Table 1.
Characteristics of included studies
| Authors | Year | Location and study period | Total pregnancies | Cases | Controls | Primary outcomes | Secondary outcomes | Trimester of fasting | Length and duration of fasting (days and average hours/day) | Risk of bias (ROBINS-I) |
|---|---|---|---|---|---|---|---|---|---|---|
| Alwasel | 2011 | Saudi Arabia, August 2000–April 2009 | 17,626 | 13,220 | 4406 | – | BW, PW | 1st, 2nd, 3rd | n/a | Moderate |
| Arab | 2001 | Iran, 1999 | 4343 | 3086 | 1257 | SGA | BW, LBW | n/a | 1 to 20+ days n/a | Moderate |
| Awwad | 2012 | Lebanon, September 2008 | 402 | 201 | 201 | PTB | BW, LBW | 1st, 2nd, 3rd | 22 +/− 9 days n/a | Low |
| Azizi | 2004 | Iran, April–September 2001 | 191 | 98 | 93 | – | BW | 3rd | 28 +/− 2 days 13 h20 min | Low |
| Bayoglu Tekin | 2016 | Turkey, June–July 2014 | 48 | 23 | 25 | – | BW | 3rd | 18.2 +/− 2 days 17.24 h | Low |
| Daley | 2017 | United Kingdom, March 2007 – December 2010 | 5156 | 479 | 4677 | PTB | BW, LBW | 1st | n/a | Moderate |
| Hefni | 1993 | Egypt, 1991 | 322 | 167 | 155 | – | BW, SB | 3rd | n/a > 10 h | Low |
| Hızlı | 2012 | Turkey, August–September 2010 | 110 | 56 | 54 | – | BW | 3rd | 12.9 +/− 2.5 days 15.3 h (12–19) | Low |
| Karateke | 2016 | Turkey, June–July 2014 | 240 | 120 | 120 | – | BW, LBW | 1st, 2nd, 3rd | n/a n/a | Low |
| Kavehmanesh | 2004 | Iran, January–September 2000 | 539 | 284 | 255 | PTB | BW | n/a | 24 +/− 9 days 13 h | Low |
| Makvandi | 2013 | Iran, 2013 | 300 | 150 | 150 | – | BW, LBW | 3rd | 16.6+/−13.2 days n/a | Low |
| Malhotra | 1989 | United Kingdom, April–May 1987 | 22 | 11 | 11 | SGA | BW, CA, NND, PW | 3rd | n/a 7 h | Moderate |
| Naderi | 2004 | Iran, November 2001 | 101 | 51 | 50 | – | BW | n/a | 20+ days n/a | Low |
| Ozturk | 2011 | Turkey, September 2008 | 72 | 42 | 30 | PTB | – | 2nd | 10+ days Approximately 12 h | Low |
| Petherick | 2014 | United Kingdom, October–December 2010 | 300 | 128 | 172 | PTB | BW, GD, Hyp, LBW | 1st, 2nd, 3rd | 1–29 days Up to 18 h | Moderate |
| Rezk | 2016 | Egypt, June–July 2015 | 450 | 210 | 240 | – | BW | 3rd | 30 days 12-16 h | Low |
| Sakar | 2016 | Turkey, August–October 2013 | 338 | 168 | 170 | – | BW, PW | 3rd | 25.17 +/− 5.44 days n/a | Low |
| Sarafraz | 2014 | Iran, 2008 | 293 | 200 | 93 | – | BW | 1st, 2nd, 3rd | 1 to 20+ days n/a | Low |
| Savitri | 2018 | Indonesia, July 2012 – July 2014 | 139 | 110 | 29 | – | BW | 1st, 2nd, 3rd | 1–30 days n/a | Moderate |
| Seckin | 2014 | Turkey, July–August 2013 | 169 | 82 | 87 | – | BW | 3rd | 23 +/− 3.6 days 18.7 h (17–20) | Low |
| Shahgheibi | 2005 | Iran, (dates unknown) | 163 | 63 | 100 | – | BW, LBW | 3rd | 10 to 20+ days n/a | Low |
| Ziaee | 2010 | Iran, October 2004 | 189 | 123 | 66 | – | BW, LBW | 1st, 2nd, 3rd | 1 to 20+ days 13 h | Low |
Primary outcomes: SGA small for gestational age, PTB preterm birth. Secondary outcomes, BW birth weight, CA congenital abnormalities, GD gestational diabetes, Hyp hypertension, LBW low birth weight, NND neonatal death, PW placental weight, SB stillbirth