SUPPORTING FERTILITY & HEALTHY PREGNANCY WITH FISH

Authored by: Shadae Zamyad, Nutritionist

Starting a family is a journey filled with joy, anticipation, and countless questions for both prospective parents. As the world becomes increasingly aware of the importance of reproductive health, one question that often arises is, "What should we eat to support our fertility and ensure a healthy pregnancy?" In a sea of conflicting advice and overwhelming information, the role of fish in a fertility and pregnancy diet has long been a topic of debate.

Over the years, concerns about mercury content and other potential risks have led to confusion and uncertainty about the safety of consuming fish when trying to conceive or during pregnancy. Couples may wonder, "Should we avoid fish altogether? Will the benefits outweigh the risks?" These questions are not uncommon, as the desire to make the best choices for oneself, one's partner, and their future baby is completely understandable. However, as our understanding of nutrition and reproductive health has evolved, so too has the consensus on the importance of fish in supporting fertility for both men and women. A wealth of scientific studies has shed light on the numerous benefits that fish can offer for reproductive health and fetal development, challenging fears and misconceptions.

From the essential Omega-3 fatty acids that support sperm health and fetal brain development to the high-quality protein and micronutrients that nourish the reproductive system, we'll examine the unique nutritional profile of fish and how it contributes to optimal fertility and pregnancy outcomes. We'll also address the concerns surrounding mercury and other contaminants, providing evidence-based guidance on how to safely incorporate fish into your diet while minimizing potential risks!

 

The Central Role of Omega-3 for Fertility

In recent years, a silent crisis has been unfolding in the realm of reproductive health. Across the globe, fertility rates are plummeting, with more and more couples struggling to conceive. The statistics are alarming. In the United States alone, the fertility rate has dropped by 20% since 2007, reaching a record low in 2020. This trend is not unique to the U.S.; countries worldwide are grappling with similar challenges, as the dream of starting a family becomes increasingly elusive for many.

As the fertility landscape shifts, the demand for assisted reproductive technologies like in vitro fertilization (IVF) has skyrocketed. Couples are turning to medical interventions in unprecedented numbers, seeking hope and solutions in the face of infertility. However, while these advanced treatments offer a lifeline for some, they also come with significant financial, emotional, and physical burdens.

Amidst this fertility crisis, a growing body of research has emerged, shedding light on the crucial role that nutrition plays in reproductive health. At the forefront of this conversation is a nutrient that has long been recognized as a pillar of human health: Omega-3 fatty acids. Found in abundance in fish, Omega-3s have captured the attention of scientists and health-conscious individuals alike for their wide-ranging benefits, particularly in the context of fertility. To understand the profound importance of Omega-3s for fertility, we must first consider their evolutionary significance. Throughout human history, Omega-3s have played a central role in our development and survival. In fact, these essential fatty acids are most richly concentrated in two critical areas of the body - the brain and the reproductive organs – giving a strong hint at their importance for fertility and the entire reproductive process. 

Dr Hibbeln on “The Role of Omega-3s for Fertility & Healthy Pregnancy”

The human brain, the most complex and energy-demanding organ in the body, relies heavily on Omega-3s for proper function and development. The presence of Omega-3s in the brain has been linked to cognitive performance, emotional regulation, and overall neurological health. But the brain is not the only beneficiary of these powerful nutrients.

The reproductive organs, the very essence of our ability to create new life, are also deeply dependent on Omega-3s. The high concentration of these fatty acids in the testes, ovaries, and other reproductive tissues is a testament to their evolutionary importance. It is no coincidence that the organs responsible for perpetuating our species are so intimately connected to the presence of Omega-3s.

As researchers have delved deeper into the role of Omega-3s in fertility, a compelling body of evidence has emerged. Study after study has demonstrated that individuals with higher levels of Omega-3s in their bodies tend to have better reproductive outcomes and overall reproductive health.

One landmark study, published in the European Journal of Clinical Nutrition, investigated the relationship between Omega-3 intake and fertility in a population of Danish women (Matsumura et al., 2023). The researchers found that women with higher levels of Omega-3s in their blood had a significantly higher likelihood of becoming pregnant compared to those with lower levels. In fact, women in the highest quartile of Omega-3 intake had a 50% higher chance of conceiving compared to those in the lowest quartile! Those are very significant results!

