exploring what causes it, what’s true and what isn’t, and ways to combat it.

Keep scrolling for all the details!

 

What is Secondary Infertility?

Secondary infertility¹ is when a woman has successfully conceived before, with very little to no issues, but is unable to (or struggles to) conceive or carry a child to term afterwards. It can impact any woman, regardless of age or underlying medical conditions, and is estimated to impact 5 per cent of women in the UK.²

 

What Causes Secondary Infertility?

There are many people who mistakenly believe fertility is permanent, or that once a woman becomes pregnant, it “proves” she is fertile and therefore she won’t experience problems in the future. This absolutely isn’t the case.

So how common is secondary infertility? Ultimately, it depends on a variety of factors³ such as age, underlying medical conditions, and lifestyle factors. According to the Medical News Today,⁴ secondary infertility affects approximately 11% of couples in the US. 

For couples or individuals who have successfully conceived before, experiencing secondary infertility can be confusing and frustrating. If you’re in this situation, it’s normal to want to know why you’re experiencing this sudden change and what can be done to address it.

The answer to this question isn’t quite as straightforward as you might think, however, as secondary infertility causes vary between men and women. Let’s take a closer look at each.

Causes of Secondary Infertility in Women

Secondary infertility in women can stem from a variety of causes, some of which develop or worsen after the first successful pregnancy. Here are the main culprits:

• Ovulation disorders like polycystic ovarian syndrome (PCOS) or hypothalamic amenorrhea – These can develop or become more pronounced over time, particularly if lifestyle factors (weight, stress) have changed since the first pregnancy.
• Thyroid disorders, particularly hypothyroidism – Thyroid function can change after pregnancy, and postpartum thyroiditis is relatively common. A sluggish thyroid disrupts the hormonal balance required for ovulation.
• Endometriosis – This condition can develop or worsen between pregnancies. It affects fertility by causing inflammation, creating scar tissue, and sometimes blocking the fallopian tubes.
• Uterine fibroids or polyps – These benign growths can develop or enlarge after pregnancy, particularly in women over 35, and may interfere with implantation or embryo development.
• Blocked or damaged fallopian tubes – Scarring from previous pregnancy complications, infections, or endometriosis can obstruct the tubes, preventing sperm and egg from meeting.
• Recurrent miscarriage or implantation failure – Some women experience repeated losses or fail to implant properly in subsequent pregnancies, sometimes due to undiagnosed chromosomal or immune issues.
• Weight changes – Significant weight gain after the first pregnancy can disrupt hormonal balance and ovulation, whilst significant weight loss can also impair fertility.
• Nutritional deficiencies – Pregnancy depletes maternal nutrient stores. If these aren’t adequately replenished, deficiencies in folate, iron, vitamin B12, zinc, and other key nutrients can impair fertility.
• Stress and lifestyle factors – The demands of parenting, work-life balance, and emotional stress can suppress ovulation and reduce libido, making conception more difficult.

Causes of Secondary Infertility in Men

Men, too, can experience secondary infertility, though it’s less commonly discussed. Changes in sperm quality, hormone levels, or physical health after the first child can all contribute:

• Declining sperm quality and motility – Sperm count and function naturally decline with age, particularly after 40. Environmental toxins, heat exposure, and tight clothing can also impair sperm.
• Varicocele – Enlarged veins in the scrotum can develop or worsen over time, raising testicular temperature and impairing sperm production.
• Hormonal changes – Testosterone levels decline naturally with age, and conditions like metabolic syndrome or diabetes can further suppress testosterone production and sperm function.
• Lifestyle factors – Weight gain, smoking, excessive alcohol consumption, poor sleep, and a sedentary lifestyle all negatively impact sperm health.
• Infections or STIs – Untreated infections can cause inflammation or scarring of the reproductive tract, reducing fertility.
• Medications or substance use – Certain medications (including some for blood pressure or depression) and recreational drugs can impair sperm production or sexual function.

 

How to Address Secondary Infertility

If you’re struggling with secondary infertility, there are several evidence-based approaches that can help:

Lifestyle Modifications

Before exploring medical interventions, optimising lifestyle factors can significantly improve fertility prospects. This includes maintaining a healthy weight, eating a nutrient-dense diet, managing stress through exercise or mindfulness, limiting alcohol, avoiding smoking, and ensuring adequate sleep (7–9 hours per night). These changes benefit both partners and can take 2–3 months to impact sperm and egg quality.

Nutritional Support

Pregnancy and breastfeeding deplete maternal nutrient reserves. Replenishing stores of folate, iron, vitamin B12, vitamin D, zinc, and selenium can restore ovulatory function and support conception. Many women find that targeted supplementation jumpstarts fertility after nutritional depletion from pregnancy and lactation.

Medical Evaluation and Diagnosis

A comprehensive fertility workup is essential. This typically includes hormone testing (FSH, LH, prolactin, thyroid function), semen analysis for the male partner, imaging (ultrasound or hysterosalpingography to assess fallopian tube patency), and sometimes laparoscopy if endometriosis is suspected. Identifying the underlying cause is crucial for effective treatment.

