Dietary fibre intake and lifestyle characteristics in relation to nausea or vomiting during pregnancy—a questionnaire-based cohort study

Figures & data

Figure 1. Participant flow.

Table 1. Assessment table for daily intake of cereal- derived and fruit/vegetable-derived fibre.

Fibre-containing food items	Portion	Number of portions per day	Fibre coefficient for each food item
Cereal-derived fibre
Rye bread/ crisp bread/ multigrain bread with grains	1 slice/ piece		× 3
Other multigrain bread/ oat bread/ barley bread/ graham bread/ rolls	1 slice/ piece		× 2
French bread, baquette or other white bread	1 slice/ piece		× 1
Breakfast cereals, what?	1 dl		× 6 (All- Bran PLUS) × 3 (All- Bran REG) × 0.5 (regular)
Muesli or piece of Weetabix	1 dl/ piece		× 0.5
Flake porridge	1 dl		× 4
Brans	1 tablespoon		× 1
Fruit/vegetable-derived fibre
Plums or raisins	1 piece of plums/ 1 tablespoon of raisins		× 0.5
Fruits or berries	1 piece of fruits/ 1 dl of berries		× 2
Fresh or cooked vegetables	1 dl		× 2

In the questionnaire, the patients estimated their typical daily consumption of ten different kinds of fibre-containing food items. Daily fibre intake was calculated by multiplying the amount of the special food item by its fibre coefficient.

Table 2. Characteristics of mothers before pregnancy according to nausea or vomiting (NVP) during the first trimester (N = 188).

	NVP during I trimester			Univariable
	No (n = 97)	Yes (n = 91)	p	N	OR	(95% CI)
Age (y), mean (Sd)	28.8 (5.1)	29.2 (4.9)	.604	188	1.02	(0.96–1.08)
BMI (kg/m²), Md (range)	23.1 (18.4–39.1) n = 95	22.4 (18.7–33.3)	.064	186	0.91	(0.84–0.99)
BMI, n (%)			.007
Normal <25	57 (59)	71 (78)		128	2.37	(1.24–4.51)
≥25	38 (39)	20 (22)		58	1.00
Parity, n (%)			.073
Nulliparas	63 (65)	49 (54)		112	1.00
Multiparas	34 (35)	42 (46)		76	1.59	(0.88–2.86)
Chronic disease, n (%)			.202
No	88 (91)	77 (85)		165	1.00
Yes	9 (9)	14 (15)		23	1.78	(0.73–4.34)
Smoking, n (%)			.315
No	73 (75)	74 (81)		147	1.00
Yes	24 (25)	17 (19)		41	0.70	(0.35–1.41)
Alcohol use, n (%)			.062
No	9 (9)	17 (19)		26	1.00
Yes	88 (91)	74 (81)		162	0.45	(0.19–1.06)
Special diet, n (%)			.069
No	81 (84)	66 (73)		147	1.00
Yes	16 (16)	25 (27)		41	1.92	(0.95–3.89)
Vigorous physical activity, n (%)			.142
No	29 (30)	17 (19)		46	1.00
Yes	66 (68)	73 (80)		139	1.89	(0.95–3.74)
Constipation, n (%)			.859
No	76 (78)	70 (77)		146	1.00
Yes	20 (21)	21 (23)		41	1.14	(0.57–2.28)
Heartburn, n (%)			.514
No	74 (76)	73 (80)		147	1.00
Yes	23 (24)	18 (20)		41	0.79	(0.39–1.59)

Differences between groups were tested by independent samples t-test, Mann–Whitney U test or by Pearson Chi-square test or Fisher’s exact test with p values (p). Missing values were not shown, but they were included into the analyses. Results of univariable logistic regression models NVP during the first trimester were shown by odds ratios (OR) with 95 % confidence intervals (CI). Md: median; y: year; kg: kilograms.

Bold value signifies BMI p = .007.

Table 3. Intake of fibre g/day (N=188) before pregnancy and during the first trimester according to nausea or vomiting (NVP) during the first trimester.

