"For years research has shown that babies born by cesarean section are more likely to develop health problems. Now a groundbreaking study suggests that not all Csections are equally risky. The research looked at all fullterm firstborn births in Scotland over a year period and tracked the babies longterm health. It is one of the largest and longest studies to explore how planned Csections differ from other deliveries. Surprisingly the data showed more health problems among babies born by planned Csection than among those delivered by emergency Csection or vaginal birth even though the planned surgery is done under more controlled conditions. The finding suggests that the arduous experience of labor  that exhausting sweaty utterly unpredictable yet often strangely exhilarating process  may give children a healthy start even when its interrupted by a surgical birth. The new findings published in JAMA this month https are important because the number of babies born by Csection has increased tremendously. In the United States nearly one in three https babies are born by Csection. Cesarean births that had no medical indication increased to . percent of lowrisk women in  up from . percent of such women in  https Dr. Mairead Black the University of Aberdeen obstetrician who led the study said that as cesarean births had increased in Scotland and worldwide the researchers wondered what if anything children born by Csection are missing out on. Our thinking was If a baby is born naturally it comes into contact with bacteria from the mother which might help with immune system development Dr. Black said. Even attempted labor may provide some exposure to bacteria she said. But babies delivered by a planned Csection which is usually scheduled to take place well before the first pang of labor may miss out entirely. When you dont wait for labor to begin on its own you cut short all kinds of physiological changes and preparations for birth that are taking place toward the end of pregnancy said Carol Sakala the director of the nonprofit Childbirth Connection https programs at the National Partnership for Women  Families. What is the effect of cutting off those processes so casually on such a large scale Studies have consistently found that children born by Csection are at higher risk for health problems like obesity  httpsjournals.plos.orgplosonearticleid.journal.pone.and allergies https Csection birth has also been associated with a higher risk for Type  httpslink.springer.comarticle.Fsz diabetes. The Scottish study took advantage of the small countrys rich trove of linked birth and medical databases to track the longterm health of  babies. Nearly  percent were born by planned Csection and  percent were delivered by emergency surgery. The remaining  were vaginal births. The researchers compared a range of health outcomes among the babies including asthma irritable bowel syndrome obesity Type  diabetes early death and cancer. Over all the differences between a scheduled Csection and an emergency Csection were slight. However the data do begin to shed light on why babies born through vaginal birth may have fewer health risks than babies born by Csection. The biggest difference between babies born by scheduled and unscheduled Csection appeared in risk for Type  diabetes. The results showed that babies born by planned Csection had a  percent higher risk of Type  diabetes compared with babies born by emergency Csection after adjusting for differences among the mothers. All of the babies born by Csection were slightly more likely to use an asthma inhaler at age  . percent of planned Csection babies and . percent of unscheduled Csection babies wound up using an inhaler compared with . percent of vaginally born babies. Asthma hospitalization rates were also higher for babies born by planned Csection with a statistically significant increase of  percent over vaginally born babies. Although all of the Csection babies were more likely to be obese at age  the differences were not statistically significant after adjusting for differences among the mothers. There were no significant differences in cancer and irritable bowel disease among any of the types of births. No one knows exactly why labor may be protective but the spontaneous onset of labor prompts fluid to clear from a babys lungs said Dr. Aaron Caughey who helped draw up  guidelines https for the American College of Obstetricians and Gynecologists that urged providers to let women spend more time in labor and avoid an unnecessary Csection. The step is just one of a cascade of physiological changes that take place in mother and baby during the labor process including surges in stress hormones and reproductive hormones like oxytocin that may help the fetus adapt during labor preserve blood flow to the organs and keep the baby alert and prepared for breastfeeding. During labor a newborn absorbs maternal microbes into its mouth and gastrointestinal tract said Dr. Josef Neu a neonatologist at the University of Florida who has written about Csection babies and the hygiene hypothesis. The theory is that maternal microbes train the infants immune system so it doesnt overreact or become destructive and precipitate autoimmune disorders like Type  diabetes. Its an education process that says Calm down youre going to be seeing this antigen again you dont have to be so aggressive Dr. Neu said. Dr. Neu said the broadspectrum antibiotics prescribed to the mother before a surgical delivery were another concern the antibiotics can be transmitted to the baby through breast milk if not before birth decreasing the diversity of natural bacteria. The findings are a reminder that although Csections are appropriate in some circumstances they are a poor substitute for labor. Childbirth and labor are a physiological process that weve evolved to over millions of years Dr. Caughey said. Its been really welldesigned by evolution."