British Journal of Obstetrics and Gynaecology March 1992, Vol. 99, pp. 203-206

OBSTETRICS

Determinants of caesarean section rates in Italy FABIO PARAZZINI Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy N I C 0L E T T A P I R O T T A Consorzio Interuniversitario Lombard0 per I’Elaborazione Automatica Milan, Italy CARLO LA VECCHIA Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy LUIGI FEDELE Prima Clinica Ostetrico-Ginecologica Universitii di Milano Milan, Italy

ABSTRACT Objective To analyse the determinants of caesarean section rates in Italy. Design Analysis of information using a standard form on all the deliveries after the 28th week of gestation routinely collected by the Italian Central Institute of Statistics. Setting National data of all Italian deliveries in the periods 1980-1983. Subjects A total of more than 2 400 000 deliveries occurred in Italy in the period and are considered in this analysis. Results The frequency of caesarean section rose from I 1.2/100 deliveries in 1980 to 14.5/100 in 1983. Caesarean section rates were lower in the Southern (less rich) areas, and rose steadily with maternal age, being about three times higher in women aged 240 years than in teenagers. Maternal education was directly associated with caesarean section rates: compared with women with only primary school education, those with a college education reported an about 40% higher rate of caesarean section, but this difference dropped markedly after allowance for maternal age and birthweight. The section rate was 13.3/100 deliveries in public hospitals and 11.8/100 in private ones, but this reflected the different utilization of public and private services in various geographical areas. Birthweight and gestational age at delivery were important determinants of caesarean section rates; lowest values were observed for verylow-birthweight and very preterm deliveries and babies weighing 3000-3999 g and term deliveries. Caesarean section rates were about 20% higher in nulliparous than in parous women and the rates increased with number of stillbirths or miscarriages; further, the rate ratio was about double in multiple than in single births. Conclusion Caesarean section rates in Italy in the early 1980s were still lower than in North America, but their determinants share several similarities with those reported in other areas.

There have been substantial increases in the frequency of caesarean section in developed countries (Taffel et al. 1987; Notzon et a/. 1987). For example in the United States caesarean section rates were about 5% of deliveries in 1965, but rose to 24% in 1987 (Taffel et al. 1987). Many factors have been put forward to explain this upward trend, including repeat caesarean section, the increasing early recognition of fetal distress by fetal monitoring techniques, changing childbearing patterns (i.e., increased frequency of older primiparous mothers) and the decreasing use of forceps (Taffel eta/. 1987; Notzon et al. 1987; Shiono et al. 1987). For example, in the United States forceps deliveries declined from 37% in 1972 to 18% of all deliveries in 1980 (Placek et a/. 1983). Besides obstetric indications and fear of malpractice suits, socio-economic factors have been proposed as having a role in the frequency of caesarean section. Several reports, generally from the United States, have shown that higher social class (Gould et al. 1989), as well as private (or clinic) care (Haynes de Regt eta/. 1986; Placek et al. 1988; Kizer & Ellis 1988; Williams & Chen 1983), are associated with more frequent caeCorrespondence: Dr Fabio Parazzini, Istituto di Ricerche Farmacologiche, “Mario Negri”, Via Eritrea 62,29 157 Milano, Italy.

sarean sections. These associations were independent of age, parity, birthweight and obstetric fetal complications (Gould et al. 1989). In Europe the frequency of caesarean section has been steadily rising, although in most European countries the rate is still 30-50% lower than in the United States or Canada. For example, in the early 1980s the rate ranged from 5 to 7% of deliveries in Belgium, Austria, Czechoslovakia and from 1 1 to 12% in France and Scandinavian countries (against 16-18% in the USA and Canada) (Notzon e t a / . 1987; Thiery et ul. 1989). Few data are available on the obstetric and socio-economic determinants of caesarean section in Southern European countries. Therefore, this article considers rates and determinants of caesarean section in Italy, using information routinely collected on more 2 400 000 deliveries in 1980-1983 (Parazzini et al. 1990).

Methods In Italy, information on the deliveries after the 28th week of gestation are routinely collected by law using a standard form by the Italian Central Institute of Statistics. Data collected include: maternal and fetal characteristics, and the modalities

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F . P A R A Z Z ~ N IET A L .

Table I. Caesarean section rates according to calendar year, geographical area, place of birth and selected maternal characteristics, Italy. 19801983 Caesarean section rate/100 deliveries

Total Calendar year 1980 1981 1982 1983 Geographic area North Centre South Maternal age (years) s I9 20-24 25-29 30-34 35-39 4044 2 45 Maternal education College ( 2 14 years education) High school (9- 13 years education) Intermediate school (6-8 years education) Primary school ( S S years education) Place of birth Public hospital Private hospital

Number of caesarean sections”

Crude

Standardized?

