Association Between Nausea and Vomiting During Pregnancy and Sleep Quality: Mediating Effect of Depressive Symptoms

Figures & data

Table 1 Characteristics of Participants and Sleep Quality (N=2494)

Characteristics	Total n (%)	Poor Sleep Quality^a		χ^2	p
		With n (%)	Without n (%)
Total	2494 (100.0)	1355 (54.3)	1139 (45.7)	NA	NA
Maternal age (years)^b	29.6 (4.8)	29.7 (4.8)	29.5 (4.8)	1.04	0.531
Gestational age (weeks)^b	22.9 (10.1)	23.5 (10.3)	22.1 (9.8)	1.49	0.137
Gestational age				29.39	<0.001
First trimester	617 (24.8)	332 (53.8)	285 (46.2)
Second trimester	942 (37.8)	455 (48.3)	487 (51.7)
Third trimester	935 (37.4)	568 (60.8)	367 (39.2)
Education level				4.12	0.127
Junior high school or below	607 (24.3)	324 (53.4)	283 (46.6)
Senior high school	584 (23.4)	300 (51.4)	284 (48.6)
College or university	1297 (52.0)	729 (56.2)	568 (43.8)
Missing data	6 (0.2)	NA	NA
Work status				8.69	0.003
Not working	609 (24.4)	362 (59.4)	247 (40.6)
Working	1871 (75.0)	984 (52.6)	362 (47.4)
Missing data	14 (0.6)	NA	NA
Household income per capita (CNY/month)				2.10	0.351
≤3000	452 (18.1)	234 (51.8)	218 (48.2)
3001–7000	963 (38.6)	538 (55.9)	425 (44.1)
>7000	1053 (42.2)	572 (54.3)	481 (45.7)
Missing data	26 (1.0)	NA	NA
Marital status				1.59	0.208
Married	2379 (95.4)	1285 (54.0)	1094 (46.0)
Unmarried or divorced	108 (4.3)	65 (60.2)	43 (39.8)
Missing data	7 (0.3)	NA	NA
Depressive symptoms^c				93.43	<0.001
No	1615 (64.8)	768 (47.6)	847 (52.4)
Yes	854 (34.2)	580 (67.9)	274 (32.1)
Missing data	25 (1.0)	NA	NA

Notes: ^aPoor sleep quality was defined as PSQI global score > 5. ^bMaternal age and gestational age are presented as mean (SD), and were compared using a t-test. ^cDepressive symptoms was defined as EPDS score ≥ 9.

Abbreviations: CNY, China Yuan; EPDS, Edinburgh Postnatal Depression Scale; NA, not applicable or no data available; PSQI, the Pittsburgh Sleep Quality Index.

Table 2 Self-Reported Sleep Quality by Nausea and Vomiting of Pregnancy (N=2494)

Characteristics	Total	NVP^a			F	p
		Mild (n=1225) Mean (SD)	Moderate (n=1229) Mean (SD)	Severe (n=40) Mean (SD)
Sleep duration (hour/day)	7.76 (1.38)	7.73 (1.34)	7.79 (1.41)	7.74 (1.6)	0.61	0.545
Global PSQI score	6.39 (3.18)	6 (3.11)	6.73 (3.17)	8.05 (4)	22.04	<0.001
PSQI Components
Subjective sleep quality	1.31 (0.67)	1.24 (0.66)	1.36 (0.67)	1.48 (0.78)	11.50	<0.001
Sleep latency	1.15 (1.01)	1.08 (1.01)	1.20 (1.01)	1.58 (1.17)	8.28	<0.001
Sleep duration	0.59 (0.87)	0.58 (0.85)	0.59 (0.88)	0.70 (1.11)	0.36	0.700
Habitual sleep efficiency	0.64 (0.92)	0.62 (0.90)	0.66 (0.93)	0.88 (1.26)	1.80	0.166
Sleep disturbance	1.11 (0.60)	1.07 (0.59)	1.13 (0.61)	1.33 (0.57)	6.11	0.002
Use of sleeping medication	0.01 (0.10)	0.01 (0.11)	0.01 (0.10)	NA	NA	NA
Daytime dysfunction	1.60 (0.91)	1.40 (0.91)	1.78 (0.87)	2.10 (0.98)	61.52	<0.001
Poor sleep quality^b,c	1355 (54.3)	600 (49.0)	726 (59.0)	29 (72.5)	30.16	<0.001

Notes: ^aNVP was assessed using the Modified Pregnancy-Unique Quantification of Emesis and Nausea: mild NVP, < 6 points; moderate NVP, 7–12 points; severe NVP, ≥ 13 points. ^bPoor sleep quality was defined as PSQI global score > 5, and presented as numbers (%). ^cA chi-square test was used for poor sleep quality.

Abbreviations: NA, not applicable or no data available; PSQI, the Pittsburgh Sleep Quality Index; NVP, nausea and vomiting of pregnancy.

Table 3 Association Between Nausea and Vomiting of Pregnancy and Sleep Quality

Variates	Model 1^a (n=2494) COR (95% CI)	Model 2^b (n=2457) AOR (95% CI)	Model 3^c (n=2432) AOR (95% CI)
NVP^d
Mild	1.00	1.00	1.00
Moderate	1.50 (1.28, 1.76)	1.66 (1.40, 1.96)	1.53 (1.29, 1.81)
Severe	2.74 (1.36, 5.53)	2.95 (1.44, 6.02)	2.69 (1.30, 5.55)

Notes: ^aModel 1: Univariate logistic regression, not adjusted for covariate. ^bModel 2: Adjusted for maternal age, gestational age, education level, work status, household income per capita, and marital status. ^cModel 3: Adjusted for the covariates in Model 2 plus depressive symptoms. ^dNVP was assessed using the Modified Pregnancy-Unique Quantification of Emesis and Nausea: mild NVP, < 6 points; moderate NVP, 7–12 points; severe NVP, ≥ 13 points.

Abbreviations: AOR, adjusted OR; COR, crude OR; CI, confidence interval; NVP, nausea and vomiting of pregnancy.

Table 4 Mediating Effect of Depressive Symptoms on the Association Between NVP and Poor Sleep Quality (N=2432)

Characteristics	Estimate^a	p	95% CI
Path
NVP → depressive symptoms	0.053	<0.001	0.033–0.087
Depressive symptoms → sleep quality	1.127	0.007	0.682–2.954
NVP → sleep quality	0.293	<0.001	0.211–0.415
Standardized effect
Indirect effect	0.060	0.033	0.028–0.180
Total effect	0.353	<0.001	0.263–0.480

Notes: ^aAdjusted for maternal age, gestational age, education level, work status, household income per capita, and marital status. Model fit indices: CFI=0.992; RMSEA=0.041, 90% CI=0.038–0.043; SRMR=0.027.

Abbreviations: NVP, nausea and vomiting of pregnancy; CI, confidence interval; CFI, comparative fit index; RMSEA, root mean square error of approximation; SRMR, standardized root mean square residual; Arrows, direction of effects.