Demographic characteristics of the included study participants
| Study (year) | Study design | Location | Gestation (week) (Mean±SD) | Patients (n) | Age (mean±SD) | BMI (mean±SD) | ||||
| HP (+ve) | HP (−ve) | HP(+ve) | HP (−ve) | HP (+ve) | HP (−ve) | HP (+ve) | HP (−ve) | |||
| Ali et al (2018)40 | Case control study | Iraq | 34.8±5.5 | 33.6±5.9 | 50 | 50 | 28.1±6.2 | 29.1±5.6 | NM | NM |
| Felkner et al (2007)38 | Case control study | USA | NM | NM | 95 | 147 | 22.9±4.2 | 23.5±4.7 | 24±2.3 | 24±3.8 |
| Golalipour et al (2012)37 | Case control study | Iran | 40±3.3 | 41±3.3 | 35 | 53 | 25.3±5.4 | 25.4±5.1 | NM | NM |
| Mulayim et al (2008)39 | Case control study | Turkey | 30±2.4 | 30±2.7 | 72 | 45 | 28.5±3.47 | 30±3.1 | 27±2.1 | 24±3.6 |
| Mubarak et al (2014)36 | Cross-sectional study | Sudan | 25.1±2.6 | 25.1±2.6 | 125 | 54 | 26±6.8 | 26±6.8 | 28.8±6.32 | 28.8±6.32 |
| Ugwuja et al (2010)35 | Mixed method | Nigeria | 21.77±3.14 | 21.77±3.14 | 84 | 265 | 28.19±4.89 | 26.7±4.65 | 29.0±3.89 | 26.86±4.1 |
BMI, body mass index; HP(-ve), Helicobacter pylori negative; HP(+ve), Helicobacter pylori positive; NM, not mentioned.