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Prediction of preterm delivery

Wilms, F.F.

Publication date2014

Link to publication

Citation for published version (APA):Wilms, F. F. (2014). Prediction of preterm delivery.

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Download date:05 May 2021

1Introduction

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Introduction

Preterm delivery (PTD) is in quantity and severity an important issue in the obstetric

care in the Western world. It is defined as a delivery before a gestational age less than

37 completed weeks or 259 days. Worldwide, 5-13% of all deliveries are preterm. It

therefore is a major cause of perinatal mortality and severe neonatal morbidity.1,2

Spontaneous PTD can either be preceded by preterm prelabor rupture of membranes

(PPROM) or by preterm labor (PTL), defined as regular uterine contractions leading

to cervical changes at a preterm gestation.

The exact pathogenesis of preterm labor, leading to preterm delivery, is unknown.

PTL is thought of as a syndrome, which underlying mechanisms include infection or

inflammation, uteroplacental ischemia or hemorrhage, overdistention of the uterus,

stress and other immunologically mediated processes.3,4 There is considerable

knowledge on maternal and obstetric risk factors for preterm labor contributing

to these mechanisms.

Race is one of the maternal risk factors. Disparity between preterm delivery

rates exists especially between the non-Hispanic black and non-Hispanic white

women with PTD rates of 16-18% and 5-9% respectively. This disparity in preterm

birth rates is poorly understood.5,6 The association between a higher risk of PTD and

other demographic characteristics as low socio-economic and educational status,

low and high maternal age and single marital status remains also unexplained.4

Thin women (Body Mass Index (BMI) < 19 kg/m2) have increased spontaneous PTD

rates, probably related to their nutritional status. The association between BMI and

spontaneous PTD seems to be inverse.7 In women who smoke, vasoconstriction

and a systemic inflammatory response might be of influence of the increased risk

of spontaneous PTD.4

Women with previous spontaneous PTD have a 2.5-fold increased risk of

PTD in their next pregnancy. This risk is inversely related to the gestational age of

the previous PTD and a prior spontaneous PTD is more closely associated with

subsequent early spontaneous PTD at <28 weeks’ gestation than with spontaneous

PTD overall.8 The interval between two pregnancies is more often shorter in women

who delivered prematurely previously, and a short interval between two gestations

even further increases the risk of spontaneous PTD. Other pregnancy characteristics

known to be associated with a high risk of spontaneous preterm delivery are

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Introduction

11

multiple pregnancy, intra-uterine infection and high levels of psychological and/

or social stress.4

Accurate identification of those women with symptoms of PTL who actually will

deliver prematurely is difficult. Of the women with symptoms of PTL, only a small

portion (3.6%) delivers within seven days after admission to the hospital, whereas

about 50-70% of these women deliver after 37 weeks’ gestation.9-12

Shortening of the cervix precedes spontaneous PTD. Measurement of the cervical

length (CL) by transvaginal ultrasound to detect this shorting is a useful diagnostic

test in the prediction of preterm delivery in women with symptoms of preterm

labor. The likelihood ratio (LR) of PTD within seven days after presentation in

women with symptoms of PTL and a CL below 15 is 5.7 (95% confidence interval

(CI) 3.8 to 8.65), compared to the likelihood ratio of 0.5 (0.3 to 0.8) for women with

a CL above 15 mm. These LR’s are 3.74 (95% CI 2.77 to 8.65) and 0.51 (95% CI 0.33

to 0.80) in women with PTL and a CL below or above 20 mm, and 2.77 (95% CI

2.15 to 3.59) and 0.33 (95% CI 0.22 to 0.50) when the CL is below or above 25 mm

respectively.13-15 Women with a CL above 30 mm are at low risk of PTD within seven

days (LR of a negative test of 0.2 (95% CI 0.005 to 0.53), with a negative predictive

value of 97% (95% CI 93 to 99). 10

Of the many biomarkers related to inflammation associated with spontaneous PTD, like

cytokines and chemokines, fetal fibronectin (fFN) has shown to be the most powerful

biomarker to predict PTL and of most clinical use in symptomatic women. Fetal

fibronectin (fFN) is an extracellular glycoprotein produced in the decidua and chorion,

and acts as a marker of choriodecidual disruption which can be detected with a swab

taken from the posterior fornix. In an uncomplicated pregnancy fFN is only detectable

in cervicovaginal secretions before 21 weeks of gestation. If it is detectable between a

gestational age of 24 and 34 weeks it is associated with an increased risk of PTD.