322 363

12.9

-

12 447 19 641 82 430 87 845

11.2 12.7 13.2 14.5

-

135 172 64 224 122 967

14.9 15.1 10.5

14.8 15.0 10.7

13 860 78 760 103 688 76 456 36 662 10 738 173

8.7 10.5 12.5 15.0 19.5 24.3 24.2

8.3 10.5 124 14.8 19.6 25.2 25.2

19 042 73 269 121 439 107 191

17.0 14.0 12.4 12.3

14.1 13.9 12.9 11.9

282 526 38 394

13.3 11.8

13.3 11.5

-

-

*In some cases the sum does not add up to the total because of missing values. +Directly standardized for maternal age, education and birthweight.

of delivery. Forms are completed by the midwives or the physician at the time of delivery. We obtained copies of the original computer tapes including records of all deliveries in Italy in the period 1980-1983. More recent data are riot available at the time of writing this report due to delay in preparing the computer tapes by the Central Institute of Statistics. From these records we extracted information on caesarean or vaginal delivery, maternal age and education and obstetric history, place of birth, fetal sex, gestational week at birth, birthweight, presentation and multiple pregnancy. The proportion of caesarean sections per 100 deliveries (caesarean section rate) was computed per calendar year and for the total quadriennium in strata of the various maternal and fetal characteristics. Caesarean section rates standardized for maternal age and education and birthweight were derived by the direct method (Armitage 1971) using the total population of-deliveries as standard.

Results Table 1 considers caesarean section rates according to calendar year, geographical area, selected maternal characteristics and place of birth. In the period considered, the frequency of caesarean section rose steadily from 11.2% deliveries in 1980 to 14.5% in 1983. There were marked geographical differences in

caesarean section rates, which were about 40% lower in the Southern (less rich) areas than in the North or Centre of Italy. The rate of abdominal deliveries increased with maternal age, being, about three times higher in women aged 2 4 0 years than in teenagers. Compared with women with primary (i.e., ~5 years of education) or intermediate schooling (6-8 years), those with a college education reported an about 40% higher rate of caesarean sections. This difference, however, was reduced after taking into account maternal age and birthweight, and it is possible that the some of residual difference is due to underadjustment for these variables. The proportion of caesarean sections was 13.3% of deliveries in public hospitals and 11.8% in private ones; the difference did not change after allowance for covariates. However, analysis of the data according to the three broad Italian geographical areas (North, Centre and South) showed lower caesarean section rates in private hospitals in the South ( I 1.5% of deliveries in public hospital and 8.1% in private clinics), but the frequency of birth by caesarean section was about 30% higher in private hospitals in the North and Centre of Italy (public and private hospital rates were respectively 14.7 and 18.5% of deliveries in the North and 14.6 and 19.6% in the Centre). Obstetric determinants of caesarean section rates are considered in Tables 2 and 3. There were non linear relations between caesarean section rates and birthweight and ges-

C A E S A R E A N B I R T H R A T E I N ITALY

Table 2. Caesarean section rates according to birthweight and gestational age M y , 1980-1983 Number of

caesarean sections" Birthweight (g) < 1000 1000- 1499 1500- I999

2000-2499 2500-2999 3000-3499 3500-39 99 40004499 24500

768 2 638 6 199 17 476 58 742 123 226 84 006 24 539 4 680

Caesarean section rate/100 deliveries Crude

Standardized?

10.2

9.8 19.0 23.5 18.9 14.4 12.1

19.1

23.7 1x.x

14.3 11.9 11.8 13.6 16.3

11.8 13.5 16.4

Gestational age (weeks) 25-27 28-3 1 32-36 3 7 41 342

420 3 004 24 363 281 322 13 135

8.4 I74 11.7 12.9 16.0

5.7 14.1 9.1 13.0 16.3

*In some cases the sum does not add up to the total because of' missing values. ?Directly standardized for maternal age, education and birthweight (for week of gestation at delivery). tational age at birth. The values were lowest for very-lowbirthweight (< 1000 g) and deliveries between 25 and 27 weeks gestation; they increased in subsequent strata of weight or weeks (up to 3000 g or 3 1 weeks), but decreased again in term births and in babies weighing 3000-3999 g at birth (about 12% deliveries in these strata). Finally, they rose to about 16% deliveries in post-term or in high-birthweight (34500 g) babies (Table 2). Only 3% of all deliveries were breech presentation, but 55% of those were delivered by caesarcan section and percentages were similar for shoulder presentation (0.1% of all deliveries) and slightly lowcr (about 4045%) for other abnormal presentations (Table 3). Nulliparae were at a higher risk of caesarean section than parous women and the risk increased after allowance for maternal age, education and birthweight. The caesarean section rate increased with numbers of stillbirths and miscarriages and was about double in multiple than in single births (Table 3).

