Opioids is known that produce not only analgesia but also hyperalgesia through activation of central glutaminergic system-GABA. At the same time, recently it was found that the main opioid receptor (OPRM1) is present on human granulosa cells and exogenous opiates and their antagonists can influence granulosa cell vascular endothelial growth factor (VEGF) production via OPRM1, causing ovarian hyperstimulation syndrome.

This study aims to investigate if a single exposure to opioids is enough to produce activation of stress mechanism during oocyte retrieval.

The main opioid receptor (OPRM1) is present on human granulosa cells and exogenous opiates and their antagonists can influence granulosa cell vascular endothelial growth factor (VEGF) production via OPRM1, causing ovarian hyperstimulation syndrome.

This study aims to investigate if a single exposure to opioids is enough to produce activation of stress mechanism during ultrasound-guided oocyte retrieval. It will be measured the level of cortisone before and 15min after iv administration of fentanyl on blood and on oocyte fluid.

Inclusion Criteria:

• American Physical Status I-III, BMI<30,

Exclusion Criteria:

• Heart failure
• hepatic failure, hepatitis,
• drug abuse
• receiving b blockers
• receiving b agonists (even bronchodilators)

Healthy volunteers oocyte donor