Thyroid dysfunction in Iranian pregnant women: a systematic review and meta-analysis

Abstract

Background: Thyroid dysfunction during pregnancy is associated with adverse outcomes for both mother and fetus. The present meta-analysis was conducted to evaluate thyroid dysfunction in Iranian pregnant women. Methods: We registered this review at PROSPERO (registration number: CRD42020166655). The research steps in this systematic review and meta-analysis were performed according to the MOOSE protocol, and finally, reports were provided based on the PRISMA guidelines. The literature search was performed in October 2019 using the international online databases, including Web of Science, Ovid, Science Direct, Scopus, EMBASE, PubMed/Medline, Cochrane Library, EBSCO, CINAHL, Google Scholar as well as national databases were reviewed. Data were extracted after applying the inclusion and exclusion criteria and qualitative evaluation of the studies. I 2 index and Q test were used to assess differences in studies. All analyses were performed using Comprehensive Meta-Analysis Software. Pvalue less than 0.05 was considered statistically significant. We identified 1261 potential articles from the databases, and 426 articles remained after removing the duplicate and unrelated studies. After evaluating the full text, 52 articles were removed. Results: Finally, 19 eligible studies including 17,670 pregnant women included for meta-analysis. The prevalence of thyroid dysfunction in Iranian pregnant women was 18.10% (95%CI: 13.89-23.25). The prevalence of hypothyroidism, clinical hypothyroidism, and subclinical hypothyroidism in Iranian pregnant women was respectively estimated to be 13.01% (95%CI: 9.15-18.17), 1.35% (95%CI: 0.97-1.86) and 11.90% (95%CI: 7.40-18.57). The prevalence of hyperthyroidism, clinical hyperthyroidism, and subclinical hyperthyroidism in Iranian pregnant women was respectively estimated to be 3.31% (95%CI: 1.62-6.61), 1.06% (95%CI: 0.61-1.84) and 2.56% (95%CI: 0.90-7.05). The prevalence of anti-thyroperoxidase antibody was estimated to be 11.68% (95%CI: 7.92-16.89). Conclusion: The results of this meta-analysis showed a high prevalence of thyroid disorders, especially hypothyroidism. The decision to recommend thyroid screening during pregnancy for all women is still under debate, because the positive effects of treatment on pregnancy outcomes must be ensured. On the other hand, evidence about the effect of thyroid screening and treatment of thyroid disorders on pregnancy outcomes is still insufficient. Nevertheless, a large percentage of general practitioners, obstetricians and gynecologists perform screening procedures in Iran.

Prevalence of Hypothyroidism in Pregnant Women in India: A Meta-Analysis of Observational Studies

“…Sepasi et al conducted a meta-analysis to report prevalence of hypothyroidism clinical and subclinical hypothyroidism in Iranian pregnant women. Prevalence estimate for hypothyroidism, clinical hypothyroidism, and subclinical hypothyroidism was 13.01% (95% CI: 9.15–18.17), 1.35% (95% CI: 0.97–1.86), and 11.90% (95% CI: 7.40–18.57), respectively, which are very similar to our study [ 87 ]. However, prevalence reported in our study is remarkably higher as compared to the reported prevalence of antenatal hypothyroidism in other countries [ 3 – 5 ].…”

“…e sixty-one studies included in the current review have reported prevalence of maternal hypothyroidism ranging from 1.2% to 67.0% [6,7]. is meta-analysis estimates the prevalence of hypothyroidism in pregnant women in India to be 11 (95% CI: 0.97-1.86), and 11.90% (95% CI: 7.40-18.57), respectively, which are very similar to our study [87]. However, prevalence reported in our study is remarkably higher as compared to the reported prevalence of antenatal hypothyroidism in other countries [3][4][5].…”

Short-Term Adverse Pregnancy Outcomes in Women with Subclinical Hypothyroidism: A Comparative Approach of Iranian and American Guidelines

“…Numerous comorbidities may threaten pregnancy, one of which is subclinical hypothyroidism (SCH) [ 1 ]. Iranian and American reference ranges have introduced different levels of TSH as a criterion for initiating treatment in SCH during pregnancy.…”

“…The information obtained from systematic reviews and meta-analysis is so limited which necessitates further studies in this field. An important meta-analysis in Iranian pregnant women showed a high prevalence of thyroid disorders especially subclinical and clinical hypothyroidism [ 1 ]. Another meta-analysis evaluated the complications of pregnancy in mothers with subclinical hypothyroidism and showed that these women were at a higher risk for pregnancy loss, neonatal death, placental abruption, and premature rupture of membranes compared to euthyroid women [ 10 ].…”

Adherence to treatment for hypothyroidism in pregnancy and relationship with thyrotropin control: a retrospective observational cohort study

“…In many studies, clinical and subclinical hypothyroidism have been associated with adverse effects in pregnancy, such as miscarriage and preterm birth [ 5 , 6 ]. In addition, low T4 levels in pregnant women have been correlated with the presentation of long-term neuro-cognitive problems for the newborn [ 7 , 8 ]. Therefore, a good maternal and foetal health outcome depends on treating maternal hypothyroidism by administrating thyroid hormone (T4).…”