Maternal thyroid function during gestation is related to breech presentation at term

Kuppens SM; Kooistra L; Wijnen HA; Crawford S; Vader HL; Hasaart TH; Oei SG; Pop VJ

doi:10.1111/j.1365-2265.2009.03729.x

Birth and Delivery Birth Outcomes

Maternal thyroid function during gestation is related to breech presentation at term

Kuppens SM, Kooistra L, Wijnen HA, Crawford S, Vader HL, Hasaart TH, Oei SG, Pop VJ

Published June 2010 Clinical Endocrinology, 72(6), 820-824

DOI 10.1111/j.1365-2265.2009.03729.x PMID 19832853

RRM Academy Synopsis

Higher maternal TSH at 36 weeks is linked to breech presentation

Higher thyroid-stimulating hormone late in pregnancy was associated with breech presentation at term. This prospective study of 1,058 healthy Dutch women measured the hormone (TSH) at 12, 24 and 36 weeks. In the highest tenth of TSH at 36 weeks, about 11 out of 100 women had a breech baby, against about 5 out of 100 in the rest.

Breech baby at term: Highest tenth of TSH, 11 in 100; All other women, 4.8 in 100. Source: Kuppens SM et al., 2010, PMID 19832853.

Study at a glance, prospective study of 1,058 healthy Dutch women: Higher TSH at 36 weeks was linked to breech presentation. Source: Kuppens SM et al., 2010, PMID 19832853.

Key Findings

Of 1,058 women who delivered at term, 58 (5.5%) had a breech baby. Their TSH was higher at 36 weeks (P = 0.007), and at no earlier assessment.
At 36 weeks, 11% (12 of 108) of women in the highest tenth of TSH had a breech baby, against 4.8% (46 of 950) of the remaining women (P = 0.006).
After adjustment for other factors, high TSH at 36 weeks was independently related to breech presentation (odds ratio 2.23, 95% CI 1.14-4.39). No such relation appeared at 12 or 24 weeks.
Women with TSH below the 5th percentile at 36 weeks (n = 54) had no breech presentations. Free T4 showed no between-group differences at any assessment.
Raised thyroid peroxidase antibody levels at 36 weeks showed no relation to breech presentation.

Interpretation

The study is a prospective follow-up study: women were enrolled at 12 weeks, tested three times, and followed to delivery. The analysis reports an association between TSH at 36 weeks and breech presentation. The women were healthy and Dutch Caucasian. Five community midwifery practices near Eindhoven recruited them. None of the 1,058 women received treatment for thyroid disease during pregnancy. The authors note that breech births were relatively few and that cord length and amniotic fluid volume were not assessed. They add that no TSH receptor has been described in the uterus, so the mechanism is still open.

RRM Context

Restorative reproductive medicine considers thyroid function part of how the body supports reproductive health, from before conception through pregnancy. The authors cite earlier studies linking thyroid dysfunction in pregnancy to poorer pregnancy and birth outcomes. Their own earlier work suggested a link between low free T4 at 12 weeks and breech presentation. This study adds late-pregnancy TSH to the maternal factors examined in relation to fetal position.

Our editorial summary of this paper, not the article's abstract.

Abstract

Objective

To study the relationship between suboptimal maternal thyroid function during gestation and breech presentation at term.

Design

Prospective follow-up study during three trimesters of gestation.

Patients

A total of 1058 Dutch Caucasian healthy pregnant women were prospectively followed from 12 weeks gestation until term (>or=37 weeks) delivery.

Measurements

Maternal thyroid parameters [TSH, free T4 (FT4) and auto-antibodies to thyroid peroxidase] were assessed at 12, 24 and 36 weeks gestation as well as foetal presentation at term.

Results

At term, 58 women (5.5%) presented in breech. Compared with women with foetuses in the cephalic position, those women who presented in breech at term had significantly higher TSH concentrations, but only at 36 weeks gestation (P = 0.007). No between group differences were obtained for FT4 level at any assessment. The prevalence of breech presentation in the subgroup of women with TSH >or= 2.5 mIU/l (90th percentile) at 36 weeks gestation was 11%, compared with 4.8% in the women with TSH < 2.50 mIU/l (P = 0.006). Women with TSH below the 5th percentile had no breech presentations. Breech position was significantly and independently related to high maternal TSH concentration (>or=2.5 mIU/l) at 36 weeks gestation (O.R.: 2.23, 95% CI: 1.14-4.39), but not at 12 and 24 weeks gestation.

Conclusions

Women with TSH levels above 2.5 mIU/l during end gestation are at risk for breech presentation, and as such for obstetric complications.

Topics

Birth and Delivery Birth Outcomes Maternal Morbidity

Birth and Delivery › Birth Outcomes › Maternal Morbidity

PMID 19832853 19832853 DOI 10.1111/j.1365-2265.2009.03729.x 10.1111/j.1365-2265.2009.03729.x Kuppens et al. 2010, Kuppens 2010

Keywords

Adult, Breech Presentation/epidemiology/etiology, Female, Humans, Longitudinal Studies, Mothers, Pregnancy/physiology, Pregnancy Complications/blood/epidemiology, Term Birth/physiology, Thyroid Diseases/blood/complications/epidemiology, Thyroid Function Tests, Thyroid Gland/physiology, Thyroid Hormones/blood, Thyrotropin/blood, Young Adult, Thyroid Hormones, Thyrotropin

Maternal thyroid function during gestation is related to breech presentation at term

Higher maternal TSH at 36 weeks is linked to breech presentation

Key Findings

Interpretation

RRM Context

Abstract

Topics

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Keywords