The requirement by many hospitals in Japan that women wear face masks while in labor to prevent coronavirus transmission has stirred debate among new mothers online, with some saying it was distressing while others argue it is essential to reduce infection risks.

Health experts say mask-wearing during delivery poses no danger of oxygen deprivation to mother and child -- one of the concerns raised by critics. But some suggest medical facilities should take a more flexible approach by recognizing the additional stress imposed by the pandemic on parturient women.

A masked mother holds her newborn baby that is wearing a face shield at a hospital in Toyota, central Japan, on May 28, 2020, amid continuing worries about the coronavirus. (Kyodo)

In mid-July, an online conversation was sparked when a photo of a notice requiring women to wear face masks during childbirth was posted on Twitter. It is believed to have been taken by a woman during a hospital visit.

"Won't it lead to a lack of oxygen?" asked the woman. "(Labor) is already tough as it is," one person responded, while another countered by saying, "It is necessary to prevent infections at hospital."

A 26-year-old woman who shared online her experience of giving birth to a daughter in May at a Tokyo hospital while wearing a face mask told Kyodo News she thought the requirement could not be helped.

But she said it made it harder to breathe after her contractions started, adding that she was only told of the hospital's requirement after labor pains hit. "I wish they could have explained it to me earlier," she said.

According to a May survey conducted by the Japan Society of Obstetrics and Gynecology, to which 766 delivery facilities across Japan responded, 64 percent ask mothers to wear face masks during childbirth.

Mask-wearing by both medical service providers and mothers lowers the risk of the virus spreading, the society said, asking people to "cooperate as much as possible."

The University of Tokyo Hospital, which oversees around 1,000 deliveries a year, has required women in labor to wear a face mask since April.

The hospital conducts novel coronavirus tests on expectant mothers before labor, but the possibility of false-negative results has led it to maintain the requirement.

"Large amounts of (possibly virus-carrying) droplets are discharged when mothers breathe deeply to ease labor pain or during delivery. We would like to maintain our request until the pandemic subsides," said a university hospital official.

Meanwhile, Saitama Medical University Hospital has amended its mask-wearing policy following complaints from women and now does not ask them to don face masks during labor if their polymerase chain reaction, or PCR, tests, conducted shortly before delivery, come out negative.

Doctors and midwives assisting in the birth wear protective gear such as surgical masks, waterproof gowns and face guards.

"We don't know what is the correct thing to do. We can only implement thoroughly steps that can be taken as we keep an eye on the virus situation," said Yoshimasa Kamei, a professor of the university's obstetrics and gynecology department.

Kaori Ichikawa, an associate professor of nursing at Tokyo University of Information Sciences, said that while mask-wearing is necessary, the increased anxiety and stress on mothers giving birth during the pandemic must be recognized.

"Medical facilities should fully explain to them the necessity of mask-wearing, check up on them more, and be more sensitive to their feelings than usual," she added.