Parathyroid Disease in Pregnancy and Lactation: A Narrative Review of the Literature

Abstract

Pregnancy and lactation are characterized by sophisticated adaptations of calcium homeostasis, aiming to meet fetal, neonatal, and maternal calcium requirements. Pregnancy is primarily characterized by an enhancement of intestinal calcium absorption, whereas during lactation additional calcium is obtained through resorption from the maternal skeleton, a process which leads to bone loss but is reversible following weaning. These maternal adaptations during pregnancy and lactation may influence or confound the presentation, diagnosis, and management of parathyroid disorders such as primary hyperparathyroidism or hypoparathyroidism. Parathyroid diseases are uncommon in these settings but can be severe when they occur and may affect both maternal and fetal health. This review aims to delineate the changes in calcium physiology that occur with pregnancy and lactation, describe the disorders of calcium and parathyroid physiology that can occur, and outline treatment strategies for these diseases in the above settings.

Ionised and total hypocalcaemia in pregnancy: An analysis of prevalence and risk factors in a resource-limited setting, Cameroon

“…In neighbouring Nigeria, the third-trimester prevalence of vitamin D deficiency and insufficiency of 22.5% and 60%, respectively, have been reported [ 38 ]. The prevalence of hypoparathyroidism in the general population is low, ranging from 0.5–6.6% [ 39 ], while the prevalence in pregnancy has not been reported [ 40 ].…”

A Scoping Review of the Apparent Phenomenon of the Improvement in Hypoparathyroidism in Pregnant and Postpartum Females

“…Conversely, inappropriate continuation may lead to hypercalcemia in the mother (and suppression of the fetal parathyroid glands). Tsourdi et al [ 84 ] recommended monitoring calcium every four to six weeks during lactation to ensure that normocalcemia is present and to wean as appropriate. Khan et al [ 83 ] recommended weekly albumin-corrected (or ionized) calcium levels during the first month postpartum, with a target of achieving calcium within the low-normal reference range (in a manner similar to a non-breastfeeding female).…”

“…Furthermore, records during prior pregnancies should be obtained in women with hypoparathyroidism to assess when hypercalcemia (or hypocalcemia) occurred during a previous pregnancy (or postpartum period) and to consider a proactive dosage reduction in supplementation should hypercalcemia have occurred in a prior pregnancy. As a final consideration, in patients who do require active vitamin D supplementation during gestation and lactation, Tsourdi et al [ 84 ] suggested calcitriol due to its shorter half-life (more rapid recovery from hypercalcemia).…”

“…As noted by Kovacs [ 90 ], during pregnancy, there is an ‘artefactual’ decline in total calcium noted by the increased intravascular volume (hemodilution) and depleted albumin; this must be addressed in future studies, as many authors have not accounted for this finding (nor has the ionized calcium been measured), leading to unnecessary supplementation with calcium and/or calcitriol. A final consideration, as noted by Tsourdi and Anastasilakis [ 84 ], is that calcitriol has a shorter half-life compared to other active vitamin D supplements; in case reports in which other supplements have been used, it will take longer for the hypercalcemia to resolve.…”

Hypercalcemia in Pregnancy Due to CYP24A1 Mutations: Case Report and Review of the Literature

“…Pregnant women with hypercalcemia and reduced PTH concentrations may suffer from a variety of diseases including, e.g., disorders of vitamin D metabolism, vitamin D intoxication per se, malignancy, granulomatous diseases (sarcoidosis and tuberculosis), pseudohyperparathyroidism (due to elevated PTH related peptide (PTHrP) levels), milk-alkali syndrome (due to excess intake of calcium and antacid drugs), etc. posing a diagnostic and therapeutic challenge [2][3][4][5][6].…”