Increase in stillbirths found at London hospital: JAMA. Was it the pandemic, chance, or an explanation for reduced prematurity?

EM of coronavirus by NIAID

JAMA on July 10 reported a study done at St. George’s University Hospital, London, that found an increase in stillbirths during the pandemic (none of the mothers with stillbirths had symptoms of  COVID-19):

We compared pregnancy outcomes at St George’s University Hospital, London in 2 epochs: from October 1, 2019, to January 31, 2020 (preceding the first reported UK cases of COVID-19), and from February 1, 2020, to June 14, 2020.

…

There were 1681 births (1631 singleton, 22 twin, and 2 triplet pregnancies) in the prepandemic period and 1718 births (1666 singleton and 26 twin pregnancies) in the pandemic period. There were fewer nulliparous women in the pandemic period than in the prepandemic period (45.6% vs 52.2%; P < .001) and fewer women with hypertension (3.7% vs 5.7%; P = .005) in the pandemic period than the prepandemic period, and there were no significant differences in other maternal characteristics (Table 1).

The incidence of stillbirth was significantly higher during the pandemic period (n = 16 [9.31 per 1000 births]; none associated with COVID-19) than during the prepandemic period (n = 4 [2.38 per 1000 births]) (difference, 6.93 per 1000 births [95% CI, 1.83-12.0]; P = .01)

The study reported a total of 19 mothers with COVID-19 in the delivery ward during the pandemic.

This might, at least partially, account for the decrease in preterm deliveries that I posted about yesterday– although the number of stillbirths was small (16 during the pandemic) in comparison to the potential number of premature babies.  As I noted yesterday, there is as yet no obvious explanation for the observed decrease in prematurity.  However, this just adds another layer of uncertainty because there is no obvious explanation for an increase in stillbirths either.

There were limitations in the study, most notably that the mothers with stillbirths were not specifically evaluated for presence of SARS-COV-2 RNA by nasopharyngeal swabs; the study noted that as many as 90% of mothers in another study were asymptomatic despite having positive tests.  They did note that there was no pathological evidence of viral infection in the placentas or fetal tissue, although it doesn’t appear that virus RNA was specifically looked for.

The authors speculated that mothers with warning signs, such as cessation of fetal movement, may have hesitated to come to hospital emergently because of the pandemic and fear of being infected.  Reduced attendance at prenatal clinics or reduced use of ultrasounds might also have played a role.  None of these things was specifically evaluated.

In addition, the number of premature deliveries at this hospital was not evaluated.  This information could have been valuable.

We are left with more questions than before.  Why more stillbirths at this one hospital?  Was it chance or the pandemic?  Why fewer premature births at other hospitals?