How Many Embryos Should I Transfer

Embryos Transfer – Introduction

The 1st successful invitro fertilisation (IVF) or test tube baby was born in the year 1978 and since then this Test tube baby technique is being used for last four decades as a mode of treatment for childless couples. In this technique we prepare the embryo in the IVF laboratory by the fusion of egg of female with the sperm of male and transfer it into the uterus of the women after preparing the endometrium. We usually transfer the embryo in Day3 (cleavage stage) or day 5 (blastocyst stage) of the embryo formation. The success rate of day 5 embryo transfer is more compared to day 3 embryo.

The success of IVF treatment depends on many factors such as age of the female, quality of the embryos formed, endometrial thickness of the patient’s uterus, number of embryos transferred, availability of surplus amount of embryo for cryo preservation/ storage. Hence the number of embryos to be transferred is an important parameter for a successful pregnancy in a patient having infertility. Transfer of more than one embryos into the uterus of a female in one cycle although increases positive pregnancy test but at the same time the pregnancy is not a normal one because multiple pregnancy is considered as a complicated pregnancy which has its own consequence. Twin/triplet pregnancy is associated with maternal complications such as miscarriage, hypertension and diabetes mellitus, premature delivery, more chance of caesarean section and fetal complications such as low birth weight baby, NICU admission, respiratory distress syndrome.Hence to avoid such complications ideally one good quality embryo should be transferred in one cycle.

Because of availability of more advanced techniques in IVF treatment such as extended culture system for blastocyst formation, facility of cryopreservation of excess embryos , pre implantation genetic testing for embryo and time lapse monitoring for proper selection of embryos the IVF success rate has increased significantly now a days.So with better availability of IVF techniques and to avoid the risk of multiple pregnancy elective single embryo transfer (eSET) is a preferred method and widely practiced now days. Elective SET is defined as selection and transfer of one good quality embryo among the available multiple embryos in cleavage or blastocyst stage. But there are exceptions to eSET like previous multiple IVF failures, multiple fibroid uterus, poor endometrial lining, poor embryo quality where we should transfer more than one embryos to increase the success rate by counselling and recording it in her medical record about the risk of multiple pregnancy. According to different studies the cumulative pregnancy rate of eSET is equivalent to success rate of double embryo transfer in a single cycle. It also reduces the risk of multiple pregnancy from 50% to 0% when compared to double embryo transfer (DET). Elective SET in two different cycles is more cost effective than DET in single cycle due to complication of multiple pregnancy and its sequelae such as preterms, problems in breast feeding, nursery admissions, psychological and financial burden to parents. To reduce the risk of multiple pregnancy we should move towards eSET so that we can achieve the goal of ART that is singleton pregnancy.

According to American Society of Reproductive Medicine (ASRM) guidelines and society of assisted reproductive technology (SART) guidelines we should always transfer a single euploid embryo at any age of women. Even Indian regulating body Indian council of medical research (ICMR) says to transfer maximum 3 embryos in case of cleavage stage or maximum 2 in case of blastocyst in a single cycle.

To achieve the goal i.e. singleton pregnancy after embryo transfer when you are going for IVF treatment please discuss with your doctor about the advantages and disadvantages of single/multiple embryo transfer. Also enquire about availability of advanced technique like blastocyst culture, laser assisted hatching, facility to test for common chromosomal abnormalities in a embryo called PGT-A which helps in improving the pregnancy rates future. If affordability of IVF cost is concern then discuss about the facility of EMI and insurance coverage. Finally knowing everything you can plan for a successful pregnancy without much complications.