Journal of Obstetric Anaesthesia and Critical Care

: 2023  |  Volume : 13  |  Issue : 1  |  Page : 24--29

Maternal oxygenation and neonatal outcome in pregnant women with COVID-19: A case series of 20 patients

Takumi Yamaguchi, Tomoaki Fujii, Hiroyuki Hirate, Yusuke Ota 
 Department of Anesthesia and Intensive Care, Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital, Nagoya, Japan

Correspondence Address:
Dr. Takumi Yamaguchi
Department of Anesthesia and Intensive Care, Japanese Red Cross Aichi Medical Center Nagoya Daini Hospital, 2-9 Myokencho, Showa-ku, Nagoya, Aichi 466-8650


Purpose: Management of delivery in pregnant women with coronavirus disease 2019 (COVID-19) is mainly based on extrapolated evidence or expert opinion. This study aimed to assess the clinical manifestations and maternal and perinatal outcomes of COVID-19 during pregnancy. Methods: We retrospectively reviewed the cases of 20 pregnant women infected with the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Their demographic data and clinical characteristics, including symptoms, laboratory examination, and imaging findings, were evaluated. We also assessed the delivery method and timing and clinical courses of mothers, including oxygenation and treatment for COVID-19, as well as neonatal outcomes. Results: The most common symptoms were fever (65%) followed by cough (45%). Seven cases (35%) of preterm birth were observed. Eight patients (40%) required oxygen administration during pregnancy. Among them, two patients (10%) required a high-flow nasal cannula, and one patient (5%) required venovenous extracorporeal membrane oxygenation (VV-ECMO). No maternal death was observed; however, one instance of severe neonatal asphyxia and one intrauterine fetal death were observed. Conclusion: Although most pregnant women with COVID-19 were discharged without any major complications, some cases became severe. Therefore, the timing and method of delivery should be considered for each case to control maternal and infant respiratory conditions.

How to cite this article:
Yamaguchi T, Fujii T, Hirate H, Ota Y. Maternal oxygenation and neonatal outcome in pregnant women with COVID-19: A case series of 20 patients.J Obstet Anaesth Crit Care 2023;13:24-29

How to cite this URL:
Yamaguchi T, Fujii T, Hirate H, Ota Y. Maternal oxygenation and neonatal outcome in pregnant women with COVID-19: A case series of 20 patients. J Obstet Anaesth Crit Care [serial online] 2023 [cited 2023 Mar 27 ];13:24-29
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In December 2019, an outbreak of respiratory disease caused by a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported in China. The disease has been officially named coronavirus disease 2019 (COVID-19) by the World Health Organization, and a pandemic was declared on March 11, 2020.[1] In general, the physiological changes during pregnancy make the mother more vulnerable to severe infections.[2] Anatomical changes, such as an increased lateral diameter of the rib cage and height of the diaphragm, reduce the mother's tolerance to hypoxia.[3] Since SARS-CoV-2 targets the lungs,[4] in this context, COVID-19 may make it more difficult to control the maternal and infant delivery of oxygen because delivery is associated with decreasing hemoglobin concentration because of hemorrhage. Therefore, when a pregnant woman is infected with COVID-19, prompt delivery may be needed for the safety of the mother and the fetus. However, maternal and neonatal data on COVID-19 are still scarce and scattered, and the evidence regarding the management of pregnancy, delivery, and the newborn when the mother has a suspected or confirmed diagnosis of COVID-19 remains fragmented.[5],[6] Early reports from China, the epicenter of the pandemic, suggest that pregnant women are less severely affected than the general COVID-19 population.[7],[8] However, reports from other countries on pregnant women have shown a series of severe cases of maternal illness, including death.[9],[10],[11] Additional information from worldwide is urgently needed to determine whether pregnant women with COVID-19 are at risk of severe disease and discuss the appropriate time of delivery. In addition, since anesthesiologists are responsible for the systemic management of the patient during cesarean section (CS), it is important to understand the clinical course in pregnant women with COVID-19. We aim to show the clinical features and course in consecutive pregnant women with COVID-19 managed at a single center in Japan.

