Primary hyperparathyroidism is rarely diagnosed in pregnancy; not only because it is uncommon in that age group but also because many of the symptoms overlap with non-specific pregnancy symptoms (nausea, vomiting, fatigue, constipation). Primary hyperparathyroidism with significant hypercalcaemia can potentially cause serious maternal (preeclampsia, nephrolithiasis, pancreatitis and hypercalcaemic crisis) and foetal (miscarriage, stillbirth, neonatal hypocalcaemia leading to tetany and rarely long term hypoparathyroidism) complications. We present a series of five primary hyperparathyroidism cases; all of whom had successful pregnancy outcome. Only one case was diagnosed before conception. This was managed conservatively during pregnancy as corrected calcium was 2.71 mmol/l at diagnosis and remained in the same range throughout the pregnancy. PTH was (6.1 pmol/l, reference range 1.67.2) and familial hypocalciuric hypercalcemia (FHH) was excluded. Her hypertension has persisted post-pregnancy and she is awaiting parathyroidectomy. Of the other four cases, all were diagnosed during pregnancy and all had corrected calcium levels at diagnosis greater than 3.0 mmol/l. Two cases were diagnosed during the second trimester (at 18 and 24 weeks) and had parathyroidectomy respectively during week 24 and 28 of gestation. The other two cases were diagnosed during the third trimester (at weeks 30 and 32) and were closely monitored throughout the remainder of the pregnancy. Both underwent parathyroidectomy post-partum. Four of five women were South Asian, four of five were in their mid to late thirties and four of five were deficient in vitamin D at diagnosis. None of the neonates had hypocalcaemia.