Maternal SARS-COV-2 infection and prematurity: the Southern Michigan COVID-19 collaborative

Figures & data

Figure 1. Effect of COVID-19 on prematurity rates. (A)Medically indicated and spontaneous prematurity rates by COVID-19 status. ***p < .001; *p < .05, by Fisher’s exact test. (B) Adjusted relative risk with COVID-19 for prematurity related outcomes by Poisson regression models. PTB: preterm birth; iPTB: medically indicated PTB; PPROM: preterm prelabor rupture of membranes; sPTB: spontaneous PTB; sPTB_Other: spontaneous PTB with intact membranes; Early PTB: PTB <34 weeks. iPTB_PE: medically indicated prematurity involving preeclampsia; iPTB_Other: medically indicated prematurity for causes other than preeclampsia

Table 1. Crude and adjusted relative risk carried by Covid19 for prematurity related outcomes

	No Covid (n = 1090)% (n)	Covid (n = 369)% (n)	p	RR	aRR	Adjusted for
iPTB	3.2 (35)	9.2 (34)	0.000	2.87 (1.82–4.53)	2.55 (1.6–4.08)	Insurance type, history of PTD, CHTN, twins
iPTB_PE	2.7 (29)	7.6 (28)	0.000	2.85 (1.72–4.73)	2.46 (1.47–4.12)	Insurance type, nulliparous, history of PTD, CHTN, diabetes, substance abuse, twins
iPTB_Other	1.4 (15)	3.3 (12)	0.025	2.36 (1.12–5)	2.32 (1.12–4.79)	History of PTD, twins
sPTB	5.7 (62)	6.5 (24)	0.565	1.14 (0.72–1.8)	1.1 (0.72–1.69)	Race, ethnicity, BMI, insurance type, history of PTD, asthma, twins
sPTB_PPROM	2.8 (31)	3.8 (14)	0.362	1.33 (0.72–2.48)	1.3 (0.68–2.49)	BMI, history of PTD, diabetes, twins, history of smoking
sPTB_Other	3.6 (39)	3.5 (13)	0.961	0.98 (0.53–1.82)	0.92 (0.52–1.62)	Race, ethnicity, BMI, history of PTD, asthma, substance abuse, twins, history of smoking
PTL	6 (65)	8.7 (32)	0.071	1.45 (0.97–2.18)	1.38 (0.93–2.05)	Insurance type, history of PTD, CHTN, substance abuse, twins
Early_PTB	2.6 (28)	5.1 (19)	0.017	2 (1.13–3.55)	1.8 (1.02–3.16)	History of PTD, CHTN, asthma, sex, twins
PTB	8.9 (97)	15.7 (58)	0.000	1.77 (1.3–2.39)	1.62 (1.2–2.18)	BMI, insurance, history of PTD, CHTN, diabetes, asthma, substance abuse, twins

Covariates included as fixed effects in the Poisson models are listed for each outcome. RR: relative risk; aRR: adjusted relative risk; PTD: preterm delivery; CHTN: chronic hypertension; PTB: preterm birth; iPTB: iatrogenic PTB; PPROM: preterm prelabor rupture of membranes; sPTB: spontaneous PTB; sPTB_Other: spontaneous PTB with intact membranes; Early PTB: PTB <34 weeks. iPTB_PE: iatrogenic prematurity involving preeclampsia; iPTB_Other: iatrogenic prematurity for causes other than preeclampsia; PTL: preterm labor.

Figure 2. Effect of COVID-19 symptomatology on prematurity rates. Medically indicated and spontaneous prematurity rates are shown by COVID-19 status and symptoms. ***p < .001; *p < .05, by Fisher’s exact test comparing the frequency of PTB in Covid symptomatic vs all other patients. sPTB: spontaneous PTB; sPTB_Other: spontaneous PTB with intact membranes; Early PTB: PTB <34 weeks. iPTB_PE: medically indicated prematurity involving preeclampsia; iPTB_Other: medically indicated prematurity for causes other than preeclampsia.