Background: Information about pregnancy in females with primary hyperoxaluria types I and II (PH-I, PH-II) is limited to isolated case reports. This study sought to determine the number and outcomes of pregnancies in a series of women with PH-I and PH-II, to assess the incidence of complications during pregnancy, and to characterize infant outcomes.

Methods: From a database of patients with PH followed at the Mayo Clinic, we identified 16 females who had been pregnant. A retrospective medical record review and telephone survey were performed.

Results: Forty pregnancies occurring between 1961 and 1998 were identified: 26 pregnancies in 11 patients with PH-I and 14 pregnancies in 5 patients with PH-II. Thirty (75%) of the pregnancies were carried to term, and 33 infants were born. Four miscarriages, 4 preterm births, and 2 elective abortions occurred. No maternal complications were reported in half of the pregnancies. In the remaining pregnancies, the most common complications were hypertension, urinary tract infection, and urolithiasis-associated symptoms. One PH-I patient developed pre-eclampsia resulting in a stillborn infant, and another PH-1 patient developed hyperemesis gravidarum with a decline in renal function. Approximately 75% of the infants had no perinatal problems. All of the PH-I patients eventually required initiation of renal replacement therapy at a mean of 17.5 years following their first pregnancy. No PH-II patients have required renal replacement therapy.

Conclusion: Overall, pregnancy appeared to be well tolerated in this series of women with primary hyperoxaluria, with 1 of 16 women experiencing loss of renal function during 1 of 40 pregnancies.