Maternal CMV seroprevalence rate in early gestation and congenital cytomegalovirus infection in a Chinese population

Figures & data

Figure 1. Estimation of the prevalence of cCMV. Note: N_u is the number of newborns not followed up after showing a positive result on screening, and R_u is the rate of cCMV infection in newborns without follow-up. N_≤21 is the number of newborns who tested positive on confirmatory testing within 21 days of birth, and R_≤21 is the rate of cCMV cases in newborns who underwent confirmatory testing within 21 days of birth. N_>21 is the number of newborns who tested positive on confirmatory testing beyond 21 days of birth, and R_>21 is the rate of cCMV cases in newborns who underwent confirmatory testing beyond 21 days of birth. R_t is the rate of true cCMV cases in newborns who tested positive beyond 21 days of birth on confirmatory testing.

Figure 2. Flow diagram of enrolment and cCMV screening.

Table 1. CCMV by maternal serostatus in early pregnancy

	Maternal IgG status
	Seropositive n (%)	Seronegative n (%)	P-value
Number	6228 (98.1)	122 (1.9)	-
Newborn cCMV status
Positive	48 (0.77)	1 (0.82)	0.82
Highly suspected positive	35 (0.56)	0 (0.00)
Suspected positive	32 (0.51)	1 (0.82)
Negative	6113 (98.16)	120 (98.36)

Note: Newborns who were not followed up after testing positive in saliva and/or urine on screening were defined as being suspected of having cCMV. Newborns who were positive on screening but who underwent confirmatory testing beyond 21 days of birth were defined as being highly suspected of having cCMV. The samples for confirmation of highly suspected cases were collected from 22 to 51 days of birth with a median age of 27 days, including one newborn whose confirmatory samples were not recorded on the date of collection.

Table 2. Sociodemographic factors relevant to maternal CMV seroprevalence.

	CMV-IgG serostatus (N=6729)
	Positive, n (%)	Negative, n (%)	P-value^1	P-value^2
Overall	6602 (98.11)	127 (1.89)	–	–
Maternal age in years*
<25	1788 (97.28)	50 (2.72)	0.003	0.016
≥25	4701 (98.39)	77 (1.61)
Residence
Rural area	3900 (98.09)	76 (1.91)	0.90	–
Urban area	2679 (98.13)	51 (1.87)
First pregnancy*
Yes	2604 (97.89)	56 (2.11)	0.25	–
No	3132 (98.31)	54 (1.69)
First live birth*
Yes	3676 (97.74)	85 (2.26)	0.006	0.032
No	2065 (98.76)	26 (1.24)

Note: *Missing values: maternal age, 113; residence, 23; first pregnancy, 883; first live birth, 877. ¹The P-value was calculated by means of Pearson’s chi-square tests or Fisher’s exact tests. ²The P-value was calculated by means of multiple regression analysis.

Table 3. Sociodemographic factors relevant to congenital cytomegalovirus infection

	In total	Confirmed or highly suspected cCMV cases	Crude prevalence of cCMV infection (%)	Estimated prevalence of cCMV infection (%)	P1#	P2#
Maternal age in years*
<25	1747	36	2.06	1.89	0.002	0.006
≥25	4570	48	1.05	1.03
Residence*
Rural area	3730	49	1.31	1.26	0.87	0.90
Urban area	2569	35	1.36	1.29
Maternal first pregnancy*
Yes	2645	43	1.63	1.59	0.28	0.15
No	3187	41	1.29	1.15
Maternal first live birth *
Yes	3738	60	1.61	1.54	0.15	0.08
No	2100	24	1.14	0.99
Preterm birth (<37 weeks) *
Yes	201	5	2.49	2.25	0.19	0.21
No	6086	79	1.30	1.24
Sex*
Male	2967	43	1.45	1.38	0.96	0.8
Female	2862	41	1.43	1.31
Perinatal asphyxia*
No	5763	84	1.46	1.36	–	–
Yes	44	0	0.00	0.00
Weight at birth in grams*
<2500	162	5	3.09	2.57	0.2	0.38
2500–4000	5174	72	1.39	1.30
≥4000	493	7	1.42	1.43
Singleton pregnancy*
Yes	6226	78	1.25	1.22	0.001	0.002
No (twins)	91	6	6.52	4.85

Note: *Missing values: maternal age, 33; residence, 51; first pregnancy, 518; first live birth, 512; preterm birth, 63; type of delivery, 512; sex, 521; perinatal asphyxia, 543; weight at birth, 521; singleton pregnancy, 33. # P₁: test for difference in crude prevalence of cCMV among different groups for each variable; P₂: test for difference in estimated prevalence of cCMV among different groups for each variable.