(Image source from: More Children Is Most Stressful For Mom)

Third time seems to be the charm when it comes to raising Mom's stress levels. According to a recent survey of American mothers, three is the most stressful number of children for a woman to have.

The survey, released yesterday, found that mothers of three report experiencing more stress than moms of one or two children. Perhaps that isn't surprising, but stress levels also seemed to drop off as number of children increased, with mothers of four or more children reporting lower stress levels than those moms of three.

The survey polled over 7,000 mothers across the country, and had them rate their stress levels on a scale of 1 to 10, with 10 being the most stressed. The average stress level for mothers across the board was 8.5. Their biggest cause of stress? Sixty percent of moms say it's not having enough time to get everything done, and it seems that mothers of three are particularly affected by this pressure.

“Going from one to two was an easy, breezy transition,” author and "Scary Mommy" blogger Jill Smokler (and the leader of the newest HuffPost Stress-Less Parenting workshop), told TODAYMoms. “Two to three, everything was turned upside down. I do not feel like I have it together. You only have two hands! Just crossing the street and not being able to physically hold all their hands I find tremendously stressful.”

Blogger Steve Wiens, a father of three boys under the age of five, echoes this sentiment in a recent HuffPost Parents blog post, "To Parents of Small Children: Let Me Be The One Who Says It Out Loud," urging parents not to let the pressure to "enjoy every moment" during their children's early years add even more stress to their lives.

"There are many moments where they are utterly delightful," Wiens writes. "But there are also many moments when I have no idea how I'm going to make it until their bedtime. The constant demands, the needs and the fighting are fingernails across the chalkboard every single day."

And parents' stress can in turn have significant effects of kids. Researchers have found that negative experiences caused by parental anxiety can cause gene changes in children that persist into their teenage years, and author David Code even alleges that all the ailments of contemporary children are connected to the stress levels of their parents.