Abstract
Background
The aim of this study was to assess the relationship
between maternal anti-thyroid peroxidase (anti-TPO)-negative subclinical
hypothyroidism (SCH) in the first trimester with complications of pregnancy
and neonatal outcomes.
Methods
The study was done at a maternity and children's research training
hospital. First-trimester thyroid function tests (TFTs) (free thyroxine
(FT4), thyroid stimulating hormone (TSH), anti-TPO) were checked for mothers
who gave birth at the center, and their newborns were accepted for the
study. Based on the results of the TFTs, two groups were formed, the normal
thyroid function (euthyroid) and SCH groups. The neonatal and maternal
outcomes were noted.
Results
This study included 150 mothers, of whom 110 (73.3%) had normal thyroid
function and 40 (26.7%) had anti-TPO-negative subclinical hypothyroidism
(SCH). Based on thyroid function tests (TSH: 0.1–4.0 mIU/L, FT4: 0.7–1.8
ng/dL), significant differences in pregnancy complications wereobserved,
with higher rates of placental abruption, preeclampsia, and postpartum
hemorrhage in the SCH group (p<0.001). Neonatal outcomes in the SCH group
showed significantly higher rates of small for gestational age (SGA)
(52.5%), NICU admission (77.5%), low Apgar score (52.5%), and transient
tachypnea of the newborn (TTN) (67.5%) (all p<0.001). Logistic regression
analysis identified SCH as a significant risk factor for TTN (OR=7.24; 95%
CI: 3–17; p<0.001), while no significant associations were found with
gestational age (p=0.194) or maternal age (p=0.600).
Conclusion
Anti-TPO-negative SCH in pregnancy has undesirable effects, not only during
pregnancy but also in siblings, and surprisingly, it may be a risk factor
for TTN.
Keywords
Maternal thyroid function - subclinical hypothyroidism - prenatal and neonatal outcomes
