September 5, 2006, New York Times
Voluntary C-Sections Result in More Baby Deaths
By NICHOLAS BAKALAR
A recent study of nearly six million births has found that the risk of death to newborns delivered by voluntary Caesarean section is much higher than previously believed.
Researchers have found that the neonatal mortality rate for Caesarean delivery among low-risk women is 1.77 deaths per 1,000 live births, while the rate for vaginal delivery is 0.62 deaths per 1,000. Their findings were published in this month's issue of Birth: Issues in Perinatal Care.
The percentage of Caesarean births in the United States increased to 29.1 percent in 2004 from 20.7 percent in 1996, according to background information in the report.
Mortality in Caesarean deliveries has consistently been about 1½ times
that of vaginal delivery, but it had been assumed that the difference
was due to the higher risk profile of mothers who undergo the operation.
This study, according to the authors, is the first to examine the risk of Caesarean delivery among low-risk mothers who have no known medical reason for the operation.
Congenital malformations were the leading cause of neonatal death regardless of the type of delivery. But the risk in first Caesarean deliveries persisted even when deaths from congenital malformation were excluded from the calculation.
Intrauterine hypoxia -- lack of oxygen -- can be both a reason for performing a Caesarean section and a cause of death, but even eliminating those deaths left a neonatal mortality rate for Caesarean deliveries in the cases studied at more than twice that for vaginal births.
"Neonatal deaths are rare for low-risk women -- on the order of about one death per 1,000 live births -- but even after we adjusted for socioeconomic and medical risk factors, the difference persisted," said Marian F. MacDorman, a statistician with the Centers for Disease Control and Prevention and the lead author of the study.
"This is nothing to get people really alarmed, but it is of concern given that we're seeing a rapid increase in Caesarean births to women with no risks," Dr. MacDorman said.
Part of the reason for the increased mortality may be that labor, unpleasant as it sometimes is for the mother, is beneficial to the baby in releasing hormones that promote healthy lung function. The physical compression of the baby during labor is also useful in removing fluid from the lungs and helping the baby prepare to breathe air.
The researchers suggest that other risks of Caesarean delivery, like possible cuts to the baby during the operation or delayed establishment of breast-feeding, may also contribute to the increased death rate.
The study included 5,762,037 live births and 11,897 infant deaths in the United States from 1998 through 2001, a sample large enough to draw statistically significant conclusions even though neonatal death is a rare event.
There were 311,927 Caesarean deliveries among low-risk women in the analysis.
The authors acknowledge that the study has certain limitations, including concerns about the accuracy of medical information reported on birth certificates.
That data is highly reliable for information like method of delivery and birth weight, but may underreport individual medical risk factors.
It is possible, though unlikely, that the Caesarean birth group was inherently at higher risk, the authors said.
Dr. Michael H. Malloy, a co-author of the article and a professor of pediatrics at the University of Texas Medical Branch at Galveston, said that doctors might want to consider these findings in advising their patients.
"Despite attempts to control for a number of factors that might have accounted for a greater risk in mortality associated with C-sections, we continued to observe enough risk to prompt concern," he said.
"When obstetricians review this information, perhaps it will promote greater discussion within the obstetrical community about the pros and cons of offering C-sections for convenience and promote more research into understanding why this increased risk persists."
Original source: Voluntary C-Sections Result in More Baby Deaths
Abstract of the article:
Volume 33 Page 175 - September 2006
Volume 33 Issue 3
Infant and Neonatal Mortality for Primary Cesarean and Vaginal Births to Women with "No Indicated Risk," United States, 1998–2001 Birth Cohorts
Marian F. MacDorman, PhD1, Eugene Declercq, PhD2, Fay Menacker, DrPH, CPNP1, and Michael H. Malloy, MD, MS3
Background: The percentage of United States' births delivered by cesarean section has increased rapidly in recent years, even for women considered to be at low risk for a cesarean section. The purpose of this paper is to examine infant and neonatal mortality risks associated with primary cesarean section compared with vaginal delivery for singleton full-term (37–41 weeks' gestation) women with no indicated medical risks or complications.
