Maternal thyrotropin is independently related to small for gestational age neonates at term.

OBJECTIVE: Small for gestational age (SGA) newborns constitute still a major cause of perinatal morbidity and mortality. Overt thyroid disease is a known cause of preterm birth and low birthweight but in its untreated condition it is rare today. In this study, we investigated the possible relation between maternal thyroid function assessed in euthyroid women at each trimester and the incidence of term born SGA neonates. DESIGN: A prospective cohort study was performed. PATIENTS: Thyroid function was assessed at 12, 24 and 36 weeks gestation in 1051 healthy Caucasian women who delivered at ≥ 37 weeks gestation. MEASUREMENTS: One-way anova was used to compare mean TSH and FT4 levels between women with SGA neonates and controls. Multiple logistic regression analysis was performed to adjust for known risk factors of SGA. RESULTS: Seventy (6·7%) SGA neonates were identified and they were significantly more often born to women with a TSH ≥ 97·5th at first and third trimester. Multiple logistic regression analysis showed that smoking (OR: 4·4, 95% CI: 2·49-7·64), pre-eclampsia (OR: 2·8, 95% CI: 1·19-6·78) and TSH ≥ 97·5th percentile (OR 3·3, 95% CI 1·39-7·53) were significantly related to SGA. Maternal FT4 levels and TPO-Ab status were not associated with SGA offspring. CONCLUSIONS: Our data show that TSH levels in the upper range of the reference interval at different trimesters (3·0-3·29 mIU/l) are independently related to an increased risk of delivering SGA neonates at term.

Increased maternal TSH and decreased maternal FT4 are associated with a higher operative delivery rate in low-risk pregnancies: A prospective cohort study.

BACKGROUND: The increasing number of operative deliveries is a topic of major concern in modern obstetrics. Maternal thyroid function is of known influence on many obstetric parameters. Our objective was to investigate a possible relation between maternal thyroid function, and operative deliveries. Secondary aim was to explore whether thyroid function was related to specific reasons for operative deliveries. METHODS: In this prospective cohort study, low-risk Caucasian women, pregnant of a single cephalic fetus were included. Women with known auto-immune disease, a pre-labour Caesarean section, induction of labour, breech presentation or preterm delivery were excluded. In all trimesters of pregnancy the thyroid function was assessed. Differences in mean TSH and FT4 were assessed using t-test. Mean TSH and FT4 levels for operative deliveries were determined by one way ANOVA. Repeated measurement analyses were performed (ANOVA), adjusting for BMI, partiy, maternal age and gestational age at delivery. RESULTS: In total 872 women were included, of which 699 (80.2%) had a spontaneous delivery. At 36 weeks gestation women who had an operative delivery had a significantly higher mean TSH (1.63 mIU/L versus 1.46 mIU/L, p = 0.025) and lower mean FT4 (12.9 pmol/L versus 13.3 pmol/L, p = 0.007)) compared to women who had a spontaneous delivery. Mean TSH was significantly higher (p = 0.026) and mean FT4 significantly lower (p = 0.030) throughout pregnancy for women with an operative delivery due to failure to progress in second stage of labour, compared to women with a spontaneous delivery or operative delivery for other reasons. CONCLUSIONS: Increased TSH and decreased FT4 seem to be associated with more operative vaginal deliveries and Caesarean sections. After adjusting for several confounders the association remained for operative deliveries due to failure to progress in second stage of labour, possibly to be explained by less efficient uterine action.

The aetiology of meconium-stained amniotic fluid: pathologic hypoxia or physiologic foetal ripening? (Review).

INTRODUCTION: Despite the many efforts to study the (patho)physiology of meconium release before delivery, it still remains an indistinct subject. Some studies have reported a relationship between hypoxia and MSAF, whilst others have not. The most common association found however, is between MSAF and the term of gestation. METHODS: MEDLINE, EMBASE and the Cochrane library were electronically searched. Papers about the (patho)physiology of meconium-stained amniotic fluid in English were included. Papers about management strategies were excluded (see elsewhere this issue). RESULTS: Different theories have been proposed including acute or chronic hypoxia, physiologic foetal ripening and peripartum infection. CONCLUSION: We suggest that meconium-stained amniotic fluid should be regarded as a symptom rather than a syndrome becoming more prevalent with increasing term and which might be associated with higher levels of infection or asphyxia.

Maternal thyrotrophin in euthyroid women is related to meconium stained amniotic fluid in women who deliver at or over 41 weeks of gestation.

BACKGROUND: Maternal thyroid dysfunction is of known influence on pregnancies in the preterm period. However little is known about its effect on term and post term pregnancies. Meconium stained amniotic fluid (MSAF) is known to occur preferentially in (post)term pregnancies. AIMS: To assess a possible independent relation between maternal thyroid function and MSAF. STUDY DESIGN AND SUBJECTS: 1051 women, in whom thyroid function was assessed at each trimester, were followed prospectively (delivery ≥37weeks). We compared the difference in mean TSH and FT4 between women with (152) and without (899) MSAF using one way ANOVA. Thyroid function was assessed in subgroups regarding gestational age. Finally we performed multiple logistic regression analysis with MSAF as dependent variable and TSH as independent variable adjusting for various confounders. RESULTS: Maternal thyroid function was not associated with the incidence of MSAF when analysing all deliveries ≥37weeks. However, in the "at-risk" group for MSAF (>41weeks), multiple logistic regression showed an independent relation between MSAF and TSH (O.R.: 1.61, 95% CI: 1.10-2.43). CONCLUSIONS: The present study shows that in women delivering ≥41weeks of gestation, higher TSH is independently related to MSAF.