Comparative Study of Pregnancy Outcomes Before and During the COVID-19 Pandemic

In December 2019, the World Health Organization (WHO) was alerted to cases of severe acute respiratory syndrome caused by a novel coronavirus in Wuhan, China. The WHO subsequently declared COVID-19 a global pandemic (1). The highest disease prevalence has been reported in the United States, India, and Brazil, while Iran ranks 17th worldwide with over seven million confirmed cases and more than 143,000 deaths (2). Pregnant women represent a vulnerable population during disease outbreaks like COVID-19 and require special precautions (3-5). Previous research on SARS and MERS epidemics demonstrated that pregnant women face elevated risks of complications that may adversely affect pregnancy outcomes (5-7). The COVID-19 pandemic led to significant reductions in prenatal care services, resulting in missed screenings for critical pregnancy-related conditions such as gestational diabetes (8-11). Physiological changes during pregnancy not only increase susceptibility to infection but may also accelerate progression to respiratory failure when the respiratory system is affected (12). Thromboembolic events represent a serious complication of COVID-19, stemming from coagulation pathway activation, disseminated intravascular coagulation (DIC), and fibrinolysis with dynamic coagulation alongside thrombocytopenia (13, 14). Pregnant women with COVID-19 face synergistic risks for thrombosis (3), with those at risk for thromboembolism showing higher mortality rates (15, 16). A systematic review by Di Masio et al. reported significantly higher rates of preeclampsia among COVID-19-positive pregnant women compared to their non-infected counterparts. Maternal mortality rates during SARS and MERS outbreaks reached 25.8% and 28.6%, respectively, with these infections associated with preterm delivery, fetal growth restriction, and pregnancy loss (4). While some studies have documented increased preterm birth rates during the COVID-19 pandemic (14, 17, 18), observational data from Ireland and Denmark paradoxically show significant decreases in preterm births, the reasons for which remain unclear (19, 20). Viral infections during pregnancy may exert long-term effects on fetal development. Elevated maternal inflammatory responses to viral infection can influence fetal brain development, potentially leading to diverse neurological complications (21). Current evidence suggests no definitive negative outcomes for infants born to COVID-19-positive mothers. Among 13 studies examining neonatal COVID-19 status, only three reported positive cases, with affected infants typically presenting as asymptomatic or with mild, self-limiting symptoms (17, 22, 23).

The full impact of the COVID-19 pandemic on maternal and neonatal outcomes remains uncertain, with study results often contradictory. Limited research has addressed the unique challenges pregnant women face during disease outbreaks that exacerbate their vulnerability. A comprehensive analysis of pregnancy outcomes during pandemics could provide valuable insights for future preparedness. This study compares pregnancy outcomes before and during the COVID-19 pandemic, evaluates existing evidence on effects of COVID-19 on pregnancy, and identifies areas requiring further investigation. The present study provides a rigorous comparison of pregnancy outcomes before and during the COVID-19 pandemic, offering critical insights into the disease’s impact on maternal and neonatal health. By identifying key research gaps and proposing priority areas for future investigation, this work establishes a scientific framework to guide subsequent studies. Our findings not only contribute substantially to the existing body of knowledge but may also inform the development of targeted interventions to mitigate pregnancy risks during future public health crises. Given the profound effects of the COVID-19 pandemic on healthcare systems worldwide and the particular vulnerability of pregnant women, the evidence from this study serves as an authoritative resource for policymakers, obstetricians, and public health researchers. A deeper understanding of the virus’s impact on pregnancy outcomes will not only enhance prenatal care protocols during similar outbreaks but could ultimately save countless maternal and neonatal lives in future emergencies.

This cross-sectional analytical study examined pregnant women referred to Imam Reza Hospital in Kermanshah, Iran, across two distinct periods: Pre-pandemic (2017 - 2019) and during the COVID-19 pandemic (2020 - 2022). The study utilized clinical records from 1,500 pregnant women, comprising 1,000 pre-pandemic cases and 500 cases from the pandemic period. Participants were selected through convenience sampling. Inclusion criteria required: (1) Pregnancy without pre-existing comorbidities; and (2) availability of complete medical documentation. The study excluded pregnant women whose medical records were incomplete or inaccessible for data collection.