Methods: National linked birth and infant death data for the 1998–2001 birth cohorts (5,762,037 live births and 11,897 infant deaths) were analyzed to assess the risk of infant and neonatal mortality for women with no indicated risk by method of delivery and cause of death. Multivariable logistic regression was used to model neonatal survival probabilities as a function of delivery method, and sociodemographic and medical risk factors.
Results: Neonatal mortality rates were higher among infants delivered by cesarean section (1.77 per 1,000 live births) than for those delivered vaginally (0.62). The magnitude of this difference was reduced only moderately on statistical adjustment for demographic and medical factors, and when deaths due to congenital malformations and events with Apgar scores less than 4 were excluded. The cesarean/vaginal mortality differential was widespread, and not confined to a few causes of death.
Conclusions: Understanding the causes of these differentials is important, given the rapid growth in the number of primary cesareans without a reported medical indication.
(BIRTH 33:3 September 2006)
Immune system and 'friendly' bacteria
From News @ nature.com
April 28, 2006
Natural birth teaches newborn gut a lesson
Babies born by caesarean may miss immune system trigger.
by Helen Pearson
A messy birth could be good for the baby's digestion. So say researchers in Germany, who have found evidence that baby mice squeezing through the birth canal swallow bacterial molecules that help their gut grow healthily. The finding suggests that kids born by caesarean might miss out.
Swarms of friendly bacteria normally live in our guts, and cells lining the intestinal tubes do not attack them. Mathias Hornef at the University Clinic of Freiburg, Germany, and his colleagues, have found that, in mice at least, these intestinal cells 'learn' not to harm the bugs sometime around birth.
The team extracted intestinal cells from mice embryos before birth and exposed them to a component of bacteria. The embryonic cells reacted and produced inflammatory molecules. But the same gut cells from one-day-old newborn mice or adult mice did not. Somehow, the cells in the more developed mice had learned to ignore the bacterial trigger.
The researchers think that bacterial scraps naturally slopping around in the birth canal and mother's faeces are swallowed by the baby mice as they make their entry into the world. These molecules pass down into the gut, where they stimulate the gut cells; a single exposure is enough to teach the cells to tolerate friendly bugs in the future.
To show this, Hornef's team looked at the responses of gut cells of baby mice born both naturally and by caesarean. Those born through the vagina fired up an inflammatory response in the two hours after birth, a sign that their cells had been stimulated by bacterial molecules. In contrast, babies born by caesarean did not show signs of such activation. But feeding these babies fragments of bacteria after their birth did fire up this response.
This first exposure could teach a newborn infant's gut cells to ignore the harmless bacteria that begin to colonize the intestine in the days and weeks after birth. Hornef's study, reported in the Journal of Experimental Medicine, suggests that the immune systems of babies born naturally have a head start.
In theory, this could mean that the intestines of babies born by caesarean are less welcoming to gut bacteria - perhaps with long-lasting effects for the babies' health. "It's a very interesting speculation," Hornef says.
One study in 2004, for example, showed that human babies born by caesarean seem to be more prone to diarrhoea during their first year of life than babies born naturally. The fact that caesarean babies aren't exposed to bacteria in the birth canal was proposed as a possible cause for this difference, but the idea wasn't tested.
It is possible that children born by caesarean encounter bacteria or other triggers that similarly activate their immune system very soon after birth, perhaps through breastfeeding. But the finding adds to an already vigorous debate about whether caesareans carry greater risks for a mother and baby than vaginal birth (see ' caesarean risks hard to pin down' ).
The results may also have implications for adults with intestinal problems, notes Bruce Vallance from the University of British Columbia in Vancouver, Canada. It will be interesting to examine whether people with inflammatory bowel disease lose the ability to ignore friendly bacteria later in life, he says. "Maybe their intestinal cells go back to this neonatal state."
