Discussion
In Bhutan, the rate of COVID-19 infection in pregnancy is low as compared to 27.8% in India[4]. The low rate of infection during pregnancy in Bhutan is due to stringent control measures in place to curb the spread of COVID-19 infections.
The majority of the pregnant mothers got infected with COVID-19 in their second and third trimesters [5], which is comparable to the current case.
Preterm delivery is the most reported perinatal effect of COVID-19 infection during pregnancy[6]. Polyhydramnios in COVID-19 infection is not reported in the literature. In the current case, a pregnant mother got infected with COVID-19 at 16 weeks of gestation and developed polyhydramnios later in the pregnancy. The exact cause of polyhydramnios could not be established. Viral infection during pregnancy causes the release of cytokines and cause oxidative stress and disrupts the placental functions and causes polyhydramnios[7]. Since COVID-19 is a viral infection, it may have caused placental insult due to cytokine storm during the pregnancy and resulted in polyhydramnios. The detailed effects of COVID-19 at biochemical levels in the body were studied. However, the effects of COVID-19 at the placenta are not studied; the exact effects of the COVID-19 virus on the placenta remain uncertain because it is a new disease and detailed information is not available in the literature.
This case concludes polyhydramnios may have been caused by COVID-19 infection during pregnancy due to placental insult and oxidative stress.

Acknowledgments

The author is grateful to Dr. Tshewang Gyeltshen (Dental surgeon, Tsirang District Hospital, Bhutan) for reviewing the manuscript and providing feedback.