Introduction
Material and methods
Protocol and eligibility criteria
Search strategy
Selection of studies
Data extraction
Risk of bias, summary measures and synthesis of the results
Results
Study selection and characteristics
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 |
Risk of bias
Summary of results
Type of Pollutant | Population | Effect |
---|---|---|
NO2 | IVF | Lower live birth rates |
General population | Higher miscarriage rate | |
CO | General population | Higher stillbirth in second and third trimester |
O3 | IVF | Lower live birth rates |
PM2.5 | IVF | Lower pregnancy rates |
General population | Reduced fecundability ratio | |
PM10 | IVF | Higher miscarriage rate |
General population | Higher miscarriage rate | |
PM2.5–10 | General population | Reduced fertility rate |
SO2 | IVF | No effect |
General population | Higher early miscarriage and third trimester still births. Reduced conception rate | |
Traffic pollutants | General population | Higher miscarriage rate; Higher infertility rates. |
Coal combustion products | General population | Higher trend of miscarriage |