Table 1.
Summary of characteristics of studies included in the meta-analysis.
| Study | Study population | Type of study | Number* | Maternal age* | Gravidity* | Parity* | BMI* (kg/cm) | Fetal sex* (male%) | Perinatal mortality*% |
|---|---|---|---|---|---|---|---|---|---|
| Mladen Predanic (2005) | American | Retrospective case-control study | 84/ 84 | (31.2±5.2)/(33.4±4.7) | [2(1,3)]/ [2 (1, 2)] | [0(0,1)]/[0 (0,1)] | NR | NR | NR |
| Annette E. Bombrys (2008) | American | Retrospective case-control study | 255/ 289 | (26.9±6.2)/(24.9±5.9) | (2.7±1.7)/(2.9±2.4) | (1.2±1.4)/(1.3±1.4) | NR | NR | NR |
| Shu-Chi Mu (2008) | Taipei | Retrospective case-control study | 14/ 28 | (30.7±3.9)/(29.5 ± 4.2) | (1.9±1.0)/(2.0±1.1) | (1.3±0.5)/(1.5±0.6) | NR | NR | NR |
| Amanda L. Horton (2010) | American | Retrospective cohort study | 68/ 68 | (27.3±4.6)/(25.4±5.1) | NR | NR | (24.2±1.1)/(6.1±1.3) | 47/ 51.4 | NR |
| Lynn Murphy Kaulbeck (2010) | Canada | Retrospective cohort study | 725/ 196024 | NR | NR | NR | NR | NR | 3.35/ 0.39 |
| Meiling Hua (2010) | American | Retrospective cohort study | 392/ 63655 | (29.8±6.4)/(30.2±6.3) | (2.5±1.3)/(2.7±1.6) | (1.0±1.1)/(1.1±1.2) | NR | 46.0/ 50.8 | NR |
| Shilpa Chetty-John (2010) | American | Prospective study | 263/ 41415 | (25.02±5.6)/(24.08±6.0) | – | – | NR | 41.1/ 49.8 | NR |
| Shimon Burshtein (2011) | Russia | Retrospective cohort study | 243/ 194566 | (28.5±5.6)/(28.5±5.9) | – | – | NR | NR | 6.6/0.9 |
| Mohamed Ibrahim Khalil (2013) | Saudi Arabia | Retrospective cohort study | 159/ 35026 | (31.41±6.3)/(31.57±6.5) | (4.5±2.6)/(4.5±2.7) | (2.8±2.0)/(2.8±2.0) | (24.1±4.56)/(24.5±5.01) | NR | 3.14/0.99 |
| Eran Ashwal (2014) | Israel | Retrospective cohort study | 91/ 182 | (28.8±5.1)/(28.8±4.5) | [2(2–3)]/[2(1–3)] | [1(0–2)]/[1(0–2)] | NR | 38.5/ 47.8 | NR |
| Joel Baron (2014) | Israel | Prospective case-control study | 29/ 29 | (29.7±5.3)/(30.3±5.2) | NR | NR | NR | NR | NR |
| Lorena Mesquita Caldas(2014) | Brazil | Retrospective case-control study | 134/ 759 | (30.8±6.7)/(30.3±6.6) | NR | NR | NR | NR | NR |
| S. Doğan (2014) | Turkey | Retrospective cohort study | 77/ 95 | (30.3±5.1)/(29.6±5.9) | (1.9±1.0)/(2.1±1.2) | (0.7±1.0)/(0.76±0.8) | NR | NR | NR |
| Fırat Tülek (2015) | Turkey | Retrospective cohort study | 93/ 100 | (27.1±5.37)/(27.4±5.28) | (3.9±2.0)/(3.8±1.0) | (2.1±1.0)/(2.3±1.2) | (28.3±4.28)/(28.3±3.38) | NR | NR |
| Mariella Mailath-Pokorny (2015) | Austria | Retrospective cohort study | 136/ 500 | 28.6±6.5 | 2.7±1.6# | 1.1±1.1# | – | 48.1# | NR |
*
(Isolated SUA/normal umbilical artery)
#
total (all the fetal); BMI – body mass index; NR – no refer; ‘–’ – cloud not collect from article.