• A new collaborative research network set up by maternity hospitals here studied 16 pregnant women who contracted Covid-19
• So far, five have given birth, two suffered miscarriages and all the women have made a full recovery
• Two of the women experienced severe pneumonia with one needing supplemental oxygen in intensive care
• The study found no evidence of transmission of the coronavirus from mother to baby

SINGAPORE — Being pregnant during the Covid-19 pandemic, Madam Nurshila Zainal was “very careful” but her worst fears came true when she tested positive for the coronavirus 25 weeks into her pregnancy, along with six other family members.

Madam Nurshila, 35, who said that she was “very scared” at the height of the outbreak here, is one of 16 women in Singapore to contract Covid-19 while pregnant and who are the subject of the country’s first study of pregnant women with the coronavirus.

The recently published study concluded that while most pregnant women with Covid-19 were mildly infected, severe Covid-19 could occur in older pregnant women with a high body mass index (BMI).

All 16 women in the study made a full recovery, and there was no evidence the virus was transmitted from the mother to baby.

The study was conducted by a collaborative research network set up by Singapore’s three public hospitals offering maternity services, KK Women’s and Children’s Hospital (KKH), Singapore General Hospital (SGH) and the National University Hospital (NUH). It is called the Singapore Obstetrics and Gynaecology Research Network (Sorn).

A media release issued on Friday (Dec 18) by the three hospitals stated that “the study's results were reassuring”. 

“This demonstrates that the incidence and severity of Covid-19 among pregnant women parallels general population trends, and that the majority of patients will recover from Covid-19,” they added.

Associate Professor Citra Mattar (left) with Madam Nurshila Zainal (right) and her daughter Adinda Asy Syifaa. Photo: National University Health System

Madam Nurshila told TODAY that she had been very careful in trying to avoid Covid-19.

“Even when I took public transport, I was very scared to hold on to the handrails. I was very paranoid. Once, there was this 'uncle' beside me who was coughing very badly (so) I immediately got off the bus and rushed to the toilet to wash my hands and my bag.

“Knowing I was pregnant, I was very scared. I really wanted to keep myself safe,” she said.

Ultimately, she contracted Covid-19 from her father-in-law who works at Singapore Changi Airport. She was admitted to NUH on March 28 with symptoms of a sore and itchy throat and a bad cough.

After results came back confirming that she was positive for the virus, Madam Nurshila was transferred to Mount Alvernia Hospital where she was isolated for 23 days.

She made a full recovery and delivered her second child, a daughter, in July.

The 16 women in the study were 23 to 36 years old, and were variously infected with Covid-19 between March 15 and Aug 22 in all three trimesters of pregnancy.

The findings among the 16 patients seen at all four public healthcare institutions – KKH, SGH, NUH, and the National Centre for Infectious Diseases — were that:

• 37.5 per cent of them were infected in the first trimester of pregnancy 

• 43.8 per cent were infected in the second trimester

• 18.7 per cent were infected in the third trimester

To date, five women, including Madam Nurshila, have delivered babies at term and displayed both maternal and neonatal immunity to Sars-CoV-2 — the virus that causes Covid-19 — with no evidence of viral transmission from mother to baby.

At a media briefing on Friday, Associate Professor Citra Mattar, a consultant at NUH’s division of maternal fetal medicine from the department of obstetrics and gynaecology, said that questions remained about this lack of transmission.

“We don’t know if these antibodies are produced by the individual as a response to the virus or if this is the longer lasting antibody that is a sort of memory antibody, which is the typical antibody that's passed from mother to baby,” she said.

“Unfortunately, we don't have many details as to what kind of antibodies these are and how protective these are. What we know is that from the patients that we have observed, these antibodies do tend to decay, as they often do with time,” she added.

“So we anticipate that if these are antibodies passed from mother to baby as a result of the mother having the infection and passing her protection onto the baby, that these antibodies will decay in time.”

Assoc Prof Citra added that the number of antibodies varied among the five babies.

“A shorter duration from the time of infection to the time of delivery, the higher the level of antibodies. And conversely, the longer the duration from the time of the infection to the mum, to the time of delivery, the lower the antibodies,” she said.

“So we anticipate that the women who were infected in their first trimester, by the time they deliver, they will probably have very low antibodies or they may not have any antibodies at all because they would be delivering six months or more after the initial infection.”

Plans are underway to monitor these babies at six months and again at 12 months. The authors said that they are in talks with the Ministry of Health on whether the project could continue for longer.

Two pregnant women in the study suffered severe pneumonia, while two had miscarriages. One of the women required transfer to an intensive care unit for supplemental oxygen support.

Assoc Prof Citra explained that one of the miscarriages was in the first trimester. The woman had minimal symptoms and no other medical issues. As such, her pregnancy loss was most likely not related to Covid-19, the study concluded.

The other patient who miscarried, however, had a “severe disease” with Covid-19.

She had flown in from the United Kingdom when she was 23 weeks’ pregnant and was older. The miscarriage occurred at the point when she had taken a turn for the worse with pneumonia and a fever. The resulting inflammation caused her to miscarry.

When asked if the small sample size of 16 is enough to draw conclusions, Associate Professor Yong Tze Tein, SGH’s head and senior consultant from the department of obstetrics and gynaecology, said it is “reassuring” that the Singapore findings mirror those of studies with larger sample sizes such as the United Kingdom where 427 pregnant with Covid-19 were observed.

“One in 10 were very sick but their miscarriages were not more than normal, so that’s very reassuring,” she said, referring to the UK study.

The hospitals’ media release attributed the low incidence of Covid-19 among pregnant women in Singapore to government success in containing the virus.