Pregnancy after renal transplantation: 25 years experience in Spain.

OBJECTIVE: To study the outcome of pregnancy in renal transplant patients in Spain.

DESIGN: A retrospective review based on two consecutive national inquiries.

SETTING: Departments of Obstetrics and Gynaecology and Renal Transplant Units in Spain.

SUBJECTS: Pregnant women who had renal transplants between 1965 and 1989.

MAIN OUTCOME MEASURES: From the preliminary inquiry the frequencies of miscarriage, therapeutic abortion, preterm birth, fetal malformation, twins, stillbirths, neonatal deaths and loss of maternal renal function were recorded. The subsequent, more detailed inquiry provided additional information including donor type, previous rejection episodes and interval between rejection and pregnancy, previous creatinine level, previous hypertension and development of hypertension in pregnancy, developments during labour and delivery and the occurrence of intra uterine growth retardation and low birth weight.

RESULTS: The preliminary inquiry yielded information about 133 pregnancies. The miscarriage rate was 10% and the therapeutic abortion rate was 16%. Of the 99 pregnancies that continued, 46% ended before term and 53% progressed to term. The perinatal mortality rate was 107.8 per 1000 and 4% of the infants had minor congenital malformations. The second inquiry yielded more detailed data about 66 pregnancies. There were no therapeutic abortions and 12% of the pregnancies ended in miscarriage. Among the 58 pregnancies that reached > or = 28 weeks gestation, preterm birth occurred in 28 (48%) and intra uterine growth retardation occurred in 17 (29%). Among 48 women with normal renal function before pregnancy, the perinatal mortality rate was 68 per 1000, the miscarriage rate was 8% and in 10 of these women (21%) renal function was impaired after pregnancy. In contrast, among 18 women with impaired renal function before pregnancy, the perinatal mortality rate was 142 per 1000, the miscarriage rate was 22% and in six of these women (33%) renal function deteriorated after the pregnancy. Impairment of renal function was most common in women with hypertension during pregnancy or with rejection episodes during the year before conception.

CONCLUSIONS: Women with a renal transplant can have a successful pregnancy, but there are definite risks for both mother and fetus. Pregnancy should be discussed with the woman and encouraged only if there is good renal graft function.