Hormonal Treatments

Depending on the diagnosis, hormonal therapies may help. For ovulatory disorders, clomiphene citrate or letrozole can stimulate ovulation. For thyroid disorders, thyroid hormone replacement restores normal function. For low testosterone in men, testosterone replacement therapy (TRT) may be considered under medical supervision.

In Vitro Fertilisation

IVF is a highly effective solution for those living with ovulatory disorders, blocked fallopian tubes, endometriosis, or unexplained infertility. It bypasses many structural and ovulatory barriers and offers excellent success rates, particularly when combined with preimplantation genetic testing (PGT) to screen for chromosomal abnormalities.

Surgical Interventions

In some cases, surgery can address structural barriers. Hysteroscopic removal of fibroids or polyps, laparoscopic treatment of endometriosis, or surgical repair of blocked tubes can restore fertility. Success rates vary, but surgery can be a cost-effective first step before pursuing IVF.

Natural Supplements

There are many secondary infertility statistics and studies that link the condition to hormonal and nutritional deficiencies. For example, we know that ovulation disorders account for approximately 25 percent of all infertility cases,⁷ and nutritional supplements like folic acid, vitamin E, and zinc have been shown to help regulate ovulation cycles.⁸ We also know that overweight men with poor nutritional habits are 11 per cent more likely to have a lower sperm count.⁹

Whilst supplements alone won’t resolve all cases of secondary infertility, they can address nutritional gaps and support reproductive health when combined with lifestyle modifications and, if necessary, medical treatment.

 

Key Takeaways

• ✓ Secondary infertility is more common than you might think – affecting approximately 11% of couples in the US, and it’s often misunderstood.
• ✓ Causes vary widely between men and women – from age-related decline and ovulation disorders to hormonal changes, structural barriers, and lifestyle factors.
• ✓ Many causes are treatable – including nutritional deficiencies, hormonal imbalances, and structural issues that may respond to supplements, lifestyle changes, or medical intervention.
• ✓ A comprehensive evaluation is essential – to identify the root cause and determine the most effective treatment approach for your situation.
• ✓ Optimising nutrition and lifestyle is a valuable first step – and may improve fertility prospects without invasive treatment.

 

If you’re struggling with secondary infertility and would like to discuss your options with our expert team, please get in touch. We’re here to support you on your journey, and we’ll get back to you as soon as possible.

References

¹ Cleveland Clinic. Secondary Infertility. https://my.clevelandclinic.org/health/diseases/21139-secondary-infertility

² Bourn Hall Clinic. The Heartbreak of Secondary Infertility. https://www.bournhall.co.uk/fertilityblog/heartbreak-of-secondary-infertility/

³ Penn Medicine. Secondary Infertility. https://www.pennmedicine.org/for-patients-and-visitors/find-a-program-or-service/penn-fertility-care/secondary-infertility

⁴ Medical News Today. Secondary Infertility: Causes, Treatments, and Support. https://www.medicalnewstoday.com/articles/secondary-infertility#causes-in-females

⁵ World Health Organization. Infertility. https://www.who.int/news-room/fact-sheets/detail/infertility

⁶ American College of Obstetricians and Gynecologists (ACOG). Evaluation and Treatment of Recurrent Pregnancy Loss: A Committee Opinion. Obstetrics & Gynecology, 2019.

⁷ Fertility New Jersey. Ovulation Disorders. https://fertilitynj.com/infertility/female-infertility/ovulation-disorders/

⁸ National Center for Biotechnology Information (NCBI). Nutritional Supplements and Ovulation: A Systematic Review. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8634384/

⁹ Harvard School of Public Health. Excess Weight and Sperm Fertility. https://www.hsph.harvard.edu/news/hsph-in-the-news/excess-weight-sperm-fertility/

¹⁰ Chen, M. H., et al. Mechanisms of Endometriosis-Related Infertility. Reproductive Sciences, 2018; 25(8): 1155–1168.

¹¹ Doherty, D. A., et al. Postpartum Changes in Thyroid Function and Autoimmunity. Clinical Endocrinology, 2009; 71(3): 313–318.

¹² Practice Committee of the American Society for Reproductive Medicine. Diagnostic Evaluation of the Infertile Female: A Committee Opinion. Fertility and Sterility, 2021; 116(6): 1255–1265.

¹³ Sharma, R., et al. Lifestyle Factors and Reproductive Health: Bridging the Gap. International Journal of Fertility & Sterility, 2013; 7(4): 220–229.

¹⁴ Society for Assisted Reproductive Technology (SART). Success Rates in Assisted Reproductive Technology. https://www.sartcorsonline.com/

¹⁵ Zegers-Hochschild, F., et al. The International Glossary on Infertility and Fertility Care. Human Reproduction, 2017; 32(9): 1786–1801.