Hypoparathyroidism in pregnancy

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

Hypoparathyroidism requires management with both calcium supplementation and active vitamin D to avert a state of hypocalcemia. During late gestation and the postpartum period (specifically lactation), there is an under-recognized, yet intriguing occurrence of apparent 'pseudohyperparathyroidism', whereby supplementation dosages may need to either be reduced or discontinued, to prevent hypercalcemia. The explanation for this apparent phenomenon of improved parathyroid status ('remission' or 'resolution') is incompletely understood; the purpose of this review is to analyze the case reports of this enigma within the medical (and grey) literature, providing an overall pathophysiological explanation and recommendation for the management of such patients. A literature search was conducted through PubMed/Medline, CINAHL, Cochrane Library Database, Scopus, UpToDate, Google Scholar, and the grey literature without a time-restricted period, analyzing all available articles within the literature describing an apparent improvement in parathyroid status in late-gestation and postpartum (lactating) females. Non-hypoparathyroid case reports were also included to further analyze and synthesize an overall likely pathophysiological explanation. Through the literature search, 24 papers were identified covering such a phenomenon in patients with hypoparathyroidism, alongside multiple additional reports of a similar occurrence in patients without underlying hypoparathyroidism. The pathophysiology is believed to occur due to the placental production of parathyroid hormone-related peptide (PTHrP) during gestation, with further production from the lactating mammary glands during the postpartum period. A typical pattern is observed, with increased PTHrP and suppressed PTH throughout both gestation and lactation (present in both normal and hypoparathyroid subjects). The concept of PTHrP-induced hypercalcemia is further demonstrated in patients without hypoparathyroidism, including subjects with placental hypersecretion and mammary gland enlargement. It is evident that patients with hypoparathyroidism may require a dosage reduction during late gestation and lactation, due to the risk for hypercalcemia. In addition to patients with hypoparathyroidism, this pathophysiological phenomenon occurs in unsuspecting patients, demonstrating the need for all clinicians in contact with pregnant females to be aware of this uncommon - yet perilous - occurrence.

Management of Hypoparathyroidism

Hypoparathyroidism (HypoPT) is a rare disorder characterized by hypocalcemia in the presence of a low or inappropriately normal parathyroid hormone level. HypoPT is most commonly seen after neck surgery, which accounts for approximately 75% of cases, whereas approximately 25% have HypoPT due to nonsurgical causes. In both groups of patients, conventional therapy includes calcium and active vitamin D analogue therapy aiming to maintain serum calcium concentration in the low normal or just below the normal reference range and normalize serum phosphorus, magnesium concentrations, and urine calcium levels. The limitations of conventional therapy include wide fluctuations in serum calcium, high pill burden, poor quality of life, and renal complications. Parathyroid hormone (PTH) replacement therapy may improve the biochemical profile in those in whom conventional therapy proves unsatisfactory. Based on a systematic review and meta-analysis of the literature, the panel made a graded recommendation suggesting conventional therapy as first line therapy rather than administration of PTH (weak recommendation, low quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers use of PTH. Because pregnancy and lactation are associated with changes in calcium homeostasis, close monitoring is required during these periods with appropriate adjustment of calcium and active vitamin D analogue therapy to ensure that serum calcium remains in the mid to low normal reference range in order to avoid maternal and fetal complications. Emerging therapies include molecules with prolonged PTH action as well as different mechanisms of action that may significantly enhance drug efficacy and safety. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Changes in Serum Calcium and Treatment of Hypoparathyroidism During Pregnancy and Lactation: A Single-center Case Series

BACKGROUND

Hypoparathyroidism (hypo-PT) is rare, and studies on hypo-PT, especially during pregnancy and lactation, are limited.

DESIGN AND SETTING

This was a retrospective study on a relatively large case series in a single center from mainland China.

METHODS

A total of 19 patients with 25 pregnancies, diagnosed with hypo-PT before pregnancy, were enrolled. Data on clinical characteristics and treatment strategies at onset time and around pregnancy period were collected.

