Unselected women at term of pregnancy (37-41 weeks of gestation) undergoing cardiotocography (CTG) according to routine clinical care and with a complete postnatal follow-up were consecutively recruited.~The two groups of women were selected in a random way, and it was an unblended randomization controlled trial (RCT), according to a list created by the website ww.randomization.com.~If the CTG was non-reactive for 10 minutes women who were eligible for the study were randomized into two groups.~An auditive stimulus was generated in group A. This stimulus was produced by hitting a diapason on an acoustic surface, at a distance of 2-3 cm from the mother's skin (in order to avoid mechanical vibration to reach the fetus) in the area near the fetus' head.~The same procedure was repeated three times, waiting 30 seconds between one stimulus and the following one. The total duration of stimulation was about 2 minutes. Cardiac accelerations on the CTG and fetal movements perceived by the mother were recorded in the ten minutes after the stimulus was produced.~No stimulation was produced in group B, but the CTG was prosecuted until the clinical criteria were satisfied. The total length of the CTG was variable from a minimum of 20 minutes to a maximum of one hour.~All the clinical variables were recorded in the Case Report Form (CRF) in particular the lapse of time needed for the first fetal cardiac acceleration and for the first fetal movement to occur.~A complete postnatal follow-up was obtained through the examination of medical records and parental interview.~A power analysis was carried out using Power Analysis Sample Size (PASS) software (Kaysville,UT,USA) and was conducted before the enrollment started. It was estimated that, for a survival comparison test (Log Rank), given the sample allocation ratio=1:1, 100 cases per group would be needed to validate a hazard ratio between group A and group B of 1.5 with a power of 80% and a Type I error of 5%.
The objective of this randomized controlled study was to demonstrate whether fetal hearing can be assessed in utero.