A South American study suggested that women who waited too long [to conceive a subsequent baby] had a greater likelihood of having an adverse maternal outcome, such as preeclampsia or eclampsia," says Dr. Christine M. Derzko, MD, associate professor OB-GYN and Internal Medicine at University of Toronto and head of the division of Reproductive Endocrinology and Infertility at St. Michael's Hospital in Toronto. Preeclampsia results in swelling, elevated blood pressure, and protein in the urine during pregnancy. With eclampsia, seizures occur during the third trimester.
Greater spacing between pregnancies decreases the benefits gained from a previous pregnancy, such as an already enlarged uterus and increased blood flow to the womb. With shorter spacing, however, a new mother may not have time to recover from vitamin depletion, blood loss, reproductive-system damage or other postpartum problems. A short post-cesarean section interval can result in uterine rupture, says Dr. Derzko. And, in either type of delivery, it may be harder for a woman to return to her normal weight.
A woman's body sometimes provides a "natural spacing" between pregnancies as nursing can suppress ovulation, says Dr. Milowic; however, this system is certainly not foolproof, she adds, and is dependent on how much and how often a mother breastfeeds.
Family needs may also impact spacing. When determining the timing of a subsequent pregnancy, many parents consider factors such as finances, employment, and age. Dr. Derzko, the mother of four (ages 31, 30, 23 and 21), spaced her pregnancies around work. "The first two were prior to starting residency in OB-GYN; the second two were when I was finished."
Similarly, Dr. Milowic, the mother of three kids (ages seven, five and four), says she and her husband made a conscious decision to have their children close together since they had married older and already had careers. Milowic had her children before returning to residency. "It was very rough to have three kids in diapers. The first six months are literally a blur," she says.
While some parents want to get the diaper phase and nighttime wakings out of the way, others want to avoid having two kids in college at the same time. Some parents also prefer to wait until the older child is a bit more independent, is able to understand, and even wants another child in the home, as Ilona's son does. "Max has a real sense of himself as both our child and as an individual, which I think will help to reduce any fears he may have of losing any of our affection," she says. "By the time the baby comes [Max will] be old enough to help us a bit with taking care of him or her, which should be a source of pride and accomplishment for him."
Pat, a book editor in New York and mother of three (ages 40, 38 and 32), believed her two oldest would be playmates and the best of friends growing up. Instead, she says, having her babies so close together "was very hard on the oldest child because she didn't have enough time to be the center of attention."