Live-birth rates and multiple-birth risk using in vitro fertilization

Area of Science:

• Reproductive Medicine
• In Vitro Fertilization (IVF)
• Maternal Health

Background:

• Physicians performing in vitro fertilization (IVF) often transfer multiple embryos to maximize birth rates, increasing the risk of multiple births.
• Live-birth and multiple-birth rates can be influenced by patient age and embryo quality, with cryopreservation of extra embryos serving as a potential marker for embryo quality.

Purpose of the Study:

• To investigate the relationship between the number of embryos transferred during IVF and the rates of live birth and multiple births.
• To analyze these rates stratified by maternal age and the availability of extra embryos for cryopreservation.

Main Methods:

• A retrospective cohort study involving 300 US clinics reporting IVF transfer procedures.
• Analysis of 35,554 IVF transfer procedures to determine live-birth and multiple-birth rates.

Main Results:

• Maximum live-birth rates were achieved with two embryos transferred for women aged 20-34 when extra embryos were cryopreserved.
• For women 35 and older, live-birth rates were lower and increased with more than two embryos transferred, regardless of cryopreservation.
• Multiple-birth rates varied by age and embryo number transferred but not by cryopreservation status; rates increased significantly with three embryos transferred for younger age groups.

Conclusions:

• The risk of multiple births in IVF is dependent on maternal age and the number of embryos transferred.
• Embryo quality, indicated by cryopreservation, did not correlate with multiple birth risk but was associated with higher live-birth rates when fewer embryos were transferred.