The health emergency due to COVID-19 has caused the restriction in access to health services, including care for pregnant women, whose prenatal control in person is limited in Peru. The objective of the research was to evaluate the influence of a telehealth intervention on the knowledge of danger signs in pregnancy, childbirth and postpartum in pregnant women during the health emergency due to COVID-19. A quasi-experimental research was carried out with 64 pregnant women attended by telehealth (experimental group) and 64 pregnant women attended by face-to-face appointments (control group) in the city of Huaraz (Ancash, Peru, 3,052 m.a.s.l.). A telehealth intervention was applied only to the experimental group between September and November 2020, having assessed the knowledge of danger signs in pregnancy, childbirth and postpartum using a previously validated questionnaire. The SPSS V22.0 statistical package and the Chi square test were used. After the intervention, it was evidenced that the proportion of pregnant women with a high level of knowledge was upper in the experimental group compared to the control group, with respect to the danger signs in pregnancy [43 (67.2%) vs. 28 (43.8%)], childbirth [42 (65.6%) vs. 27 (42.2%)] and postpartum [47 (73.4%) vs. 31 (48.4%)], determining the existence of statistically significant differences between the experimental and control groups (p < 0.05). It was concluded that the application of telehealth intervention increased the knowledge of danger signs in pregnancy, childbirth and postpartum in pregnant women during the health emergency due to COVID-19.