Table 1 Characteristics of included studies
From: Insulin resistance in women with recurrent miscarriage: a systematic review and meta-analysis
Author/year published | Country | RPL | Control | Definition of RM | Outcome measurements | Measurement timing | Exclusion of known cause | Matched variables | ||
|---|---|---|---|---|---|---|---|---|---|---|
Number of cases | Age of cases | Number of controls | Age | |||||||
Craig 2002 [26] | United States | 74 | 32.7 ± 5.4 | 74 | 32.8 ± 6.0 |  >  = 2 times before 20 weeks or fetal weight of less than 500 g | FBG, FIN, GI ratio, IR status | Not pregnant | No | Age, weight, race |
Diejomaoh 2007 [27] | Kuwait | 35 | 28.6 ± 4.3 | 30 | 27.5 ± 4.6 |  >  = 3 times | FBG, FIN, HOMA-IR, GI ratio, IR status | Not pregnant | No | Age, ethnic, BMI |
Baban 2010 [23] | Iraq | 64 | 27.53 ± 8.84 | 51 | 28.72 ± 8.18 |  >  = 3 times | FBG, FIN | pregnant | Yes | None |
Celik 2011 [25] | Turkey | 64 | 29.5 ± 6.0 | 64 | 30.7 ± 6.0 |  >  = 2 times before 20 weeks | FBG, FIN, HOMA-IR, GI ratio, IR status | Not pregnant | Yes | Age, BMI |
Wang 2011 [38] | China | 97 | 30.81 ± 4.01 | 52 | 29.15 ± 4.62 |  >  = 2 times | FBG, FIN, HOMA-IR | Gestational age of 5–13 weeks | Yes | None |
Maryam 2012 [36] | Iran | 50 | 28.15 ± 4.76 | 50 | 28.28 ± 4.77 |  >  = 3 times before 24 weeks | FBG, FIN, GI ratio, IR status | Not pregnant | No | Age, BMI |
Hong 2013 [30] | China | 161 | 27.1 ± 2.9 | 465 | 26.8 ± 3.0 |  >  = 2 times | FBG, FIN, HOMA-IR, GI ratio | first trimester pregnancy | No | None |
Ispasoiu 2013 [31] | Romania | 65 | 30.12 ± 4.904 | 53 | 29.36 ± 5.274 |  >  = 2 times | FBG, FIN | Not pregnant | Yes | None |
Kazerooni 2013 [34] | Iran | 60 | 24.8 ± 3.9 | 60 | 24.6 ± 4.7 |  >  = 3 times before 20 weeks | FBG, FIN | 10th day of the menstrual cycle | Yes | Age, BMI, parity |
Ota 2014 [37] | United States | 63 | 35.8 ± 4.8 | 30 | 35.1 ± 4.1 |  >  = 3 times before 20 weeks | FBG, FIN | Periovulatory phase of menstrual cycle | Yes | Age |
El-Dorf 2016 [29] | Egypt | 35 | 27.08 ± 4.102 | 35 | 28.12 ± 4.825 |  >  = 2 times at first trimester | FIN | pregnancy between 5 and 12 weeks | Yes | None |
Jiao 2016 [33] | China | 154 152 | 35.2 ± 3.7 35.6 ± 4.1 | 155 151 | 35.1 ± 4.5 35.7 ± 3.8 |  >  = 3 times before 20 weeks | FBG | Not pregnant | Yes | Age |
Azizi 2019 [22] | Iran | 28 | 27.39 ± 4.12 | 42 | 26.31 ± 3.81 |  >  = 3 times before 20 weeks | FBG | luteal phase of menstrual cycle | Yes | None |
Lin 2019 [35] | China | 403 | 29.58 ± 5.48 | 342 | 29.88 ± 5.28 |  >  = 2 times | FBG, FIN, HOMA-IR | Not pregnant | Yes | None |
Bahia 2020 [24] | Tunisia | 332 | 35.8 ± 7.7 | 286 | 32.5 ± 6.2 |  >  = 3 times before 20 weeks | FBG | normo-ovulatory cycle | Yes | Age, menopause status, ethnic |
Edugbe 2020 [28] | Nigeria | 80 | 28.09 ± 6.14 | 80 | 28.10 ± 6.21 |  >  = 2 times before 13 weeks | FBG, FIN, HOMA-IR | Not pregnant | Yes | Age |
Jiang 2021 [32] | China | 133 | 34.1 ± 3.9 | 140 | 33.4 ± 2.9 |  >  = 2 times at first trimester | FBG, FIN, HOMA-IR | at least 12 weeks after the last abortion | Yes | None |
Habets 2022 [39] | Netherlands | 65 58 | 32.6 ± 4.5 33.5 ± 4.6 | 20 | 33.1 ± 6.8 |  >  = 2 times before 24 weeks | FBG, FIN | at least 3 months after miscarriage | None | None |
Singh 2022 [40] | India | 50 | 25.1 ± 3.0 | 50 | 25.8 ± 2.8 |  >  = 2 times | FBG, FIN, HOMA-IR, IR status | Not pregnant | Yes | Age, BMI |