Rosa Vissenberg

Significance of (sub)clinical thyroid dysfunction and thyroid autoimmunity before conception and in early pregnancy: a systematic review

BACKGROUND Thyroid dysfunction and thyroid autoimmunity are prevalent among women of reproductive age and are associated with adverse pregnancy outcomes. Preconception or early pregnancy screening for thyroid dysfunction has been proposed but is not widely accepted. We conducted a systematic review of the literature on the clinical significance of thyroid dysfunction and thyroid autoimmunity before conception and in early pregnancy. METHODS Relevant studies were identified by searching Medline, EMBASE and the Cochrane Controlled Trials Register. RESULTS From a total of 14 208 primary selected titles, 43 articles were included for the systematic review and 38 were appropriate for meta-analyses. No articles about hyperthyroidism were selected. Subclinical hypothyroidism in early pregnancy, compared with normal thyroid function, was associated with the occurrence of pre-eclampsia [odds ratio (OR) 1.7, 95% confidence interval (CI) 1.1-2.6] and an increased risk of perinatal mortality (OR 2.7, 95% CI 1.6-4.7). In the meta-analyses, the presence of thyroid antibodies was associated with an increased risk of unexplained subfertility (OR 1.5, 95% CI 1.1-2.0), miscarriage (OR 3.73, 95% CI 1.8-7.6), recurrent miscarriage (OR 2.3, 95% CI 1.5-3.5), preterm birth (OR 1.9, 95% CI 1.1-3.5) and maternal post-partum thyroiditis (OR 11.5, 95% CI 5.6-24) when compared with the absence of thyroid antibodies. CONCLUSIONS Pregnant women with subclinical hypothyroidism or thyroid antibodies have an increased risk of complications, especially pre-eclampsia, perinatal mortality and (recurrent) miscarriage. Future research, within the setting of clinical trials, should focus on the potential health gain of identification, and effect of treatment, of thyroid disease on pregnancy outcome.

Treatment of thyroid disorders before conception and in early pregnancy: a systematic review

BACKGROUND Thyroid disorders are associated with pregnancy complications. Universal screening is currently not recommended because of a lack of evidence on the effectiveness of treatment. Women with hyperthyroidism and hypothyroidism evidently require treatment but this is less clear for women with subclinical hypothyroidism and thyroid autoimmunity. Therefore, we conducted a systematic review to provide a comprehensive overview on the available treatment interventions. METHODS Relevant studies were identified by searching Medline, EMBASE and Cochrane Controlled Trials Register, published until December 2011. RESULTS From a total of 7334 primary selected titles, 22 articles were included for the systematic review and 11 were appropriate for meta-analyses. Eight studies reported on hyperthyroidism. Propylthiouracil (PTU) and methimazole reduce the risk for preterm delivery [risk ratio (RR): 0.23, confidence interval (CI): 0.1-0.52], pre-eclampsia (RR: 0.23, CI: 0.06-0.89) and low birthweight (RR: 0.38, CI: 0.22-0.66). The nine studies that reported on clinical hypothyroidism showed that levothyroxine is effective in reducing the risk for miscarriage (RR: 0.19, CI: 0.08-0.39) and preterm delivery (RR: 0.41, CI: 0.24-0.68). For treatment of subclinical hypothyroidism, current evidence is insufficient. The five studies available on thyroid autoimmunity showed a not significant reduction in miscarriage (RR: 0.58, CI: 0.32-1.06), but significant reduction in preterm birth by treatment with levothyoxine (RR: 0.31, CI: 0.11-0.90). CONCLUSION For hyperthyroidism, methimazole and PTU are effective in preventing pregnancy complications. For clinical hypothyroidism, treatment with levothyroxine is recommended. For subclinical hypothyroidism and thyroid autoimmunity, evidence is insufficient to recommend treatment with levothyroxine. The overall lack of evidence precludes a recommendation for universal screening and is only justified in a research setting.

