To the Editor:
Data from viral respiratory illnesses such as influenza, severe acute respiratory
syndrome coronavirus 1, and Middle East respiratory syndrome suggest that viral respiratory
infection during pregnancy may worsen both maternal and fetal outcomes (1, 2). Existing
data in critically ill pregnant women with coronavirus disease (COVID-19) are mainly
limited to case series or systematic reviews lacking nonpregnant control subjects
(3–5). To better understand this potentially at-risk population, we describe the clinical
course of 32 critically ill pregnant women admitted to ICUs across the United States.
Furthermore, we compare the characteristics, treatment, and outcomes of these pregnant
women with those of women who were not pregnant at the time of ICU admission.
We used data from STOP-COVID (Study of the Treatment and Outcomes in Critically Ill
Patients with COVID-19), a multicenter cohort study of critically ill adults with
laboratory-confirmed COVID-19 admitted to 67 participating ICUs across the United
States (6). For the current analysis, we included all COVID-19–positive pregnant women
admitted to ICUs between March 4 and May 2, 2020. We matched each pregnant woman with
two nonpregnant women according to age (±2 yr) and the Quick Sequential Organ Failure
Assessment (qSOFA) score at admission to the ICU (7). For purposes of matching, we
dichotomized the qSOFA score into lower risk (score of 0–1) and higher risk (score
of 2–3). All patients were followed up until hospital discharge, death, or a minimum
of 28 days after ICU admission. We compared outcomes between pregnant and nonpregnant
women using chi-square or Fisher exact tests for categorical variables and the Wilcoxon
rank-sum test for continuous variables.
Among 4,145 patients in the parent cohort, we identified 32 pregnant women and matched
these to 64 nonpregnant women. The median age in both groups was 32 years (interquartile
range, 27–35). In both groups, 62.5% of patients had a qSOFA score of 2 or 3 at admission.
The frequency and severity of acute respiratory failure, assessed by receipt of invasive
mechanical ventilation and the PaO2
/Fi
O2
ratio at ICU admission, were similar between groups (Table 1).
Table 1.
Characteristics, Therapies, and Outcomes according to Pregnancy Status
Characteristic
Pregnant (N = 32)
Nonpregnant (N = 64)
P Value
Age, yr, median (IQR)
32 (27–35)
32 (27–35)
0.99
qSOFA score at ICU admission
0.99
0–1
12 (37.5)
24 (37.5)
2–3
20 (62.5)
40 (62.5)
Race, n (%)
0.49
White
10 (31.2)
23 (35.9)
Black
7 (21.9)
20 (31.2)
Asian
3 (9.4)
4 (6.2)
More than one or not reported
12 (37.5)
17 (26.5)
Hispanic ethnicity, n (%)
9 (28.1)
20 (31.3)
0.75
Body mass index, kg/m2, median (IQR)*
33.7 (27.0–38.2)
36.7 (29.9–42.2)
0.10
Coexisting conditions, n (%)
Diabetes mellitus
4 (12.5)
22 (34.4)
0.02
Hypertension
3 (9.4)
16 (25.0)
0.07
Asthma
9 (28.1)
16 (25.0)
0.74
Chronic kidney disease
1 (3.1)
2 (3.1)
0.99
Time from symptom onset to ICU admission, d, median (IQR)
7 (5–10)
NA
NA
Vital signs on day of ICU admission, median (IQR)
Temperature, °C*
37.5 (37.0–38.0)
38.4 (37.3–39.3)
<0.01
Systolic blood pressure, mm Hg
99 (91–110)
99 (89–106)
0.64
Heart rate, beats/min
116 (108–128)
119 (102–132)
0.81
Respiratory rate, breaths/min
28 (23–37)
34 (27–40)
0.02
Laboratory findings on day of ICU admission, median (IQR)*
White blood cell count, ×109 cells/L
9.4 (7.8–12.7)
7.6 (5.3–11.1)
0.04
Creatinine, mg/dl
0.5 (0.5–0.7)
0.7 (0.6–0.9)
<0.01
D-dimer, ng/ml