2 Lotz M., et al. Journal of Experimental Medicine, 203. 973 - 984 (2006).
1 Laubereau B., et al. Arch. Dis. Child., 89. 993 - 997 (2004).
...In cases where normal vaginal delivery incurs considerable risk to the mother and fetus, elective caesarean section may be justified, but decisions must take into account the risk to the infant associated with delivery before 39 weeks' gestation.
It is now clear that respiratory distress syndrome is indeed seen in "term" infants and is a considerable source of morbidity and mortality in this group. A recent article by Madar et al shows that mechanical ventilation to treat presumed surfactant deficiency is 120 times more likely to be needed after elective delivery at 37-38 weeks than after delivery at 39-41 weeks.
We recently revisited this issue as part of a departmental audit...These findings are consistent with the findings of previous studies and confirm that babies delivered before 39 weeks' gestation are at increased risk of respiratory distress and that for term infants caesarean section before the onset of labour results in a considerably greater risk of neonatal respiratory morbidity than delivery by any other means. Moreover, the risk of respiratory morbidity is halved with each completed week of gestation between 37 and 41 weeks.
Evidence based guidelines should be established so that when there is no clear benefit to mother or fetus elective caesarean section before 39 weeks' gestation is avoided.
Milner AD, Saunders RA, Hopkin IE
Arch Dis Child 1978 Jul;53(7):545-8
Lung function tests were carried out in the first 6 hours of life on 26 babies born by vaginal delivery and 10 born by caesarean section. The babies born by caesarean section had a mean thoracic gas volume of only 19.7 ml/kg body weight compared with 32.7 ml/kg for the babies born vaginally. We conclude that this is owing to an excess of lung fluid in the babies born by caesarean section.
PMID: 686790, UI: 78255610
There is some interesting stuff on this in the proceedings of a conference on the rising rates of caesareans - held Nov 1999 - it can be ordered by calling 0141 636 0600
Very interesting - confirms what happened after my elective c/s for pre-eclampsia - the paediatrician came to tell me my poor mite was on an antibiotic for suspected pneumonia - but no, the X-ray showed "wet lung"! I had transferred (Due to pre-eclampsia) from the care of independent domiciliary midwife Ann Kelly, whose comment on the wet lung theory was "What do they expect him to have after being in the womb?!" - with no expulsive help of vaginal delivery to clear his lungs.
Home Birth Association of Ireland
WESTPORT, CT (Reuters Health) Mar 01 - The incidence of persistent pulmonary hypertension in newborns delivered by cesarean section is nearly five times higher than that observed among babies delivered vaginally, according to a database analysis of deliveries at the Illinois Masonic Medical Center, in Chicago.
Among 25,318 deliveries between 1992 and 1999, 4301 were cesareans, report Dr. Elliot M. Levine and associates in the March issue of Obstetrics & Gynecology. The incidence of persistent pulmonary hypertension was 4.0 per 1000 live cesarean births, compared with 0.8 per 1000 live vaginal births.
The authors suggest that labor and vaginal delivery, perhaps by physical compression in the birth canal, is advantageous for the pulmonary vascular bed of the neonate. They advise obstetricians to discuss the increased risk of pulmonary hypertension associated with cesarean section when offering a woman delivery options.
Obstet Gynecol 2001;97:439-442.
Abstract of the study mentioned above:
Obstet Gynecol 2001 Mar;97(3):439-42
Levine EM, Ghai V, Barton JJ, Strom CM.
Department of Obstetrics & Gynecology, Illinois Masonic Medical Center, Chicago, Illinois 60657, USA.
OBJECTIVE: To determine whether there is an increased incidence of persistent pulmonary hypertension in neonates delivered by cesarean, with or without labor, compared with those delivered vaginally.
METHODS: We did a computerized retrospective review of 29,669 consecutive deliveries over 7 years (1992-1999). The incidences of persistent pulmonary hypertension of the newborn, transient tachypnea of the newborn, and respiratory distress syndrome (RDS) were tabulated for each delivery mode. Cases of persistent pulmonary hypertension were reviewed individually to determine delivery method and whether labor had occurred. The three groups defined were all cesarean deliveries, all elective cesareans, and all vaginal deliveries.
