Sex warning for IVF couples

Extra eggs were released and fertilised

Doctors have been asked to warn some couples having IVF not to have sex during treatment after a woman got pregnant "twice".

The couple involved - who had been unable to conceive, despite appearing to be physically normal, were being treated in California.

It is thought that not only did the IVF work, but the woman managed to conceive naturally at the same time.

The woman ended up carrying quads - despite only having two embryos transferred back into her womb by doctors.

The freakish outcome was the result of having sex five days prior to the retrieval of eggs for IVF.

Both IVF embryos implanted successfully in the womb lining - and the embryo resulting from the natural pregnancy split in two to make identical twins.

It may be prudent to caution IVF patients with no tubal or semen abnormalities against unprotected intercourse once the early days of ovarian hyperstimulation are over

Dr Amin Milki

Genetic tests on the identical twin's placenta revealed that splitting had taken place before implantation in the womb wall.

Dr Amin Milki, of the Department of Gynaecology and Obstetrics at Stanford University, said: "It is just possible that the identical twins could have resulted from one of the embryos splitting.

"But even if that were true at least one foetus would have been conceived spontaneously. That is incontestable based on the genetic testing."

He said that the risks involved with multiple pregnancy meant that couples should be taking care to avoid even a tiny risk, especially if tests have shown no apparent problems with either semen quality or the woman's fallopian tubes.

If a woman is on this particular regime, we do advise her to avoid unprotected sex during a cycle

Dr Simon Fishel, Care Clinic, Nottingham

Dr Milki said: "It may be prudent to caution IVF patients with no tubal or semen abnormalities against unprotected intercourse once the early days of ovarian hyperstimulation are over."

However, a UK fertility expert said he already advised couples undergoing IVF to abstain from unprotected sex during some of the days of a treatment cycle.

Dr Simon Fishel, director of the Care fertility centre in Nottingham, told BBC News Online: "There is a particular drug given to women at the beginning of the cycle so that doctors can control their ovaries.

"This drug, when it is first given, can stimulate the ovaries, and this may be what has happened here."

He added: "If a woman is on this particular regime, we do advise her to avoid unprotected sex during a cycle."

Having quadruplets increases the risk to both mother and babies, and in this case all four were delivered at 32 weeks.

The case was outlined in the journal Human Reproduction.