890 (640–1,374)
845 (441–1,688)
0.68
C-reactive protein, mg/L
99 (77–118)
119 (53–237)
0.27
Invasive mechanical ventilation on ICU admission, n (%)
18 (56.2)
37 (57.8)
0.88
PaO2
/Fi
O2
, mm Hg, median (IQR)*
†
183 (108–261)
144 (100–230)
0.42
Gestational age at ICU admission, wk, median (IQR)
30.4 (25.8–33.5)
NA
NA
Treatments and organ injury within the first 14 d of ICU admission
Interventions for hypoxemia, n (%)
Prone position
11 (34.4)
25 (39.1)
0.65
Neuromuscular blockade
9 (28.1)
28 (43.8)
0.14
Inhaled epoprostenol or nitric oxide
3 (9.4)
10 (15.6)
0.40
Medical therapy, n (%)
Remdesivir
16 (50.0)
7 (10.9)
<0.01
Tocilizumab
3 (9.4)
15 (23.4)
0.10
Convalescent plasma
4 (12.5)
6 (9.4)
0.73
Any experimental therapy
‡
17 (53.1)
25 (39.1)
0.19
Therapeutic anticoagulation
13 (41.1)
28 (43.8)
0.77
Acute respiratory distress syndrome, n (%)
16 (50.0)
16 (50)
0.03
Invasive mechanical ventilation, n (%)
23 (71.9)
48 (75.0)
0.74
Mechanical ventilation duration, d, median (IQR)
†
11 (6–14)
13 (8–14)
0.53
Vasopressors, n (%)
23 (71.8)
23 (71.9)
0.23
Acute kidney injury, n (%)
§
4 (12.5)
15 (25.0)
0.16
Renal replacement therapy, n (%)
0 (0)
6 (10.0)
0.09
Arrhythmia, n (%)
1 (3.1)
1 (1.6)
0.99
Extracorporeal membrane oxygenation, n (%)
3 (9.4)
3 (4.7)
0.40
Thrombosis, n (%)
2 (6.2)
7 (10.9)
0.71
Outcomes
In-hospital death, n (%)
‖
0 (0)
6 (9.4)
0.17
ICU length of stay, d, median (IQR)
‖
10 (3–18)
13 (5–24)
0.28
Hospital length of stay, d, median (IQR)
‖
14 (8–24)
11 (5–23)
0.13
Delivered during hospitalization, n (%)
¶
19 (59.4)
NA
NA
Cesarean delivery, n (%)
¶
17 (53.1)
NA
NA
Gestational age at delivery, wk, median (IQR)
32.9 (30.1–34.4)
NA
NA
Definition of abbreviations: IQR = interquartile range; NA = not applicable; qSOFA = Quick
Sequential Organ Failure Assessment.
*
Data were missing for creatinine for 3 nonpregnant patients, C-reactive protein for
10 pregnant and 21 nonpregnant patients, D-dimer for 8 pregnant and 29 nonpregnant
patients, and PaO2
/Fi
O2
for 10 pregnant and 11 nonpregnant mechanically ventilated patients.
†
PaO2
/Fi
O2
was only assessed in patients receiving invasive mechanical ventilation. Days of mechanical
ventilation were limited to the first 14 days of hospitalization.
‡
Experimental therapies were remdesivir, tocilizumab, and convalescent plasma.
§
Acute kidney injury was defined as doubling of baseline creatinine or need for renal
replacement therapy. Patients with end-stage renal disease (n = 4) were excluded.
‖
In-hospital mortality data were available for all patients for a minimum of 28 days
after ICU admission. Because of ongoing hospitalization, data on ICU length of stay
were incomplete for 14 patients, and data on hospital length of stay were incomplete
for 24 patients.
¶
Indications for delivery were maternal respiratory failure (n = 10), fetal status
(n = 5), spontaneous labor or rupture of membranes (n = 3), and preeclampsia (n = 1).
Pregnant women were more likely to receive remdesivir (50.0% vs. 10.9%) and less likely
to receive tocilizumab than nonpregnant women (9.4% vs. 23.4%). The rate of invasive
mechanical ventilation, prone positioning, and neuromuscular blockade during the 14
days after ICU admission was similar between groups. The incidences of venous thromboembolism
and other acute organ injuries, together with ICU and hospital length of stay, were
similar between groups (Table 1). There were no maternal or fetal deaths, whereas
6 of the 64 nonpregnant women (9.4%) died during hospitalization.
