While the findings also do not demonstrate any overt abnormality in germ cell numbers or development in MBP-exposed animals, some changes were detected at birth in a minority of animals that could indicate an effect, especially as only six animals were evaluated at birth for these parameters; this requires clarification.
We disregarded fourth and higher order births for this group because of the low number of observations.
Finally we excluded an additional 103 (0.6%) births for which birth weight/gestational age combination were implausible based on the algorithm advocated by Alexander et al. [ 16], leaving 17,072 births for this analysis.
This was compared with the U5MR per 1,000 live births for this region of northwestern Nigeria (217 in 1,000 live births) as a way to crudely estimate excess mortality in the villages (NPC and ICF Macro 2009).
In 2007, the number of hospital deliveries for mothers aged 15 to 19 years old was 232 for Durham Region out of 5,256 Ontario births for this same age group [ 28].
Since monthly birth data were available only for 1901 30, the monthly average number of births for this period was calculated and then multiplied by 31 920 (the total number of registered births during 1903 1950) and divided by 25 757 (the total number of registered births during 1903 1930).
* Rapaport (1957) did not report the total number of births, for this study the population figures are provided and the crude risk is the risk per 100 000 population Six studies investigating the association of Down's syndrome with water fluoride level were identified [ 3, 14, 15, 16, 17, 18] these were all ecological in study design.
Because we were interested in the occurrence of neonatal deaths associated with out-of-hospital birth for the overall population of women giving birth, the denominator for this measure is total births.
Informative data for the matched design are those birth pairs with different outcomes between second and third births (for preterm birth, for example, this is when a mother's second child was term and her third child was preterm or vice versa).