RESULTS: Among 4301 cesareans done, 17 neonates had persistent pulmonary hypertension (four per 1000 live births). Among 1889 elective cesarean deliveries, seven neonates had persistent pulmonary hypertension (3.7 per 1000 live births). Among 21,017 vaginal deliveries, 17 neonates had persistent pulmonary hypertension (0.8 per 1000 live births). chi2 analysis showed an odds ratio 4.6 and P <.001 for comparison of elective cesarean and vaginal delivery for that outcome.
CONCLUSION: The incidence of persistent pulmonary hypertension of the newborn was approximately 0.37% among neonates delivered by elective cesarean, almost fivefold higher than those delivered vaginally. The findings have implications for informed consent before cesarean and increased surveillance of neonates after cesarean.
In brief: A study on rats by Boksa and El-Khodor (report of a meeting, I've only read the web page and haven't followed this up further):
"To our surprise we kept finding dopamine system differences." When the caesarean rats were given amphetamines, drugs that activate the dopamine system in the brain, they became far more active than the other group [no c/s] the caesarean rats also had a far worse response to repeated tail pinching, a standard test for stress reactions. "Boksa thinks the absence of hormonal surges [that occur] when a baby is born naturally may play a role, because these may be important for brain development"
The rest of this email comes from me not the New Scientist: I have a gut feeling that babies are 'meant' to be born naturally, that birth itself gives a message to the baby's brain/mind saying something like: "This is the worse stress you will ever come across, use this biochemical/emotional experience as a template to measure future life experiences and secrete stress hormones etc as necessary to affect behaviour to regain equilibrium."
In the case of the endorphins I call this 'setting the endogenous opiostat' but perhaps an ACTHstat and corticostat or adrenostat are also set at birth? This is just my way of trying to understand what might be going on. The only bit of evidence we have that an opiostat might be set at birth is the tendency of children whose mothers took opiates during labour to be more likely to become addicted to heroin.
If the mother is allowed to start labour, it gives the baby time to start priming its stress hormone system. There are so many hormonal messages going to and fro through the placenta from baby to mother and vice versa and we can't possibly know all the ramifications for the baby's future mental functioning, but we should certainly not ignore the messages and treat them as if they were of no account by bypassing labour for our own convenience. (Though when a mother's or baby's life is at immediate risk then of course we might have to.)
I think we need lots of long-term psychological follow up of babies born by elective c/s in the absence of labour, perhaps comparing them to babies born by emergency c/s. My own gut feeling is that even when a c/s is necessary and planned, it should be planned to take place once a mother has gone into labour naturally, the policy of elective section at 38 weeks gives me the shudders when we know so little about the mental effects. Anyway, Boksa and El-Khodor have taken steps in the right direction - even if it was a study in rats!
The article doesn't spell it out, but as far as I understand this refers to elective c/s with no experience of labour, and nto to c/s after some labour. Presumably if the baby has experienced some labour then it will already have had much of the 'hormonal surges' mentioned. And this research was done on rats, not people!!!
From New Scientist, 21 November 1998
Caesarian babies may be more susceptible to schizophrenia than children born naturally, say Canadian researchers who studied the effects of the operation on rats. The finding raises doubts about the increasing number of Caesarean sections performed for convenience.
The finding, announced at a Los Angeles meeting of the Society for Neuroscience, is expected to force doctors and parents to reconsider the increasing numbers of Caesarean sections performed for convenience.
Patricia Boksa and Bassem El-Khodor of McGill University in Montreal found that rats delivered by Caesarean section appeared normal at birth. However, in later life these rats had an overactive response to dopamine, a neuro-transmitter, and responded less well to repeated tail pinching, a standard test for stress reactions.
The findings indicate that Caesarean-born babies could be more vulnerable to schizophrenia, a disease which has been linked to birth complications and which is believed to involve an overactive dopamine system.
