Association between previously unknown connective tissue disease and subclinical hypothyroidism diagnosed during first trimester of pregnancy

Undifferentiated Connective Tissue Disease in Pregnancy: A Topic Yet to be Explored

Undifferentiated connective tissue disease (UCTD) is characterized by signs and symptoms suggestive of a connective tissue disease (CTD), but not fulfilling criteria for a specific CTD. Although UCTD is probably the most common rheumatic disease diagnosed in pregnant women, data about disease course during pregnancy and perinatal outcomes are very limited. Compared to other CTDs, UCTD seems to have milder clinical manifestations in pregnancy. Its natural history is related to disease activity at conception. In fact, if the disease is in a state of remission or minimal activity at conception, pregnancy outcomes are generally good. On the contrary, patients who become pregnant in a moment of high disease activity and/or who have multiple antibodies positivity show an increased risk of disease flares, evolution to a definite CTD and obstetric complications, such as fetal growth restriction, preeclampsia and preterm birth. Therefore, a preconception assessment is essential in women with UCTD to evaluate maternal and fetal risks, to initiate interventions to optimize disease activity, and to adjust medications to those that are least harmful to the fetus. The aim of the present study was to review the available literature about pregnancy course, maternal and fetal outcomes and therapeutic approaches of pregnant women with UCTD.

Placental pathologic features in thyroid autoimmunity

INTRODUCTION

Data on placental pathologic features associated with thyreoperoxidase antibodies (TPO Ab) and/or hypothyroidism are limited. The objective of the study was to analyze placental pathologic features of women with TPO Ab positivity.

METHODS

Prospective case-control observational study of pregnancy outcome among women screened for TPO Ab positivity and/or isolated hypothyroidism (TSH>4mU/L) during the first trimester of pregnancy. Placenta pathologic findings were recorded according to standard classification.

RESULTS

The overall rates of TPO Ab positivity and isolated hypothyroidism with negative TPO Ab were 9.6% (86/899) and 2.7% (24/899), respectively. Among TPO Ab positive cases, 77.9% (67/86) and 22.1% (19/86) had TSH ≥2.5mU/L or <2.5mU/L, respectively. Compared to controls, mean first and second trimester uterine artery Doppler pulsatility indices (PI) were higher, placental volume and area were lower among cases with TSH≥2.5mU/L. The rates of fetal growth restriction (FGR)/small for gestational age (SGA) (20/67 versus 8/110, Adjusted Odds Ratio (AdjOR) = 10.8,95%CI = 2.7-44), placental pathological features suggesting decidual vasculopathy (37/67 versus 27/110, AdjOR = 2.7,95%CI = 1.1-6.8) or severe maternal vascular malperfusion (MVM) (22/67 versus 9/110, AdjOR = 5.8,95%CI = 1.6-20.1) were higher among cases with TSH ≥2.5mU/L than in controls. Similar results were obtained comparing overall TPO Ab positive subjects to controls. The increased risk of defective placentation and FGR associated with TPO Ab was independent of simultaneous presence of antinuclear antibodies (ANA) and TSH concentration.

DISCUSSION

First trimester TPO Ab positivity was associated with increased rates of abnormal uterine artery Doppler PI and placental features of MVM. This association was independent of TSH concentration and presence of ANA.

Effect of levothyroxine supplementation on pregnancy loss and preterm birth in women with subclinical hypothyroidism and thyroid autoimmunity: a systematic review and meta-analysis

BACKGROUND

Subclinical hypothyroidism (SCH) and thyroid autoimmunity (TAI) are associated with adverse pregnancy outcomes such as pregnancy loss and preterm birth. However, the ability of levothyroxine (LT4) supplementation to attenuate the risks of these outcomes remains controversial.

OBJECTIVE AND RATIONALE

This systematic review and meta-analysis was conducted to determine the effect of LT4 supplementation on pregnancy loss rate (PLR) and preterm birth rate (PBR) among pregnant women with SCH and TAI.

SEARCH METHODS

A systematic literature search of the PubMed, EMBASE, Web of Science and Cochrane Controlled Trials Register databases and Clinicaltrials.gov was performed to identify all relevant English studies published up to April 2018. The following terms were used for the search: [subclinical hypothyroidism OR thyroid autoimmunity OR thyroperoxidase antibody (TPO-Ab) OR thyroglobulin antibodies (Tg-Ab)] AND (levothyroxine OR euthyrox) AND [pregnancy outcome OR miscarriage OR abortion OR pregnancy loss OR preterm birth OR premature delivery OR early labo(u)r]. The reference lists of the relevant publications were also manually searched for related studies. Published manuscripts were included if they reported data on pregnancy loss, preterm birth or both. We separately analysed the pooled effects of LT4 supplementation on PLR and PBR in women with SCH and TAI.