The fetal fibronectin test is 4.2 times (95% CI 3.5 to 5.0) more likely to be positive

in symptomatic women who will deliver within seven to ten days after testing,

than in symptomatic women who stay pregnant beyond that period of time. The

corresponding likelihood ratio for the negative test is 0.29 (95% CI 0.22 to 0.38).11

Making the test particularly of clinical interest if its result is negative, virtually ruling

spontaneous PTD within the following seven days out.16,17

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Combining measurement of the CL and fFN testing improves the prediction

of spontaneous PTD within seven days after presentation, in comparison to

performing only a CL measurement or fFN test. Different methods in combining

the two tests have been published, performing CL and fFN in all women with PTL,

or performing a two-step contingent approach in which fFN was tested in women

with a midrange CL (16-30 mm). The LR for preterm delivery within seven days of

a combined positive test of the used methods in literature (CL under the used cut-

off and a positive fFN test) is 22.0 (95% CI 13.6 to 35.7).9 No additional value for fFN

testing was found in women with a cervical length above 30 mm.10,18,19 The LR of a

negative fFN test in women with a CL above 30 mm is 0.76 (95% CI 0.14 to 1.13).10

The LR of preterm delivery within seven days in women with a CL < 15 mm for a

positive fFN test is 2.29 (95 % CI 0.95 to 6.60) and for a negative fFN test 0.43 (95%

CI 0.18 to 1.07), showing that fFN testing in women with a short cervix has virtually

no additional value. Moreover, over 90% of the women with a cervical length less

than 10 mm have a positive fFN test.20

In the Dutch obstetric care system initial assessment of women with symptoms of PTL

is mostly performed by midwives, who take care for low-risk women in primary care.

Their risk assessment that involves digital cervical examination to determine cervical

dilatation or effacement is thought to influence the accuracy of the fibronectin test.21

Consequences of preterm deliveryNeonates that are born prematurely are at increased risk of acute and chronic

medical complications and mortality. The complications of preterm birth arise from

immature organ systems that are not yet prepared to support life in the extrauterine

environment. The risk of acute neonatal illness decreases with gestational age.

In general, the earlier premature delivery occurs, the more neonatal life support

is required.22 Innovation in the treatment of preterm infants has improved their

survival, but short term morbidity, including respiratory distress syndrome (RDS),

intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), retinopathy of

prematurity (ROP), patent ductus arteriosus (PDA) and sepsis, still complicates the

premature life. Long-term morbidity includes cerebral palsy, visual and hearing

impairment and behavioral issues.23

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Introduction

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Antenatal corticosteroidsTo optimize neonatal health after preterm delivery, women with symptoms of

preterm labor are treated with tocolysis to prolong pregnancy and antenatal

corticosteroids (ACS) to prepare the fetal lungs for a life independent of the

mother.23-30

Graham Liggins, in the late 1960’s, incidentally discovered that preterm

lambs that were exposed to corticosteroids had more mature lungs than expected,

were viable at an earlier gestational age and had less severe respiratory distress at

birth.31 Together with pediatrician Ross Howie he published a landmark article in

1972. In their randomized controlled trial (RCT) that followed their initial findings, they

found a significant reduction of the incidence of RDS from 15.6 % to 10.0% in those

preterm neonates whose mothers received two 12-mg injections of betamethasone

administered 24 hours apart.27 Furthermore a reduction in mortality from 11.6%

to 6.0% and a significant reduced risk of IVH in preterm neonates was found after

antenatal betamethasone.28 It took over 20 years before the administration of

antenatal corticosteroids to mothers at risk of a premature birth was implemented,

due to fears of potential side effects.32 After a consensus conference, held in 1994

by the National Institutes of Health (NIH), administration of ACS was recommended

to all women between 24 and 34 weeks’ gestation at risk of premature delivery.

Endorsement of these recommendations by the American College of Obstetricians

and Gynecologists (ACOG) resulted in a drastically increase of the use of ACS.33

A possible diminishing effect of the initial course ACS, the optimal interval

of 7 to 14 days between the administration of ACS and delivery, and the difficulty

to accurately predict which women with symptoms of PTL actually will deliver

in the short term, created a clinical dilemma.34-37 Consequently, despite initial

hesitation to adopt the use of a single course ACS, in the 1990’s ACS courses were

routinely repeated all around the world.38-40 Seven years after the first consensus

conference, the NIH held a second one which concluded that repeat courses

should be reserved for patients enrolled in randomized controlled trials, since the

implementation of repeat courses was not based on sufficient data concerning

safety and efficacy.41 The subsequently conducted RCT’s and a Cochrane review on

repeat doses ACS concluded a reduction in occurrence and severity of neonatal

lung disease and serious infant morbidity.42-44 Although a lower birth weight and

smaller head circumference were reported after repeat courses,44 the long-term

outcomes at 2-3 years of age seemed to be reassuring. However, no evidence was

found for long-term benefit of repeat doses ACS. 46,47

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Currently, over four decades after the initial trial that showed a beneficial effect of

