Cottle M K, Van Petten G R, van Muyden P
Am J Obstet Gynecol. 1983 Jul 15;146(6):678-85. doi: 10.1016/0002-9378(83)91011-6.
Timolol, one of the newer beta-adrenergic antagonists, has less depressive effects on the heart than propranolol, so that it has the potential for use by pregnant women. In chronically cannulated ewes, timolol at 0.01 and 0.1 mg/kg of body weight induced maternal and fetal bradycardia; the higher dose also depressed uterine blood flow and fetal PaO2. When this higher dose preceded brief compression of the umbilical cord, uterine flow was further depressed and the usual posthypoxia rebound tachycardia did not develop. Both the blocking of fetal responses to hypoxia (precluding detection of fetal distress) and the reduction in uterine flow led us to conclude that timolol taken by a mother could pose particular hazards for her fetus in hypoxic conditions, such as during cord compression at parturition.
噻吗洛尔是较新的β-肾上腺素能拮抗剂之一，对心脏的抑制作用比普萘洛尔小，因此有可能供孕妇使用。在长期插管的母羊中，体重0.01和0.1毫克/千克的噻吗洛尔可引起母体和胎儿心动过缓；较高剂量还会降低子宫血流量和胎儿动脉血氧分压。当在短暂压迫脐带之前给予较高剂量时，子宫血流量进一步降低，且通常的缺氧后反弹性心动过速未出现。胎儿对缺氧反应的阻断（妨碍检测胎儿窘迫）和子宫血流量的减少使我们得出结论，母亲服用噻吗洛尔在缺氧情况下，如分娩时脐带受压期间，可能会给胎儿带来特殊危害。
