In a nutshell
This study investigated the effect of embryo retention (ER) on fertility outcomes in women undergoing embryo transfer (ET).
They found that ER was associated with lower live birth (LBRs) and clinical pregnancy rates (CPRs).
Some background
Assisted reproduction (AR) is used to treat couples with infertility. There are a number of steps involved in AR. In vitro fertilization (IVF) is a well-known AR technique. It involves allowing a sperm to fertilize an egg in a dish in a lab. Embryo transfer (ET) is the final step in AR. Embryos are delivered to the uterus using a catheter. Some times embryos can become stuck in the catheter. This is called embryo retention (ER). ER is usually caused by mucus or blood on the catheter.
ER is an uncommon but significant problem. It can prevent the delivery of embryos. If ER occurs then ET will be repeated. This could involve removing the embryo from the catheter and using a new one. It is unclear if the retransfer of embryos after ER affects fertility outcomes.
Methods & findings
This study included 6,089 ET cycles. ER rate and fertility outcomes were analyzed. The main fertility outcomes were implantation rate (IR), clinical pregnancy rate (CPR), and live birth rate (LBR).
97 embryos (1.59%) were retained. 94 of these embryos were successfully transferred the second time. The remaining 3 embryos were transferred at the 3rd attempt.
The 97 retained embryos were compared to 194 couples without ER. Couples in the ER group had lower IR, CPR, and LBR compared to the non-ER group. There was also a higher rate of ectopic pregnancy (the embryo implants outside the uterus) in the ER group. ER was more common in fresh ET cycles (2.71%) compared to frozen ET (1.08%). The rate of mucus on the catheter was associated with higher ER rates in fresh ET.
The bottom line
The authors concluded that ER was associated with lower LBRs and CPRs.
The fine print
This study was based on medical records. Other factors could also affect fertility outcomes. This includes embryo quality. More studies are needed.
Published By :
Fertility and Sterility
Date :
Aug 05, 2020
