Daniel Allan via Getty Images The threat of Zika virus is changing some family planning decisions.

Like many women, Claire, 31, is not totally certain when she wants to start trying for another baby. She has a 6-year-old from a previous marriage, and a 5-month-old with her current husband. They would like at least a two year gap between their youngest and another baby, so they're not pulling double diaper duty.

But at the same time, Claire has begun questioning whether she should move up her timeline due to Zika, the disease that can lead to birth defects like microcephaly -- and that might soon be more of an issue in the United States.

"We're not totally sure how we want to deal with it yet, since Zika isn't fully understood," said Claire, who currently lives in Indiana but is planning on a move to the South. "We tentatively talked about moving the conception of another child up, before things really take off with the virus this summer, but we're not really in a position to have another child right now."

The Centers for Disease Control and Prevention is currently monitoring nearly 300 pregnant women in the United States and its territories who have tested positive for Zika. To date, there has not been a single case of the virus that has been contracted in this country (that is not true of Puerto Rico), but many experts believe it's only a matter of time before there are pockets of the disease that originate here. All of which means that many women and their partners have begun to grapple with the possibility of Zika, and whether it means they should change their plans for pregnancy in any way.

"My husband and I have always wanted to have children who are two to three years apart," said Samantha*, 30, from Texas. The couple's first child, a girl, is 14 months old, so this is right around when they hoped to start trying. Zika, however, has given her pause.

"I'm definitely concerned," said Samantha. "I'm not scared, but I'm also not feeling super gung-ho, like, 'Yes, of course we're going to start trying regardless of the risks.'"

Though her husband says he isn't worried at all, Samantha has thought about postponing trying for a year or two, at least until scientists understand more about the disease and how much of an issue it will ultimately become in the United States.

Things are potentially even more difficult for families who have been trying, unsuccessfully, to get pregnant for months or years, and who feel they simply cannot wait, no matter the potential risk. Lauren, 36, has a 6-year-old and has been trying for two years to have a second child. She has had two miscarriages and she and her husband have gone to a reproductive endocrinologist, though they are not currently undergoing fertility treatment.

"I thought about [putting things on hold]," she said. "My sister and sister-in-law are both medical professionals, and they both want to have another baby. One of them is moving forward and trying for another one, and one is not."

"If I were younger, I would probably hold off on having a baby," Lauren added. "I would also hold off if they were close to coming out with a vaccine. My main reason for moving forward is that I don't feel like I have the luxury of time at my age."

A major challenge faced by women and couples grappling with such issues is that it's not entirely clear to experts how much of an issue Zika might be in the United States (a large outbreak seems highly unlikely), or how long men and women should wait before trying to conceive if they've been exposed to the virus. The American Society for Reproductive Medicine says that women who have symptoms of Zika should wait for eight weeks before attempting reproduction. For men, it's six months. Anyone possibly exposed to the virus, but not showing symptoms, should also wait eight weeks. But as Ali Watkins, a Buzzfeed correspondent, detailed in her first-person account of being infected the virus in Mexico, the fact that experts are still scrambling to understand Zika means that advice can be contradictory.

"My doctor told me if I do indeed test positive for Zika, I shouldn’t get pregnant for three years," she wrote. "The CDC, meanwhile, said I would have to wait only eight weeks. How long did the disease stay in my system? Not sure, and scientists don’t even know yet."

The good news for men and women in the United States is that while there are certainly no guarantees, not one medical group has said it's necessary for potential parents-to-be who haven't been exposed to the virus elsewhere or by a sexual partner to hold off on trying to conceive. That's very different than the situation in countries that have been hit hard by the virus and where health officials are desperately torn about what to tell women, in many cases urging them simply to wait.

"Basically, the situation is that at this point there’s very little risk right now of being affected by a mosquito," said Dr. James Segars, chair of the ASRM’s Zika working group.

"In the U.S., the risk for mosquito-borne illness is relatively small, if not negligible, as long as [a person is] working primarily inside and uses precautions," he added.

That is Samantha's game plan. Though she thought, momentarily, about putting her pregnancy plans on hold, a large age gap between children is simply not what she had envisioned for her family, so she has gone off the pill.

Claire is going a different route. She and her husband aren't actively trying at the moment, and they may not necessarily start before they move down South. In that case, given the higher temperatures and humidity that make that area a fertile ground for mosquitoes, she says it feels right for them to wait.

"At this point, we feel that if we don't have another child up here in Indiana, then we should just wait until a vaccine is developed for Zika," she said.

Like most things when it comes to family planning decisions, it's complicated.