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Gynecological Endocrinology

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© 2012 Informa UK, Ltd.

10.3109/09513590.2011.633654

0951-3590

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Gynecological Endocrinology, 2012; 28(6): 436–439© 2012 Informa UK, Ltd.ISSN 0951-3590 print/ISSN 1473-0766 onlineDOI: 10.3109/09513590.2011.633654

Background: The aims of this study were to analyze the trend of cesarean section (CS), determining possible risk factors and also comparing the rate of CS in mothers with gestational diabetes (GDM) and normal pregnant population. Materials and methods: A hospital-based midwives data collection including 37,997 pregnancies in Tehran was used for this study. The study popula-tion included all women giving birth between 1 January 1980 and 31 December 2009. Results: The global rate for CS was 37.8 and 85.9% in normal pregnant population and GDM subjects, respectively. An increase in the rate of CS was observed in normal population from 16.97% during 1980–1989 to 71.08% during 2000–2009. There was a similar upward trend for GDM subjects from 79.17 to 93.55%. The most frequent indications for CS in GDM subjects were unsuccessful induction (31%) and repeat CS (22.76%). Conclusion: The rate of CS is surprisingly very high in normal pregnant population as well as subjects with GDM. This should be an alarming issue for healthcare policy-makers and a trigger for monitoring situation in the country.

Keywords: Cesarean section, gestational diabetes, pregnancy

IntroductionThe steady worldwide rise in cesarean section (CS) rate is alarming. The rate has increased far beyond the optimal recommended level of 10–15% [1].

The trend is no longer confined to high-income countries such as North America and Western European [2–7]. Similar trends have also been reported from low-income countries such as India and China [8,9].

Medical conditions may complicate the pregnancy outcomes. Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with first recognition or onset during preg-nancy. The incidence of GDM varies from 1 to 14% in different populations [10]. GDM is associated with significant maternal and fetal complications and poorly controlled diabetes during pregnancy is considered as a risk factor for macrosomia, birth trauma and CS [11–13].

In hyperglycemia and adverse pregnancy outcomes (HAPO) study, the investigators reported a significant association between maternal hyperglycemia and cesarean delivery [14]. In parallel

to the results of HAPO study, London and colleagues showed that even mild GDM is associated with fetal macrosomia and an increased rate of cesarean delivery [15].

On the other hand, others claimed that the higher rate of CS in this group might be attributed to the attitude of obstetric care providers towards pregnant women with a diagnosis of GDM [16–18].

The aim of this study was to analyze the type of delivery and risk factors for CS in a large cohort of pregnant women and to determine and compare the rate in women with GDM and normal pregnant population.

MethodsA retrospective cohort of 37,997 pregnancies was evaluated from 1980 to 2009. The women were consecutive subjects, referred to maternity clinic of a public general hospital in Tehran, Iran. Data was obtained from their medical records during follow-up visits in the clinic including maternal age, parity, gestational age and indications for cesarean delivery, as well as the results for glucose challenge test (GCT) and glucose tolerance test (GTT) tests, if available. These data had been recorded by the specialists who had followed the subjects in the maternity clinic. The routine protocol in the hospital was to screen high risk individuals for GDM with a 50 g oral glucose challenge test (OGCT) between the 24th and 28th weeks of gestation. One-hour glucose values more than 140 were considered as a positive result. High risk indi-viduals were defined according to American Diabetes Association guidelines. Definite diagnosis of GDM was made based on the results of a 100 g oral glucose tolerance test (OGTT) according to the Carpenter and Coustan criteria [19,20]. FBS ≥ 95 mg/dl, 1-hour ≥ 180 mg/dl, 2-hour ≥ 155 mg/dl, 3-hour ≥ 140 mg/dl. Two abnormal test results were considered as positive.

The indications for CS and the type of delivery were obtained from the patient’s records reported by the specialists. The study examined the observed time-trends in type of delivery in a public hospital setting and the reported risk factors for cesarean delivery in this cohort.

We also compared the CS trends between pregnancies compli-cated by diabetes and normal pregnant population. Normal preg-nant population was defined as pregnancies not complicated by

GESTATIONAL DIABETES MELLITUS

A thirty-year analysis of cesarean section rate in gestational diabetes and normal pregnant population in Tehran, Iran: a concerning trend

Mohammad H. Badakhsh1, Mohammad E. Khamseh2, Mojtaba Malek2, Gita Shafiee2, Rokhsareh Aghili2, Sedigheh Moghimi1, Hamid R. Baradaran2 & Mahsan Seifoddin2

1Department of Obstetrics and Gynecology, Faculty of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran and 2Endocrine Research Center (ERC), Institute of Endocrinology and Metabolism (IEM), Tehran University of Medical Sciences (TUMS), Tehran, Iran

Correspondence: Dr. Mohammad E. Khamseh, Associate professor of Internal Medicine and Endocrinology, Endocrine Research Center (ERC), Institute of Endocrinology and Metabolism (IEM), Tehran University of Medical Sciences (TUMS), Tehran, Iran, P.O. Box: 1593748711. Tel: +98 21 88945247. Fax: +98 21 88945173. E-mail: m-khamseh@tums.ac.ir

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pre-eclampsia and or any other medical conditions diagnosed during pregnancy.

