Validation of self-reported data on assisted conception in The Danish National Birth Cohort†

Department of Epidemiology, Institute of Public Health, NANEA, University of Aarhus, 8000 Arhus, Denmark.
Human Reproduction (Impact Factor: 4.57). 06/2009; 24(9):2332-40. DOI: 10.1093/humrep/dep179
Source: PubMed


An increasing number of children are born after assisted conception and in surveillance programmes information on mode of conception is often achieved via maternal self-report. We assessed the validity of self-reported assisted conception in The Danish National Birth Cohort (DNBC), a prospective pregnancy cohort. Here, the term assisted conception refers to IVF, ICSI, ovulation induction and insemination.
We compared self-reported assisted conception in the DNBC to corresponding data from Danish national registers; the IVF Register and Danish Drug Prescription Register, providing method of conception in the entire population. In the DNBC, 101,042 women accepted the invitation in early pregnancy from 1996 to 2002. Our final study population comprised 88,151 DNBC women aged 20 years and older who participated in the first DNBC interview with a pregnancy resulting in a live born child.
In the DNBC, assisted conception was reported with a sensitivity of 83% and positive predictive value of 88%. Misclassification was largely explained by ambiguous phrasing of the DNBC interview question and interview skip patterns. Women with false negative reporting were more often multipara (P < 0.001) and older (P = 0.027 for IVF/ICSI and P = 0.002 for ovulation induction). The risk ratio (RR) for being born preterm in IVF/ICSI children was lower for children identified via the DNBC, RR 3.61 (95% confidence interval (CI) 3.31-3.94), than the IVF Register, RR 4.36 (95% CI 4.02-4.74).
There was a high positive predictive value of self-reported assisted conception in the DNBC, but the structure of the DNBC interview represented a problem and misclassification could introduce bias.

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    • "The study population, described in detail elsewhere (Hvidtjorn et al., 2009a), comprises all women who participated in the first interview (administered around 16 weeks of gestation) of the Danish National Birth Cohort (Olsen et al., 2001) and whose pregnancy resulted in a live birth between 1997 and 2003. In the interview, women were asked whether their pregnancy was planned, and if so, how long they had tried to become pregnant before succeeding. "
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    ABSTRACT: Children born after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) have been reported to have a higher risk of cerebral palsy (CP), perhaps due to the higher frequency of preterm birth, multiple births or vanishing embryo in the pregnancies. However, it has been suggested that the underlying infertility may be part of the pathway. In this study, we examined whether untreated subfecundity (measured by time to pregnancy) or infertility treatment was associated with an increased risk of CP in the offspring. Using the Danish National Birth Cohort (1997-2003), we compared children born after 0-2 months of waiting time to pregnancy (n = 35 848) with those born after a time to pregnancy of 3-5 months (n = 15 361), 6-12 months (n = 11 528) and >12 months (n = 7387), as well as those born after IVF/ICSI (n = 3617), ovulation induction with or without intrauterine insemination (n = 3000), and unplanned pregnancies (n = 13 462). CP cases were identified through the Danish CP Register. In total, 165 (0.18%) children were diagnosed with CP in the entire cohort. We found no significant association between time to pregnancy and the risk of CP in children conceived spontaneously. Children born after IVF/ICSI had an increased risk of CP, even after adjustment for preterm birth and multiplicity (hazard ratio 2.30, 95% confidence interval 1.12-4.73). Subfecundity per se did not appear to be associated with the risk of CP in children, whereas being born after IVF/ICSI conferred an increased risk.
    Human Reproduction 11/2010; 25(12):3142-5. DOI:10.1093/humrep/deq206 · 4.57 Impact Factor
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    ABSTRACT: Pregnancies achieved in one clinic by in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) and resulting in boys between 2000 and 2009 were reviewed. There were significant differences between the IVF and ICSI pregnancies, with the mothers of the ICSI boys being significantly younger at the time of embryo transfer (p<0.05) and the ICSI boys being significantly heavier than their IVF counterparts (p<0.01). There was a trend towards an increased incidence of abnormalities in boys after ICSI (18/326; 5.5%) compared with IVF (8/309; 2.6%) though this did not reach significance, a higher proportion of urogenital abnormalities after ICSI, and an increased number of abnormalities after ICSI in males compared to females. The data would support the need for further follow-up studies and continued vigilance. National regulatory authorities would seem ideally placed to gather such data, but they should differentiate between sex of the offspring when reporting on pregnancy outcomes following assisted reproduction.
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