In Asia, women who give birth via cesarean section may be at an increased risk for negative health consequences.1 According to an observational study conducted by the World Health Organization (WHO) in nine Asian countries, women who undergo an unplanned cesarean section before or during labor or who have an assisted (operative) vaginal delivery are more likely than those who have a spontaneous vaginal delivery to experience morbidity. Furthermore, infants born by assisted vaginal delivery or a medically indicated cesarean section have about twice the odds of dying during delivery, spending at least seven days in intensive care or both than do those born without surgical aid (odds ratios, 1.9–2.1). Women who have elective cesarean deliveries before going into labor are more likely than those with spontaneous vaginal deliveries to require admission to the intensive care unit (9.9). For infants with a breech presentation, however, cesarean delivery is associated with reduced neonatal mortality.
Cesarean section is often perceived to be safer than vaginal delivery for mothers and their infants, and thus has become increasingly common around the globe. However, research shows that the procedure may actually be detrimental to maternal and infant health, while consuming valuable resources, especially in poorer countries.
In the current analysis—part of WHO's global study examining maternal and perinatal care—the researchers used stratified multistage cluster sampling and random selection to choose 128 health facilities in Cambodia, China, India, Japan, Nepal, the Philippines, Sri Lanka, Thailand and Vietnam for assessment. To be included in the study, facilities had to offer cesarean section and manage more than 1,000 deliveries annually; they also had to be located in each country's capital city or in one of the two provinces that were randomly selected for each country. Six facilities declined to participate, leaving a total of 122 sites. From October 2007 to May 2008, data were collected over a two-month period from facilities that anticipated more than 6,000 deliveries yearly, and over a three-month period from those that expected 6,000 or fewer deliveries. At each facility, staff provided data on all deliveries, including information on women's demographic characteristics, pregnancy-related risk factors, delivery type, and maternal and neonatal complications. For mothers, the outcomes of interest were death, blood trans- fusion, admission to the intensive care unit, hysterectomy and surgery to control pelvic arterial bleeding; for infants, the key outcomes were death or receiving at least seven days of neonatal intensive care. The researchers conducted univariate and multivariate analyses to assess associations between study variables and maternal and neonatal outcomes.
The final sample consisted of 107,950 deliveries, half of which were in India, China or Sri Lanka. About nine in 10 women were married (94%) and a similar proportion (90%) were aged 17–34; for 43%, the pregnancy was their first. One in five (19%) had come to the hospital because of pregnancy or delivery complications. The overall cesarean rate was 27%; rates were highest in China (46%), Vietnam (36%) and Thailand (34%). Women who underwent a medically necessary cesarean section most often did so because they had had a previous cesarean delivery (24%). Other common reasons included fetal distress (21%) and breech or other abnormal presentation (13%). Almost two-thirds of facilities offered doctors a financial incentive for performing a cesarean section.
In multivariate analyses, the researchers found that the odds of maternal death among women who had had an assisted vaginal delivery were three times those among women who had had a spontaneous vaginal delivery (odds ratio, 3.1). Women who had had an assisted vaginal delivery also had an elevated likelihood of being admitted to intensive care (2.4), as did women who had had an elective antepartum cesarean delivery (9.9) or a medically necessary cesarean delivery (42.8– 55.7).
The odds of receiving a blood transfusion were greater among women who had had an assisted vaginal delivery, who had undergone a medically necessary cesarean section before labor or who had had an elective cesarean delivery during labor (odds ratios, 2.1–4.7) than among women who had had a spontaneous vaginal birth. The odds of having had a hysterectomy were elevated only for women who had had a medically necessary cesarean section (5.8– 6.9). Overall, the odds of either dying, being admitted to the intensive care unit, or having a transfusion, a hysterectomy or pelvic arterial ligation surgery were elevated among women with a surgical vaginal delivery (2.1), an elective antepartum cesarean delivery (2.7) or a medically necessary cesarean section (10.6–14.5).
In analyses that took into account fetal presentation (e.g., breech or other non-headfirst positions), the odds of fetal death were lower for infants delivered by cesarean section prior to labor than for those with a spontaneous vaginal birth (odds ratio, 0.6). Infants born via assisted vaginal delivery or medically necessary intrapartum cesarean section were more likely than those born spontaneously to die during delivery (1.6 and 1.5, respectively) or before leaving the hospital (2.5 and 2.6, respectively); infants delivered by a medically necessary antepartum cesarean section also had elevated odds of dying before discharge (1.7). Compared with spontaneously delivered infants, those whose mother required surgical assistance to deliver had about double the odds of receiving neonatal intensive care for at least seven days (1.9–2.4) or of either needing this type of care or dying during delivery (1.9–2.1).
In a subgroup analysis focusing on infants who were in a breech or other abnormal presentation prior to labor, the odds of neonatal death before or during delivery were lower for cesarean deliveries than for spontaneous vaginal deliveries (odds ratios, 0.1–0.6). How-ever, infants born during medically necessary surgical deliveries had increased odds of needing seven or more days of intensive care (1.7–2.1). Death before hospital discharge was reduced only among infants delivered by medically indicated antepartum cesarean section (0.4).
Despite the large scale of this study, the investigators caution that these findings cannot be applied to each country as a whole or to smaller hospitals, and that, among other limitations, they may not have been able to fully segregate women's and infants' risk factors from the risks of surgical intervention. Noting that in this study, as in other research, cesarean delivery was associated with poorer health outcomes for women but with improved neonatal outcomes in cases of abnormal fetal presentation, the researchers suggest that cesarean section be performed only when medically necessary. They urge "women who choose to have caesarean section, and the doctors who recommend the operation with no medical indication…to make that decision with the understanding of the increased risks." —S. Ramashwar
REFERENCE
1. Lumbiganon P et al., Method of delivery and pregnancy outcomes in Asia: the WHO global survey on maternal and perinatal health 2007–08, Lancet, 2010, 375(9713):490–499.