RESULTS

During pregnancy, except for 2 patients with missing data, 5 patients with 6 pregnancies (6/23, 26.1%) experienced improved hypo-PT condition, defined as an increased serum calcium level; 4 patients with 4 pregnancies (4/23, 17.4%) experienced worsened hypo-PT condition, defined as a more than 0.2 mmol/L decline in the serum calcium level; and 3 patients with 3 pregnancies (3/23, 13.0%) remained in stable hypo-PT condition. The prevalence of adverse pregnancy outcomes was 30.4% (4/23 for preterm delivery; 3/23 for miscarriage). The serum calcium and 24-hour urine calcium levels significantly increased during lactation compared with pregnancy (2.57 ± 0.34 vs 1.99 ± 0.11 mmol/L, P < 0.001; 12.28 ± 5.41 vs 8.63 ± 3.22 mmol/L, P = 0.013), and 5 patients with 5 lactations (5/12, 41.7%) developed hypercalcemia in the first 2 months after delivery.

CONCLUSIONS

Female patients with hypo-PT had different changes in calcium homeostasis and a high prevalence of adverse outcomes during pregnancy. Thus, they should be monitored closely to maintain the optimal serum calcium level. Decreasing drug dosage during the lactation period should be considered to avoid hypercalcemia.

Hypoparathyroidism and pseudohypoparathyroidism in pregnancy: an Italian retrospective observational study

Background

Hypoparathyroidism (HypoPT) or pseudo-hypoparathyroidism (pseudo-HypoPT) during pregnancy may cause maternal and fetal/neonatal complications. In this regard, only a few case reports or case series of pregnant or lactating women have been published. The purpose of this study was to describe clinical and biochemical course, pharmacological management, and potential adverse events during pregnancy and post-partum in pregnant women with HypoPT or pseudo-HypoPT. This was a retrospective, observational, multicenter, study involving nine Italian referral centers for endocrine diseases affiliated with the Italian Society of Endocrinology and involved in “Hypoparathyroidism Working Group”.

Results

This study identified a cohort of 28 women (followed between 2005 and 2018) with HypoPT (n = 25, 84% postsurgical, 16% idiopathic/autoimmune) and pseudo-HypoPT (n = 3). In HypoPT women, the mean calcium carbonate dose tended to increase gradually from the first to third trimester (+ 12.6%) in pregnancy. This average increase in the third trimester was significantly greater compared to the pre-pregnancy period (p value = 0.03). However, analyzing the individual cases, in 44% the mean calcium dosage remained unchanged throughout gestation. Mean calcitriol doses tended to increase during pregnancy, with a statistically significant increase between the third trimester and the pre-pregnancy period (p value = 0.02). Nevertheless, analyzing the individual cases, in the third trimester most women with HypoPT (64%) maintained the same dosage of calcitriol compared to the first trimester. Both mean calcium carbonate and calcitriol doses tended to decrease from the third trimester to the post-partum six months. Most identified women (~ 70%) did not display maternal complications and (~ 90%) maintained mean serum albumin-corrected total calcium levels within the low-to-mid normal reference range (8.5 ± 0.8 mg/dl) during pregnancy. The main complications related to pregnancy period included: preterm birth (n = 3 HypoPT women), and history of miscarriages (n = 6 HypoPT women and n = 2 pseudo-HypoPT women).

Conclusion

This study shows that mean serum albumin-corrected total calcium levels were carefully monitored during pregnancy and post-pregnancy, with limited evaluation of other biochemical parameters, such as serum phosphate, 24 h urinary calcium, 25-OH vitamin D, and creatinine clearance. To avoid complications in mothers affected by (HypoPT) or (pseudo-HypoPT) and offspring, intense biochemical, clinical and pharmacological monitoring during pregnancy and breastfeeding is highly recommended.

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

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.

