The Human Fertilisation and Embryology Authority (HFEA) is recommending that people returning from Zika-virus prone areas should not try to conceive naturally, donate eggs or sperm, or proceed with fertility treatment for 28 days.
The advice follows guidance issued by Public Health England, which notes that while Zika is almost always transmitted by mosquitoes, there is some evidence that it can be sexually transmitted.
The HFEA statement said: 'There is evidence that the Zika virus can be found in semen and that it may persist in semen after the acute infection has resolved. The Zika virus is [also] likely to survive the freeze and thaw of donated gametes.
'Whilst the situation is still evolving, and given the potentially significant consequences for a pregnancy if Zika is transmitted via the sperm, donors should be asked about recent travel.'
In the US, the Food and Drug Administration has issued guidance to blood banks not to accept donors who have travelled to Zika-prone areas for 28 days – the length of time it takes to clear from the blood. It is expected to issue similar advice to sperm banks very soon. In the meantime, US fertility clinics are issuing their own precautions.
The Seattle Sperm Bank has turned away a male sperm donor who had recently visited family in South America. Pacific Northwest Fertility has issued new rules for egg donors.
'We basically provide donors with a list of what at this point is considered a Zika virus zone,' Dr Lorna Marshall, a reproductive endocrinologist with the centre, told the Seattle Times. 'They must sign a consent saying they haven't travelled to or had sex with someone from those areas for 12 months.'
There is no commercial test yet for Zika virus, though companies are racing to develop one.
Public Health England also advises that, if a man has shown clinical signs of Zika virus infection or had the infection confirmed by a laboratory, he should use a condom during sex for six months.
The Zika virus outbreak in Central and South America has been linked to nearly 5000 babies being born with microcephaly, a birth defect that results in a very small head and brain damage.
Although there is no confirmed connection with the virus, it has been found in the saliva and urine of mothers and newborn babies. A new report in the The Lancet: Infectious Diseases has used metagenomic analysis to detect the virus in the amniotic fluid of two women who went on to have babies with microcephaly.
'This study reports details of the Zika virus being identified directly in the amniotic fluid of a woman during her pregnancy, suggesting that the virus could cross the placental barrier and potentially infect the fetus,' said report author Dr Ana de Filippis of the Oswaldo Cruz Institute in Rio de Janeiro, Brazil.