Undiagnosed Primary Hyperparathyroidism and Recurrent Miscarriage: The First Prospective Pilot Study

Area of Science:

• Endocrinology
• Reproductive Medicine

Background:

• Primary hyperparathyroidism (pHPT) in pregnancy is linked to adverse maternal and fetal outcomes, including increased miscarriage risk.
• The true incidence of pHPT in pregnancy and its prevalence in recurrent miscarriage (RM) remain largely unknown.
• This study is the first prospective investigation into undiagnosed pHPT in women experiencing RM (≥3 consecutive miscarriages).

Purpose of the Study:

• To determine the prevalence of undiagnosed primary hyperparathyroidism (pHPT) in women with recurrent miscarriage (RM).
• To assess the potential association between pHPT and recurrent pregnancy loss.

Main Methods:

• Recruited 300 women with a history of 3 or more consecutive miscarriages from a nationwide RM clinic.
• Measured serum corrected calcium, phosphate, parathyroid hormone (PTH), and vitamin D levels.
• Recalled patients with abnormal results for confirmatory testing, aiming for a minimum of 272 participants for statistical power.

Main Results:

• Analyzed data from 289 women; 17% (50/289) had abnormal initial tests and were recalled.
• Diagnosed one case of pHPT (0.34% prevalence) in a woman who underwent successful parathyroidectomy.
• Found high rates of vitamin D deficiency (8.7%) and insufficiency (67.8%).

Conclusions:

• The prevalence of undiagnosed pHPT in RM (0.34%) is substantially higher than the expected 0.05% for this age group.
• These findings suggest a potential link between pHPT and recurrent miscarriage, warranting further investigation.
• Routine serum calcium testing in women with RM should be considered.