Statistical analysis

Mean (standard deviation: SD) values for continuous and frequen-cies (%) for categorical variables of the baseline characteristics are given for women with GDM. Student’s t-test and χ2 test were used for comparison of means and frequencies, respectively. To test the effect of covariates such as gestational age, parity and maternal age on type of delivery in GDM population, a logistic regression analysis was performed.

SPSS program (SPSS Inc., Chicago, IL; Version 15) was used for data analysis and p values ≤0.05 were considered as statisti-cally significant.

ResultsThe study cohort comprised of a total of 37,997 pregnant women during three decades. The overall rate of cesarean delivery of the total cohort was 38.2%. The rate of cesarean delivery was 37.8 and 85.9% for normal pregnant population (NPP) and GDM, respec-tively. An upward trend for CS is observed in NPP from 16.97% during 1980–1989 to 71.08% during 2000–2009 (Figure 1). A similar trend can be seen in pregnancies complicated by diabetes. For this group, the rate shows an increase from 79.17 to 93.55% (Table I). Table II illustrates the clinical characteristics of the NPP and the GDM subjects. The mean age of pregnant women with GDM was 29.3 ± 5.7 years and the mean gestational age was 37.6 ± 1.2 weeks.

The most frequent risk factors for cesarean delivery in the total cohort were repeat CS (36.78%), and dystocia (29.46%). Table III illustrates primary indications for CS in normal pregnant popula-tion across the three decades.

In GDM subjects, the most frequent risk factors for CS were unsuccessful induction (31%) and repeat CS (22.76%). (Table IV).

Among individuals with GDM, multivariate adjusted model showed significant odds for the age of mother and parity. An increase in maternal age was associated with 12% increased risk of CS. An inverse relationship between parity and CS was also observed (Table V).

Table I. Rates of birth by caesarian section (CS) and normal vaginal delivery (NVD) in normal pregnant population (NPP) and gestational diabetes mellitus (GDM) subjects.

NPP GDM TotalCS NVD p value CS NVD p value CS NVD p value

0.000 0.000 0.0001980–1989 2800 (16.97) 13,699 (83.03) 19 (79.17) 5 (20.83) 2819 (17.06) 13,704 (82.94) 1990–1999 4866 (40.83) 7051 (59.17) 75 (73.53) 27 (26.47) 4941 (41.11) 7078 (58.89) 2000–2009 6588 (71.08) 2681 (28.92) 174 (93.55) 12 (6.45) 6762 (71.52) 2693 (28.48) Data are n (%).

Table II. Clinical characteristics of normal pregnant population (NPP) and gestational diabetes mellitus (GDM) subjects.Variables NPP GDMMaternal age (year) 28.9 ± 4.7 29.3 ± 5.7Gestational age (week) 37.9 ± 1.1 37.6 ± 1.2Parity 2.4 ± 1.3 2.2 ± 1.2CS (%) 37.8 85.9Fetal birth weight (gr) 3125.4 ± 415.2 3354.2 ± 632.4Mean ± SD are shown for continuous variables and % is shown for categorical

variables.

Table III. Primary indications for caesarian section (CS) in normal pregnant population. 1980–1989 1990–1999 2000–2009Dystocia 588 (21.00) 1508 (31.00) 2151 (32.65)Abnormal presentation 167 (5.96) 315 (6.47) 295 (4.48)Fetal distress 164 (5.86) 561 (11.53) 571 (8.67)Repeat CS 1496 (53.43) 1519 (31.22) 2266 (34.40)Elective section 107 (3.82) 459 (9.43) 530 (8.04)Others 278 (9.93) 504 (10.35) 775 (11.76)Data are n (%).p Value 0.000.

Table IV. Primary indications for caesarian section (CS) in gestational diabetes mellitus (GDM) subjects. 1980–1989 1990–1999 2000–2009Dystocia 2 (10.53) 9 (9.3) 20 (11.49)Abnormal presentation 0 4 (5.3) 4 (2.30)Fetal distress 1 (5.26) 7 (9.3) 7 (4.02)Repeat CS 1 (5.26) 14 (13.3) 46 (26.44)Elective section 0 10 (28) 8 (4.60)Unsuccessful induction 14 (73.69) 18 (32) 51 (29.31)Others 1 (5.26) 13 (2.7) 38 (21.84)Data are n (%).p Value 0.002.

