The reliability of perinatal and neonatal mortality rates: Differential under-reporting in linked professional registers vs. Dutch civil registers

Official Dutch perinatal mortality rates are based on birth and death certificates. These civil registration data are not detailed enough for international comparisons or extensive epidemiological research. In this study, we linked and extrapolated three national incomplete, professional registers from midwives, obstetricians and paediatricians, containing detailed perinatal information. This linkage and extrapolation resulted in one detailed professional database which is representative of all Dutch births and from which gestational age-specific perinatal mortality rates could be calculated. The reliability of these calculated mortality rates was established by comparing them with the rates derived from the national civil registers. The professional database reported more perinatal deaths and fewer late neonatal deaths than the civil registers. The underreporting in the civil registers amounted to 1.2 fewer perinatal deaths per 1000 births and was most apparent in immature newborns. We concluded that under-reporting of perinatal and neonatal deaths depends on the data source used. Mortality rates for the purpose of national and international comparison should, therefore, be defined with caution. This study also demonstrated that combining different incomplete professional registers can result in a more reliable database containing detailed perinatal information. Such databases can be used as the basis for extensive perinatal epidemiological research

Periconceptional folic acid use and the prevalence of neural tube defects in The Netherlands

Objective: To study the effect of increased folic acid intake on the prevalence of neural tube defects (NTD) in The Netherlands. Study design: Using the capture–recapture method, the prevalence of NTD was estimated on the basis of five different registries on births affected by NTD. Results: Total prevalence over the 1988–1998 period varied between 1.43 and 1.96 per 1000 live and still births. No decrease in total prevalence was found to have taken place during that period. Scrutiny of the last 2 years, 1997 and 1998, in which increased folic acid intake might be expected to have had an effect, did not give any indication that the prevalence of NTD was falling. Conclusions: A decrease in the Dutch prevalence of NTD during the study period could not be demonstrated due to the relatively small number of women using folic acid periconceptionally. This does not mean automatically that periconceptional folic acid use is ineffective in reducing the Dutch prevalence of NTD. Further monitoring is needed

Roken tijdens de zwangerschap: Trends in de periode 2001-2010

Doel. Het vaststellen van trends in de rookprevalentie onder zwangeren in de periode 2001-2010 en deze prevalentie relateren aan verschillen naar opleidingsniveau. Opzet. Beschrijvend; landelijke peilingen. Methode. In 2001, 2002, 2003, 2005, 2007 en 2010 werden via organisaties voor jeugdgezondheidszorg tijdens het periodiek gezondheidsonderzoek 28.720 vragenlijsten uitgedeeld aan moeders van kinderen ≤ 6 maanden. In totaal vulden 16.358 moeders (57%) de vragenlijst in. Resultaten. In de periode 2001-2010 is het aantal zwangeren dat rookte tijdens de zwangerschap gehalveerd (p < 0,001). In 2010 rookte 6,3% (95%-BI: 5,0-7,6) van de zwangeren dagelijks gedurende de hele zwangerschap. De rookprevalentie was het hoogst onder laagopgeleide zwangeren (13,8% in 2010; 95%-BI: 9,3-18,4) en het laagst onder hoogopgeleiden (2,4% in 2010; 95%-BI: 1,2-3,6). Tijdens de zwangerschap stopte 4% van de rokende vrouwen. De mediaan van het aantal gedurende de zwangerschap gerookte sigaretten was 5 per dag, tegenover 10 in het laatste half jaar vóór de zwangerschap. In 2001 was de het verschil in rookprevalentie tussen laag- en hoogopgeleide zwangeren 18,9%, in 2010 was dat 11,4%. Het verschil tussen middelbaar- en hoogopgeleide zwangeren was 6,5 en 5,4% in respectievelijk 2001 en 2010. Conclusie. Het percentage vrouwen dat gedurende de gehele zwangerschap rookt is tussen 2001 en 2010 gehalveerd, maar in 2010 rookte nog steeds 6,3% van de zwangeren. De rookprevalentie verschilde sterk tussen de opleidingsniveaus; de absolute verschillen veranderden niet gedurende het onderzoek

Increasing awareness of and behaviour towards periconceptional folic acid consumption in The Netherlands from 1994 to 1995

Objective: In November 1993, Dutch health authorities advised that women planning a pregnancy should take folic acid in the periconceptional period to reduce the risk of fetal neural tube defects. In the autumn of 1995 a national campaign was organized to inform women and health care professionals in a systematic way. Methods: We assessed the awareness and behaviour of women at their first or second antenatal visit in two surveys in the spring of 1994 and the autumn of 1995, in order to evaluate the impact of non-systematic information during that period, and to collect baseline data to evaluate the effect of the national folic acid campaign. The two surveys were carried out in the north and the west of The Netherlands. Results: The proportion of women who had heard of folic acid increased from 28% to 78%. The proportion that used folic acid during any period in pregnancy increased from 7.8% to 26%. The proportion that took folic acid tablets during the whole of the recommended period increased from 0.8 to 4.4%. In the group of women wits did not take folic acid, the proportion who did 'not like to use anything during pregnancy' decreased, as did the proportion who did 'not think it is useful'. Conclusion: In The Netherlands, non-systematic information about periconceptional folic acid use has already led to significant changes in awareness and behaviour before the start of the national folic acid campaign