Short-term effects of antenatal betamethasone on fetal cardiovascular and circulation status: A quasi-experimental observational (before-after) study.

Background: The administration of antenatal corticosteroid is a standard treatment to reduce the rate of perinatal mortality and morbidity; however, there is limited evidence regarding the potential effects of betamethasone on the constriction of the ductus arteriosus (DA).

Objective: This study aimed to investigate the short-term effects of antenatal betamethasone on fetal cardiovascular and circulation status.

Materials And Methods: This quasi-experimental observational (before-after) study was conducted on 32 singleton fetuses. The participants were healthy pregnant women with a diagnosis of placenta accreta spectrum who were eligible for 2 doses of betamethasone and referred to prenatal care clinic, Vali-E-Asr hospital, Tehran, Iran from January 2021-May 2022. The results of fetal echocardiography and Doppler sonography were compared before and after the administration of antenatal corticosteroid therapy.

Results: Following betamethasone injection, significant increases were observed in peak systolic and diastolic velocity of the DA without constriction of the DA (p 0.001, p = 0.002 respectively). However, no significant changes were observed in right ventricular function, tricuspid valve function, Doppler of ductus venous, and peak systolic velocity of the aortic isthmus (p 0.05). Doppler examination of the uterine, umbilical, and middle cerebral arteries also showed no significant changes (p 0.05).

Conclusion: Considering the benefits of antenatal corticosteroid therapy, its administration seems reasonable in preterm births. The transient changes in ductal blood flow are not prohibitive.