A total of 19 women (59.3%) delivered during the hospitalization, with 11 of the 19
deliveries (57.9%) occurring on the day of ICU admission. Among the 19 deliveries,
18 (94.7%) were preterm, defined as occurring at less than 37 weeks’ gestation. Only
three of these preterm births were spontaneous, with the remainder performed for medical
or obstetric indications. The most common indications for delivery were maternal respiratory
failure (52.6%), spontaneous labor or rupture of membranes (25.0%), and nonreassuring
fetal status (21.1%) (Table 2). A total of 17 of the 19 women (89.5%) who delivered
underwent cesarean section, with maternal critical illness reported as the most common
indication (41.2%). Among the 17 women with pregnancies at more than 30 weeks’ gestation
at ICU admission, 15 (88.2%) delivered, as compared with 4 out of 15 (26.7%) who delivered
at less than 30-weeks’ gestation.
Table 2.
Case Details of Critically Ill Pregnant Patients with COVID-19
Case*
Gestational Age at ICU Admission (wk)
Delivery during Admission
Days between Admission and Delivery
Gestational Age at Delivery (wk)
Mode of Delivery
Indication for Delivery
Indication for Cesarean Delivery
PaO2
/Fi
O2
on Intubation
Duration of Mechanical Ventilation
†
(d)
ICU Length of Stay
†
(d)
Hospital Length of Stay
†
(d)
1
≥37
Yes
<1
40.6
Vaginal
Spontaneous labor
NA
513
1
1
5
2
34.0–36.9
Yes
<1
36.4
Cesarean
Respiratory failure
Breech
NA
0
5
8
3
34.0–36.9
Yes
>2
37.0
Cesarean
Fetal status
Fetal heart rate
NA
0
1
8
4
34.0–36.9
Yes
<1
35.6
Cesarean
SROM
Breech
268
6
7
13
5
34.0–36.9
Yes
<1
34.3
Cesarean
Fetal status
Fetal heart rate
117
14
25
35
6
34.0–36.9
Yes
1–2
34.4
Cesarean
Respiratory failure
Critical illness
116
12
12
24
7
28.0–33.9
Yes
>2
34.4
Cesarean
Preeclampsia
Critical illness
NA
0
1
4
8
28.0–33.9
Yes
<1
33.6
Cesarean
Respiratory failure
Uterine surgery
NA
0
1
6
9
28.0–33.9
No
NA
NA
NA
NA
NA
NA
0
1
3
10
28.0–33.9
Yes
<1
33.4
Cesarean
Respiratory failure
Critical illness
101
5
6
14
11
28.0–33.9
Yes
>2
32.9
Cesarean
Respiratory failure
Breech
158
14
15
24
12
28.0–33.9
Yes
<1
31.6
Cesarean
Respiratory failure
Critical illness
232
14
18
22
13
28.0–33.9
Yes
>2
32.7
Cesarean
SROM and labor
Fetal heart rate
184
6
14
21
14
28.0–33.9
Yes
<1
30.7
Cesarean
Respiratory failure
Critical illness
62
14
25
28
15
28.0–33.9
No
NA
NA
NA
NA
NA
NA
0
1
7
16
28.0–33.9
Yes
>2
31.4
Cesarean
Respiratory failure
Critical illness
102
11
15
18
17
28.0–33.9
Yes
<1
30.1
Cesarean
Respiratory failure
Critical illness
576
9
9
13
18
28.0–33.9
Yes
<1
29.4
Cesarean
Respiratory failure
Critical illness
66
14
36
44
19
28.0–33.9
No
NA
NA
NA
NA
NA
NA
0
3
8
20
24.0–27.9
No
NA
NA
NA
NA
NA
NA
0
3
23
21
24.0–27.9
Yes
>2
30.0
Vaginal
SROM and labor
NA
161
14
29
38
22
24.0–27.9
No
NA
NA
NA
NA
NA
420
7
10
23
23
24.0–27.9
Yes
1–2
26.0
Cesarean
Fetal status
Fetal heart rate
92
10
12
13
24
24.0–27.9
No
NA
NA
NA
NA
NA
NA
13
15
21
25
24.0–27.9
No
NA
NA
NA
NA
NA
254
6
8
12
26
24.0–27.9
No
NA
NA
NA
NA
NA
183
14
41
61
27
24.0–27.9
Yes
>2
26.1
Cesarean
Fetal status
Fetal heart rate
417
8
21
38
28
24.0–27.9
No
NA
NA
NA
NA
NA
348
7
10
12
29
<24
No
NA
NA
NA
NA
NA
197
1
1
7
30
<24
No
NA
NA
NA
NA
NA
252
13
19
30
31
<24
No
NA
NA
NA
NA
NA
310
13
19
25
32
<24
No
NA
NA
NA
NA
NA
NA
0
2
5
Definition of abbreviations: COVID-19 = coronavirus disease; NA = not applicable;
SROM = spontaneous rupture of membranes.