But the benefits of Omega-3s extend beyond female fertility. In a study published in the Journal of Nutrition, researchers examined the impact of Omega-3 supplementation on male fertility parameters (Hosseni et al., 2019). The double-blind, placebo-controlled trial involved 238 infertile men who were randomly assigned to receive either Omega-3 supplements or a placebo for 32 weeks. The results were striking. Men who received Omega-3 supplementation experienced significant improvements in sperm count, motility, and morphology compared to the placebo group. These findings suggest that Omega-3s play a crucial role in supporting male reproductive health and fertility.

 

The Nutritional Profile of Fish: A Fertility Powerhouse

While Omega-3s are undoubtedly the star players in the fish and fertility story, it's important to recognize that fish offer a comprehensive package of nutrients that support reproductive health. Beyond the Omega-3 essential fatty acids EPA and DHA, fish provide a rich array of vitamins and minerals that work synergistically to optimize fertility.

Selenium, a trace mineral found in high concentrations in fish, has been shown to be particularly beneficial for sperm health. This powerful antioxidant helps protect sperm from oxidative stress, a major contributor to male infertility. A study published in the Journal of Assisted Reproduction and Genetics found that men with higher levels of selenium in their seminal plasma had significantly better sperm motility and morphology compared to those with lower levels (Türk et al., 2014).

Iodine, another essential nutrient abundant in fish, plays a critical role in thyroid function. The thyroid gland, often referred to as the "master gland" of the endocrine system, regulates hormone production and balance throughout the body. Adequate iodine intake is crucial for maintaining proper thyroid function, which in turn supports reproductive health and fetal development. A study published in the Journal of Nutrition found that women with higher urinary iodine concentrations, an indicator of iodine status, had a significantly lower risk of infertility compared to those with lower levels (Mills et al., 2018).

Vitamin D, often called the "sunshine vitamin," is yet another nutrient found in fish that has been linked to improved fertility outcomes. This fat-soluble vitamin plays a role in regulating the immune system and reducing inflammation, both of which are important for reproductive health. A systematic review and meta-analysis published in the journal Human Reproduction Update found that women with higher levels of vitamin D had a significantly higher likelihood of becoming pregnant through IVF compared to those with lower levels (Chu et al., 2018).

 

Omega-3s and Pregnancy: Nourishing two brains

The importance of Omega-3 fatty acids, particularly DHA, during pregnancy cannot be overstated. This essential nutrient plays a critical role in the development of the fetal brain and eyes, setting the stage for a child's lifelong cognitive abilities. The impact of maternal DHA consumption on a child's future is a measurable, significant difference in IQ points that can shape the course of their life! 

A pioneering study published in the Lancet investigated the relationship between maternal seafood consumption during pregnancy and child cognitive development (Hibbeln et al., 2007). The researchers analyzed data from a large cohort of mother-child pairs, assessing the mothers' seafood consumption during pregnancy and the children's IQ scores at age 8. The results were striking. Children whose mothers consumed more than 340 grams of seafood per week during pregnancy had significantly higher IQ scores compared to those whose mothers who ate less seafood! The difference was equivalent to an average of 7.7 IQ points. Remarkable! But the benefits don't end there. The study also found that children of mothers who consumed more seafood during pregnancy had better social and communication skills, as well as lower risk of suboptimal outcomes in various aspects of neurodevelopment. This suggests that the advantages of maternal seafood consumption extend beyond IQ and encompass a broader spectrum of cognitive and behavioral development! 

 

The Impact of Omega-3 Deficiency on Maternal Mental Health

The importance of Omega-3s during pregnancy extends beyond just the developing fetal brain. When a woman's dietary intake of Omega-3s is insufficient, her body prioritizes the needs of the growing fetus, drawing on her own brain's Omega-3 stores to support the baby's development. This can leave the mother depleted of these essential fatty acids by the end of the pregnancy, putting her at increased risk for health and mental wellbeing challenges. One of the most significant consequences of maternal Omega-3 deficiency is an increased likelihood of postpartum depression. Studies consistently show that women with lower Omega-3 levels are more prone to experiencing depression and anxiety after giving birth (Markhus et al., 2013). This is thought to be due, in part, to the depletion of Omega-3s in the maternal brain during pregnancy, leaving the mother with insufficient resources to support her own mental well-being during the challenging postpartum period.

The postpartum period is a time of significant physical, emotional, and social transitions for new mothers. They are recovering from the demands of pregnancy and childbirth, adapting to the responsibilities of caring for a newborn, and often coping with sleep deprivation and hormonal fluctuations. This perfect storm of stressors can be overwhelming, and a brain depleted of Omega-3s may struggle to maintain emotional equilibrium in the face of these challenges.

