BACKGROUND AND PURPOSE:  

• Flavenols found in dark chocolate have antioxidant effects and promote direct nitric-oxide dependent vasodilation  
• Meta-analyses of RCTs have demonstrated that chocolate can lead to a reduction in blood pressure  
  • Data specific to preeclampsia prevention is inconsistent and studies
    have primarily been observational rather than randomized
• Babar et al. (Hypertension in Pregnancy, 2018) sought to determine the impact of a high flavanol high theobromine (HFHT) chocolate diet on the health of women at risk of preeclampsia 

METHODS:  

• Double blind single-center randomized control trial (RCT)  
• Participants: Women at risk for preeclampsia between 18 and 38 years of age  
• Risk of preeclampsia was determined during routine Doppler between 11 and 14 weeks gestation with bilateral uterine artery diastolic notches and  
  • Uterine artery pulsatility index (UtA PI) > 95th percentile on one side and/or bilateral UtA PI > 50th percentile  
• Women were randomized into two groups  
  • High flavanol high theobromine (HFHT) chocolate  
  • Low flavanol low theobromine (LFLT) chocolate  
• Changes in plasma flavanol and theobromine (methylxanthine compound found in cacao seeds, chemically similar to caffeine), peripheral arterial tonometry and blood pressure (BP) were assessed  
  • Acute phase: At 0, 60 and 120 minutes after 40 g dose of chocolate  
  • Chronic phase: At 6 and 12 weeks, following daily intake of 30 g of chocolate (10 g chocolate three times a day with meals) 
• Reactive hyperemia index (RHI) was used as a marker for endothelial function and adjusted augmentation index (AIx)  was used as a marker for arterial stiffness 

RESULTS:  

• 131 pregnant women were involved in the study  
• Compared to LFLT, acute HFHT intake significantly 
  • Increased theobromine (p < 0.0001), both initially and chronic intake  
  • Decreased AIx (p < 0.0001)  
  • Increased diastolic BP (3.49 ± 3.40 mmHg increase in HFHT group vs 1.55 ± 2.59 mmHg increase in LFLT group; p = 0.0008)  
  • There was no change in endothelial function  
• Rates of pregnancy induced hypertension 
  • Without preeclampsia: 3% in the HFHT group vs 6% in LFLT group and was not significantly different (p=0.44) 
  • With preeclampsia: 1.5% in HFHT group vs 6.1% in LFLT group and was not significantly different (p=0.21)   
• No other significant differences within group or between group changes were observed  

CONCLUSION:  

• Acute consumption of HFHT 
  • Increased levels of theobromine and decreased arterial stiffness
  • No changes in endothelial function  
  • No changes in acute systolic BP, but there was a significant increase in diastolic BP  
• Chronic consumption 
  • Theobromine concentrations were elevated 
  • There were no differences in BP between groups at 12 weeks  
• Neither chronic or acute HFHT chocolate diet had a clinically significant impact on endothelial function, arterial stiffness, or BP compared to LFLT in women at risk for preeclampsia
• These results do not validate positive results of previous observational and cohort studies 

Learn More – Primary Sources:  

Changes in endothelial function, arterial stiffness and blood pressure in pregnant women after consumption of high-flavanol and high-theobromine chocolate: a double blind randomized clinical trial.

Related ObG Topics:

Aspirin Treatment for Women at Risk for Preeclampsia – ACOG and USPSTF Recommendations  

Results from the SPREE Trial: How Does First Trimester Preeclampsia Screening Compare to Current Guidelines?

Which Markers Can We Use to Screen for Early and Late Preeclampsia?