 Material and Methods

This single-center retrospective study included 20 consecutive pregnant women with COVID-19 who gave birth between August 1, 2020 and July 31, 2021. All 20 pregnant women with COVID-19 pneumonia tested positive for SARS-CoV-2 by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) using samples from their airways. Data on maternal and neonatal-perinatal outcomes, including clinical symptoms, maternal oxygen administration, and treatment, were extracted and analyzed. Data were presented as mean (standard deviation), median [range], or n (%). Inferential statistical analysis was not performed due to the small number of overall cases. This study was reviewed and approved by the medical ethics committee of the hospital (Date of the approval was 2021/9/16).


Demographic data

Twenty patients who tested positive for COVID-19 during the course of pregnancy were included in this study. Preterm delivery occurred in seven patients (35%), five patients (25%) had anemia, three patients (15%) had hypertension, and two patients (10%) had diabetes mellitus (DM) [Table 1].{Table 1}

Clinical characteristics

Four patients (20%) were asymptomatic, 13 (65%) had fever, 9 (45%) had cough, 3 (15%) had dyspnea, 3 (15%) had dysgeusia, 2 (10%) had fatigue, 1 (5%) had chest distress, and 1 (5%) had diarrhea. Blood tests at the time of the positive COVID-19 result showed lymphopenia in eight patients (42%). The liver enzymes and renal function were normal in all patients. Eleven patients (55%) had evidence of pneumonia on chest X-ray or computed tomography (CT). Some data from hematological examinations were missing because not all tests were performed when the COVID-19 PCR test was positive in one case of vaginal delivery [Table 2].{Table 2}

Method and time of delivery

The method of delivery was CS in 16 patients (80%) and vaginal delivery in 4 patients (20%), including 1 stillbirth due to intrauterine fetal death. Six patients (30%) were followed up until they tested negative for COVID-19 and then delivered, with three delivering via vaginal delivery and three via CS. The mean gestational age at delivery was 36 weeks. There were four patients (20%) who delivered at less than 37 weeks, two (10%) at less than 32 weeks, and one (5%) at less than 28 weeks. The cause of delivery at less than 32 weeks was deterioration in oxygen saturation due to maternal COVID-19 in two patients and premature separation of the normal placenta in one patient.

Maternal oxygenation and treatment for COVID-19

Four patients (20%) started oxygen administration before delivery and five patients (25%) after delivery. Three out of four patients with oxygen before delivery had an increase in oxygen administration after delivery. Finally, nine patients (45%) required oxygen administration through the perinatal period. A low-flow system with a nasal cannula or mask was used for oxygen administration in six patients (30%), a high-flow nasal cannula was used in two patients (10%), and venovenous extracorporeal membrane oxygenation (VV-ECMO) was used in one patient (5%) [Table 3]. The characteristics and clinical course of eight pregnant women (40%) with COVID-19 who required oxygen administration are described in [Table 4]. Six patients had lymphopenia (<1.0 × 109 cells/L) and seven patients had evidence of pneumonia on chest X-ray or CT. Four patients had at least one of the following complications: obesity, hypertension, or DM.{Table 3}{Table 4}

Five patients (25%) required treatment for COVID-19, and all treatments were started after delivery. All mothers survived and were discharged.

Neonatal outcomes

All mothers had singleton pregnancies. One was stillborn, and one neonate had severe neonatal asphyxia due to premature separation of the normal placenta. No other neonatal deaths or instances of severe neonatal asphyxia were observed.

There were seven infants (37%) with low birthweight. In preterm births, the 1-min Apgar score ranged from 2 to 8, and the 5-min from 6 to 9. Six newborns underwent endotracheal intubation due to problems associated with preterm birth or low birthweight. All neonates and the stillborn baby tested negative for SARS-CoV-2 by qRT-PCR from their airway, and all surviving neonates were eventually discharged from the hospital [Table 5].{Table 5}


In this study, we reported 20 cases of COVID-19 during pregnancy, and delivery was performed on a standby or emergency basis. Eight cases (40%) started receiving oxygen or required more oxygen administration after delivery. Patients who required VV-ECMO support had DM and obesity and were discharged after a severe course of illness that required VV-ECMO support for 46 days. The maternal severity of the disease was similar to those reported worldwide.[6],[10],[11],[12] The clinical findings of pregnant women with COVID-19 did not tend to be significantly different from previously reported symptoms.[6],[13] Pregnant women who required oxygen through the perinatal period were more likely to have lymphopenia at the time of COVID-19 diagnosis (6/8 [75%] with oxygen and 2/11 [18%] without oxygen; data missing for one patient). Although the small amount of data did not allow for a significant difference, there might be an association between these, as lymphopenia was reported to be associated with poorer clinical prognosis and more severe disease in the non-pregnant population with COVID-19.[14]

