Fecundability among Danish women with a history of miscarriage: a prospective cohort study.

OBJECTIVE: To examine the association between history of miscarriage and fecundability (the cycle-specific probability of conception). DESIGN: Nationwide prospective cohort study using web-based questionnaires. SETTING: Denmark, 2007-2012. PARTICIPANTS: 977 women attempting to conceive, not using fertility treatment, and with a reproductive history of only miscarriage or only live birth. EXPOSURE AND OUTCOME MEASURES: Information on previous pregnancy outcomes, including miscarriage, came from self-report or from relevant registries. Participants were followed for up to 12 months or until they reported a pregnancy, stopped trying to conceive or started fertility treatment, whichever came first. We used Kaplan-Meier methods to estimate cumulative probabilities of conception for women whose reproductive history included only miscarriage or only live birth. Using proportional probabilities regression modelling, we computed fecundability ratios (FR) with 95% CI comparing women with a history of only miscarriage with women with a history of only live birth. RESULTS: After adjustment for potential confounders, the cumulative probabilities of conception within 12 cycles of follow-up were 85% (95% CI 81% to 89%) for women with a history of 1 miscarriage, 85% (95% CI 73% to 92%) for women with a history of ≥2 miscarriages and 88% (95% CI 87% to 89%) for women whose reproductive history included only live birth. Adjusted FRs were 0.87 (95% CI 0.71 to 1.07) and 0.65 (95% CI 0.36 to 1.17) for women with a history of 1 and ≥2 miscarriages, respectively. CONCLUSIONS: Our results indicate that women with a history of miscarriage may have slightly reduced fecundability compared with women with a history of only live birth. The reduction in fecundability was greater for women with repeated miscarriages, although the estimates were imprecise. Despite a potential delay in conception, women with previous miscarriage may have similar probability of pregnancy by 12 cycles of attempts to women with proven fertility.

Weight at birth and subsequent fecundability: a prospective cohort study.

OBJECTIVE: To examine the association between a woman's birth weight and her subsequent fecundability. METHOD: In this prospective cohort study, we included 2,773 Danish pregnancy planners enrolled in the internet-based cohort study "Snart-Gravid", conducted during 2007-2012. Participants were 18-40 years old at study entry, attempting to conceive, and were not receiving fertility treatment. Data on weight at birth were obtained from the Danish Medical Birth Registry and categorized as <2,500 grams, 2,500-2,999 grams, 3,000-3,999 grams, and ≥ 4,000 grams. In additional analyses, birth weight was categorized according to z-scores for each gestational week at birth. Time-to-pregnancy measured in cycles was used to compute fecundability ratios (FR) and 95% confidence intervals (CI), using a proportional probabilities regression model. RESULTS: Relative to women with a birth weight of 3,000-3,999 grams, FRs adjusted for gestational age, year of birth, and maternal socio-demographic and medical factors were 0.99 (95% CI: 0.73;1.34), 0.99 (95% CI: 0.87;1.12), and 1.08 (95% CI: 0.94;1.24) for birth weight <2,500 grams, 2,500-2,999 grams, and ≥ 4,000 grams, respectively. Estimates remained unchanged after further adjustment for markers of the participant's mother's fecundability. We obtained similar results when we restricted to women who were born at term, and to women who had attempted to conceive for a maximum of 6 cycles before study entry. Results remained similar when we estimated FRs according to z-scores of birth weight. CONCLUSION: Our results indicate that birth weight appears not to be an important determinant of fecundability.

Registration of acute stroke: validity in the Danish Stroke Registry and the Danish National Registry of Patients.

BACKGROUND: The validity of the registration of patients in stroke-specific registries has seldom been investigated, nor compared with administrative hospital discharge registries. The objective of this study was to examine the validity of the registration of patients in a stroke-specific registry (The Danish Stroke Registry [DSR]) and a hospital discharge registry (The Danish National Patient Registry [DNRP]). METHODS: Assuming that all patients with stroke were registered in either the DSR, DNRP or both, we first identified a sample of 75 patients registered with stroke in 2009; 25 patients in the DSR, 25 patients in the DNRP, and 25 patients registered in both data sources. Using the medical record as a gold standard, we then estimated the sensitivity and positive predictive value of a stroke diagnosis in the DSR and the DNRP. Secondly, we reviewed 160 medical records for all potential stroke patients discharged from four major neurologic wards within a 7-day period in 2010, and estimated the sensitivity, specificity, positive predictive value, and negative predictive value of the DSR and the DNRP. RESULTS: Using the first approach, we found a sensitivity of 97% (worst/best case scenario 92%-99%) in the DSR and 79% (worst/best case scenario 73%-84%) in the DNRP. The positive predictive value was 90% (worst/best case scenario 72%-98%) in the DSR and 79% (worst/best case scenario 62%-88%) in the DNRP. Using the second approach, we found a sensitivity of 91% (95% confidence interval [CI] 81%-96%) and 58% (95% CI 46%-69%) in the DSR and DNRP, respectively. The negative predictive value was 91% (95% CI 83%-96%) in the DSR and 72% (95% CI 62%-80%) in the DNRP. The specificity and positive predictive value did not differ among the registries. CONCLUSION: Our data suggest a higher sensitivity in the DSR than the DNRP for acute stroke diagnoses, whereas the positive predictive value was comparable in the two data sources.

Change in the prevalence of obesity and use of health care in Denmark: an observational study.

PURPOSE: The purpose of this study was to examine the influence of the increasing prevalence of obesity on the development of health care utilization in Denmark in the period 1987-2005. PATIENTS AND METHODS: From a random sample of adult Danes (19,142 women and 18,335 men) who participated in the Danish Health Interview Surveys in 1987, 1994, 2000, and 2005, self-reported data on type of health care utilization within the previous 3 months and on height and weight were obtained. RESULTS: Adjusted odds ratios (ORs) showed that an increased use of health care among obese men compared with those of normal weight was pronounced and significant for those aged 45-64 years, whereas it was weaker and borderline significant for those aged 25-44 and 65+ years. Among obese men, there was an increasing use of health care until 2005. Among women, there was also an increased use of health care among the obese women in comparison with the normal weight women. An increase in the use of health care was found among obese women during 1987-2000, followed by a leveling of utilization during 2000-2005. CONCLUSIONS: In conclusion, this study showed that the increase in health care utilization in Denmark could, in part, be attributed to an increase in prevalence of obesity and to an increase in health care utilization among obese men in particular.