Purpose: In 2020, a lockdown due to COVID-19 was ordered by the German government, resulting in population-wide restrictions. In this retrospective study, we question the extent to which health policy restrictions have influenced medical diagnoses. Methods: The incidence rates of relevant pregnancy complications during all trimesters of pregnancy were evaluated for a 6-month pre-pandemic period (April–September 2019), in comparison to the same period during the lockdown in 2020. Mothers and newborns who presented at the University Hospital St. Hedwig, Regensburg, Germany, were included in the study. The incidence rates of preeclampsia and suspected FGR (fetal growth retardation), as relevant obstetric diseases, were further compared with those in a post-pandemic period (April–September 2023). Results: A total of 5137 newborns were included, with 1709 born during the 6-month pre-pandemic period, 1806 during the 6-month lockdown period and 1687 during the 6-month post-pandemic period. During the pandemic period, significantly fewer patients were hospitalized due to hyperemesis gravidarum (1.8% vs. 0.9%, p = 0.04). No differences were observed concerning the incidence of miscarriages before and after 14 weeks of gestation (WG), preterm deliveries (<37 WG), gestational age at preterm birth and birth weight. Likewise, within the group of preterm-born babies, no difference was observed in preeclampsia among the two periods. However, in the pandemic period, the frequency of preterm-born babies with suspected FGR was significantly lower than in the pre-pandemic period (1.5% and 0.6%, p = 0.01). Regarding this point, we analyzed data of all newborns in a comparative post-pandemic period in 2023 (n = 1687). This group presented a significantly increased FGR incidence compared to that during the pandemic, therefore returning to the pre-pandemic level (1.5% and 1.4%, p = 0.145). Conclusions: During the COVID-19 pandemic, there were significantly fewer deliveries with suspected FGR. After all specific restrictions on elective and outpatient services were lifted, the incidence of suspected FGR returned to its initial level, suggesting that the diagnosis—as a solely machine-dependent and not symptom-based diagnosis—was partly exaggerated in both the pre-and post-pandemic periods.