Postpartum airway responsiveness and exacerbation of asthma during pregnancy – a pilot study

Figures & data

Table 1 Characteristics of women (n=50) followed throughout pregnancy in the Management of Asthma during Pregnancy program with postpartum assessment of asthma status

Characteristics	Women (n=50)
Time since birth (days)	124±39 (33–207)
Age (years)	32±5 (22–42)
Body mass index (kg/m^2)	26±5 (19–37)
Rhinitis	40 (80)
Nulliparous	16 (32)
Male child	24 (48)
Exacerbation of asthma during pregnancy
Total exacerbations	13 (26)
Mild exacerbations	8 (16)
Severe exacerbations	8 (16)
Asthma controller therapy
Daily dose of inhaled corticosteroid (n=50)a
Low	36 (72)
Middle	11 (22)
High	3 (6)
Second controller therapy
Long-acting β2-agonist	21 (42)
Leukotriene receptor antagonist	1 (2)
Smoking status
Current-smoker	1 (2)
Pack-years	14
Ex-smoker	9 (18)
Pack-years	7± 4 (2–15)
Never-smoker	40 (80)
Environmental tobacco exposure	5 (10)
Self-reported adherence
Good/acceptable	39 (78)

Notes: Data are given as mean ± SD with range in brackets or numbers with percentages in brackets.

a Given in beclomethasone dipropionate equivalent doses.

Figure 1 Neutrophil count in induced sputum vs airway responsiveness to inhaled mannitol, expressed as the RDR, in a postpartum evaluation of 50 women with asthma followed throughout pregnancy in the Management of Asthma during Pregnancy program.

Note: RDR, the percentage decline in FEV₁ after the last mannitol dose divided by the cumulative mannitol dose in milligrams.
Abbreviations: FEV₁, forced expiratory volume in the first second; RDR, response–dose ratio.

Table 2 Univariate analyses of 50 women (31 without and 13 with asthma exacerbation) followed throughout pregnancy in the Management of Asthma during Pregnancy program with postpartum asthma evaluation

Variables	No exacerbation, n=37	Exacerbation, n=13	ORcrude (95% CI)	ORadj (95% CI)	p-valueadj
Atopic	32 (86)	8 (62)	0.20 (0.44–0.92)	0.11 (0.02–0.69)	0.02
Exhaled nitric oxide
FE NOa (ppb)	18±12	20±13	1.02 (0.97–1.07)	1.01 (0.96–1.08)	NS
FE NO > 25 ppb	10 (27)	4 (31)	1.20 (0.30–4.79)	1.13 (0.24–5.30)	NS
Lung function parameters
FEV1 % predicted	100.6±18.5	93.1±19.7	0.98 (0.94–1.01)	0.98 (0.94–1.02)	NS
FEV1 <80% predicted	4 (11)	4 (31)	3.67 (0.76–17.62)	4.24 (0.7822.97)	NS
FEV1/FVC ratio (%)	77.3±6.0	76.4±7.9	0.98 (0.89–1.08)	0.99 (0.89–1.10)	NS
FEV1/FVC < LLNb	6 (16)	4 (31)	2.30 (0.53–9.95)	2.19 (0.49–9.69)	NS
Total lung capacity % predicted	113.3±23.3	110.9±10.0	0.99 (0.96–1.03)	1.00 (0.96–1.03)	NS
Residual volume % predicted	111.6±18.9	126.2±37.2	1.02 (0.98–1.05)	1.02 (0.98–1.05)	NS
Vital capacity % predicted	113.7±32.0	103.3±14.1	0.98 (0.94–1.02)	0.97 (0.93–1.02)	NS
Functional residual capacity % predicted	109.5±19.9	113.1±19.5	1.01 (0.98–1.04)	1.01 (0.98–1.05)	NS
Specific airway conductance % predicted	100.7±25.8	107.5±58.1	1.01 (0.99–1.02)	1.01 (0.99–1.02)	NS
Diffusing capacity % predictedc	74.8±8.8	74.4±6.7	0.99 (0.92–1.07)	0.98 (0.89–1.07)	NS
Mannitol challenge test
Positive test	27 (73)	12 (92)	3.86 (0.44–33.91)	4.65 (0.49–43.88)	NS
Geometric mean of mannitol PD15 (mg)	171 (118–246)	82 (44–156)	0.99 (0.98–0.99)	0.99 (0.98–0.99)	0.05
Inflammatory phenotype
Eosinophilic	9 (24)	2 (15)	0.30 (0.03–2.52)	0.30 (0.02–4.80)	NS
Neutrophilic	4 (11)	3 (5)	3.38 (0.40–28.74)	3.31 (0.21–52.48)	NS
Mixed granulocytic	0 (0)	2 (15)	–	–	NS
Paucigranulocytic	16 (43)	4 (31)	–	–	NS

Notes: Data are given as mean ± SD or numbers with row percentages in parentheses. The cumulative dose of mannitol causing a 15% decline in FEV1 (PD₁₅) are given as geometric mean with 95% CI. Results are reported as OR_crude with 95% CI and OR_adj with 95% CI and p-value. The associations are adjusted for age, smoking status (never smoker vs ever smoker), ICS treatment (low dose vs middle and high dose), and self-reported adherence with ICS (good/acceptable vs poor).

a Fractional exhaled nitric oxide.

b Lower limit of normal.

c For carbon monoxide.

Abbreviations: adj, adjusted; CI, confidence interval; OR, odds ratio; FVC, forced vital capacity; FEV₁, forced expiratory volume in the first second; F_ENO, fractional exhaled nitric oxide; ICS, inhaled corticosteroids; LLN, lower limit of normal; NS, not significant.