Background <p>Evidence as to whether COVID-19-mitigating measures affected the metabolic status of pregnant women is lacking. This is the first study to analyze changes in pre-pregnancy weight, body mass index (BMI), gestational weight gain (GWG), the prevalence of overweight and obese women conceiving, and delivery-associated complications during the COVID-19 pandemic compared to pre-pandemic times. </p> Methods <p>This nationwide cohort study analyzed birth registry data from all obstetric departments in Austria. The period from 05 to 12/2020 was defined as the pandemic period (<i>N</i> = 30,806), whereas the period from 05–12/2015–2019 was defined as the pre-pandemic period (<i>N</i> = 162,463).</p> Results <p>The pre-pregnancy weight and BMI were 64 (57–73) kg and 23.03 (20.70–26.37) kg/m² during the COVID-19 pandemic versus 63 (56–72) kg and 22.7 (20.57–22.77) kg/m² during the pre-pandemic period (<i>p</i> &lt; 0.001). The GWG remained constant at 13&#xa0;kg and 4.8&#xa0;kg/m² between the exposure and control periods (<i>p</i> = 0.69; <i>p</i> = 0.65). A multivariate analysis revealed that the COVID-19 pandemic had a significant impact on pre-pregnancy weight (OR 1.01; 95% CI 1.00-1.02; <i>p</i> &lt; 0.001) after adjusting for covariates (age, height, parity). During the COVID-19 pandemic period, a significantly higher percentage of women with overweight and obesity class I-III were reported compared to pre-pandemic times (<i>p</i> = 0.003, <i>p</i> &lt; 0.001, <i>p</i>&lt; 0.001). Finally, both more macrosomic infants (<i>p</i> = 0.003) and vacuum-assisted deliveries (<i>p</i> = 0.020) occurred during the COVID-19 pandemic.</p> Conclusions <p>COVID-19-mitigating measures worsened the metabolic status of pregnant women. To counteract this, targeted intervention programs must be implemented immediately as an integral part of the pandemic recovery plan.</p>