Dr Boksa suggests in New Scientist that the absence of hormonal surges which occur naturally when a baby is born conventionally may increase the risk of schizophrenia in Caesarean births. Dr Boksa said: "I would question the Caesarean section of convenience." She called for further investigation of the operation's effects.
Neuroreport 2000 Feb 28;11(3):639-43
Berger N, Vaillancourt C, Boksa P
Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Verdun, Quebec, Canada.
Genetic predisposition and environmental factors such as perinatal complications are believed to contribute to the etiology of schizophrenia, a disorder involving enhanced CNS dopaminergic activity. This study used a rat model to test whether genetic factors and a minor birth complication, i.e. Caesarean section (C-section) birth, interact in producing longterm effects on dopamine-mediated behavior. For this, we compared the effects of vaginal and C-section birth on amphetamine (AMPT)-induced locomotor activity in strains of rats differing in genetic composition. In Sprague-Dawley rats, C-section birth increased AMPT-induced locomotion compared with vaginal birth. By contrast in Lewis rats, C-section birth reduced AMPT-induced locomotion compared with vaginal birth. In Fischer rats, AMPT-induced locomotion was increased by C-section under maternal anesthesia but decreased by C-section after maternal decapitation, compared with vaginal birth.
It is concluded that a minor birth complication like C-section can have differing long-term effects on dopaminergic function in the rat, depending on the genetic composition of the individual.
PMID: 10718328, UI: 20181256
Exp Neurol 1997 May;145(1):118-29
El-Khodor BF, Boksa P
Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec, Canada.
Epidemiological evidence indicates a higher incidence of pregnancy and birth complications among individuals who later develop schizophrenia, a disorder linked to alterations in mesolimbic dopamine (DA) function. Two birth complications usually included in these epidemiological studies, and still frequently encountered in the general population, are birth by Caesarean section (C-section) and fetal asphyxia. To test the hypothesis that birth complications can produce long-lasting changes in DA systems, the present study examined the effects of Caesarean birth, with or without an added period of anoxia, on steady state monoamine levels and metabolism in various brain regions in a rat model. Pups born vaginally served as controls.
At 2 months of age, in animals born by rapid C-section, steady state levels of DA were decreased by 53% in the prefrontal cortex and increased by 40% in both the nucleus accumbens and striatum, in comparison to the vaginally born group. DA turnover increased in the prefrontal cortex, decreased in the nucleus accumbens, and showed no significant change in the striatum, in the C-section group. Thus, birth by a Caesarean procedure produces long-term reciprocal changes in DA levels and metabolism in the nucleus accumbens and prefrontal cortex. This is consistent with the known inhibitory effect of increased prefrontal cortex DA activity on DA release in the nucleus accumbens.
By contrast to birth by rapid C-section alone, young adult animals, that had been born by C-section with 15 min of added anoxia, showed no change in steady state DA levels in the prefrontal cortex, nucleus accumbens, or striatum and a significant decrease in DA turnover only in the nucleus accumbens, in comparison to the vaginally born group.
Levels of norepinephrine, serotonin, and its metabolite, 5-hydroxyindole acetic acid, were unchanged in all groups, indicating relatively specific effects on DA systems.
Although appearing robust at birth on gross observation, more subtle measurements revealed that rat pups born by C-section show altered respiratory rates and activity levels and increased levels of whole brain lactate, suggestive of low grade brain hypoxia, during the first 24 h of life, in comparison to vaginally born controls.<.p>
Pups born by C-section with 15 min of added acute anoxia were pale, hypotonic, and inactive at birth and showed reduced respiration and high brain lactate levels. However, these alterations resolved by 1-5 h after birth and, with few exceptions, animals in the anoxic group remained normal with respect to these parameters during the remainder of the first 24 h of life.