		NVP
		No (n = 97)	Yes (n = 91)	p
Intake of fibre derived from cereal products (g/day)
Before pregnancy	n	97	91	.026
	Md (IQR)	10.4 (7.6–15.0)	12.9 (9.7–16.3)
During the first trimester	n	97	91	.559
	Md (IQR)	12.0 (8.0–16.0)	12.6 (8.4–16.3)
		NVP
		No (n = 97)	Yes (n = 91)
Intake of fibre derived from fruit and vegetables (g/day)
Before pregnancy	n	97	91	.160
	Md (IQR)	4.6 (2.4–8.0)	5.1 (4.0–8.0)
During the first trimester	n	97	91	.099
	Md (IQR)	6.0 (3.1–10.0)	8.0 (5.0–10.0)
		NVP
		No (n = 97)	Yes (n = 91)
Intake of total fibre (g/day)
Before pregnancy	n	97	91	.043
	Md (IQR)	16.0 (11.1–22.0)	19.1 (14.6–23.9)
During the first trimester	n	97	91	.253
	Md (IQR)	19.0 (13.4–24.8)	20.6 (15.4–25.7)

IQR: interquartile range. Differences between nausea groups were tested by Mann–Whitney U test and change in time were tested by related samples’ Wilcoxon Signed rank test. Md: median; NVP: nausea or vomiting during pregnancy; g/day: grams/day.

Bold value signifies p values under .05.

Table 4. Risk factors for nausea or vomiting (NVP) during the first trimester (N=188).

	NVP			Univariable
	No (n = 97)	Yes (n = 91)	p	N	OR	(95% CI)
Special diet during the first trimester, n (%)			.257
No	81 (84)	70 (77)		151	1.00
Yes	16 (16)	21 (23)		37	1.52	(0.74–3.14)
Vigorous physical activity during the first trimester, n (%)			.243
No	46 (47)	52 (57)		98	1.00
Yes	50 (52)	39 (43)		89	0.69	(0.39–1.23)
Constipation during the first trimester, n (%)			.011
No	78 (80)	57 (63)		135	1.00
Yes	19 (20)	33 (36)		52	2.38	(1.23–4.60)
Heartburn during the first trimester, n (%)			.108
No	49 (51)	39 (43)		88	1.00
Yes	45 (46)	52 (57)		97	1.45	(0.81–2.59)

Differences between groups were tested by independent samples t-test, Mann–Whitney U test or by Pearson Chi-square test or Fisher’s exact test with p values (p). Missing values were not shown, but they included into the analyses. Results of univariable logistic regression models for nausea or vomiting during the first trimester were shown by odds ratios (OR) with 95 % confidence intervals (CI).

Bold value signifies p = .011.

Table 5. Change of risk factors from before pregnancy to the first trimester for nausea or vomiting (NVP) during the first trimester (N=188).

	NVP			Univariable			Multivariable
	No (n = 97)	Yes (n = 91)	p	N	OR	(95% CI)	OR	(95% CI)
Special diet, n (%)			.029
None	81 (84)	66 (73)		147	1.00		1.00
Continue to follow during pregnancy	16 (16)	20 (22)		36	1.53	(0.74–3.19)	1.26	(0.54–2.92)
Gave up	0 (0)	5 (5)		5	*		*
Change of physical activity, n (%)			.004
About same level	84 (87)	63 (69)		147	1.00		1.00
Much less during pregnancy	13 (13)	28 (31)		41	2.87	(1.38–5.99)	2.50	(1.03–6.03)
Change of constipation, n (%)			.027
Same	80 (83)	62 (68)		142	1.00		1.00
Less during pregnancy	9 (9)	9 (10)		18	1.29	(0.48–3.44)	1.11	(0.31–4.06)
More during pregnancy	8 (8)	20 (22)		28	3.23	(1.33–7.81)	2.57	(0.94–7.03)
Change of heartburn, n (%)			.113
About same level	76 (78)	62 (68)		138	1.00		1.00
Much more during pregnancy	21 (22)	29 (32)		50	1.69	(0.88–3.26)	1.39	(0.62–3.08)
Change of total fibre consumption, n (%)			.736
Same	34 (35)	31 (34)		65	1.00		1.00
Less (over 2 g/day) during pregnancy	16 (16)	19 (21)		35	1.30	(0.57–2.97)	0.90	(0.33–2.44)
More (over 2 g/day) during pregnancy	47 (49)	41 (45)		88	0.96	(0.50–1.82)	1.06	(0.49–2.27)
Change of total fibre consumption g/day, Md (IQR)	1.7 (–0.9–5.8)	1.4 (–1.3–5.0)	.575	188	0.99	(0.94–1.03)	–

Md: median; IQR: inter quartile range. Differences between groups were tested by Mann–Whitney U test, Pearson Chi-square test or Fisher’s exact test with p values (p). Missing values were not shown, but they included into the analyses. Results of univariable logistic regression models for nausea or vomiting during the first trimester were shown by odds ratios (OR) with 95% confidence intervals (CI). g: grams; *cannot be computed due to the zero frequency. Multivariable: adjusted by risk factors before pregnancy, age, BMI, smoking, use of alcohol and primiparity.

Bold value signifies special diet, change in physical activity, changes in constipation.

Data availability statement

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.