Hypoparathyroidism in Pregnancy and Lactation: Current Approach to Diagnosis and Management

Background: Hypoparathyroidism is an uncommon endocrine disorder. During pregnancy, multiple changes occur in the calcium-regulating hormones, which may affect the requirements of calcium and active vitamin D during pregnancy in patients with hypoparathyroidism. Close monitoring of serum calcium during pregnancy and lactation is ideal in order to optimize maternal and fetal outcomes. In this review, we describe calcium homeostasis during pregnancy in euparathyroid individuals and also review the diagnosis and management of hypoparathyroidism during pregnancy and lactation. Methods: We searched the MEDLINE, CINAHL, EMBASE, and Google scholar databases from 1 January 1990 to 31 December 2020. Case reports, case series, book chapters, and clinical guidelines were included in this review. Conclusions: During pregnancy, rises in 1,25-dihydroxyvitamin D (1,25-(OH)2-D3) and PTH-related peptide result in suppression of PTH and enhanced calcium absorption from the bowel. In individuals with hypoparathyroidism, the requirements for calcium and active vitamin D may decrease. Close monitoring of serum calcium is advised in women with hypoparathyroidism with adjustment of the doses of calcium and active vitamin D to ensure that serum calcium is maintained in the low-normal to mid-normal reference range. Hyper- and hypocalcemia should be avoided in order to reduce the maternal and fetal complications of hypoparathyroidism during pregnancy and lactation. Standard of care therapy consisting of elemental calcium, active vitamin D, and vitamin D is safe during pregnancy.

Hypocalcemia After Thyroidectomy and Parathyroidectomy in a Pregnant Woman

Hypoparathyroidism during pregnancy is a very rare endocrine disorder. The majority of cases are postsurgical (75%). Managing pregnant or nursing women with hypoparathyroidism is challenging due to complications arising from either under- or overtreatment, including premature delivery or fetal death, abortion, stillbirth, perinatal death, and neonatal tetany. Specific adaptations are needed within each time period to meet the fetal, neonatal, and maternal calcium requirements. A systematic search was performed on PubMed using the search terms "pregnancy" and "hypoparathyroidism." Included were articles published in English between January 1, 1966, and January 1, 2018. We provide an overview of all published cases (n = 43) of hypoparathyroidism in pregnancy, including a case report of a 29-year-old pregnant woman who underwent a total thyroidectomy before her current pregnancy because of a therapy-resistantant Graves' disease. The procedure was complicated by postsurgical hypoparathyroidism. She carried out the pregnancy to term with minor complaints of paresthesia and muscle cramps. Furthermore, we discuss treatment, complications, and follow-up of hypoparathyroidism in pregnancy. Treatment of hypoparathyroidism in pregnancy should still be individualized, depending on the patient's complaints and serum levels of calcium, which should be maintained in the lower normal range of 2.15 to 2.55 mmol/l, according to the literature. We recommend monitoring calcium levels every 3 to 4 weeks throughout the pregnancy, within 1 week postpartum, and monthly during lactation to ensure normocalcemia.

Clinical presentation and management of hypoparathyroidism

The clinical manifestations of hypoparathyroidism are variable and can involve almost any organ system. The main clinical features of the hypoparathyroidism are typically signs or symptoms due to neuromuscular irritability owing to low serum calcium level. In addition to hypocalcemia, hyperphosphatemia can contribute to long-term complications, including extra-skeletal calcifications. Bone turnover markers are generally decreased, and bone mass density is usually normal-increased compared to age- and gender-matched controls. It is still unclear whether or not these bone features could have an impact on the risk of fracture. Impaired renal function is a common complication described in patients treated for hypoparathyroidism. Other complications include premature cataracts, seizures, basal ganglia calcifications, and cardiac arrhythmias. Lastly, some clinical studies have also reported a reduced quality of life of patients with hypoparathyroidism. Increased awareness of the clinical manifestations of this disease is important to improve its clinical management.

