The COVID 19 pandemic represents a major stress factor for non-infected pregnant women. Although maternal stress during pregnancy increases the risk of preterm birth and intrauterine growth restriction, an increasing number of studies yielded no negative effects of COVID 19 lockdowns on pregnancy outcome. The present study focused on pregnancy outcome during the first COVID 19 lockdown phase in Austria. In particular, it was hypothesized that the national lockdown had no negative effects on birth weight, low birth weight rate and preterm birth rate. In a retrospective medical record-based single center study, the outcome of 669 singleton live births in Vienna Austria during the lockdown phase between March and July 2020 was compared with the pregnancy outcome of 277 live births at the same hospital during the pre-lockdown months of January and February 2020 and, in addition, with the outcome of 28,807 live births between 2005 and 2019. The rate of very low gestational age was significantly lower during the lockdown phase than during the pre-lockdown phase. The rate of low gestational age, however, was slightly higher during the lockdown phase. Mean birth weight was significantly higher during the lockdown phase; the rates of low birth weight, very low birth weight and extremely low birth weight were significantly lower during the lockdown phase. In contrast, maternal gestational weight gain was significantly higher during the lockdown phase. The stressful lockdown phase in Austria seems to have no negative affect on gestational length and newborn weight among non-infected mothers.