The National Women's Health Study: assembly and description of a population-based reproductive cohort.

BMC Public Health. 2004 Aug 7;4(1):35. Epub 2004 Aug 07.
  
The National Women's Health Study: assembly and description of a population-based
reproductive cohort.

Maconochie N, Doyle P, Prior S.

Background: Miscarriage is a common event but remarkably difficult to measure in 
epidemiological studies. Few large-scale population-based studies have been 
conducted in the UK. 

Methods: This was a population-based two-stage postal survey of reproductive 
histories of adult women living in the United Kingdom in 2001, sampled from the 
electronic electoral roll. In Stage 1 a short "screening" questionnaire was sent 
to over 60,000 randomly selected women in order to identify those aged 55 and 
under who had ever been pregnant or ever attempted to achieve a pregnancy, from 
whom a brief reproductive history was requested. Stage 2 involved a more lengthy 
questionnaire requesting detailed information on every pregnancy (and fertility 
problems), and questions relating to socio-demographic, behavioural and other 
factors for the most recent pregnancy in order to examine risk factors for 
miscarriage. Data on stillbirth, multiple birth and maternal age are compared to 
national data in order to assess response bias. 

Results: The response rate was 49% for Stage 1 and 73% for the more targeted 
Stage 2. A total of 26,050 questionnaires were returned in Stage 1. Of the 
17,748 women who were eligible on the grounds of age, 27% reported that they had 
never been pregnant and had never attempted to conceive a child. The remaining 
13,035 women reported a total of 30,661 pregnancies. Comparison of key 
reproductive indicators (stillbirth and multiple birth rates and maternal age at 
first birth) with national statistics showed that the data look remarkably 
similar to the general population. 

Conclusions: This study has enabled the assembly of a large population-based 
dataset of women's reproductive histories which appears unbiased compared to the 
general UK population and which will enable investigation of hard-to-measure 
outcomes such as miscarriage and infertility.

PMID: 15298712 [PubMed - as supplied by publisher]


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