Premium
Hypothyroidism and pregnancy loss: comparison with hyperthyroidism and diabetes in a Danish population‐based study
Author(s) -
Andersen Stine Linding,
Olsen Jørn,
Laurberg Peter
Publication year - 2016
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.13136
Subject(s) - medicine , pregnancy , hazard ratio , abortion , diabetes mellitus , population , confidence interval , obstetrics , endocrine system , cohort study , endocrinology , pediatrics , hormone , genetics , environmental health , biology
Summary Background Hypothyroidism is a common endocrine disease. The frequency of pregnancy loss in women with known hypothyroidism as opposed to women with a later diagnosis of hypothyroidism has not been evaluated and compared with other common endocrine diseases. Design Population‐based cohort study using Danish nationwide registers. Participants All pregnancies in Denmark, 1997–2008, resulting in live birth ( n = 732 533), spontaneous abortion ( n = 112 487) or stillbirth ( n = 2937) were identified together with information on maternal hypothyroidism, hyperthyroidism and diabetes. Methods Cox model was used to estimate adjusted hazard ratio ( aHR ) with 95% confidence interval (95% CI ) for spontaneous abortion and stillbirth, reference: no hypo‐ or hyperthyroidism or diabetes ( n = 824 310). Results We identified 4951 pregnancies where maternal hypothyroidism was diagnosed before the pregnancy (group 1) and 2464 pregnancies where maternal hypothyroidism was diagnosed in the 2‐year period after the pregnancy (group 2). In group 1, 825 pregnancies (16·7%) resulted in spontaneous abortion which was more frequent than in nonexposed (13·2%), ( aHR 1·19 (95% CI 1·12–1·27)), and of the same magnitude as in hyperthyroidism (17·2%, P = 0·5) and diabetes (17·5%, P = 0·2) diagnosed before the pregnancy. In group 2, the frequency was 12·2% ( aHR 0·92 (0·84–1·02)). In group 2, 16 pregnancies (0·65%) resulted in stillbirth which was more frequent than in nonexposed (0·36%), ( aHR 1·81 (1·11–2·97)), of the same magnitude as in hyperthyroidism (0·82%, P = 0·5) and less frequent than in diabetes (2·9%, P < 0·001) diagnosed after the pregnancy. In group 1, the frequency was 0·40% ( aHR 1·11 (0·68–1·82)). Conclusions Hypothyroidism increased the risk of both early and late pregnancy loss as did hyperthyroidism and in particular diabetes. We hypothesize that undetected or insufficiently treated maternal disease in the pregnancy may be of causal importance.