Background: It is unclear if maternal and foetal outcomes of pregnant women admitted to the intensive care unit (ICU) with severe A/H1N1pdm and SARS-CoV-2 infection are different. Methods: Clinical profile, treatment and outcomes were compared between A/H1N1pdm and SARS-CoV-2 infected women. Factors associated with maternal mortality were explored using logistic regression analysis and expressed as odds ratio (OR) with 95% confidence interval (CI). Results: Fifty-six women (A/H1N1pdm=42, SARS-CoV-2=14) were admitted at a median (interquartile) gestational age of 32.3 (27.3-36) weeks. Gestational diabetes (p=0.02), hypothyroidism (p=0.04), hypertension (p=0.09) and infertility treatment (p= 0.09) were more frequent among SARS-CoV-2 than A/H1N1pdm. Time from symptom onset to ICU admission was 4 (3-5) days. Although APACHE-II score was similar in both groups, more patients with A/H1N1pdm were tachycardic (87.8% vs. 21.4%, p=0.001) and had lower median oxygen saturation (89% vs. 94%, p=0.02) at admission. Ventilatory support was required in all A/H1N1pdm patients and 78.6% with SARS-CoV-2 (p=0.013). Ventilation duration was 12 days (4-18) for SARS-CoV-2 and 4 days (2-7) for A/H1N1pdm (p<0.001). Cardiac and renal dysfunction occurred with similar frequency. Maternal mortality was 21.4% in A/H1N1pdm and 28.6% in SARS-CoV-2 (p=0.44). Foetal loss occurred in 26.3% of SARS-CoV-2 and 16.7% of A/H1N1pdm infections (p=0.15). There were 4 neonatal deaths. On multivariate regression analysis, delayed presentation was independently associated (OR 1.8, 95%CI 1.07-3.06) with maternal mortality. Conclusions: Respiratory failure due to A/H1N1pdm and SARS-CoV-2 infections in pregnancy is associated with maternal mortality and foetal loss. Delayed presentation is independently associated with maternal death.