Early pregnancy loss in Preimplantatory Genetic Diagnosis

Abstract

To evaluate prospectively the incidence of early pregnancy loss (EPL) (before menstruation occurs) in Preimplantatory Genetic Diagnosis (PGD) compared to conventional in vitro fertilization (IVF) cycles. Prospective controlled study. One hundred and three patients undergoing PGD (n=40) vs conventional IVF (n=63) were included. Starting on day 6 after oocyte collection, patients were instructed to collect their first urine sample of the day every 2 days. Each patient collected four different specimens of urine (days 6, 8, 10, and 12 after oocyte collection). β-hCG was measured on each urine sample with a standarized microparticle enzyme immunoassay. A positive result shown in at least two urine determinations was considered as diagnostic of embryo implantation. Reproductive outcome was assessed with blood β-hCG determination 14 days after oocyte collection. For IVF, 37 of 63 (58.7%) patients showed a positive blood β-hCG level 14 days after oocyte collection. Twenty nine of them (78.4%) continued as viable pregnancies, 2 (5.4%) were biochemical pregnancies, 5 (13.5%) miscarried, and one (2.7%) was an ectopic pregnancy. Of the 26 negative blood β-hCG tests, 10 (38.5%) had positive implantation, registered in at least two of the four urine samples collected. For PGD patients, 22 of 40 (55.0%) had a positive blood β-hCG level 14 days after oocyte collection. Seventeen (77.3%) were viable, 2 (9.1%) were biochemical pregnancies, 2 (9.1%) miscarried, and 1 (4.5%) was an ectopic pregnancy. Of those 18 patients with a negative blood β-hCG test, 2 (11.1%) showed positive implantation. Thus, the incidence of early pregnancy loss (before menstruation) in patients undergoing IVF was 38.5% vs 11.1% of those patients that underwent PGD (p=0.03). Our results demonstrate that patients undergoing IVF without PGD have an increased rate of early pregnancy loss compared to those patients that performed PGD. These data suggest a chromosomal origin of early pregnancy loss, as long as the performance of PGD decreases significantly its incidence.