The Claim

In fetal sheep during late gestation, the natural increase in glucocorticoid and thyroid hormone concentrations is associated with increased mitochondrial content, abundance of electron transport chain complexes, and enhanced oxidative phosphorylation capacity in skeletal muscle, liver, heart, and brain tissues.

Source: Developmental regulation of fetal mitochondrial respiratory function towards term: the role of glucocorticoid and thyroid hormones

What the research says

Roughly balanced

Support and challenge are close. The picture may shift as more studies come in.

Supports
1score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

During late pregnancy in sheep fetuses, rising levels of glucocorticoid and thyroid hormones coincide with higher mitochondrial density, more electron transport chain proteins, and greater energy production capacity in skeletal muscle, liver, heart, and brain tissues.

See the scientific wording

In fetal sheep, the natural rise in glucocorticoid and thyroid hormone concentrations during late gestation is associated with increased mitochondrial content, electron transport chain complex abundance, and oxidative phosphorylation capacity in skeletal muscle, liver, heart, and brain tissues, preparing the fetus for the metabolic demands of birth.

Why this might work

As the fetus nears birth, rising stress and thyroid hormones activate energy factories inside cells of the muscle, liver, heart, and brain. These hormones turn on genes that build more mitochondria and assemble the protein machines that make energy. The stress hormone also triggers the conversion of an inactive thyroid form into its active version, which further boosts energy production. This ensures the fetus has enough power to breathe, move, and stay warm right after birth.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Developmental regulation of fetal mitochondrial respiratory function towards term: the role of glucocorticoid and thyroid hormones

    As a baby sheep gets ready to be born, its body releases more stress and thyroid hormones, which tell its cells to make more energy factories (mitochondria) in muscles, liver, brain, and heart—so it has enough power to breathe and move after birth.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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