Introduction:
The administration of steroids during pregnancy up to 34 weeks accelerates the development of fetal lungs and stimulates surfactant production, therefore, it protects premature neonates against infant respiratory distress syndrome. It has been proven that the administration of steroids causes a temporary decrease in the fetal heart rate in fetuses appropriate for gestational age (AGA). How long does the temporary decrease in fetal heart rate (FHR) after steroid administration persist in intrauterine growth restriction fetuses (IUGR)?

Material and methods:
The study was conducted on 152 patients from the Clinic of Obstetrics and Gyneacology MUS in Katowice in 2013–2016, divided into two groups: AGA – 109 cases and IUGR – 43 cases. Steroid prophylaxis – betamethasone or dexamethasone was given in both groups. CTG and Monako records at admission and 24 and 48 hours after steroid administration were analysed with assessment of: FHR baseline, bradycardia episodes as well as LTV and STV parameters. All the results were analysed in the Statistica 12PL program.

Results:
Bradycardia after steroids occurred more frequently in AGA than in IUGR. After the first dose of steroids significantly lower bradycardia was noticed in the AGA group than IUGR (p = 0.0001). The FHR decrease after the first dose of steroids was bigger in the AGA group than in the IUGR group (p = 0.0001). The average STV value after the second dose of steroids was significantly lower in group the AGA group than in the IUGR group (p = 0.006). Oxygen partial pressure was higher in the IUGR group (p = 0.001).

Conclusions:
In the light of the results, it seems that fetuses with intrauterine growth restriction exhibit better tolerance to steroid administration in the form of a less frequent occurrence of bradycardia, higher STV values and smaller fluctuations in FHR.