Author Name: Dr. Sunil Yadav Mentor Name: Dr. Shyam N Gupta on April 08, 2020

As the quote by Josh billing “there are two things in life for which we are never prepared:twins” goes it is very important that we understand the above topic as to be well prepared.

What is IVF – multiple ova (eggs) are retrieved from ovary of female and fertilized with sperms in laboratory to form embryos which is later transferred in uterus through the cervix, the embryo implants in endometrium resulting in pregnancy.

How many embryos are to be transferred?
In early days of IVF multiple embryo transfer were done in order to achieve higher pregnancy rate, the only logic was at least one will implant to give pregnancy. But it resulted in multiple pregnancies most of the times. Multiple pregnancy i.e. twins, triplets etc. is also associated with various complications both to mother and the babies. The complications to mother are increase chances of preterm labor, premature rupture of membrane, PIH, anemia ,PPH and to the babies are low birth weight, NICU admission, jaundice, respiratory distress etc. Also the couple has increased financial burden due to prolong hospital admission and further ultimately take home baby is not so promising due to several twins related problems as compare to singleton mothers.

Hence the criteria of IVF success should not be achieving only pregnancy but achieving healthy singleton pregnancy. This can be effectively done by elective single blastocyst embryo transfer to reduce or eliminate incidence of multiple pregnancy while maintaining similar pregnancy rates as suggested by various retrospective studies over the past few years.

According to Society of assisted reproductive technologies (SART), SET(single embryo transfer)is defined as decision taken of transferring single top quality embryo among the total number of embryos formed after appropriate patient selection and counselling .

The two most important aspects of SET

Patient selection-
Age, first IVF cycle, top quality embryo, ovum donor cycle, Day 5 stage of embryo selected.

Patient counseling-
The most important criteria for single embryo transfer is consent of couple. There is fear among couple going for IVF that SET will reduce the chances of pregnancy. With history of IVF and multiple pregnancy being so frequent that couple who desires only pregnancy take risks to come out of stigma of infertility.

However it should be understood that 40 yrs since the first IVF baby was born and today many studies have been conducted and it is a prove fact today that if condition are favorable like age, day 5 stage (i.e. blastocyst) good quality embryo and endometrium there is hardly any difference is pregnancy rates between single or double embryo transfers. According to a retrospective observational study conducted by R. J. Stillman et. al between 2002-2006, 12135 IVF cycles were studied which shows the pregnancy rate after double and single embryo transfer was 67-71% and 64-67% respectively .A study conducted in Iowa city USA by J.D. Kresowik and team, showed that after implementation of mandatory SET in women <38yrs, no prior failed cycle and good quality blast the live birth rate in fact improved from 51% to 55%and multiple pregnancy rate reduced by half.

With all said and done there arises the question can single embryo transfer still result in twins the answer is yes though the chances are very less still twin pregnancy is a possibility.

Various observation studies have been conducted to find the chances of twins with single embryo transfer ,one such study carried out in Japan by Ylkemoto et al where 937848 SET pregnancies between year 2007-2014 was studied .The study showed that the overall chance of twin is only 1.6 percent in single embryo transfer out of which 1.36 is monozygotic twins (identical twins)and 0.3 percent is dizygotic twins. Dizygotic /non identical twins this was mainly due to occurrence of 2 pregnancies at a time one from natural ovulation or from unretrieved oocyte and coitus with subsequent fertilsation and second pregnancy derived from SET.

Chances of dizygotic pregnancy are more in obese patient with unexplained infertility as oocyte retrievel is difficult leading to some unretrieved eggs which may be fertilised if they have coitus however there not enough studies to prove so. Another study conducted between 2010-2013 by R.Fritz showed that among 14986 birth after SET 14737(98.3%) were singleton pregnancy,1.6% twins and among those 0.3 % were dizygotic in simple terms there 1 in 6 chance of dizygotic pregnancy if twins occur in SET. So in cases of unexplained infertility atleast using barrier contraception at time of IVF cycle can prevent dizygotic twins in SET and thereby reducing chance of twins by 0.3-0.5%.

Cause of twins in SET is zygote splitting-Zygote is formed after fertilization of ovum with sperm which further develops in an embryo.

Due to zygotic splitting phenomenon instead of one ,two embryos develop as seen in above picture resulting in twin pregnancy.This occurs rarely in spontaneous conceptions also but the overall occurrence of zygote splitting is more in IVF cycle as compared to spontaneous conception.

The reason of zygote splitting more in IVF is not exactly known but various studies suggest increased manipulation of embryo in laboratory .Manipulation can be at various levels like blastocyst culture,freezing,laser assisted hatching,embryo biopsy for pregenetic testing nothing is pinpoint or proven.Study conducted by B.J vollenhoven et al in 2007-08 concluded that mono zygotic(mz) twin rate with IVF in there study was 7-8 times the natural mz twin rate and twin rate was not influenced by blastocyst transfer neither by frozen embryo.

Furthermore, the study done by Peyser A et al 2018 collectively gives an overview that Fresh eSET increases the risk for monozygotic twins compare to FET and also FET of blastocyst seems to be protective for embryo splitting and monozygosity. Some studies says post 5 or 6.3 days of fertilisation, there is higher chances of embryo splitting to monozygote twins.

Saudnders PA et al 2013 studies that SET blastocyst had higher pregnancy outcome with no multiple pregnancies as compare to DET (double embryo) at cleavage stage where pregnancy outcome is significantly lower with 27.5% twin incidence.