Discussion The frequency of caesarean section increased steadily in Italy in the early 198Os, although the 14%) rate for 1983 was still appreciably lower than American values in the same calendar period (Taffel et al. 1987). The present analysis covered only the period 1980-1983, but data available for selected areas suggest that the same upward trend was present in the middle 1980s, too (Bertolini et d.1987). The present study has both strengths and limitations of the analyses of vital statistics. Its major strength and interest lies, of course, in the nation-wide coverage of all deliveries and the large data set (more than 2 400 000 deliveries). The quality and completeness of data were generally satisfactory. For

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example there were no missing values for mode of delivery (vaginal or abdominal) or birthweight and only 0.5% of the records failed to report maternal age (Parazzini et a / . 1990). Further, the present analysis considered only 'hard' maternal variables, such as age, education and parity, which are unlikely to be substantially affected by recall, classification or collecting bias. The major drawback of the analysis is the lack of data on obstetric complications (i.e., dystocia, fetal distress) and previous caesarean section in parous women. However, standardization for birthweight did not markedly influence the differences in the frequency of caesarean sections, suggesting that a large proportion of them is unlikely to be due to a different baseline distribution of obstetric disorders. The Italian caesarean section rate of about 14% deliveries compares well with available data for France in the same calendar period (Notzon etal. 1987), but is at least 40-50% higher than those of other European countries such as Belgium or Austria (Notzon et al. 1987). Large differences in caesarean section rates also emerged among the three main Italian geographical areas: the Southern (less rich) areas of the country reported an about 40% lower rate than the North or Centre. Maternal age was a strong determinant of caesarean section rates in Italy; the rate in women aged 3 4 0 years was about three times the rate reported in teenagers. Similar ratios between age groups were observed in other countries, independently from their baseline caesarean section rates (Gould et a / . 1989; Thiery et al. 19x9; Yudkin & Redman 1986). Over 50% of babies presenting by the breech were born by caesarean section. This is about one third lower than the perTable 3. Caesarean section rates according to selected obstetrical variables Italy, 1980-1983

Number of caesarean sections*

Caesarean section rate/100 deliveries Crude

Standardized?

312 307 10 056

12.7 21.5

12.8 23.8

275 775 34 377 2 975 1 327 I324 764 4 823

11.5 55.3 56.7 36.7 46.9 20.9 22.4

62.1 53.3 37.0 46.7 21.1 22.3

165 687 102 957 34 357 19 362 Previous stillbirths/miscarriages 1 7 213 2 1911 33 754

14.2 12.5 10.9 10.0

17.0 12.3 10.0 9. I

21.7 29.5 35.8

22.8 27.6 29.3

Type of birth Single Multiple Presentation at birth Vertex

Breech Shoulder Face Brow

Bregma Other Previous pregnancies 0 I 2 23

11.6

*In some cases the sum does not add up to the total because of missing values. .}-Directlystandardized for maternal age, education and birthweight.

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F . P A R A Z Z I N 1 ET A L .