Research has shown that consuming Omega-3-rich fish during pregnancy can help both prevent and treat postpartum depression. A study published in the Journal of Affective Disorders found that women who consumed more seafood during pregnancy had a lower risk of developing postpartum depression compared to those who ate less fish (Hibbeln et al., 2002). Even more significantly, Omega-3s have emerged as a powerful therapeutic tool for mothers already experiencing postpartum depression. During pregnancy and breastfeeding, a mother's Omega-3 stores can become severely depleted as these essential fats are prioritized for the baby's development. Replenishing these stores through regular consumption of fatty fish such as Black Cod, salmon, sardines, or mackerel can help alleviate postpartum depression symptoms without the potential side effects associated with traditional antidepressants. This natural approach is particularly valuable for breastfeeding mothers, as it not only supports their mental health but continues to provide benefits for their nursing infant's development. 

Another common experience among new mothers is "pregnancy brain" or "mom brain" - the forgetfulness, confusion, and difficulty concentrating that many women report during pregnancy and after birth. While often dismissed as a normal part of pregnancy, emerging research suggests that Omega-3 deficiency may contribute to these cognitive changes (Parra-Cabrera et al., 2008). The good news is that these risks can be mitigated by ensuring adequate Omega-3 intake during pregnancy, particularly DHA. By consuming a diet rich in fish and taking a high-quality Omega-3 supplement, expectant mothers can support the cognitive development of their children while also protecting their own brain health. This simple yet powerful nutritional strategy can have far-reaching effects, promoting the well-being of both mother and child.

In contrast, other protein sources like beef and chicken, while nutritious, do not offer the same high levels of Omega-3 DHA and EPA found in seafood. This makes fish a uniquely valuable food for pregnant women looking to optimize their baby's brain development and their own mental well-being!

 

Mercury In Seafood: What’s Fact and What’s Fiction?

For many pregnant women, the fear of mercury contamination in seafood is a significant barrier to incorporating this nutritious food into their diets. While it's true that some types of fish can contain high levels of mercury, which can be harmful to fetal development, it's important to approach this issue with a balanced perspective and not let fear overshadow the numerous benefits of seafood consumption during pregnancy.

Mercury is a naturally occurring element that can accumulate in the bodies of fish, particularly those species that are long-lived and are at the top of the food chain like shark, swordfish, king mackerel, and tilefish. When consumed in high amounts, mercury can pose risks to fetal brain and nervous system development. However, it's crucial to note that only a few fish species contain dangerous levels of mercury, while most consumed species in the US have low or moderate levels of mercury.  And the benefits of eating seafood during pregnancy often outweigh the potential risks. 

The U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) have issued guidelines to help pregnant women make informed choices about seafood consumption. They recommend that pregnant women eat 2-3 servings (8-12 ounces) of low-mercury fish per week, such as Dover Sole, Lingcod, black cod, salmon, sardines, cod, rockfish or shrimp. These species are not only lower in mercury but also contain essential nutrients like Omega-3 fatty acids, which are crucial for fetal brain development and maternal mental health. It's essential for pregnant women to be informed about the types of fish to choose and the appropriate serving sizes, rather than avoiding seafood altogether out of fear.

 

The Protective Role of Selenium in Seafood

When considering the potential risks of mercury in seafood, it's important to recognize the presence of another essential nutrient that can help mitigate these concerns: Selenium. Selenium is a trace mineral found in many foods, including seafood, and it plays a crucial role in supporting thyroid function, immune health, and antioxidant defense systems.

Dr Hibbeln Explains how Selenium Protects Against Mercury

Interestingly, selenium has been shown to have a protective effect against mercury toxicity. In fact, many species of seafood naturally contain more selenium than mercury, which can help neutralize the potential negative impacts of mercury exposure. This is because selenium binds to mercury, forming a complex that prevents mercury from being absorbed into the body and causing harm. In essence, selenium acts as a natural defense mechanism against mercury toxicity, allowing us to benefit from the numerous nutritional advantages of seafood while minimizing the potential risks. A landmark study published in Neurotoxicology found that the ratio of selenium to mercury in fish is a key factor in determining the risk of mercury toxicity (Ralston et al. 2008). It's worth noting that the protective effect of selenium is most pronounced in fish species that are naturally high in this mineral, such as Pacific Dover Sole, Lingcod, tuna, cod, or salmon. By choosing seafood options that are rich in selenium and low in mercury, pregnant women can further optimize the benefits of this nutritious food for both them and their developing babies!