Table V. Multivariate adjusted analysis of risk factors for caesarian section (CS) in gestational diabetes mellitus (GDM) subjects. B OR (95% CI) p valueMaternal age 0.110 1.12 (1.03–1.21) 0.006Parity −0.524 0.59 (0.42–0.83) 0.002Gestational age 0.163 1.14 (0.89–1.47) 0.3CI, confidence interval; OR, odd ratio.p Values ≤0.05 were considered significant.Figure 1. Trend of CS rate during 1980–2009 years. p For trend = 0.000.

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DiscussionIn this study, we found a dramatic increase in the rate of cesarean delivery in normal pregnant population far beyond WHO recom-mendations, especially in the last decade. In addition, CS was surprisingly the preferred method of delivery in over 90% of subjects with GDM.

In US, the rate of cesarean delivery reached to a peak level of 26.1% in 2002 [21]. The estimated rate in England and Wales reported to be 21.4% of all deliveries [22], and National Health Service (NHS) described an increase in cesarean rate from 12% in 1990 to 24% in 2008 in UK. Similar trends have also been reported from low-income countries [8]. In China, a linear increase for cesarean delivery occurred from 4.9% in 1993–1994 to 20.4% in 2001–2002 [23]. In Brazil, the rate is near 100% in some hospitals, with an upper limit of 35% in public hospitals [24]. The lowest reported rate belongs to Sweden, Denmark and Netherland (10%).

The reported rate of CS in women with GDM varies in different studies. In a multicenter study in Italy, the rate of CS in women with GDM was not different from that of the normal pregnant population [25]. However, others found it 35.3% in GDM and 22% in glucose tolerant women [16]. In another study, CS rate for treated women with GDM was 22.3% compared to 34% for untreated women with GDM [18]. The higher rate of cesarean delivery in women with GDM might be attributed to lower threshold for surgical delivery by obstetric care providers, because doctors are usually more comfortable with CS [26]. In addition, it has been reported that 82% of physicians preferred CS to avoid claims [27]. On the other hand, Mackenzia et al. reported another issue; i.e. CS on demand. They observed maternal request as one of the main indication for surgical delivery [28]. Another report from WHO attributed the increase rate of CS to both women’s demand for the procedure and pressure of obstetricians [23]. Non-medical reasons such as avoidance of painful labor and family concerns about date of birth have been reported to be the cause in some areas [29].

In Australia, there was an increase in the rate of CS over the years [30], but the rate reported to be varied between urban and rural areas [31]. It should be mentioned that there is a marked international variation in the cesarean delivery rate [32]. However, it is not clear that the situation remains the same in view of rapid progression and use of modern obstetric technologies as well as socioeconomic changes of the population.

Our findings indicate a sharp increase in the rate of cesarean delivery in both normal pregnant population and women with GDM during the past 10 years. It is worth mentioning that this happens in a cohort of population in a public hospital and not in a private healthcare service, where financial benefits of doctors and hospitals might be claimed as a contributing factor. While non-medical factors such as socioeconomic class, insurance status and pattern of physician decision making may contribute to this increase in section rate, it might be postulated that patients are more convenient with CS as they think it would be safer and more comfortable type of delivery. Meanwhile, the time of delivery is more predictable in CS than normal vaginal delivery (NVD). On the other hand, the role of midwives has diminished in delivery rooms and obstetricians have taken the main role in decision making about the type of delivery during recent years.

Although the results cannot be generalized to the whole situ-ation in the country, it is possible that a similar pattern would be present in other parts especially in urban areas and large cities.

It should be emphasized that the high rate of surgical delivery is a huge burden for human resources and hospital infrastructures.

Although clinical guidelines are useful to guide clinicians towards appropriate medical practice, obstetricians do not necessarily apply guidelines in daily clinical practice.

This study was the first to explore the rate and trend of CS in a large cohort of population in Iran. However, it had some limitations that go back to the type of study. Most importantly, local screening protocol for high risk individuals for GDM and available records for GCT and GTT results that might lead to an underestimating the true prevalence of GDM in this cohort.

The results of this study should be alarming for healthcare policy-makers in order to design and initiate a national system-atic plan to monitor CS trends in the country and more focused continuous medical education programs for the midwives and obstetricians to restore the role of midwives in the process of childbirth.

Further research needs to be done to clarify the underlying reasons of the demand of CS in the country.

AcknowledgementsThe authors wish to thank to the all staffs that sincerely help us to complete the project.

Declaration of Interest: The authors declare no conflicts of interest.

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