[THE EFFECT OF MAGNESIUM SULPHATE AND LABETALOL ON PLACENTAL VESSELS REACTIVITY USING THE EX-VIVO PLACENTAL PERFUSION MODEL]

Background: The use of magnesium sulphate (MgSO4) in combination with antihypertensive drugs such as Labetalol is common in preeclampsia.

Objectives: We aimed to examine the effects of MgSO4 and Labetalol on placental blood vessel reactivity in response to angiotensin II (ATII).

Methods: A dual-perfused single cotyledon model was used. Placentas from normal pregnancies were obtained. Selected cotyledons were cannulated and dually perfused. The intervillous space was infused for 60 minutes with three perfusion protocols: MgSO4 [7 mg%], MgSO4 [7 mg%], with Labetalol [1×10-4 mmol/L] and controls. After 60 minutes, ATII was injected as a bolus into the chorionic artery causing contraction/relaxation response in the fetal compartment. Perfusion pressure was measured continuously during contraction and relaxation phases.

Results: Twenty complete experiments were performed (9 controls, 7 with MgSO4 (7mg%) and 4 with MgSO4 [7mg%] and Labetalol [1×10-4 mmol/L]). Basal perfusion pressure did not differ between the treatment groups. Mean area under the pressure curve (AUC), the amplitude of the contraction response and the relaxation factor did not differ significantly between the groups in response to ATII administration.

Conclusions: Magnesium sulphate and Labetalol did not have any effect on feto-placental vasculature reactivity.