RF18 | PSAT166 Hypercalcemia and hypocalcemia during pregnancy are associated with worse maternal and fetal outcomes

BACKGROUND: Hypercalcemia during pregnancy is rare. The true incidence, however, is difficult to estimate as routine calcium screening is not recommended. Hypercalcemia is linked with various maternal and fetal outcomes but overall, the literature is conflicting. AIMS: Aim of this study is to determine the frequency of hypercalcemia in pregnancy and to determine association with early maternal and fetal outcomes. METHODS: This retrospective cohort study included all confirmed gestations with expected date of delivery (EDD) between 2017-2019 at a large tertiary maternity unit. Baseline demographic, biochemical, and clinical data collected as part of a clinical-administrative dataset was retrieved. Maternal and fetal outcomes studied were incidence of fetal loss (miscarriage/stillbirth), pre-term delivery, emergency C-section, hypertension, blood loss during delivery, neonatal intensive care unit (NICU) admission, and fetal birth weight (for term deliveries). RESULTS: Total number of gestations and livebirths recorded between 2017-2019 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 in the preceding ten months of EDD. Of these, the hypercalcemia and hypocalcemia were noted in 42 (0.81%) and 499 gestations (9.61%) respectively. The median adjusted calcium in the hypercalcemic group was 2.75 mmol/L [IQR 2.65-2.88] and underlying diagnoses were primary hyperparathyroidism (n=17), transient hypercalcemia (n=12), suspected familial hypocalciuric hypercalcemia (n=2), sarcoidosis (n=1), and unknown (n=10). Of maternal and fetal outcomes, the incidence of pre-term delivery (20.0% v 9.2%; P=0.042), emergency C-section (42.4% v 21.4%; P=0.021), neonatal intensive care unit (NICU) admission (19.4% v 8.2%; P=0.024), and blood loss during delivery (1252 v 526 mL; P<0.001) was higher in the hypercalcemic group. The incidence of fetal loss (22.5% v 18.9%; P=0.560) and hypertension (0% v 1%; P =0.561) was not different between hyper and normocalcemic groups. Interestingly, the hypocalcemic group also demonstrated higher incidence of pre-term delivery (24.2% v 9.2%; P=<0.001), emergency C-section (28.6% v 21.4%; P=0.025), NICU admission (15.9% v 8.2%; P<0.001), and blood loss (627 v 526 mL; P<0.001), but not of fetal loss (21.0% v 18.9%; P=0.281) or hypertension (2.2% v 1.0%; P =0.054) compared to the eucalcemic group. CONCLUSION: The incidence of hypercalcemia in pregnancy is low (0.81%). However, abnormal calcium levels are associated with worse maternal and fetal outcomes. Research needs to focus on whether routine calcium estimations are necessary and if treatment of these conditions improves maternal and fetal outcomes. We recommend that calcium testing should be considered in women who are at risk of worse outcomes during current or previous pregnancies. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Sunday, June 12, 2022 12:54 p.m. - 12:59 p.m.