The funding for the Women's Health theme was used to conduct a prospective cohort study of nulliparous women attending the Rosie Hospital. The study design is described in detail elsewhere (BMC Pregnancy and Childbirth 2008;8:51). The case for the utility of prospective cohort studies for clinical and translational research in adverse pregnancy outcome has previously been made by the theme leader (Lancet 2007;370: 1715-25).
The major indicator of the success of the theme in relation to the funding provided is the successful conduct of the study. Recruitment commenced in January 2008 and the Cambridge BRC Scientific Advisory Board was shown a graph of projected recruitment to the study assuming 80, 90 or 100 patients per month.
The midpoint of the estimates projected that approximately 2400 female participants were recruited by month 32 (September 2010) and the actual figure was 2411. Women are recruited at the time of booking (around 12 weeks of gestational age) and are then seen at 20, 28 and 36 weeks. Rates of attrition have been low and the numbers of patients who have attended each of these visits are 2221, 1996 and 1768, respectively (the reduction in numbers at follow up appointments is largely explained by the fact that 500-600 pregnancies are on-going; the remainder of the reduction is due in part to attrition and in part to preterm birth).
The outcome of pregnancy is ascertained by research midwives abstracting data from the clinical case record into a customised database and we currently have a total of 1213 outcome records. Although the hospital represents a generally low risk cohort, there are significant numbers of cases with the adverse events of interest. In September 2010 there were 42 (3.4%) low birth weight infants (<2500g), 64 (5.2%) infants with intra-uterine growth restriction (customised birth weight percentile <3rd), 28 macrosomic infants (>4500g), 55 (4.4) preterm births, 62 (5%) cases of preeclampsia (proteinuric hypertension in a previously normotensive, non-proteinuric woman), and 12 (1%) cases of severe pre-eclampsia requiring intravenous magnesium sulphate. The final cohort should include approximately three- times the number of each outcome and this will provide sufficient material for both translational research studies on the placenta and identification of novel biomarkers in stored serum and plasma.
The placenta is systematically sampled following delivery (see BMC Pregnancy and Childbirth 2008;8:51). There is >90% completeness of placental collection and in 30-40% of cases samples are obtained within 30 minutes of delivery and flash frozen into liquid nitrogen (60-70% of the rapid collections are within 10 minutes of delivery).
Blood sampling at each of the antenatal visits is >90% complete. Hence, we have been successful in establishing a bank of data and samples from an unselected cohort with informative numbers of adverse events.
