Use of Corticosteroids by Australian Obstetricians—A Survey of Clinical Practice

Aust. NZ J Obstet GFmzecol 1998; 38: 1: 1

THE AUSTRALIAN & NEW ZEALAND

JOURNAL OF

OBSTETRICS & GYNAECOLOGY

February, 1998

Vol. 38 - NO.1

OCCASIONAL REVIEW

Use of Corticosteroids by Australian Obstetricians - A Survey of Clinical Practice Julie A. Quinlivan:.”’ MRACOG, Sharon F. PhD, Sarah A. Dunlopi,6,8PhD, Lyn D. Beazlefl PhD and John P. Ne~nham:.~,’ FRACOG, CMFM Women and Infants Research Foundation at King Edward Memorial Hospital: University Department of Obstetrics and Gynaecology’ and Zoology: University of WesternAustralia, Perth, Western Australia

Summary: All Fellows, Members and trainees of the Royal Australian College of Obstetricians and Gynaecologists resident in Australia (n = 1,281) received a questionnaire relating to their practice of prescribing antenatal corticosteroids. 833 (65%) responded. The key findings were that 97% of Australian obstetricians prescribe antenatal corticosteroids in the classical setting of uncomplicated early preterm labour and 85% prescribe repeated courses in those cases in which the risk of preterm birth persists or recurs; 50% of obstetricians prescribe this agent weekly in cases with persisting risk of preterm birth. Some of the prescribing practices were found to be related to the number of years since obtaining specialist qualification. In view of the widespread clinical use of repeated doses of corticosteroids revealed in this present survey, it is clear that further research is warranted to determine the possible benefits and hazards of repeated exposures of the developing fetus to this therapy.

Enhancement of fetal maturation by corticosteroid therapy has been one of the major factors in recent decades responsible for improving the survival of preterm infants (1,2). It is therefore surprising that few data exist regarding the prescribing practices of obstetricians either in Australia or overseas. 1. Research Fellow. 2. Biostatistician. 3. Senior Research Fellow. 4. Professor. 5. Clinical Professor. Address for correspondence: Dr J.A. Quinlivan, Women and Infants Research Foundation, Carson House, King Edward Memorial Hospital, Bagot Road, Subiaco, Western Australia 6009, Australia.

In 1980 a survey conducted by the Royal College of Obstetricians and Gynaecologists of Members and Fellows resident in the United Kingdom revealed that 42% of practitioners frequently prescribed corticosteroids prior to early preterm birth, 40% sometimes, and 18% never (3). Opinion and practice in the United States was ascertained in 1995 using telephone interviews to survey 8 academic maternal-fetal medicine specialists, from separate geographic regions, and a series of focus groups was also held with 45 obstetricians selected from 4 geographical regions. There was a lack of consensus regarding the specific indications for use of corticosteroids (4). Clinical practice in Australia has been surveyed on 1 previous occasion. A survey in 1987 by the Royal Australian College of Obstetricians and Gynaecologists (RACOG) showed that 76% of Members and

AC:ST. AND N.2. JOURNAL OF OBSTETRICS

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Fellows in obstetric practice would prescribe antenatal corticosteroids to primigravidas in uncomplicated preterm labour at 30 weeks’ gestation (5). In a hypothetical case involving a woman with ruptured membranes presenting at 30 weeks’ gestation, corticosteroid therapy would have been prescribed by up to 70% of practitioners. In the decade since the Australian survey, many randomized controlled trials together with a metaanalysis have confirmed the benefits and safety of a single course of corticosteroids given to women at risk of early preterm birth (2). In addition, the practice of prescribing repeated courses of corticosteroids has arisen because the risk of early preterm birth can persist or recur, and the duration of the maturational effects of corticosteroids have not been fully determined. Moreover, the efficacy and safety of repeated courses of corticosteroids have not been confirmed in prospective human studies and are currently the subject of investigations using animal models. The present survey was designed to evaluate current Australian practice and was conducted through the RACOG.

Question 1

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AND GYNAECOLOGY

METHOD In March, 1997, 1,010 Fellows, and 271 Members and trainees of the Royal Australian College of Obstetricians and Gynaecologists resident in Australia were sent a questionnaire together with a reply paid envelope. Fourteen questions related to the practice of prescribing antenatal corticosteroids and 1 question related to the time which had elapsed since the practitioner had obtained specialist qualification. The format was similar to that used in other obstetric surveys (3,5).The questionnaire was piloted in Western Australia prior to general distribution. Case questions were included to estimate internal validity of responses. Data forms were returned to the RACOG and then forwarded to the Women and Infants Research Foundation at King Edward Memorial Hospital for Women, where results were collated for statistical analysis. Comparisons between the 3 groups of respondents were performed using Chi Square tests.

RESULTS There were 833 replies, yielding a response rate of 65%; of these, 130 (16%) practitioners were not currently in obstetric practice and have been excluded

Table 1. Results of QuestionnaireAbout the Use of Corticosteroidsin Pregnancy Yes

Do you prescribe corticosteroids to pregnant women at high risk of early preterm birth?

3

After the initial course, do you prescribe repeated course/s of corticosteroids to pregnant women at persisting or recurring risk of early pretenn birth? Do you prescribe corticosteroids routinely in a twin pregnancy?

4

Do you prescribe corticosteroids routinely in a triplet pregnancy?

5

Do you prescrihe corticosteroids in the presence of ruptured membranes?