Idiopathic Hypoparathyroidism and Severe Hypocalcemia in Pregnancy

The objective of this study is to report a case of severe hypocalcemia secondary to hypoparathyroidism in a pregnant woman. We report a case of a 45-year-old woman who presented for tonico-clonic seizure in the third trimester of gestation. She was diagnosed with idiopathic hypoparathyroidism for the first time during pregnancy. She was successfully treated with calcium and calcitriol in the rest of her pregnancy with resolution of symptoms but her infant was born with hypercalcemia and secondary hyperparathyroidism due to the late maternal presentation. To the best of our knowledge, hypoparathyroidism is a disorder rarely observed during pregnancy, resulting in most cases from surgical thyroidectomy.

American Thyroid Association Statement on Postoperative Hypoparathyroidism: Diagnosis, Prevention, and Management in Adults

BACKGROUND

Hypoparathyroidism (hypoPT) is the most common complication following bilateral thyroid operations. Thyroid surgeons must employ strategies for minimizing and preventing post-thyroidectomy hypoPT. The objective of this American Thyroid Association Surgical Affairs Committee Statement is to provide an overview of its diagnosis, prevention, and treatment.

SUMMARY

HypoPT occurs when a low intact parathyroid hormone (PTH) level is accompanied by hypocalcemia. Risk factors for post-thyroidectomy hypoPT include bilateral thyroid operations, autoimmune thyroid disease, central neck dissection, substernal goiter, surgeon inexperience, and malabsorptive conditions. Medical and surgical strategies to minimize perioperative hypoPT include optimizing vitamin D levels, preserving parathyroid blood supply, and autotransplanting ischemic parathyroid glands. Measurement of intraoperative or early postoperative intact PTH levels following thyroidectomy can help guide patient management. In general, a postoperative PTH level <15 pg/mL indicates increased risk for acute hypoPT. Effective management of mild to moderate potential or actual postoperative hypoPT can be achieved by administering either empiric/prophylactic oral calcium and vitamin D, selective oral calcium, and vitamin D based on rapid postoperative PTH level(s), or serial serum calcium levels as a guide. Monitoring for rebound hypercalcemia is necessary to avoid metabolic and renal complications. For more severe hypocalcemia, inpatient management may be necessary. Permanent hypoPT has long-term consequences for both objective and subjective well-being, and should be prevented whenever possible.

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

During pregnancy and lactation, female physiology adapts to meet the added nutritional demands of fetuses and neonates. An average full-term fetus contains ∼30 g calcium, 20 g phosphorus, and 0.8 g magnesium. About 80% of mineral is accreted during the third trimester; calcium transfers at 300-350 mg/day during the final 6 wk. The neonate requires 200 mg calcium daily from milk during the first 6 mo, and 120 mg calcium from milk during the second 6 mo (additional calcium comes from solid foods). Calcium transfers can be more than double and triple these values, respectively, in women who nurse twins and triplets. About 25% of dietary calcium is normally absorbed in healthy adults. Average maternal calcium intakes in American and Canadian women are insufficient to meet the fetal and neonatal calcium requirements if normal efficiency of intestinal calcium absorption is relied upon. However, several adaptations are invoked to meet the fetal and neonatal demands for mineral without requiring increased intakes by the mother. During pregnancy the efficiency of intestinal calcium absorption doubles, whereas during lactation the maternal skeleton is resorbed to provide calcium for milk. This review addresses our current knowledge regarding maternal adaptations in mineral and skeletal homeostasis that occur during pregnancy, lactation, and post-weaning recovery. Also considered are the impacts that these adaptations have on biochemical and hormonal parameters of mineral homeostasis, the consequences for long-term skeletal health, and the presentation and management of disorders of mineral and bone metabolism.

