In these circumstances, the only safe options are condoms or abstinence. Halachically, abstinence is preferable, as condom use is generally prohibited by Jewish law as a violation of hotza'at zera levatalah (spilling seed). The laws of hotza'at zera levatalah apply even when a woman is pregnant.
When abstinence is too much of a strain on the couple, the wife may use a female condom to protect herself from possible exposure to Zika during pregnancy.
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