6

Do you prescribe corticosteroids in the presence of an antepartum haemorrhage?

7

Do you prescribe corticosteroids in a hypertensive pregnancy?

8

The classical case A woman presents at 28 weeks’ gestation in strong preterm labour. Membranes are intact and there are no contraindications to tocolysis. If you give tocolysis, would you also administer corticosteroids? Repeat course of steroid and preeclampsia A woman presents at 29 weeks’ gestation with proteinuric preeclampsia. She had previously received a course of antenatal corticosteroids at 25 weeks’ gestation following an episode of threatened pretenn labour. In the absence of an immediate indication to deliver, would you administer a second course of corticosteroids? High-risk pregnancy A woman presents at 26 weeks’gestation with a high-risk pregnancy where the risk of early preterm birth will persist. She is administered a course of corticosteroids on admission. Your ongoing management until 32 weeks’ gestation includes . . . A weekly injection of corticosteroid A weekly course of corticosteroid A course/injection every 8-14 days A monthly injection of corticosteroid A monthly course of corticosteroid No further corticosteroid therapy Refer to a tertiary centre No response

9

10

No 11

No response

692 98.4% 582 82.8% 36 5.1% 188 26.7% 60 1 85.5% 577 82.1% 538 76.5%

1.6% 108 15.4% 655 93.2% 463 65.9% 81 11.5% 102 14.5% 140 19.9%

0 0% 13 1.8% 12 1.7% 52 7.4% 21 3.0% 24 3.4% 25 3.6%

679 96.6%

4 0.6%

20 2.8%

583 76.5%

140 19.9%

25 3.6%

212 136 147 8 44 86 50 20

30.2% 19.3% 20.9% 1.1% 6.5% 12.2% 7.1% 2.9%

JULIEA. QCINI.IVAN ET A L

from further analysis, leaving 703 replies as the subject of this report. Three hundred and eighty (54%) of inclusions were Fellows who had been in practice for more than 10 years, 169 (24%) were Fellows in practice for 10 years or less, 150 (21 %) were trainees or Members of the RACOG, 3 were currently overseas or recent immigrants to Australia, and 1 declined to answer this question. The results of the survey are shown in table 1. Ninety eight per cent of respondents would prescribe corticosteroids to pregnant women at high risk of early preterm delivery (question 1). In the classical case presented (question 8), 97% would have given this treatment. Of the 11 practitioners who would not prescribe corticosteroids, all but 1 were Fellows who had been in practice for more than 10 years. Eighty-three percent of practitioners would prescribe repeated courses of corticosteroids in some circumstances (question 2). In answer to the question describing a woman who presents with a high-risk pregnancy in which the risk of preterm birth persists or recurs (question lo), 78% of practitioners would prescribe repeated courses of corticosteroids, 12% would not give a repeated course, 7% stated their action would be to refer the patient to a tertiary centre, and 3% did not provide an answer. These responses demonstrated an internal consistency of 94%. There were no significant differences between the responses of Fellows, Members or trainees.

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Figure 1 shows the frequency with which respondents would prescribe repeated courses of corticosteroids in a high-risk pregnancy. In this setting, 50% of practitioners would prescribe corticosteroids weekly and a total of 70% would repeat the therapy within 14 days. The routine prescription of corticosteroids in multiple pregnancy is summarized in table 1. Five per cent of practitioners routinely prescribe corticosteroids for twin pregnancies, the majority commencing at 24 (24%) or 26 (35%) weeks’ gestation. Twenty seven per cent of practitioners would routinely prescribe corticosteroids for triplet pregnancies, the majority commencing at 24 (29%), 26 (30%) or 28 (23%) weeks’ gestation. The number of practitioners who would prescribe corticosteroids for a pregnancy complicated by preterm rupture of membranes, antepartum haemorrhage or hypertension are shown in table 1 (questions 5-7). Eighty-six per cent of respondents would prescribe corticosteroids in the presence of preterm ruptured membranes, 82% in the presence of an antepartum haemorrhage, and 77% in a pregnancy complicated by hypertension. Figure 2 shows the number of Fellows. Members and trainees who would 100

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Interval between repeat treatments (days) Figure 1. Percentage of respondents who would prescribe repeated courses of corticosteroids in high-risk pregnancies plotted against Interval of administration.

Figure 2. Percentage of respondents who would prescribe corticosteroids in 3 clinical settings: ruptured membranes, anteparturn haemorrhage (APH) and hypertension, categorized by duration from specialist training. Black represents Fellows in practice for more than 10 years, dark grey represents Fellows in practice for 10 years or less, and pale grey represents Members and trainees.

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AUST.AND N.Z. JOURNAL OF OBSTETRICS AND GYNAECOLOGY

Table 2. Choice of Corticosteroid and Protocol of Administration Protocol 2 injections at 2 injections at 4 injections at 12 hour intervals 24 hour intervals 12 hour intervals 12 mg 302 284 10 6 6 mg 12 11 10 mg 12 4 3 1 2 5 mg 1 I 3 0 336 303 21 (47.8) (43.1) (3.0) ~~~~~~~~~~

Corticosteroid Betamethasone Betamethasone Dexamethasone Dexamethasone Other Total (%)

prescribe corticosteroids in these 3 clinical settings. Prescribing practices were influenced by the number of years since obtaining specialist qualifications. In all 3 clinical settings, Fellows in practice for more than 10 years were significantly less likely to prescribe corticosteroids than Fellows in practice 10 years or less, Members and trainees (p