1999: One embryo, by choice
The Modern Laboratory · The Modern Papers
The Modern Papers · MP·11 · 1999
1999: One embryo, by choice
In Helsinki, transferring one good embryo gave almost the same pregnancy rate as two, without the twins.
The story
Sirpa Vilska, Aila Tiitinen, Christel Hydén-Granskog and Outi Hovatta looked at every fresh IVF cycle in two Helsinki clinics during 1997. Where couples had at least two embryos but chose to transfer one, 29.7 per cent of transfers led to a pregnancy. With two embryos the rate was 29.4 per cent, but almost a quarter of those pregnancies were twins.
Counting the frozen embryos transferred later, nearly half the couples who chose one embryo became pregnant from a single egg collection.
The team recommended one embryo for women of 35 or under with good quality embryos. Within a few years Belgium and Sweden had turned the idea into national practice.
“elective one-embryo transfer can be highly recommended”From the paper's abstract
The paper
Elective Transfer of One Embryo Results in an Acceptable Pregnancy Rate and Eliminates the Risk of Multiple Birth
Sirpa Vilska, Aila Tiitinen, Christel Hydén-Granskog, Outi Hovatta
Human Reproduction 1999;14(9):2392 to 2395. September 1999. Read the paper.
Find it in the museum
Room 7, One at a time, Sirpa Vilska, Aila Tiitinen, Christel Hydén-Granskog, Outi Hovatta
How we know
Citation and abstract read in PubMed (PMID 10469718) on 14 October 2026.
The IVF Museum · The Modern Papers
Compiled with AI-assisted research and checked against the original sources. Undergoing peer review. Corrections are warmly welcomed.