*
Five patients were included as cases in References 4 and 5.
†
The median ICU length of stay was 5 days (interquartile range [IQR], 2–12 d) for those
without delivery versus 12 days (IQR, 5–21 d) for those who delivered during admission.
The median hospital length of stay was 11 days (IQR, 6–22 d) for those without delivery
versus 18 days (IQR, 8–28 d) for those who delivered during admission. The median
duration of mechanical ventilation was 6 days (IQR, 0–13 d) for those without delivery
versus 9 days (IQR, 1–14 d) for those who delivered during admission.
Unlike prior viral pandemics (1–4), maternal and fetal outcomes among critically ill
pregnant women with COVID-19 in our cohort were excellent, with no reported deaths.
Consistent with prior COVID-19 studies in pregnant women, our study found high rates
of cesarean delivery and preterm birth (3–5). The majority of preterm delivery occurred
in the setting of maternal respiratory failure, with a high rate of cesarean delivery
for this indication. Complex medical decision-making is required in the management
of critically ill pregnant women. The decision regarding delivery needs to balance
multiple risks and benefits, including the risks of prematurity to the fetus, the
potential to improve or worsen maternal respiratory status with delivery, and the
known maternal hemodynamic and inflammatory burden accompanying major surgery such
as cesarean section (8). Pregnant women in our cohort at less than 30-weeks’ gestation
at the time of ICU admission were less likely to undergo delivery, which may reflect
attempts to maximize fetal survival.
Pregnant women in our cohort had lower mortality than age- and qSOFA-matched nonpregnant
women. This finding may reflect the lower burden of comorbidities among pregnant women
in our small cohort. Notably, a recently published case series from Iran reported
a high rate of mortality (77.8%) among nine critically ill pregnant women with COVID-19
(9). Potential reasons for the vastly different outcomes observed in the pregnant
women in our cohort include differences in healthcare delivery systems, patient risk
factors, and an apparently low threshold for ICU admission for pregnant patients with
COVID-19 in our cohort. We followed patients until hospital discharge, but our cohort
lacks long-term follow-up data, including neonatal outcomes. Both pregnancy and COVID-19
raise the risk of thromboembolic disease, highlighting the need for long-term follow-up
data in pregnant and postpartum women with COVID-19.
In summary, we report the maternal and fetal outcomes of 32 pregnant women in a multicenter
cohort study of geographically diverse critically ill patients with COVID-19. In contrast
to nonpregnant women of childbearing age, all pregnant women survived, and there were
no fetal deaths. Treatments and outcomes, including receipt of invasive mechanical
ventilation, the incidence of acute organ injury, and ICU and hospital length of stay,
were generally similar between pregnant and nonpregnant women. Pregnant women had
high rates of preterm delivery and cesarean section—primarily for the indication of
critical illness. Our finding that 13 pregnant women survived to hospital discharge
without delivery raises an interesting question of whether or not delivery is required
for nonobstetric indications among critically ill pregnant women (10). Additional
data are needed in critically ill pregnant women with COVID-19 to help inform clinical
practice.