Effect of levothyroxine on live birth rate in euthyroid women with recurrent miscarriage and TPO antibodies (T4-LIFE study)

BACKGROUND Thyroid peroxidase antibodies (TPO-Ab) in euthyroid women are associated with recurrent miscarriage (RM) and other pregnancy complications such as preterm birth. It is unclear if treatment with levothyroxine improves pregnancy outcome. AIM The aim of this study is to determine the effect of levothyroxine administration on live birth rate in euthyroid TPO-Ab positive women with recurrent miscarriage. METHODS/DESIGN We will perform a multicenter, placebo controlled randomized trial in euthyroid women with recurrent miscarriage and TPO-Ab. Recurrent miscarriage is defined as two or more miscarriages before the 20th week of gestation. The primary outcome is live birth, defined as the birth of a living fetus beyond 24weeks of gestation. Secondary outcomes are ongoing pregnancy at 12weeks, miscarriage, preterm birth, (serious) adverse events, time to pregnancy and survival at 28days of neonatal life. The analysis will be performed according to the intention to treat principle. We need to randomize 240 women (120 per group) to demonstrate an improvement in live birth rate from 55% in the placebo group to 75% in the levothyroxine treatment group. This trial is a registered trial (NTR 3364, March 2012). Here we discuss the rationale and design of the T4-LIFE study, an international multicenter randomized, double blind placebo controlled, clinical trial aimed to assess the effectiveness of levothyroxine in women with recurrent miscarriage and TPO-Ab.

Is there a role for assisted reproductive technology in recurrent miscarriage

Unexplained recurrent miscarriage (RM) is a significant health problem for which no effective treatment is available yet. In only 50% of couples with RM a cause can be found. In clinical practice, a frequently asked question is whether assisted reproductive technology (ART) is a treatment option. The scientific rationale and the chances of success for ART in couples with unexplained RM are still controversial. Presently, there is not enough evidence to justify IVF or intrauterine insemination (IUI) as a treatment option. Research on oocyte donation has been reported in one article. It is questionable whether couples with unexplained RM would undergo the potential risks and emotional aspects of ART. There is insufficient data on whether preimplantation genetic diagnosis improves the live birthrate in carriers of a structural chromosome rearrangement with a history of RM. No randomized controlled trials are available for preimplantation genetic screening (PGS) for unexplained RM. A recently published review concluded that the live birthrate for IVF/PGS and natural conception groups appears to be quite similar. Because evidence is lacking, we recommend refraining from ART in couples with recurrent miscarriage.

Number and sequence of preceding miscarriages and maternal age for the prediction of antiphospholipid syndrome in women with recurrent miscarriage

OBJECTIVE To investigate the relationship between the number and sequence of preceding miscarriages and antiphospholipid syndrome (APS). DESIGN Retrospective cohort study. SETTING Recurrent miscarriage (RM) clinic. PATIENT(S) Women who attended the RM clinic from 1988 to 2006. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Number, type, and sequence of previous pregnancies were compared between women with APS and women with unexplained RM. RESULT(S) A total of 1,719 patients were included; 312 (18%) had APS, and 1,407 (82%) had unexplained RM. The mean maternal age (32.6 years) did not differ between women with and without APS. The median number of miscarriages was three in both groups. A total of 865 women (50%) had a history of at least one live birth, with no difference between the two groups. In both groups, 97% of the women had a history of consecutive miscarriages. CONCLUSION(S) The number of preceding miscarriage, type and sequence of previous pregnancies, and maternal age were not associated with APS in women with RM. There is no increased diagnostic yield for APS after three miscarriages rather than after two miscarriages and no increased diagnostic yield for APS after consecutive miscarriages rather than after nonconsecutive miscarriages. Therefore, APS testing should be considered for all women with two or more miscarriages.

Recurrent miscarriage clinics

A recurrent miscarriage clinic offers specialist investigation and treatment of women with recurrent first- and second-trimester miscarriages. Consultant-led clinics provide a dedicated and focused service to couples who have experienced at least two prior miscarriages. The best treatment strategy for couples with recurrent miscarriage is to discuss a treatment plan for a future pregnancy. Evidence-based up-to-date guidelines are required to reduce ineffective management of recurrent miscarriage couples, including overdiagnostics and underdiagnostics. Scientific research is necessary to study the effectiveness of new interventions, to study patient preferences, and to evaluate health care and costs or other outcomes.

Corrigendum: Significance of (sub)clinical thyroid dysfunction and thyroid autoimmunity before conception and in early pregnancy: a systematic review

The authors would like to apologise for several errors in the above manuscript, as listed below. The authors would like to reassure the readers that these errors do not affect the other content or the conclusions of the article.

