Table 1.

Specifications and information extracted from studies entered into the meta-analysis stage

Row	Author	Publication year	Area	Participants’ Age	Sample size	Prevalence	Assessing and defining sleep disorders
1	Cai, X. H [15].	2013	China	–	1993	32.01%	Sleep status of the married women was conducted using the Berlin Questionnaire. They adapted a few other items according to the characteristics of the pregnant women in their study.
2	Dørheim, S. K [12]	2012	Norway	30.9(±4.8)	2816	61.9%	Insomnia was measured by the Bergen Insomnia Scale.
3	Dørheim, S. K [10]	2014	Norway	31.5(±4.7; range 17.4–45.7)	2088	61.6%	The Bergen Insomnia Scale (BIS) was used to measure insomnia
4	Facco, F. L. [9]	2010	America	29.7 (±5.5)	189	54.3%	The survey was composed of the following validated sleep questionnaires: Berlin Questionnaire for Sleep Disordered Breathing, Epworth Sleepiness Scale, National Institutes of Health/International Restless Legs Syndrome Question Set, Women’s Health Initiative Insomnia Rating Scale, and the Pittsburgh Sleep Quality Index.
5	Kizilirmak, A [1].	2012	Turkey	25.2 ± 5.49	281	30.24%	developed Women’s Health Initiative Insomnia Rating Scale (WHIIRS): The scale is a 5-point Likert type in which the first 4 questions aim to identify the beginning of insomnia, sleep-maintenance insomnia, and the state of waking up early in the mornings, while the last question is associated with quality of sleep. “0” score indicates that there is no problem in relation to insomnia, while “4” indicates that there are problems in relation to insomnia for 5 or more times in a week. The highest score obtained from the scale demonstrated the highest levels of insomnia symptoms.
6	Khazaie, H [2].	2013	Iran	25.3 ± 5.5	106	12.3%	Global sleep assessment questionnaire (GSAQ)
7	Lopes, E. A [16].	2004	Brazil	11–40	300	39%	The survey was composed by brief clinical interview based on directed questions. An anamnesis was performed according to the following questions, always considering the PG state: 1) Do you have any difficulty to fall asleep when you lie down in bed? 2) Do you wake up too early in the morning (earlier than you are supposed to)? 3) If you wake up during the night, do you find it difficulty to sleep again? 4) Has anyone ever told you that you snore? 5) Has anybody ever said that you have difficulty in breathing during the night (like stop breathing)? 6) Do you suddenly fall asleep during the day or in the middle of some kind of activity? 7) Do you fall asleep anywhere (as on buses, in the classroom, at work or while driving)? 8) Do you feel sleepy during the day? 9) Have you been taking naps during the day? 10) Do you wake up with the baby movements? 11) Do you wake up because of abdominal pains or contractions? 12) Do you wake up due to dreams or nightmares involving the baby or to childbirth? 13) Do you wake up with heartburn?
8	Wolynczyk-Gmaj, D [17].	2017	Poland	30.6 ± 5	266	39.8%	The assessment of variables was performed using the Athens Insomnia Scale (AIS), Beck Depression Inventory (BDI), Regestein Hyperarousal Scale (HS), Epworth Sleepiness Scale (ESS), General Practice Physical Activity Questionnaire, and a semi-structured interview about different sleep disorders
9	Bondad,R [18].	2004	Iran	12.87 ± 4.86	320	57.81%	Check the sleep pattern test (Sleep-log)
10	Okun, M. L [19]	2018	America	28.8 ± 6.3	439	33.25%	The ISQ instrument designed to identify insomnia. The ISQ is a 13-item self-report instrument which questions are based on DSM-IV criteria for primary insomnia and are consistent with the American Academy of Sleep Medicine’s (AASM) Research Diagnostic Criteria (RDC).