An Interventional Pilot Study on the Effect of Extra Virgin Olive Oil on Women with Preeclampsia Risk

Official title

Effect of Extra Virgin Olive Oil Addition in the Diet of Women with Higher Risk for Preeclampsia - Interventional Pilot Study

Overview

This study explores the potential benefits of Extra Virgin Olive Oil from early harvested olives (EVOOEH) in reducing the risk of preeclampsia (PE) in high-risk pregnant women. EVOO, particularly EVOOEH, is rich in antioxidant compounds, including polyphenols, which may help improve vascular health and reduce oxidative stress, potentially preventing complications like PE. The hypothesis is that EVOOEH may reduce microvascular damage, improve placentation, and prevent dysglycemia, ultimately lowering the risk of PE and gestational diabetes mellitus (GDM). The primary objective of this intervention is to evaluate the effect of EVOOEH on PE incidence during pregnancy, specifically assessing the impact on markers of PE, GDM, and other pregnancy-related outcomes. The study is designed as an interventional, randomized, parallel-assignment dietary trial involving 156 pregnant women at high risk for PE, aged 18 to 45. Participants will receive either a daily dose of 42 ml (three tablespoons) of EVOOEH or the Ministry of Health (MOH) general dietary recommendations for pregnancy for four weeks, starting between 8 to 16 weeks of gestation. The study arms are as follows: EVOOEH arm: Participants will consume 42 ml of EVOOEH daily along with MOH dietary recommendations for four weeks (n=78). Control arm: Participants will follow only the MOH dietary recommendations for four weeks (n=78). The intervention will occur alongside low-dose aspirin prophylaxis for PE prevention, as recommended by guidelines for women at high risk. Key compliance markers include adherence to a Mediterranean diet as measured by the Mediterranean Diet Adherence Screener (MEDASIS) and hydroxytyrosol levels in maternal blood. The study will mask data analysis to minimize bias. The primary outcome measures are maternal glucose challenge test (GCT) results and the serum soluble FMS-like tyrosine kinase 1/placental growth factor (sFlt-1/PlGF) ratio at the end of the intervention. Secondary outcomes include the incidence of GDM, PE, cesarean sections, preterm delivery, small for gestational age (SGA) births, blood pressure measurements, gestational age at delivery, and any relevant data available from participants' medical records. Eligibility criteria include pregnant women with risk factors for PE such as a history of PE, chronic hypertension, obesity, or diabetes, among others, and a gestational age between 8 to 16 weeks. Exclusion criteria involve low-risk pregnancies or women who refuse participation. Blood samples will be collected to assess 25-hydroxyvitamin D (25(OH)D), hydroxytyrosol (HT), and the sFlt-1/PlGF ratio. Laboratory analyses will be conducted at Barzilai University Medical Center and the Weizmann Institute of Science. This study seeks to determine whether EVOOEH's higher polyphenol content compared to standard EVOO can offer additional protective benefits against PE and related complications in high-risk pregnancies.

Interventions

• Other Dietary MOH recommendations and daily addition of 42 ml (three tablespoon) at each morning of EVOOEH
  Dietary intervention study: high-risk pregnant women receiving a link to MOH general dietary recommendations for pregnancy (MOH recommendations) with addition of three tablespoon (42 ml) EVOOEH (up to 0.8% free acidity) per day at each morning for four weeks during the first half of pregnancy (gestational ages between 8 to 16 weeks)
• Other Dietary MOH recommendations
  Dietary intervention study: high-risk pregnant women receiving a link to MOH general dietary recommendations for pregnancy (MOH recommendations) for four weeks during the first half of pregnancy (gestational ages between 8 to 16 weeks)

Primary outcome measures

• sFlt-1/PlGF ratio [Time frame: 4 weeks]
• GCT result [Time frame: 4 weeks]

Secondary outcome measures (8)

• SBP [Time frame: At recruitment and approximately 4 weeks post intervention initiation]
• DBP [Time frame: At recruitment and approximately 4 weeks post intervention initiation]
• PE [Time frame: From intervention to delivery]
• GDM [Time frame: From intervention to delivery]
• CS [Time frame: At delivery]
• Preterm [Time frame: At birth]
• SGA [Time frame: At birth]
• Birthweight percentile [Time frame: At birth]

Eligibility criteria

Inclusion criteria

• Pregnant women with clinical risk factors for PE \[previous PE, primigravida, chronic hypertension, chronic renal disease, autoimmune disease (systemic lupus erythematosus, antiphospholipid antibody syndrome), overweight (BMI>30), obesity (BMI>35), morbid obesity (BMI>40), presentational diabetes (type 1 or type 2), multiple pregnancy\].
• gestational ages of 8 to 16 weeks attending Barzilai University Medical Center at Ashkelon (BUMCA).

Exclusion criteria

• Refusing enrollment or participation.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Prevention

Study locations

Israel · 1 center

• Barzilai University Medical Center — Ashkelon

Publications

• Ovadia YS, Navarro DA, Rimler A, Brandis A, Ditchi E, Monsonego-Ornan E, Solt I, Anteby EY, Shenhav S. An interventional pilot study protocol on the effect of extra virgin olive oil on women with preeclampsia risk. Ann Transl Med. 2026 Feb 28;14(1):5. doi: 10.21037/atm-25-122. Epub 2026 Feb 25. PMID 41835790

Identifiers

NCT: NCT06759545 · 0049-24-BRZ

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