Interpretation
There have been limited studies looking at COVID-19 in the pregnant
population.
When a new pathogen emerges we can look to previous pandemics for
insight into the natural history and course of the disease. With
previous coronavirus spectrum infections serious acute respiratory
syndrome (SARS) and middle eastern respiratory syndrome (MERS) there was
a higher incidence of preterm birth, pre-eclampsia and caesarean section
than in the general population . In addition, the clinical outcomes were
worse for pregnant women than non-pregnant women, with a high incidence
of death, renal failure, and disseminated intravascular coagulopathy .
By contrast, SARS-CoV-2 does not appear to have worse clinical outcomes
for pregnant women compared to non-pregnant women. In a recent case
series of 158 patients who tested positive for SARS-CoV-2 in New York,
78% had mild or asymptomatic disease . This is comparable to a study of
118 SARS-CoV-2 positive pregnant patients in Wuhan, 92% of whom had
mild disease . In both settings, the risk of severe disease was similar
to that of the general population, and appears to be associated with
medical co-morbidities and increasing age.
COVID-19 is known to be a pro-coagulopathic state, with significantly
higher rates of venous thromboembolism than in the general population .
One might therefore expect evidence of thrombotic complications in the
placentas of obstetric patients infected with COVID-19. Indeed,
histopathological examinations of these placentas have demonstrated that
they are more likely to show features of maternal vascular malperfusion
(MVM) . These findings may suggest that these patients are at a higher
risk of complications of poor placental perfusion, and warrant increased
surveillance. Placental abruption ranges from the subclinical to massive
catastrophic cases, histological assessment of all placentas throughout
the pandemic period may have revealed many more cases of sub clinical
abruption, but resources limit the ability to perform this in an initial
review. We may therefore be underestimating the frequency of abruptions,
and thus the impact of the disease.
Khalil et al studied the incidence of stillbirth and preterm
birth at St George’s Hospital, London during the pandemic period
(1st Feb 2020 to 14th June 2020) and
the pre-pandemic period (1st Oct 2019 to
31st Jan 2020). Investigators found a significantly
higher incidence of stillbirth during the pandemic period compared to
the pre-pandemic period . Similar to our review, none of their patients
had tested positive to SARS-CoV-2. Although the results were
significant, they could not infer direct causality between asymptomatic
SARS-CoV-2 and stillbirth. Other possible explanations include a
reluctance of patients to attend hospital for fetal concerns, or a
change in the available obstetric services during the pandemic period.
Despite none of our patients testing positive for SARS-CoV-2 there was a
significantly lower lymphocyte count in 2020 compared to 2019.
Lymphopaenia is known to be a cardinal feature of COVID 19. In the obstetric population, lymphopaenia is
associated with moderate or severe disease . If we could consider
lymphopaenia a proxy for SARS-CoV-2 infection, our preliminary findings
could suggest an association between COVID-19 and IUD.
Learning from previous epidemics, it is widely acknowledged that
services for women and children are especially vulnerable to disruption.
In the 2014 Ebola outbreak in west Africa there was a 44% reduction in
inpatient services, with similar reductions in antenatal and postnatal
services, and family planning availability . Analysis of Sierra Leone’s
Health Management Information System found that the Ebola epidemic lead
indirectly to 3,600 additional maternal deaths, neonatal deaths, and
stillbirths . Similarly, during the COVID-19 pandemic, we have seen
restructuring of services to prioritise acute care of those affected.
This was compounded by fear of contracting the disease, healthcare
provider sickness, and disruption to the global medical supply chain.
Because of this, estimates of indirect maternal deaths during the
COVID-19 outbreak in low- and middle-income countries lie between
8.3-38.6% . It is therefore likely that some aspect of the rise in IUD
that we have seen is an indirect, rather than direct, result of
COVID-19.