Introduction: Prenatal tests can increase the stress levels of pregnant women. One of the tests performed to evaluate fetal health during pregnancy is the Nonstress Test (NST).

Objective: To evaluate the effect of NST device noise level on stress parameters in primiparous pregnant women.

Method: A randomized controlled, prospective study was conducted with 44 pregnant women in a State Hospital in Istanbul/Turkey between 01.02.2021 and 01.10.2021.

Personal Information Form, Spielberger State Anxiety Inventory, Hillrom Welch Allyn Connex Spot Monitor, Gluco Dr Glucometer, Extech SL 400 Personal Noise Dosimeter, Sennheiser HD 450BT ANC Over-Ear Bluetooth Headset, Eppendorf Tube, Philips Avalon FM20 NST were used to collect data. A p value of <.05 was considered significant in the statistical evaluation.

A number of tests are used to evaluate fetal health during pregnancy. One of these tests is the NST. NST is a frequently used fetal evaluation method in gynecology clinics/services during pregnancy and labor. The sound levels of the NST device are created in a way that the healthcare professional can adjust, and at the same time, the average dB(A) range of the sound levels is not known. It has been stated in many studies that noise causes stress in individuals, and that the stress experienced in pregnant women is associated with negative maternal and neonatal outcomes. It is important to evaluate NST noise levels and stress parameters in order to maintain NST, which is a frequently used fetal evaluation method in the prenatal period in clinical practice, without causing maternal stress and to prevent possible negative consequences. With the information to be obtained in line with the results of the research, it is aimed to maintain the noise level of the NST device used by the midwives in the most appropriate sound range for the pregnant women and thus to ensure that the stress levels of the pregnant women are at the lowest level during the procedure.

This study was carried out to evaluate the effect of NST device noise level on stress parameters in primiparous pregnant women.

Inclusion Criteria:

• Voluntarily agreeing to participate in the research,
• Over 18 years old,
• Literate,
• Fluent in Turkish
• 32-42 of your pregnancy. in the week,
• Having a healthy pregnancy,
• No adrenal insufficiency,
• No problems with hearing,
• No psychiatric diagnosis during or before pregnancy,
• No history of infertility,
• Coming to routine pregnancy and NST control,
• Have not had any food or drink for at least two hours before the procedure,
• Primiparous pregnant women without contractions were included.

Exclusion Criteria:

• Pregnant women whose contractions are detected during the NST procedure,
• Pregnant women with deceleration detected in the NST procedure were excluded from the study.

Only pregnant women were included in the study.

It was decided to make the minimum sample size required in the study by power analysis, taking into account the differences of the pre-test and post-test variables, which are the primary results. More than 2 groups analysis (ANOVA) test in repeated measurements in the calculation, effect size: 0.25, type 1 error rate (α)=0.05, power of the study (1- β) was 0.80 (Type II error= 0.20). Accordingly, the minimum number of samples to be reached was calculated as 40 in total, and the study was completed with 44 samples, taking into account the 10% risk of loss.

It is not yet known if there will be a plan to make IPD available.