Table 1.
Subject characteristics and resting pulmonary function
| PP | TM3 | Δ(TM3– PP) | P value | |
|---|---|---|---|---|
| Age (years) | 30.6 ± 1.0 | — | — | — |
| Height (cm) | 166.4 ± 1.9 | — | — | — |
| Body mass (kg) | 69.6 ± 3.1 | 80.9 ± 3.0 | 11.3 ± 0.8 | <0.001 |
| Body mass index (kg m−2) | 25.0 ± 0.8 | 29.1 ± 0.7 | 4.1 ± 0.3 | <0.001 |
| Baseline dyspnoea index (focal score) | 11.9 ± 0.1 | 8.6 ± 0.4 | −3.3 ± 0.4 | <0.001 |
| Blood biochemistry | ||||
| PaCO2 (mmHg) | 39.5 ± 0.6 | 31.6 ± 0.4 | −7.9 ± 0.7 | <0.001 |
| [H+] (nequiv l−1) | 38.7 ± 0.4 | 35.8 ± 0.2 | −2.9 ± 0.4 | <0.001 |
| [HCO3−] (mequiv l−1) | 24.6 ± 0.3 | 21.3 ± 0.3 | −3.3 ± 0.4 | <0.001 |
| Progesterone (nmol l−1) | 1.1 ± 0.2 | 877 ± 73 | 876 ± 73 | <0.001 |
| 17β-Oestradiol (pmol l−1) | 106 ± 17 | 123 397 ± 47 068 | 123 291 ± 47 071 | 0.020 |
| Pulmonary function | ||||
| FEV1 (l) | 3.14 ± 0.09 | 3.28 ± 0.09 | 0.14 ± 0.04 | 0.002 |
| FEV1/FVC (%) | 79.7 ± 2.1 | 80.2 ± 1.5 | 0.6 ± 0.9 | 0.527 |
| FVC (l) | 3.98 ± 0.15 | 4.11 ± 0.15 | 0.13 ± 0.03 | 0.001 |
| PEF (l s−1) | 6.82 ± 0.23 | 6.80 ± 0.28 | −0.02 ± 0.14 | 0.898 |
| FEF25%-75% (l s−1) | 3.07 ± 0.20 | 3.26 ± 0.16 | 0.19 ± 0.09 | 0.061 |
| IC (l) | 2.92 ± 0.11 | 2.65 ± 0.11 | 0.28 ± 0.08 | 0.003 |
| FRC (l) | 2.36 ± 0.14 | 2.71 ± 0.14 | −0.36 ± 0.06 | <0.001 |
| sRaw (cmH2O s−1) | 6.59 ± 0.60 | 6.08 ± 0.54 | −0.52 ± 0.27 | 0.072 |
| DLCO (ml min−1 mmHg−1) | 21.3 ± 0.9 | 20.6 ± 0.8 | −0.7 ± 0.4 | 0.136 |
| MIP (cmH2O) | 76 ± 4 | 76 ± 5 | 0.1 ± 2.1 | 0.975 |
| MEP (cmH2O) | 113 ± 6 | 104 ± 6 | −9 ± 5 | 0.102 |
| Cst (cmH2O l−1) | 0.25 ± 0.03 | 0.30 ± 0.06 | 0.04 ± 0.07 | 0.561 |
| Cdyn (cmH2O l−1) | 0.17 ± 0.02 | 0.21 ± 0.04 | 0.04 ± 0.04 | 0.360 |
| Pst (cmH2O) | 30.6 ± 4.5 | 31.0 ± 2.3 | 0.4 ± 2.4 | 0.864 |
Values are means ±s.e.m. PP, postpartum; TM3, third trimester; Δ, pregnancy-induced change; PaCO2, arterialized venous partial pressure of CO2; [H+], arterialized venous hydrogen ion concentration; [HCO3−], plasma bicarbonate concentration; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; PEF, peak expiratory flow; FEF25%-75%, forced expiratory flow from 25% to 75% of the FVC manoeuvre; IC, inspiratory capacity; FRC, functional residual capacity; sRaw, specific airway resistance; DLCO, single breath diffusing capacity for carbon monoxide; MIP and MEP, maximal inspiratory and expiratory pressure, respectively; Cst and Cdyn, static and dynamic lung compliance, respectively (n= 7); Pst, static lung recoil pressure (n= 7).