Effect of Maternal Chocolate Consumption on Fetal Non-Stress Test (NST) Reactivity.

Overview

This is a single-blind, randomized, parallel-group, superiority clinical trial. The study aims to determine whether a single intake of 30g of dark chocolate (≥80% cocoa) by pregnant women with a non-reactive fetal non-stress test (NST) increases the conversion rate to a reactive NST within 20 minutes, compared to observation with a sugar-free white chocolate placebo. A total of 190 singleton pregnant women at 36-41 weeks gestation with a non-reactive NST will be recruited at the Hospital General San Felipe, Tegucigalpa, Honduras. Participants will be randomly assigned to either the intervention group (dark chocolate) or the control group (placebo). The primary outcome is the proportion of NSTs that become reactive. Secondary outcomes include changes in specific cardiotocographic parameters, total monitoring time, need for additional tests, and maternal satisfaction.

Background and Rationale: The fetal non-stress test (NST) is a cornerstone of antepartum fetal surveillance, used to assess fetal well-being by evaluating heart rate accelerations in response to fetal movements. A non-reactive NST, defined by the absence of sufficient accelerations over a 20 to 40-minute period, is a common clinical occurrence. While it can indicate fetal compromise, a significant proportion (up to 50%) are false positives, leading to unnecessary maternal anxiety, prolonged monitoring, costly additional tests (e.g., biophysical profile, contraction stress test), and potentially unwarranted obstetric interventions like induction of labor or cesarean delivery. Pharmacological agents like methylxanthines (e.g., theophylline) have been used to stimulate fetal activity, but their use is limited by side effects and regulatory considerations. Dark chocolate, rich in theobromine (a methylxanthine) and flavonoids, presents a safe, low-cost, and culturally acceptable alternative. Preliminary studies suggest that maternal consumption of dark chocolate, particularly with high cocoa content (≥70-80%), may stimulate fetal movement and heart rate reactivity, potentially converting a non-reactive NST to a reactive state within minutes. However, existing evidence is heterogeneous, derived from small studies with methodological limitations, and none have been conducted in the Central American population. This study aims to fill this gap by rigorously evaluating, in a randomized controlled trial setting, whether a single dose of 30g of dark chocolate (≥80% cocoa) is superior to a placebo in converting a non-reactive NST to reactive in pregnant women in Honduras. Study Objectives: Primary Objective: To compare the proportion of non-reactive NSTs that convert to reactive within 20 minutes after maternal ingestion of 30g of dark chocolate (≥80% cocoa) versus a placebo control. Secondary Objectives: To quantify and compare the change in specific cardiotocographic parameters (number of accelerations, baseline variability) between the groups. To compare the total time spent in the fetal monitoring unit between the intervention and control groups. To determine and compare the need for additional fetal surveillance tests or urgent obstetric interventions within 24 hours following the intervention. To evaluate and compare the incidence of maternal adverse events (e.g., nausea, heartburn, palpitations) within 24 hours. To assess maternal satisfaction and acceptability of the intervention using a standardized hedonic scale.