Immediately after birth, levels of plasma epinephrine, a hormone known to play a role in neonatal adaptation to extrauterine life and protection against hypoxia, were decreased in pups born by C-section but increased in pups born by C-section with 15 min added anoxia, in comparison to levels measured in vaginally born controls. These early developmental alterations could contribute to long-term alterations in dopaminergic parameters observed in rats born by C-section, with or without added anoxia.
It is concluded that C-section birth is sufficient perturbation to produce long-lasting effects on DA levels and metabolism in the central nervous system of the rat. These findings highlight the sensitivity of DA pathways to variations in birth procedure and support the notion that birth complications might contribute to the pathophysiology of disorders involving central dopaminergic neurons, such as schizophrenia.
Neuroreport 1998 Sep 14;9(13):2953-9
Vaillancourt C, Boksa P
Department of Psychiatry, McGill University, Douglas Hospital Research Center, Verdun, Quebec, Canada.
Schizophrenia is associated with both increased dopaminergic activity and perinatal complications. To test whether dopamine-mediated behavior can be altered by birth complications, we investigated effects of amphetamine (AMPT) on activity levels in adult rats that had been born vaginally or by Caesarean section (C-section) from isoflurane-anesthetized dams with or without addition of 10 min global anoxia. For comparison with our previous results, we also included rats born by C-section from decapitated dams.
The main finding is that rats born by C-section from isoflurane-anesthetized dams, either with or without added anoxia, showed greater AMPT-induced activity as adults compared to vaginally born controls. C-section from decapitated dams also enhanced AMPT-induced activity, however the time course differed from that following maternal anesthesia. Thus subtle alterations in birth procedure can produce long-lasting increases in dopamine-mediated behavior, supporting a role for birth complications in the pathophysiology of schizophrenia.
PMID: 9804297, UI: 99019442
Neuroscience 1998 Dec;87(4):893-904
El-Khodor BF, Boksa P
Department of Psychiatry, McGill University, Douglas Hospital Research Center, Verdun, Quebec, Canada.
We have previously reported that an apparently uncomplicated Caesarean section birth produces long-term alterations in steady-state levels of dopamine in the central nervous system of the rat. In addition, adult rats that had been born by Caesarean section, either with or without acute global anoxia, showed markedly greater dopamine release from the nucleus accumbens in response to repeated stress, in comparison to vaginally born controls. The aim of the present study was to test whether these birth complications also result in long-term changes in behavior mediated by dopamine systems.
For this, we investigated effects of a low dose (0.5 mg/kg) of amphetamine on activity levels in three-month-old rats that had been born vaginally (control), by rapid Caesarean section, or by Caesarean section with 15 min of global anoxia.
Amphetamine induced a significantly greater increase in locomotor activity in animals born by Caesarean section or by Caesarean section+ 15 min anoxia, in comparison to the drug's effects in vaginally born controls. Behavioral responses were further analysed from video recordings of the animals' behavior. In confirmation of automated activity counts, both animals born by Caesarean section and by Caesarean section + 15 min anoxia showed a significant increase in the duration and frequency of moving and a decrease in the duration and frequency of standing, in comparison to vaginally born controls. Animals delivered by Caesarean section showed a significant increase in the duration of sniffing and a decrease in the duration and frequency of grooming when compared to vaginally born controls. Animals delivered by Caesarean section + 15 min anoxia showed a significant increase in the duration and frequency of rearing, in comparison to controls.
The pattern of behavioral changes observed indicates that, as adults, animals born by Caesarean section and by Caesarean section with added global anoxia both show heightened behavioral responses to amphetamine, in comparison to vaginally born animals. These findings highlight the sensitivity of dopamine pathways to variations in birth procedure and add experimental support to epidemiological evidence implicating birth complications in the pathophysiology of disorders involving central dopaminergic neurons, such as schizophrenia.
'There is evidence that Caesarean babies have an increased risk of allergic disease.'Links to other sources of information:
Fetal Lacerations from caesareans
Cesarean Voices -A web site by, for, and about cesarean born people
Argues that being born by caesarean might affect the baby's personality.
0.375 sec, (15)