Spacing Babies: What's the Ideal Interval Between Pregnancies?

"With children that are closely spaced, there is a tendency to parent them together, to push the older one to grow up a little faster, to become more independent because [he or she is] looking after the younger one," says Dr. Milowic. While her own children are close and share a lot in common, she does see some rivalry. But, she adds, "I think they learn the art of negotiation, they learn how to share, and they learn early on how to deal with other people."

Dr. Derzko and Pat also noticed sibling rivalry between their closely-spaced children during childhood. Now that their kids are older and some have children of their own, both mothers observe that their kids have become quite close.

With even greater spacing, from four to ten years, there may be a tendency for older children to tire of being the big helpers and permanent babysitters, and become frustrated with toddlers who continually mess up their personal possessions.

When she was growing up, Dr. Derzko felt the five-year difference between her and her younger sister was too much. In her own children though, "the younger ones almost 'hero worship' the two older ones, and the older two certainly are both fond and full of respect for the accomplishments of their younger siblings."

For John, Pat's youngest child, the spacing also worked out well. "By the time he was 10, Christine [the second child] was leaving for college," she says. "Between the years of 10 to 17 he had us completely to himself."

Can You Handle It?

When deciding how to space pregnancies, it mostly comes down to the overall physical stamina of a mom. Only a mother knows her body well enough to determine whether she can care for two young children at the same time. What the parents want and what a mother can bear, rather than the age difference between children, is most important. (Check out our quiz, Are You Ready for Another Baby?)

Having two children too close together is like having twins," says Pat. Having a third several years later, "gave me, as a mother, a chance to breathe."

In the end, of course, "You can plan all you want, but people don't necessarily get pregnant when they want to," says Dr. Milowic. "Keep an open mind."

*Some names have been changed.