Endocrine Abstracts

Background: Incidence of hypercalcaemia during pregnancy is difficult to estimate as routine calcium screening is not recommended. Literature is conflicting if hypercalcemia results in worse maternal and fetal outcomes.

Objectives: Aim of this study is to determine frequency and association of hypercalcaemia in pregnancy with early maternal and fetal outcomes.

Methods: This retrospective cohort study included gestations with expected delivery dates between 2017-19 at a tertiary maternity unit. Baseline demographic, biochemical, and clinical data was retrieved for analysis. Primary outcomes were incidence of hypercalcaemia and fetal loss (miscarriage/stillbirth) during pregnancy. Secondary outcomes included rate of other maternal and fetal outcomes: pre-term delivery, emergency C-section, hypertension, blood loss during delivery, neonatal intensive care unit (NICU) admission, and fetal birth weight.

Results: Total number of gestations and livebirths recorded were 33,118 and 20,969, respectively, with median age of 30.1 [IQR 25.6-34.3] years. Two-thirds of pregnancies were in Caucasian women (65.9%) followed by Asians (9.6%), Afro-Caribbean (5%), and others (19.5%). 15.7% (n=5195) of all gestations had calcium tested and incidence of hypercalcemia was 0.81% (n=42). The incidence of fetal loss was 22.5% in the hypercalcaemic group compared to 18.9% in normocalcaemic group (P = 0.560). Among other outcomes, incidence of pre-term delivery (20.0% v 9.2%;p=0.042), emergency C-section (42.4% v 21.4%;p=0.021), NICU admission (19.4% v 8.2%;p=0.024), and blood loss (1252 v 526 mL;P < 0.001) were all higher in the hypercalcemic group, however, incidence of hypertension (0% v 1%;p=0.561) was similar. The median adjusted calcium in the hypercalcemic group was 2.75 mmol/l [IQR 2.65-2.88]. Further analysis showed that incidence of hypocalcaemia in this cohort was 9.61% (n=499), and this also was associated with worse outcomes but not with fetal loss.

Conclusions: Incidence of hypercalcemia in pregnancy is low (0.81%). Abnormal calcium levels are associated with worse maternal and fetal outcomes, but rate of fetal loss is not high.