centage in the United States in the late 1970s (Placek & Taffel 1983), but the ratio of breech-to-other presentations within caesarean sections (about 5 ) is consistent with that reported in the USA (Taffel e t a / . 1987; Placek & Taffel 1983). In this analysis, socio-economic indicators appeared to be important determinants of caesarean section rates. Women of higher social class reported about 3 0 4 0 % higher rates. Similar evidence-perhaps more marked-emerged from several studies conducted in the United States (Gould et ul. 1989; Haynes de Regt et al. 1986; Placek et al. 1988; Kizer & Ellis, 1988; Williams & Chen 1983). For example a survey conducted in 1982-1983 in Los Angeles County showed that women who lived in census tracts with a median family income of more than 30 000 dollars had a primary caesareansection rate of 23%, as compared with 13% among women residing in areas with a median family income under 11 000 dollars (Gould e t a / . 1989). Only about 10% of this difference could be accounted for by difference in parity and 30% in birthweight distribution. In our analysis, too, caesarean section rates were about 20% higher among more educated women after standardization for age and birthweight. In Italy the frequency of caesarean section was lower for deliveries in priva.te hospitals than in public ones. At first sight, this finding contrasts with data from the United States (Haynes de Regt ef a/. 1986; Placek ef ul. 1988; Kizer & Ellis, 1988; Williams & Chen 1983). However, a more detailed analysis of the data according to the three broad Italian geographical areas (Parazzini ef a/. 1990) showed that this apparent abnormality was largely attributable to a lower frequency of caesarean section in private hospitals in Southern Italy. This area includes a large number of private, low technology obstetric units that have special agreements with the Italian National Health Service, whereby patients are not charged for medical expenses (sometimes only for accommodation). In the North and Centre of the country with a more ‘traditional’ pattern of public and private medicine, caesarean sections were about 25% more frequent in private clinics. In conclusion, caesarean section rates in Italy in the early 1980s were still lower than in North America, but their determinants share several similarities with those reported in other high or low rate areas. This observation suggests that the explanations for most of the intra-country or international differences in caesarean section rates should be sought in the ‘physician factor’ (Goyert ef a/. 1989) or in the organization of obstetric care, more than in different distributions of baseline obstetric and maternal determinants.

Acknowledgments This work was conducted within the framework of the CNR

(Italian National Research Council) targeted project Prevention and Control Disease Factors, subproject Disease Factors in Maternal and Infant Diseases. Ms Judy Baggott, Francesca Perego, Ivana Garimoldi and the G.A. Pfeiffer Memorial Library Staff provided helpful editorial assistance.

References Armitage P. (1971) Statistical Methods in Medical Research, Blackwell, Oxford. Bertolini R., Di Lallo D., Rapiti E. & Perucci C. A. (1987) Cesarean section rates in Italy. Am J Public Healrh 77, 1554. Gould J. H., Davey B. & Stafford R. S. (1989) Socioeconomic differences in rates of cesarean section. N Engl .I Med 321, 233-239. Goyert G. L., Bottoms S. F., Treadwell M. C. & Nehra P. C. (1989) The physician factor in cesarean birth rates. N Eng.1 Med 320,706-709. Haynes de Regt R., Minkoff H. L., Feldman J. & Schwartz R. H. (1986) Relation of private or clinic care to the cesarean birth rate. N Engl .I M d 315,619-624. Kizer K. W. & Ellis A. (1988) C-sections rate related to payment source (letter). Am J Public Healrh 78,96-97. Notzon F. C., Placek P. J. & Taffel S. M. (1987) Comparisons of national cesarean-section rates. N Engl J Med 316, 386-389. Parazzini F., Pirotta N., La Vecchia C. & Fedele L. (1990) I detenninanti della mortalith perinatale ed infantile nelle regioni Italiane 1980-1983. Determinants of perinatal and infant mortality in the Italian regions 1980-1983. Ann Ostet Giriecol Med Perinar 111, 9- 146. Placek P. J. & Taffel S. M. (1983) The frequency of complications in cesarean and noncesarean deliveries, 1970 and 1978. Pihlic, Health Rep 98, 396-400. Placek P. J., Taffel S. M. & Keppel K. G. (1983) Maternal and infant characteristics associated with cesarean section delivery. Health, United States, 1983. DHHS Pub. No. (PHS) 8&1232. National Center for Health Statistics, Hyattsville, MD. Placek P. J., Taffel S. M. & Moien M. (1988) 1986 C-Section rise; VBACs inch upward. Am ,I Public.Health 78, 562-563. Shiono P. H., McNellis D. & Rhoads G. G. (1987) Reasons for the rising cesarean delivery rates: 1978-1984. Ohstet Gynecol 69, 696-700. Taffel S. M., Placek P. J. & Liss T. (1987) Trends in the United States cesarean section rate and reasons for the 1980-85 rise. AmJ Public Health 77, 955-959. Thiery M., Deron R. & Buekens P. (1989) Frequency of cesarean deliveries in Belgium. B i d Neonate 55,90-96. Williams R. L. & Chen P. M. (19x3) Controlling the rise in cesarean section rates by the dissemination of information from vital records. Am J Public Health 73, 863-867. Yudkin P. L. & Redman C. W. G. (1986) Caesarean section dissected, 1978-1983. Br J Ohstet Gynaec’ol93, 135-144.

Received 15 April 1991 Accepted 5 September 1991

Determinants of caesarean section rates in Italy.

To analyse the determinants of caesarean section rates in Italy...
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