prophylactic

孕妇在孕期服用叶酸是一种常见的预防性措施。

Taking folic acid during pregnancy is a common ___prophylactic measure.

旅行前服用抗疟疾药物是一种有效的预防措施。

Taking anti-malaria medicine before the trip is a ___prophylactic effective measure.

医生建议每天服用维生素作为预防感冒的措施。

The doctor recommended taking daily vitamins as a ___prophylactic measure against colds.