Maternal exposure to extremely low frequency magnetic fields: Association with time to pregnancy and foetal growth.

BACKGROUND: Data on reproductive and developmental effects of extremely low frequency magnetic fields (ELF MFs) are inconclusive. This study tested the hypothesis that maternal exposure to ELF MFs is associated with increased time to pregnancy (TTP), reduced birthweight or small for gestational age (SGA). METHODS: The study cohort consisted of 373 mothers who gave birth between 1990 and 1994 in Kuopio University Hospital, Finland. To increase prevalence of high ELF MF exposure, women living in buildings near known ELF MF sources were included. Maternal exposure to ELF MF before and during pregnancy was assessed with short term measurements in residences and questionnaires. Associations between ELF MF exposure and TTP, low birth weight and SGA were analysed by logistic regression (or linear regression for continuous variables), adjusting for factors known to be associated with the selected pregnancy outcomes, such as maternal smoking, alcohol consumption and socioeconomic status. RESULTS: The MF exposure of the mothers was slightly higher than in Finnish residences in general, but very high exposures (>0.4µT) were rare. No consistent association of ELF MF with TTP, birth weight or SGA was found. CONCLUSIONS: ELF MF exposure is not likely to be associated with TTP or prenatal growth at residential exposure levels that were observable in this study.

First trimester biochemistry at different maternal ages.

BACKGROUND: The performance of first trimester biochemical screening was compared at different pregnancy weeks and maternal ages during 2002-2008 in a screened population of 76,949 women. METHODS: The detection rates, as well as the median multiples of a median (MOMs) of free ß-human chorionic gonadotropin (free ß-hCG) and pregnancy-associated plasma protein-A (PAPP-A), were compared between completed gestational weeks 8-13 and between different maternal ages separated into 5-year groupings. RESULTS: The number of singleton Down syndrome pregnancies was 221. The median age of the screened women was 30 years and the proportion of women aged ≥ 35 years 16.9%. The median age of the women with a Down syndrome pregnancy was 37 years. In women aged <35 years, the biochemical markers provided a detection rate of only 38.6%, whereas in women aged ≥ 35 years, the biochemical markers detected 82.7% of cases (p<0.01). CONCLUSIONS: Biochemical screening works best amongst women aged ≥ 35 years. For younger mothers aged <35 years, combined screening should be the method of choice.