Live-birth rate in euthyroid women with recurrent miscarriage and thyroid peroxidase antibodies

Abstract Thyroid autoimmunity with normal thyroid function is associated with recurrent miscarriage (RM), but the association with live birth is less clear. Therefore, we determined the association between thyroid peroxidase antibodies (TPO-Ab) and live-birth rate (LBR) in a retrospective cohort of euthyroid women with unexplained RM. We included 202 women of which 28 were TPO-Ab positive (13.9%) and 174 were TPO-Ab negative. TPO-Ab positive women (n = 10) without levothyroxine treatment had a lower LBR (29%) compared to TPO-Ab negative women (51%) (HR 0.23, 0.07–0.72, p = 0.012). The LBR in women with TPO-Ab receiving levothyroxine was not different compared women without TPO-Ab (60% versus 51%, p = 0.50). In conclusion, TPO-Ab are associated with a lower LBR in euthyroid women with unexplained RM and these women may benefit from treatment with levothyroxine.

Is subclinical hypothyroidism associated with lower live birth rates in women who have experienced unexplained recurrent miscarriage

Thyroid disorders have been associated with recurrent miscarriage. Little evidence is available on the influence of subclinical hypothyroidism on live birth rates. In this cohort study, women who had experienced miscarriage and subclinical hypothyroidism (defined as thyroid-stimulating hormone >97.5th percentile mU/l with a normal thyroxine level) were investigated; the control group included women who had experienced recurrent miscarriage and normal thyroid function. Multivariable logistic regression was used to investigate the association of subclinical hypothyroidism. Data were available for 848 women; 20 (2.4%) had subclinical hypothyroidism; 818 women (96%) had euthyroidism; and 10 (1.2%) had overt hypothyroidism. The live birth rate was 45% in women with subclinical hypothyroidism and 52% in euthyroid women (OR 0.69, 95% CI 0.28 to 1.71). The ongoing pregnancy rate was 65% versus 69% (OR 0.82, 95% CI 0.32 to 2.10) and the miscarriage rate was 35% versus 28% (OR 1.43, 95% CI 0.56 to 3.68), respectively. No differences were found when thyroid stimulating hormone 2.5 mU/l was used as cut-off level to define subclinical hypothyroidism. In women with unexplained miscarriage, no differences were found in live birth, ongoing pregnancy and miscarriage rates between women with subclinical hypothyroidism and euthyroid women.

Abnormal thyroid function parameters in the second trimester of pregnancy are associated with breech presentation at term: a nested cohort study

OBJECTIVE Thyroid dysfunction has been described as a possible risk factor for having an abnormal fetal position at birth. In this study we aim to determine the association between thyroid function in early pregnancy and breech presentation at term. STUDY DESIGN We used data from the Amsterdam Born Children and their Development (ABCD) cohort. 3347 pregnant women were included between January 2003 and March 2004 in Amsterdam, the Netherlands. Thyroid function tests were performed between 5 and 37 weeks gestational age (median 12.9 weeks). The main outcome measure was the association between thyroid function in early pregnancy and breech presentation at term. Univariate and multivariate analysis were performed to determine the association between thyroid function and breech presentation. RESULTS Increased TSH in pregnancy, defined as thyroid stimulating hormone (TSH) >97.5th percentile (>3.53mIU/L), was associated with a higher risk for breech presentation at term (aOR 2.32, CI 1.1-4.8, p=0.02) compared to euthyroidism (TSH between 2.5th and 97.5th percentile). After exclusion of overt hypothyroidism and hyperthyroidism the aOR was 2.34 (CI 1.1-5.0, p=0.03). Trimester specific analysis showed a significant association of increased TSH levels (>3.68mIU/L) in the second trimester with breech presentation (aOR 3.7, CI 1.7-7.8, p=0.001). In the second trimester low free thyroxine (FT4) <2.5th percentile (<6.7pmol/L) was also associated with breech presentation (aOR 2.5, CI 1.0-6.3, p=0.04). CONCLUSIONS Increased TSH and decreased FT4 in the second trimester of pregnancy are associated with an increased risk for breech presentation at term. The association of abnormal thyroid parameters in the first of third trimester is still unclear.