OUTCOMES

Overall, 13 eligible studies including 7970 women were included in the meta-analysis. Eight and five of these studies were randomized controlled trials (RCTs) and retrospective studies, respectively. The pooled results indicated that LT4 supplementation significantly decreased the PLR [relative risk (RR) = 0.56, 95% confidence interval (CI): 0.42-0.75, I2 = 1%, 12 studies] and PBR (RR = 0.68, 95% CI: 0.51-0.91, I2 = 21%, eight studies) in women with SCH and/or TAI. We further found that LT4 supplementation significantly decreased the risk of pregnancy loss (RR = 0.43, 95% CI: 0.26-0.72, P = 0.001, I2 = 0%) but not of preterm birth (RR = 0.67, 95% CI: 0.41-1.12, P = 0.13, I2 = 0%) in women with SCH. Furthermore, LT4 supplementation significantly decreased the risks of both pregnancy loss (RR = 0.63, 95% CI: 0.45-0.89, P = 0.009, I2 = 0%) and preterm birth (RR = 0.68 95% CI: 0.48-0.98, P = 0.04, I2 = 46%) in women with TAI. These results were consistent when only RCTs were included in the analysis. Further, in women with SCH, LT4 supplementation reduced the risk of pregnancy loss in pregnancies achieved by assisted reproduction (RR = 0.27, 95% CI: 0.14-0.52, P < 0.001, I2 = 14%) but not in naturally conceived pregnancies (RR = 0.60, 95% CI: 0.28-1.30, P = 0.13, I2 = 0%). By contrast, in women with TAI, LT4 supplementation reduced the risks of both pregnancy loss (RR = 0.61, 95% CI: 0.39-0.96, P = 0.03, I2 = 0%) and preterm birth (RR = 0.49, 95% CI: 0.30-0.79, P = 0.003, I2 = 0%) in naturally conceived pregnancies but not in pregnancies achieved by assisted reproduction (RR = 0.68, 95% CI: 0.40-1.15, P = 0.15, I2 = 0% for pregnancy loss and RR = 1.20, 95% CI: 0.68-2.13, P = 0.53, I2 not applicable for preterm birth).

WIDER IMPLICATIONS

This meta-analysis confirmed the beneficial effects of LT4 supplementation, namely the reduced risks of pregnancy loss and preterm birth, among pregnant women with SCH and/or TAI. The different effects of LT4 supplementation on naturally conceived pregnancies and pregnancies achieved by assisted reproduction in women with SCH and/or TAI suggest that these women should be managed separately. Due to the limited number of studies included in this meta-analysis, especially in the subgroup analysis, further large RCTs and fundamental studies are warranted to confirm the conclusions and better clarify the molecular mechanism underlying these associations.

Undifferentiated connective tissue diseases and adverse pregnancy outcomes. An undervalued association?

Undifferentiated connective tissue diseases (UCTDs) are a heterogeneous group of disorders characterized by symptoms and signs suggestive of systemic autoimmune rheumatic disease (ARD), but which do not fulfill all the established criteria for definite diagnosis of a condition. Although a third of UCTDs can progress to a definite ARD within months or years, most UCTDs can remain stable for years with minimal disease activity. The annual incidence of UCTD in the general population ranges from 14 to 140 per 100 000 people. UCTDs are associated with the persistence of several circulating autoantibodies including antinuclear, antiphospholipid or antithyroid antibodies. Immunological evaluation of subjects with UCTDs suggests a proinflammatory state and dysregulation of the Th1/Th2 balance. Autoantibodies have well-known deleterious effects on placentation and have been associated with an increased risk of prematurity, fetal growth restriction (FGR), preeclampsia, and congenital atrioventricular heart block. Although epidemiological and biological data suggest a potential negative impact on reproductive outcomes, the relationship between UCTD and pregnancy outcomes has not been adequately studied. While awaiting definitive data from large studies, obstetricians should be aware that rheumatic disorders in their early, incomplete, or undifferentiated phases can adversely affect pregnancy outcomes, increasing the likelihood of pregnancy loss, FGR, preeclampsia, and prematurity.