Table 4.
Characteristics of the present and previous longitudinal studies on the reference intervals for thyroid function in pregnancy
| Authors, year (Refs.) | Method | Age ± SD (range) | Ethnicity | Country | Ecography/Ab | Iodine assay | Subjects | Week 1 trim | Week 2 trim | Week 3 trim |
|---|---|---|---|---|---|---|---|---|---|---|
| Present study | Roche Elecsys | 33.7 ± 3.8 (23–42) | Caucasian | Italy | No/TPO | Yes (ICPM°) | 139 | 14–16 | 24–26 | 30–32 |
| Sekhri et al. 2016 [13] | Roche Elecsys | 24.5 ± 3.5 (18–45) | Indian | India | No/TPO | Yes (SK reaction°°) | 86 | 10.8(± 2.4) | NR | NR |
| Joosen et al. 2016 [14] | Roche Elecsys | Not reported | Caucasian | Netherlands | No/TPO | No | 97 | 9–13 | 27–29 | 36–39 |
| Ortega Carpio et al. 2018 [15] | Roche Elecsys | 30.7 | Caucasian | Spain | No/TPO | No | 145, 105, 67* | 9–11 | 26–28 | 34–36 |
| Kostecka-Matyja et al. 2017 [16] | Roche Elecsys | 35 (27–47) | Caucasian | Poland | No/TPO | No | 172 | NR | NR | NR |
| Yuen et al. 2020 [17] | Roche Elecsys | 31.1 ± 3.9 | Chinese | Hong Kong | No/TPO | Yes (ICPM°) | NR** | 12–13 | 16–20 | 32–36 |
| Yuen et al. 2020 [17] | Siemens Centaur | 31.1 ± 3.9 | Chinese | Hong Kong | No/TPO | Yes (ICPM°) | NR** | 12–13 | 16–20 | 32–36 |
| Yuen et al. 2020 [17] | Beckman DXI | 31.1 ± 3.9 | Chinese | Hong Kong | No/TPO | Yes (ICPM°) | NR** | 12–13 | 16–20 | 32–36 |
| Ekinci et al. 2013 [18] | Beckman DXI | 31 ± 4.7 | Not reported | Australia | No/TPO | Yes (ICPM°) | 129, 84, 71, 70*** | 9–13 | 22–26 | 35–39 |
| Yuen et al. 2020 [17] | Abbott Architect | 31.1 ± 3.9 | Chinese | Hong Kong | No/TPO | Yes (ICPM°) | NR** | 12–13 | 16–20 | 32–36 |
| Ho et al. 2017 [19] | Abbott Architect | 31.6 ± 4.6 | Chinese | Singapore | NO/TPO, Anti-Tg | No | 283 | 9–14 | 18–22 | 34–39 |
| Ho et al. 2017 [19] | Abbott Architect | 31.6 ± 4.7 | Malay | Singapore | NO/TPO, Anti-Tg | No | 143 | 9–14 | 18–22 | 34–39 |
| Ho et al. 2017 [19] | Abbott Architect | 31.6 ± 4.8 | Indian | Singapore | NO/TPO, Anti-Tg | No | 71 | 9–14 | 18–22 | 34–39 |
| Ollero et al. 2019 [20] | Abbott Architect | 33.4 ± 4 (29–37) | Caucasian | Spain | Yes/TPO, Anti-Tg | Yes (HPLC-EC°°°) | 288, 252, 236**** | 9 | 15 | 36 |
Bold indicates data of the present study
NR = Not Reported
*Among 186 women
**600 pregnant women were recruited in their first trimester and were invited to have two more blood draws during subsequent antenatal visits, at least four weeks apart, and one final blood draw on admission for delivery. Blood samples collected in each woman were between 1 (n = 524) and 4 (n = 373). Number of subjects examined in the specified gestational weeks was not detailed
***Longitudinal data available in 47 women only, results mixed with other, cross-sectional samples
****Number of participants whose blood samples were available respectively in the 1st, 2nd and 3rd trimesters, among 291 women
°Inductively Coupled Plasma Mass Spectrometry
°°Sandell–Kolthoff reaction
°°°High performance liquid chromatography with electrochemical detection