 

Summary

When you're preparing for pregnancy or nurturing a growing life inside you, nutrition plays a crucial role in supporting your health and your baby's development. Among the many nutritious foods to consider, fish stands out as a valuable source of essential nutrients that can make a real difference in your fertility and pregnancy journey!

Fish is an excellent source of Omega-3 fatty acids, protein, selenium, iodine, and vitamin D, all of which contribute to reproductive health. For couples trying to conceive, incorporating fish into your diet may help improve your chances of success by supporting healthy sperm and egg development. While fish is certainly a nutritional powerhouse, it's not the only food that supports fertility and pregnancy health. Other important foods to include in your diet are:

  • Leafy greens: Spinach, kale, and other leafy greens are rich in folate, a B vitamin essential for preventing birth defects.

  • Colorful fruits and vegetables: A variety of colorful produce provides a wide range of antioxidants that protect your baby's developing cells.

  • Eggs: In addition to being a great source of protein, eggs contain choline, a nutrient necessary for fetal brain development.


As you embark on your fertility and pregnancy journey, remember that a well-rounded, nutrient-dense diet is key. Let fish be a regular part of your healthy eating plan, but don't forget to include a variety of other nourishing foods as well. By making informed choices about your nutrition, you're taking an important step towards supporting your own health and giving your baby the best possible start in life! 

 
 

CONTINUE EXPLORING:

Link to high Omega-3 meal plans

Common Questions

  • Fish that are high in mercury include shark, swordfish, king mackerel, bigeye tuna, and marlin. These larger species, which sit higher on the food chain and have longer lifespans, accumulate mercury over time through a process called bioaccumulation. Small fish absorb trace amounts of mercury from their environment, and when larger predatory fish consume many of these smaller fish, the mercury builds up in their own tissues. When we eat these fish, the mercury can bind to selenium in our bodies. If there’s more mercury than selenium available, it can cause a selenium deficiency, which can disrupt cellular functions and lead to toxicity.

    Fish with much lower mercury levels—and higher concentrations of selenium and Omega-3s—are recommended, especially for pregnant women and children. These include salmon, cod, trout, and haddock, as well as West Coast local species like Dover Sole, Petrale Sole, Rockfish, and Lingcod. These species tend to have higher selenium concentration along with high-quality protein and essential Omega-3 fatty acids that support brain and heart health.

  • Yes, when chosen carefully, seafood is not only safe, but recommended during pregnancy because it is a great source of Omega-3 fatty acids, the “healthy fats”, particularly DHA, which is essential for the development of the baby’s brain and eyes. Studies have shown that pregnant women who ate fish 2 -3 times a week during pregnancy linked Omega-3 intake to higher IQ scores, better attention spans, and stronger language skills in children. To get the best benefits while minimizing risk, pregnant women can avoid high-mercury fish such as shark, swordfish, king mackerel, and big-eye tuna, in instead choose low-mercury options like salmon, cod, trout, sole, flounder or Black Cod/Sablefish - a buttery Omega-3 rich fish found off the West Coast. Try this nourishing, pregnancy-safe healthy Black Cod Bowl recipe packed with high-quality protein, selenium, and the Omega-3s that support both mom and baby’s long-term health.

  • As nutrition around reproductive health has evolved, studies have found numerous benefits on how fish can offer reproductive health and fetal development. Choosing low-mercury, high Omega-3 fish like sardines, anchovies, Black Cod/Sablefish, Lingcod, salmon or trout are great choices, and these species all provide a healthy dose of “good fats” needed for reproductive organs and tissues, as well as healthy fetal development. In addition to fish, it’s also important to include plenty of leafy greens like spinach and kale that are rich in folate essential B vitamins for preventing birth defects.

  • A nutrient-rich diet that includes fatty fish can have a positive effect on IVF outcomes thanks to nutrients like Omega-3s and Vitamin D. The healthy fats found in seafood, specifically EPA and DHA, help reduce inflammation, support hormonal balance, and enhance uterine receptivity—all critical for successful embryo implantation. Vitamin D is also important in reproductive health because it strengthens the immune system and helps regulate inflammation. Studies have found that women with higher levels of Vitamin D had significantly better chances of becoming pregnant through IVF. These key nutrients—Omega-3 fatty acids (EPA and DHA) and vitamin D—are abundant in many species of wild-caught seafood such as salmon, sardines, anchovies, mackerel, herring, Black Cod/Sablefish, and Pacific Rockfish. Including these in a balanced preconception diet may support fertility and improve the likelihood of IVF success.

