Observation Time. We followed 595 w

Observation Time. We followed 595 women (85 kidney donors and 510 nondonors) for a median of 10.9 years (11.0 years for donors and 10.9 years for nondonors), with a maximum follow-up of 20.0 years. The observation periods for 20 women (3.4%) were censored at the time of provincial emigration or death. The last donation occurred in December 2009, and the last childbirth in December 2012. There were 4361 total person-years of follow-up (646 for donors and 3715 for nondonors). Less than 2% of pregnancies were twins.
Characteristics of the Study Participants.
In the two study groups, the median age was 29 years (interquartile range, 26 to 32), and 29% of the women had at least one pregnancy before cohort entry (Table 1). As expected, donors had more physician visits in the year before cohort entry than nondonors because such visits are a necessary part of donor evaluation. Most donors (65%) were first-degree relatives (sibling, parent, or child) of the recipient, followed by distant relatives or genetically unrelated donors (20%) and spouses (15%). Nephrectomies were performed by means of either a laparoscopic procedure (41%) or an open procedure (59%). Before donation, the median serum creatinine level was 0.76 mg per deciliter (67 μmol per liter; interquartile range, 0.69 to 0.83 mg per deciliter [61 to 73 μmol per liter]), and the median estimated glomerular filtration rate was 114 ml per minute per 1.73 m2 of body-surface area (interquartile range, 104 to 122).