Out of 1500 cases of pregnant women referred to Imam Reza Hospital, 1000 cases belonged to the before, and 500 cases were during the COVID-19 pandemic. Table 1 compares pregnancy outcomes before and during the COVID-19 pandemic. The frequencies of preeclampsia and gestational diabetes were significantly higher during the pandemic. Chi-square tests with Yates’ correction confirmed statistically significant differences between the two groups for these outcomes (P < 0.05). Conversely, the frequencies of cesarean delivery, postpartum hemorrhage, stillbirth, placental abruption, abortion, preterm birth, and urinary tract infection were significantly lower during the pandemic compared to the pre-pandemic period. Chi-square tests (with Yates’ correction) indicated statistically significant differences between the two groups for these outcomes (P < 0.05).

As shown in Table 2, the Mann-Whitney test revealed a statistically significant difference in the mean Apgar scores at both 1 and 5 minutes between the two groups (P < 0.05), with significantly higher scores observed during the COVID-19 pandemic. The chi-square test with Yates’ correction indicated no statistically significant differences between the groups regarding the need for neonatal resuscitation, birth weight, or congenital anomalies (P < 0.05).

Fetal and neonatal outcomes are presented in Table 3. The frequency of IUGR was 1% in the pre-pandemic period compared to 0% during the COVID-19 pandemic. Fisher’s exact test revealed a statistically significant difference in IUGR incidence between the two groups (P < 0.05).

The results of comparing the variables of age, education, number of deliveries, history of abortion, history of preterm delivery, type of delivery, preeclampsia, postpartum hemorrhage, gestational diabetes, abortion, premature delivery, urinary tract infection, IUGR, and low Apgar scores in the first and fifth minutes showed significant differences between the two groups (Table 4). To investigate the effect of significant variables, a logistic regression model was applied. The results of logistic regression indicated that during the COVID-19 pandemic, the odds ratio for a history of abortion was 2.6 times, the type of natural delivery was 1.4 times, preeclampsia was 2.2 times, and gestational diabetes was 8.01 times more than before the COVID-19 pandemic (Table 4).

We compared pregnancy outcomes in women before and during the COVID-19 pandemic. Our results showed an increased incidence of preeclampsia during the pandemic, consistent with the findings of Di Masio et al. (4). In women with preeclampsia during mid-to-late pregnancy, elevated vascular resistance and endothelial cell dysfunction are common. Given the potential role of endothelial cell function in the development and progression of COVID-19, infected pregnant women may face a higher risk of complications. Our study also revealed a significant rise in gestational diabetes cases during the pandemic. Zanardo et al. reported a similar increase in their case-control study, attributing this trend to first-trimester quarantine experiences and post-traumatic stress, which may contribute to glucose metabolism disorders (24, 25).

Contrary to some previous studies (14, 17, 18), our findings indicated a decrease in preterm deliveries during the pandemic. However, observational studies from Ireland and Denmark also reported a significant reduction in preterm birth rates (19, 20). The frequency of IUGR declined during the pandemic, though birth weight remained unchanged. Similarly, Pirjani et al. found no significant association between COVID-19 infection and low birth weight, IUGR, NICU admission, or neonatal sepsis in their prospective cohort study at Arash Hospital in Tehran (6).

Cesarean delivery rates decreased during the pandemic, possibly due to more cautious decision-making by obstetricians to avoid unnecessary procedures and their long-term complications. In contrast, Kohi and Ajri reviewed 20 studies and noted a higher prevalence of cesarean deliveries among COVID-19-positive pregnant women. They concluded that while vaginal delivery does not inherently increase the risk of maternal COVID-19 transmission, its prolonged duration may elevate neonatal exposure risk (26).

Apgar scores at one and five minutes improved during the pandemic, with no cases requiring respiratory resuscitation or hospitalization for respiratory distress. This contrasts with Fayazi et al.’s review, which identified respiratory distress as a potential neonatal complication of COVID-19. Although vertical transmission via vaginal delivery remains unproven, their findings warrant further consideration (27).

Postpartum hemorrhage cases decreased during the pandemic, aligning with Pirjani et al.’s cohort study, which found no significant difference in postpartum bleeding between healthy and COVID-19-infected women (6). Notably, abortion rates declined significantly during the pandemic, likely due to reduced workplace commuting, telecommuting benefits, and local quarantine measures. Stillbirth and placental abruption rates remained unchanged. Yan et al. similarly reported no increased miscarriage risk among COVID-19 patients (28). However, Kazemi et al.’s systematic review linked COVID-19 to first- and second-trimester abortions, attributing these to placental insufficiency caused by inflammation. A pro-inflammatory cytokine storm was proposed as a potential mechanism for early pregnancy loss (29).