New Delhi: Modern in vitro fertilisation (IVF) techniques can significantly reduce the chances of twin and triplet pregnancies without compromising the success of treatment, according to a large Australian study. Researchers found that advances such as blastocyst culture, vitrification and single embryo transfer have made IVF safer while maintaining high pregnancy success rates.
The findings are based on an analysis of 18,396 women who underwent their first IVF treatment at seven fertility clinics in Australia between 2012 and 2021.
High success with fewer multiple pregnancies
The study found that nearly 68 per cent of women had a successful birth within three IVF cycles.
Researchers also reported that only 2.9 per cent of pregnancies resulted in twins or triplets, a significant reduction compared with earlier years of IVF treatment.
Around 95 per cent of IVF procedures involved the transfer of a single embryo, demonstrating that high pregnancy success can be achieved without routinely transferring multiple embryos.
According to the researchers, selecting one healthy embryo for transfer helps minimise the health risks associated with multiple pregnancies while maintaining favourable birth outcomes.
Why twins were more common in earlier IVF treatments
In the early years of IVF, pregnancy success rates were lower than they are today.
To improve the chances of implantation, fertility specialists often transferred two or three embryos during a single treatment cycle.
While this increased the likelihood of pregnancy, it also led to a higher incidence of twin and triplet pregnancies.
Medical experts note that multiple pregnancies carry greater risks for both mothers and babies, including premature delivery, pregnancy-induced hypertension, gestational diabetes, caesarean delivery and low birth weight. Babies from multiple pregnancies are also more likely to require neonatal intensive care.
Advances improve embryo selection
One of the key techniques highlighted in the study is blastocyst culture, in which embryos are allowed to develop in the laboratory for five to six days before transfer.
At the blastocyst stage, specialists can more accurately identify embryos with the highest likelihood of successful implantation.
This enables doctors to confidently transfer a single embryo rather than multiple embryos without reducing the chances of pregnancy.
Vitrification preserves embryos for future use
The study also highlighted the role of vitrification, a rapid embryo-freezing technique that prevents ice crystal formation and helps preserve embryo quality.
Unlike older freezing methods, vitrification improves embryo survival after thawing, allowing healthy embryos to be safely stored for future IVF cycles.
This reduces the need to transfer multiple embryos during the first attempt, as additional embryos remain available if another treatment cycle becomes necessary.
Single embryo transfer becoming standard practice
Researchers said the combination of blastocyst culture and vitrification has made single embryo transfer the preferred approach in many fertility centres worldwide.
Instead of transferring two embryos to improve pregnancy chances, specialists now select the healthiest embryo and preserve the remaining embryos for future use.
The strategy aims to achieve one healthy pregnancy at a time while reducing avoidable complications linked to twin and triplet pregnancies.
Techniques already available in India
Commenting on the findings, Dr Sneha Mishra, Consultant in the IVF and Infertility Department at Yashoda Medicity Hospital, Ghaziabad, said these techniques are already widely available in India.
She noted that blastocyst culture and vitrification support single embryo transfer and help lower the risk of twin pregnancies without reducing the chances of conception.
Dr Mishra added that treatment decisions should be individualised, taking into account the couple’s age, fertility history, medical condition and family planning goals.
Experts emphasise that transferring more embryos does not necessarily improve the likelihood of a successful pregnancy and that treatment decisions should always be guided by medical advice.