It has been reported that pregnant women with COVID-19 have a relatively high incidence of preterm delivery.[15] Individual decisions regarding the timing of delivery should be made based on the existing comorbidities, obstetric history, gestational age, and fetal status, and on the maternal respiratory functions including oxygenation, lung condition, respiratory rate, and imaging findings. In mild, stable cases that respond to treatment and where the fetus is not at risk, the pregnancy can be continued under close monitoring.[16] If the mother had no symptoms or mild symptoms at less than 37 weeks, we continued the pregnancy with careful observation. After that, if there was no obstetric indication for CS at the time of delivery and a COVID-19 test was negative, vaginal delivery was performed, and in all cases, both the mother and neonate had a good clinical course. The ideal timing of delivery is important to ensure the safety of the mother and fetus, and further research is needed.

There is no consensus on the method of delivery, with some suggesting that elective CS should not be considered because the clinical course of most women is not severe and vertical transmission has not been clearly demonstrated,[17] but others have suggested that CS is the overall preferred method of delivery worldwide.[18] In the early stage of our study, when COVID-19 was diagnosed, vaginal delivery was performed if the patient was asymptomatic, including imaging findings, and CS was performed if the maternal oxygenation was abnormal. However, due to safety issues for the staff and mother, such as the need for an extended period in personal protective equipment to assist in childbirth and the inability to intervene immediately in case of bleeding or other emergencies, we now perform emergent CS when the maternal oxygenation is poor, and quasi-emergent CS when oxygenation is not necessary even if there are no obstetric indications. In our study, three out of four patients who required oxygen administration before delivery had exacerbation of pneumonia after delivery and required higher levels of oxygen administration. Since the maternal oxygenation deteriorated rapidly in some cases, we believed that emergency CS was preferable in cases where there was a small demand for oxygen if the fetus was determined to be viable after delivery. However, depending on the timing of SARS-CoV-2 infection, the fetus might have inadequate lung function. Therefore, the current data do not allow us to conclude that emergent CS is always preferable in these situations.

There is no evidence that regional anesthesia is preferable compared to general anesthesia in COVID-19 patients. Some reports showed that spinal anesthesia is preferable because of the increased risk of respiratory complications with general anesthesia.[19],[20] We considered this as well, and our procedure was performed under spinal anesthesia whenever possible from the perspective of reducing the possibility of pulmonary complications due to mechanical ventilation. In all cases of CS performed under spinal anesthesia, no serious postoperative complications due to anesthesia were observed. In addition, there were no cases of exacerbation of oxygenation requiring intraoperative artificial respiration, and maternal management was safe. Two patients underwent general anesthesia; one of which was a pregnancy complicated by myelodysplastic syndrome with a low platelet count and risk of spinal anesthesia, and the other case was early placental abruption with a very emergent CS for which general anesthesia was chosen. In both cases, the COVID-19 test was negative at the time of CS, and there was no worsening of postoperative oxygenation or recurrence of COVID-19.

At this time, most of the literature indicates that the vertical transmission of COVID-19 from mother to child is uncertain.[21] In our study, all newborns tested negative for COVID-19, and there was no direct evidence of vertical transmission from the mother to the fetus. In one case of stillbirth, the mother was asymptomatic at the time of COVID-19 diagnosis, and imaging findings showed only mild pneumonia. CS was planned for the next day, but the fetal heart rate suddenly decreased after admission, leading directly to intrauterine fetal death. Placental pathology diagnosed chorioamnionitis, but SARS-CoV-2 infection of the placenta or stillborn baby could not be proven.

In summary, in our experience, most pregnant women with COVID-19 had mild symptoms; however, the infection became severe in some cases after delivery. Therefore, the timing and method of delivery should be considered for each case. When there is an oxygen demand in the mother, early delivery may be preferable if the fetus is judged to have adequate lung function.


Takumi Yamaguchi designed the study, collected and evaluated the data, and wrote the manuscript. All authors revised and approved the final manuscript. All requirements for authorship have been met and each author believes that the manuscript represents honest work.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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