Table 1.
Characteristics, findings and risk of bias of included studies
| Author, Year, (ref) | Study design | Population Country Individuals | Pollutants | Exposure | Confounders adjusted for | Significant effect size: | Effect size | 95% CI | NOS | |
|---|---|---|---|---|---|---|---|---|---|---|
| Dejmek et al. (2000) [33] | Retrospective cohort | Czech Republic | 2585 (General population) | SO2 | Monitoring station obtained from by US EPA (Air Quality System) | Maternal age; parity; conception; seasonality; currently married; temperature average; temperature maxima; signal; year; season; epidemiological situation | Conception in the first unprotected menstrual cycle | OR = 0.57 SO2 levels (40-80 μg/m3) |
0.37–0.88 | 7 |
| OR = 0.49 SO2 levels (≥ 80 μg/m3) |
0.29–0.81 | |||||||||
| Sallmen et al. (2008) [34] | Retrospective cohort | Portugal | 406 (General population) | Solvents used in shoe manufacturing (N-hexane and hexane isomers; Toluene; Methyl ethyl ketone; Acetone; Ethyl acetate; dichloromethane) | Air sampling was performed in the personal breathing zones of the exposed women, spanning roughly an 8-h work shift. | Female age; Last method of contraception; Age at menarch; Regularity of menstrual cycle; Male smoking; Female and male use of alcohol; Male exposure to metal dusts or fumes; Male exposure to engine exhausts. | Fecundability density ratio (low exposure to solvents) | FDR = 0.55 | 0.40–0.74 | 7 |
| Fecundability density ratio (high exposure to solvents) | FDR = 0.70 | 0.52–0.94 | ||||||||
| Green et al. (2009) [35] | Prospective cohort | USA | 4979 (General population) | Traffic pollutants: NO2; O3; PM 2.5; PM 10, CO2 CH4, CO, H2S, NMHC NMOC; SO2; sulphur; THC | Traffic exposure were constructed using annual average daily traffic (AADT) counts near each residence and distance from residence to major roads | Maternal age, race, employment status, stressful life events and maternal smoking | Spontaneous abortion Maximum daily traffic within 50 m2 | 7 | ||
| > 90 centile | OR = 1.18 | 0.87–1.60 | ||||||||
| > 90 centile (African American) | OR = 3.11 | 1.26–7.66 | ||||||||
| > 90 centile (non smokers) | OR = 1.47 | 1.07–2.04 | ||||||||
| Mohorovic et al. (2010) [36] | Prospective cohort | Croatia | 260 (General population) | Coal combustion (NO2; CO2; CO; other products) | Monitoring station (Labin meteorological station) | Crude data | Spontaneous abortion | OR = 2.99 | 0.91–9.80 | 5 |
| Perin et al. (2010) [31] | Retrospective cohort | Brazil | 348 (IVF women) | PM10 | PM10 concentrations taken from 14 monitoring stations categorized into quartiles (Q1-Q4). | Ovarian response patterns to gonadotrophins, exposure, patient’s age, and the year of IVF treatment | Miscarriage in IVF women (> 56.72 µg/m3) | OR = 5.05 | 1.04–25.51 | 8 |
| Live birth rates (> 56.72 µg/m3) | OR = 1.71 | 0.72–4.09 | ||||||||
| Perin et al. (2010) [32] | Retrospective cohort | Brazil | 177 (IVF women) 354 (General population) |
PM10 | PM10 concentrations taken from 14 monitoring stations categorized into quartiles (Q1-Q4). | Ovarian response patterns to gonadotrophins, exposure, patient’s age, and the year of IVF treatment | Miscarriage in general population (> 56.72 µg/m3) | OR = 2.72 | 1.51–4.89 | 7 |
| Miscarriage in IVF women (> 56.72 µg/m3) |
OR = 2.32 | 1.00–5.43 | ||||||||
| Legro et al. (2010) [28] | Retrospective cohort | USA | 7403 (IVF women) | PM2.5 PM10 SO2 NO2 O3 |
Monitoring station obtained from by US EPA (Air Quality System) | Age, IVF center and the year and season of oocyte retrieval | Live Birth Rate NO2 (after embryo transfer) O3 (after embryo transfer): |
OR = 0.76 OR = 0.62 |
0.66–0.86 0.48–0.81 |
9 |
| Pregnancy rate PM2.5 (during embryo culture) |
OR = 0.94 | 0.82–0.99 | ||||||||
| Faiz e al. (2012) [30] | Retrospective cohort | USA | 343,077 (General population) | PM 2.5 SO2 NO2 CO |
Central monitoring station monitored by Agency Air Quality System | Maternal age; Race/Ethnicity; Educational level; Prenatal care; Smoking; Neighborhood socioeconomic status; Calendar year; month of conception and; mean temperature | Stillbirths NO2 (first trimester) SO2 (first trimester) CO (second trimester) |
OR = 1.16 OR = 1.13 OR = 1.14 |
1.03–1.31 1.01–1.28 1.06–1.24 |
8 |
| Slama et al. [29] | Retrospective cohort | Czech Republic | 1916 (General population) | SO2, PM2.5, NO2, O3, carcinogenic PAHs | Central monitoring station | Maternal age, smoke habits and alcohol consumption before pregnancy,maternal education, marital status, BMI | Fertility rate PM2.5 NO2 |
FR = 0.78 FR = 0.72 |
0.65–0.94 0.53--0.97 |
9 |
| Nieuwenhuijsen et al. (2014) [9] | Cross-sectional | Spain | not available (General population) | PM10 PM2.5 PMcoarse fraction NO2 NOx O3 PM2.5 adsorbance |
Land use regression developed in the European Study of Cohorts for Air Pollution Effects | Socioeconomic status, ethnicity, age, educational level | Fertility rate PM coarse fraction |
FR = 0.88 | 0.83–0.94 | 7 |
| Mahalingaiah et al. (2016) [8] | Prospective cohort | USA | 36,294 (General population) | PM 10, PM 2.5, PM 2.5–10 | USEPA Air Quality System | Age, smoking status, Race, BMI, parity, rotation shift work, oral contraception use, diet, Census tract level median income and median home value | Hazard ratio of primary and secondary infertility Living closer a major roads |
HR = 1.11 | 1.02–1.20 | 9 |