Danielle Alice Vieira da Silva, Micaely Cristina Dos Santos Tenório, Fabiana Andréa Moura, Nassib Bezerra Bueno, Nathálya da Silva Severino, Alexandra Rodrigues Bezerra, Bianca Gomes de Souza, Marilene Brandão Tenório Fragoso, Tauane Alves Dutra, Orlando Roberto Pimentel de Araújo, Amylly Sanuelly da Paz Martins, Marília Oliveira Fonseca Goulart, Alane Cabral Menezes de Oliveira
Background/Objectives: This study aimed to evaluate the effects of oral administration of N-acetylcysteine (NAC) in pregnant women with preeclampsia (PE), using serum markers of redox imbalance and cytokine levels and perinatal outcomes. Methods: A double-blind, randomized, placebo-controlled pilot study was carried out from 2021 to 2023. The study was retrospectively registered with REBEC (Brazilian Clinical Trials Registry). After screening, women were randomized into 2 groups according to the type of supplementation: 600 mg of NAC (NAC group) or capsules containing 2% colloidal silicon dioxide and 98% microcrystalline cellulose (placebo group) until delivery. Blood samples were collected to quantify biomarkers of redox imbalance and cytokine levels. Questionnaires containing socioeconomic, clinical, obstetric, and anthropometric data were applied. Results: A total of 51 pregnant women with PE were included (26 in the placebo group and 25 in the NAC group). The use of NAC was associated with a higher gestational age at birth (GA) of the conceptus (placebo group: 37.39 weeks ± 1.96 SD vs. NAC group: 38.45 weeks ± 1.51 SD; p = 0.044). A moderate effect size was observed for this variable (Cohen's d = 0.52). However, treatment allocation (NAC vs. control) was not independently associated with gestational age at birth after adjustment for covariates (F(1,28) = 0.144; p = 0.707; η2p = 0.005). The adjusted mean difference between groups was 0.92 weeks (95% CI: -0.16 to 2.00). No other significant effects on redox and inflammatory markers were identified using NAC. Conclusions: NAC supplementation did not impact the mode of delivery between the NAC and placebo groups. As a secondary exploratory finding, a possible trend toward prolonged gestational age was observed in the NAC group; however, this result should be interpreted with caution, given the exploratory nature of the analysis, the neutrality of the primary outcome, and the limited sample size.