Fish consumption may help reduce hypertensive disorders of pregnancy — Study

Research involving more than 86,000 women in Japan suggests that eating fish before and during pregnancy may be associated with lower odds of certain hypertensive complications, particularly among first-time mothers.

The study linked higher fish consumption before and during pregnancy to lower odds of developing hypertensive disorders, including gestational hypertension and pre-eclampsia.

The findings, published in the European Journal of Nutrition on 8 September 2026, suggest that fish intake may be an important consideration in maternal nutrition. However, researchers cautioned that the study does not prove that eating fish directly prevents pregnancy-related high blood pressure.

Hypertensive disorders of pregnancy affect an estimated five to 10 per cent of pregnancies worldwide and can lead to serious complications for both mothers and babies.

To investigate the relationship between diet and these conditions, researchers led by Associate Researcher Takuya Inouye of Gunma University Graduate School of Medicine in Japan examined fish consumption and intake of omega-3 and omega-6 polyunsaturated fatty acids among pregnant women.

The team analysed data from the Japan Environment and Children’s Study, a large prospective study involving 86,009 women. Dietary intake was assessed for the year before pregnancy and during mid-to-late pregnancy.

Participants were divided into five groups according to their levels of fish and fatty acid consumption. The researchers then examined the relationship between intake and hypertensive disorders of pregnancy overall, including early-onset cases.

The results showed that women in the highest fish-consumption group before pregnancy had 34 per cent lower adjusted odds of early-onset hypertensive disorders than those in the lowest-intake group.

Among women experiencing their first pregnancy, the association was stronger, with higher pre-pregnancy fish intake linked to 43 per cent lower odds of early-onset disease.

Fish consumption during pregnancy was also associated with lower odds of complications. Women in the fourth of the five intake groups had 14 per cent lower adjusted odds of hypertensive disorders overall.

Among first-time mothers, higher fish consumption during pregnancy was associated with 21 per cent lower odds of late-onset hypertensive disorders.

However, the researchers found that total omega-3 fatty acid intake had weaker and less consistent associations with the conditions. This suggests that the relationship observed in the study may not be explained by omega-3 intake alone.

The associations were more pronounced among women experiencing their first pregnancy and were not statistically significant among those who had given birth previously.

Fish is a source of long-chain omega-3 fatty acids, which have been linked to cardiovascular health and may influence inflammation and blood vessel function. However, further research is needed to establish the mechanisms that could explain the findings.

The researchers said the results could contribute to future dietary guidance for women planning a pregnancy and those who are already pregnant.

They nevertheless cautioned that the study was observational and could not establish cause and effect. Other dietary, lifestyle or health factors may have contributed to the results.

Further studies, including controlled trials, are needed to determine whether fish consumption directly reduces the risk of hypertensive disorders during pregnancy.

The findings add to research into the role of diet in maternal health, but the researchers said more evidence is needed before fish consumption can be recommended specifically as a way to prevent pregnancy-related high blood pressure.