Primary hyperparathyroidism in pregnancy

Primary hyperparathyroidism (PHPT) is one of the most common endocrine disorders in the general population but is rarely diagnosed during pregnancy. Symptoms of gestational PHPT may be unrecognized, or masked by physiological changes in calcium homeostasis associated with pregnancy. Gestational PHPT may have severe consequences for both mother and fetus. However, nowadays, gestational PHPT is usually diagnosed in earlier stages and milder forms, with low complication rates. Treatment should be individually tailored according to gestational age, the severity of hypercalcemia, and the risk-benefit balance. The conservative approach is preferred in mild forms, whereas surgery, usually performed during the second trimester, is reserved for symptomatic hypercalcemic PHPT. Given the young age of the patients, genetic causes should be considered.

Management of hypoparathyroidism in pregnancy and lactation - A report of 10 cases

INTRODUCTION

Hypoparathyroidism in pregnancy is rare, but important, as it is associated with maternal morbidity and foetal loss. There are limited case reports and no established management guidelines. Optimal maintenance of calcium levels during pregnancy is required to minimise the risk of related complications. This study aims to identify causes and examine outcomes of hypoparathyroidism in pregnancy in a cohort of women delivering at a large referral centre.

DESIGN AND METHOD

The Monash Health maternity service database captures pregnancy and birthing outcomes in over 9000 women each year. We audited this database between 2000 and 2014 to examine the clinical course, treatment and outcomes of pregnant women with hypoparathyroidism.

RESULTS

We identified 10 pregnancies from 6 women with pre-existing hypoparathyroidism secondary to idiopathic hypoparathyroidism (n = 3), autosomal dominant branchial arch disorder with hypoparathyroidism (n = 3) and autosomal dominant hypocalcaemia (n = 1), surgery for thyroid cancer (n = 2) and Graves' disease (n = 1). Maternal calcium levels were monitored through pregnancy and management adjusted to maintain normocalcaemia. One woman was delivered by caesarean section at 34 weeks' gestation because of intrauterine growth restriction, and oligohydramnios complicated two other pregnancies. The postpartum period was complicated by severe hypercalcaemia in one woman and by symptomatic, labile serum calcium levels during lactation in another woman, requiring close monitoring over a 6 month period.

CONCLUSION

Although rare, hypoparathyroidism in pregnancy poses a management challenge for clinicians, and co-ordinated care is required by obstetricians and endocrinologists to ensure optimal outcomes for both mother and baby. Continued monitoring of maternal calcium levels during lactation and weaning is essential to avoid the potential complications of either hypercalcaemia or hypocalcaemia.

European Society of Endocrinology Clinical Guideline: Treatment of chronic hypoparathyroidism in adults

Hypoparathyroidism (HypoPT) is a rare (orphan) endocrine disease with low calcium and inappropriately low (insufficient) circulating parathyroid hormone levels, most often in adults secondary to thyroid surgery. Standard treatment is activated vitamin D analogues and calcium supplementation and not replacement of the lacking hormone, as in other hormonal deficiency states. The purpose of this guideline is to provide clinicians with guidance on the treatment and monitoring of chronic HypoPT in adults who do not have end-stage renal disease. We intend to draft a practical guideline, focusing on operationalized recommendations deemed to be useful in the daily management of patients. This guideline was developed and solely sponsored by The European Society of Endocrinology, supported by CBO (Dutch Institute for Health Care Improvement) and based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) principles as a methodological base. The clinical question on which the systematic literature search was based and for which available evidence was synthesized was: what is the best treatment for adult patients with chronic HypoPT? This systematic search found 1100 articles, which was reduced to 312 based on title and abstract. The working group assessed these for eligibility in more detail, and 32 full-text articles were assessed. For the final recommendations, other literature was also taken into account. Little evidence is available on how best to treat HypoPT. Data on quality of life and the risk of complications have just started to emerge, and clinical trials on how to optimize therapy are essentially non-existent. Most studies are of limited sample size, hampering firm conclusions. No studies are available relating target calcium levels with clinically relevant endpoints. Hence it is not possible to formulate recommendations based on strict evidence. This guideline is therefore mainly based on how patients are managed in clinical practice, as reported in small case series and based on the experiences of the authors.