Use of time to pregnancy in environmental epidemiology and surveillance

Background Potential sources of environmental pollution, such as incinerators or landfill sites, can adversely affect reproduction and/or development. Time to pregnancy (TTP) is a validated measure of biological fertility that can be studied with relatively small populations. Methods Pregnant local residents living within 3 km of a landfill site ('exposed' group, n = 200) or elsewhere in the Rhondda valleys ('unexposed' group, n = 400) were interviewed by health visitors or midwives. The response rate was 83%. Results No difference was found in the TTP distributions between the exposed and unexposed groups. Relationships of TTP with covariates were consistent with the literature. Conclusion In a context of public and scientific concern about possible reproductive toxicity, an interview study of TTP was highly acceptable to local women. A large enough sample to generate stable TTP distributions was readily achieved.