Artificial sweeteners can be hard to avoid for those of us who shun them. They're in everything now, which is so crazy considering that they were developed originally for diabetics. You know, those diabetic candies that taste strange.
Many people want to eat foods with artificial sweeteners so that they don't have to cut back on how much they eat. That's not a really good plan. Your body has to do something with what you eat, including sweeteners, and what it does may not be that helpful for you. Or for conceiving.
Saccharin was the first one out back in the 1960s, although it was discovered much earlier than that. It's still around as "Sweet'N Low." At one time, it was thought to cause bladder cancer in rats, but that warning has been removed because human studies have not shown that same risk. However, it does cross the placenta, so that's probably not one to eat while trying to conceive.
Aspartame (Nutrasweet, Aminosweet) has been linked with mental retardation due to the phenylalanine in it that crosses the placenta. There are also some disturbing links between lupus and multiple sclerosis and aspartame consumption, like heavy diet soda drinkers. Not a good option.
Splenda, which is sucralose, is not better. I would hope that FDA would be on the side of protecting the public, but in regards to artificial sweeteners, it seems to have lost all sense. Splenda is "made," so to speak, from sugar, but what they did is modify the structure of sugar to add chlorine. The scary fact is that the addition of chlorine makes it more like pesticides than sugar.
Some studies in rats fed sucralose showed that the rats developed kidney disorders and other problems. People who like sucralose say that rats aren't people so this doesn't matter. The fact is that rats metabolize sucralose exactly like humans do, so they are an excellent model for what happens.
Think, too, about a lifetime of exposure to these products. It adds up, and we don't fully know what happens in 20 years or longer.
Safe sweeteners are stevia, lo han, and xylitol which come from plants. You can find stevia sold as Truvia (but that supposedly contains MSG, so look for plain stevia). Xylitol is my personal favorite because it has no aftertaste and it measures the same as sugar so it's easy to substitute in baking.
This brings me to my key point: "natural" on a label means nothing legally. Be careful what you're eating when you're trying to conceive because you might actually be pregnant. I wish we had full information about the effects in pregnancy or on your fertility, but the manufacturers don't want to do those studies, probably because the animal studies showed disturbing results. Don't take any chances--eat real foods and safe sweeteners when you're hoping for a baby.