Single embryo transfer though very rare can result in twin pregnancy.
Since the cause is not exactly known it needs further studies and research .The impact of embryo manipulation techniques on pregnancy rate clearly outweighs the rare risk of twins in SET if any.

Couple undergoing IVF treatment opting for single embryo transfer should know that there is still a rare chance of twin pregnancy specially those who are at more risk of maternal complications due to multiple pregnancy.
However this should never be criteria of decision making of single or double embryo transfer ,according to CDC ,the incidence of low birth weight and prematurity is 9% and 14 % with singleton pregnancy whereas it is 55% and 60-65 % respectively with twin pregnancy.

The only effective way of reducing risk of multiple pregnancy is single blastocyst embryo transfer while maintaining high implantation and pregnancy rate and to achieve the goal of healthy singleton pregnancy.

You may also link with us on Facebook, Instagram, Twitter, Linkedin, Youtube & Pinterest

Talk to the best team of fertility experts in the country today for all your pregnancy and fertility-related queries.

Call now 18003092323

(Visited 511 times, 5 visits today)
Inline Feedbacks
View all comments



PCOS Awareness Month – Everything You Need to Know about PCOS and its Prevention

Polycystic ovary syndrome (PCOS or...
Read More

A Complete IVF Guide: All You Need to Know About IVF

1. When to consult for...
Read More

Is Covid-19 Vaccination dangerous for pregnant women? Know the Benefits and Risks

What do we know today...
Read More

The Impact of Covid-19 on Pregnant Women & their Babies

Pregnant women and those in...
Read More

IVF Treatment in Covid-19 Age: Yes or No?

IVF in Pandemic: Safety Measures...
Read More

Pregnancy in COVID-19: What are the Risks?

Is the infection more dangerous...
Read More

Diet Plan for Lactating Mothers: What to eat while breastfeeding?

You know breast milk is...
Read More

आईवीएफ में जुड़वा बच्चेः आईवीएफ गर्भावस्था और एकाधिक प्रेगनेंसी

सामान्य जुड़वा बच्चे बनाम आईवीएफ...
Read More

Right Time For IVF: Indications and Contraindications

The IVF procedure can be...
Read More
Female Infertility Hindi

बच्चेदानी में सूजन: लक्षण, कारण, निदान, एवं उपचार

एंडोमेट्रैटिस (Endometritis) अथवा बच्चेदानी में...
Read More
Hindi IVF

आईवीएफ के लिए ऋण: एक अवलोकन

संतान की चाह रखने वाले...
Read More
Hindi IVF

कैसे करें एक सही आईवीएफ सेंटर का चयन?

आईवीएफ एक सुप्रसिद्ध सहायक प्रजनन...
Read More

जानिए आप प्रेगनेंट हैं या नहीं

प्रेगनेंसी के 10 प्रमुख लक्षण...
Read More
Female Infertility

7 things You Must Discuss with Gynaecologist

With female friends or people...
Read More

உங்கள் பிறக்காத குழந்தையைப் புரிந்துகொள்வோம்: கருவில் குழந்தை எப்படி வளர்கிறது!

கீழ்காணுமாறு ஒவ்வொரு வாரமும் கரு வளர்ச்சியடைவதை...
Read More

ನಿಮಗೆ ಹುಟ್ಟಲಿರುವ ಮಗುವನ್ನು ಅರ್ಥಮಾಡಿಕೊಳ್ಳುವುದು: ಗರ್ಭದಲ್ಲಿ ಮಗು ಹೇಗೆ ಬೆಳೆಯುತ್ತದೆ!

ವಾರದಿಂದ ವಾರಕ್ಕೆ ಭ್ರೂಣ ಅಭಿವೃದ್ಧಿಯಬಗ್ಗೆ ಎಲ್ಲವನ್ನೂ...
Read More

ಪಿಸಿಒಡಿ – ಕಾರಣಗಳು, ಲಕ್ಷಣಗಳು ಮತ್ತು ಚಿಕಿತ್ಸೆ

ಪಾಲಿಸಿಸ್ಟಿಕ್ ಅಂಡಾಶಯದ ಕಾಯಿಲೆ (ಪಿಸಿಒಡಿ)ಯು ಮಹಿಳೆಯರಲ್ಲಿ...
Read More

ಅಂಡಾಶಯದ ಸಿಸ್ಟ್ (ಅಂಡಾಶಯದಲ್ಲಿ ಗಡ್ಡೆ): ಲಕ್ಷಣಗಳು, ಕಾರಣಗಳು ಮತ್ತು ಚಿಕಿತ್ಸೆ

ಅಂಡಾಶಯದ ಸಿಸ್ಟ್ (ಅಂಡಾಶಯದ ಸಿಸ್ಟ್‌ಗಳು) ಸಾಮಾನ್ಯವಾಗಿ...
Read More

ಗರ್ಭಪಾತದ ಲಕ್ಷಣಗಳು, ಕಾರಣಗಳು ಮತ್ತು ರೋಗನಿರ್ಣಯವನ್ನು ತಿಳಿಯಿರಿ

ಗರ್ಭಪಾತವಾಗುವುದು ಅಪರೂಪದ ವಿದ್ಯಮಾನವಲ್ಲ. ಇದು 15...
Read More
Hindi PCOD

भ्रूण स्थानांतरण के बाद आहार

इन विट्रो फर्टिलाइजेशन (IVF) एक...
Read More
Request Call Back
IVF telephone
Book An Appointment