  • A well-rounded, nutrient-rich diet can play a key role in reducing the risk of postpartum depression. Key nutrients your brain needs include Omega-3 fatty acids - particularly DHA found in fatty fish, plus vitamin D, Iron, B vitamins, magnesium, zinc, and protein. To replenish nutrients depleted during pregnancy and support brain health, selecting whole foods from a variety of sources, including wild-caught seafood rich in Omega-3s such as salmon, sardines, anchovies, Black Cod, Petrale Sole, Dover Sole, shrimp, or oysters - plus leafy greens, chia and flax seeds, walnuts, and legumes can offer natural support for mood, resilience and recovery. Understanding how a well-balanced, Omega-3-rich diet supports mental health is key—and this short video by nutritional neuroscientist Dr. Hibbeln dives deeper into the topic.

 

References

Chu J, Gallos I, Tobias A, Tan B, Eapen A, Coomarasamy A. Vitamin D and assisted reproductive treatment outcome: a systematic review and meta-analysis. Hum Reprod. 2018 Jan 1;33(1):65-80. doi: 10.1093/humrep/dex326. PMID: 29149263.

 

Hibbeln JR, Davis JM, Steer C, Emmett P, Rogers I, Williams C, Golding J. Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study. Lancet. 2007 Feb 17;369(9561):578-85. doi: 10.1016/S0140-6736(07)60277-3. PMID: 17307104.


Hibbeln JR. Seafood consumption, the DHA content of mothers' milk and prevalence rates of postpartum depression: a cross-national, ecological analysis. J Affect Disord. 2002 May;69(1-3):15-29. doi: 10.1016/s0165-0327(01)00374-3. PMID: 12103448.


Hosseini B, Nourmohamadi M, Hajipour S, Taghizadeh M, Asemi Z, Keshavarz SA, Jafarnejad S. The Effect of Omega-3 Fatty Acids, EPA, and/or DHA on Male Infertility: A Systematic Review and Meta-analysis. J Diet Suppl. 2019;16(2):245-256. doi: 10.1080/19390211.2018.1431753. Epub 2018 Feb 16. PMID: 29451828.

 

Markhus MW, Skotheim S, Graff IE, Frøyland L, Braarud HC, Stormark KM, Malde MK. Low omega-3 index in pregnancy is a possible biological risk factor for postpartum depression. PLoS One. 2013 Jul 3;8(7):e67617. doi: 10.1371/journal.pone.0067617. PMID: 23844041; PMCID: PMC3701051.


Matsumura K, Hamazaki K, Tsuchida A, Inadera H; Japan Environment and Children's Study (JECS) Group. Omega-3 fatty acid intake during pregnancy and risk of infant maltreatment: a nationwide birth cohort - the Japan Environment and Children's Study. Psychol Med. 2023 Feb;53(3):995-1004. doi: 10.1017/S0033291721002427. Epub 2021 Jun 25. PMID: 34176535; PMCID: PMC9975990.


Mills JL, Buck Louis GM, Kannan K, Weck J, Wan Y, Maisog J, Giannakou A, Wu Q, Sundaram R. Delayed conception in women with low-urinary iodine concentrations: a population-based prospective cohort study. Hum Reprod. 2018 Mar 1;33(3):426-433. doi: 10.1093/humrep/dex379. PMID: 29340704; PMCID: PMC6454505.

 

Parra-Cabrera S, Moreno-Macias H, Mendez-Ramirez I, Schnaas L, Romieu I. Maternal dietary omega fatty acid intake and auditory brainstem-evoked potentials in Mexican infants born at term: cluster analysis. Early Hum Dev. 2008 Jan;84(1):51-7. doi: 10.1016/j.earlhumdev.2007.03.005. Epub 2007 Apr 16. PMID: 17434694. 


Ralston NV, Ralston CR, Blackwell JL 3rd, Raymond LJ. Dietary and tissue selenium in relation to methylmercury toxicity. Neurotoxicology. 2008 Sep;29(5):802-11. doi: 10.1016/j.neuro.2008.07.007. Epub 2008 Aug 9. PMID: 18761370.


Eroglu, Mustafa, et al. "Blood Serum and Seminal Plasma Selenium, Total Antioxidant Capacity and Coenzyme Q10 Levels in Relation to Semen Parameters in Men with Idiopathic Infertility." Biological Trace Element Research, vol. 159, no. 1-3, 2014, pp. 46-51.https://pubmed.ncbi.nlm.nih.gov/24752972/