ACS and to strike the golden mean, clinicians started to administer a “rescue” course

ACS. The ACOG guideline of 2011 states that a rescue course may be considered

if the antecedent treatment was given more than 2 weeks prior, the gestational

age is less than 32 6/7 weeks, and the women are judged by the clinician to be

likely to give birth within the next week.48 This recommendation is based upon a

limited amount of RCT’s. ACOG therefore suggested further research on “rescue”

courses.49,50 The Dutch society of obstetrics and gynecology (NVOG) added to this

recommendation that the first course had to be given before 30 weeks’ gestation.51

Background and outline of the thesis

With the discovery of the treatment effects of antenatal corticosteroids and their

subsequent implementation, the outcome of premature neonates has improved

significantly. So clinicians do know that treatment of a woman at risk of preterm

delivery is aimed at the improvement of the outcome of the prematurely born

neonate, but keep struggling with the identification of the women who actually

need this treatment and the appropriate treatment strategy. This thesis aims

to address some of the dilemmas we face in diagnostics in preterm labor and

treatment with antenatal corticosteroids:

Part I - Diagnostic dilemmas- focuses on the identification of women at risk of

spontaneous preterm delivery.

Part II - Therapeutic dilemmas- targets the timing of antenatal corticosteroids.

Part III - General discussion and summary- provides a summary of this thesis and

describes the general considerations and clinical implications.

Part I Diagnostic dilemmasChapter 2 presents the results of a prospective cohort study on the prognostic

value of the fFN test and CL among women with preterm labor in a Dutch setting.

The influence of the digital examination, often performed prior to fFN testing, on

the predictive value of the fFN test was also assessed.

Chapter 3 reviews the methodology of studies on the clinical utility of fFN and

addresses the strengths and weaknesses of these trials.

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Introduction

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Chapter 4 evaluates the persistent risk of preterm delivery after arrested preterm

labor. Women who remained pregnant and were discharged from the hospital after

an episode of preterm labor were matched with healthy pregnant women.

Chapter 5 reports the relation between fetal gender and the onset of preterm

labor and preterm delivery in women with symptoms of PTL. Data were extracted

from the prospective cohort of the APOSTEL 1 study, a randomized controlled trial

studying the accuracy of fFN testing and CL measurement in a triage of women

with symptoms of PTL and intact membranes.

Part II Therapeutic dilemmasChapter 6 presents the results of a retrospective cohort study of preterm neonates

who received a single complete course of ACS and who were born alive before

a gestational age of 34 weeks. The relationship between respiratory morbidity,

defined as intubation, and the interval between ACS administration and delivery

was assessed. Furthermore the need for continuous positive airway pressure (C-PAP),

development of RDS, chronic lung disease (CLD) and a composite outcome was

evaluated.

Chapter 7 shows the interval from the administration of the first course of ACS to

delivery in women at risk for preterm delivery, due to different medical indications

(PTL, Preterm prelabor rupture of membranes, Pre-eclampsia/HELLP, Intra-uterine

growth restriction, vaginal blood loss and suspected fetal distress). We identified

which of the above would benefit from better risk stratification to optimize ACS

administration and neonatal outcome.

Chapter 8 studies the clinicians’ prescribing patterns of ACS in women with PTL,

included in the cohort of the APOSTEL 1 study. We suggest a strategy for prescribing

ACS according to risk stratification by CL measurement and fFN testing.

Part III Summary and general discussionChapter 9 summarizes the data presented in this thesis. A Dutch version is included.

Chapter 10 provides a general discussion of the results presented in this thesis and

outlines their clinical implication. Suggestions for future research are given.

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References

1. National Institutes of Health Consensus Development Conference statement on the effect of corticosteroids for fetal maturation on perinatal outcomes. JAMA 1995;273:413-8.

2. Slattery MM, Morrison JJ. Preterm delivery. Lancet 2002; 360(9344):1489-1497.

3. Romero R, Espinoza J, Kusanovic J, et al. The preterm parturition syndrome. BJOG 2006; 113: 17–42.

4. Goldenberg RL, Culhane JF, Iams JD, Romero R. Lancet. 2008;371(9606):75-84. Review

5. Spong CY, Iams J, Goldenberg R, Hauck FR, Willinger M. Disparities in perinatal medicine: preterm birth, stillbirth, and infant mortality. Obstet Gynecol. 2011;117(4):948-55.

6. Culhane JF, Goldenberg RL. Racial disparities in preterm birth. Semin Perinatol. 2011;35(4):234-9. Review

7. Hendler I, Goldenberg RL, Mercer BM, Iams JD, Meis PJ, Moawad AH, MacPherson CA, Caritis SN, Miodovnik M, Menard KM, Thurnau GR, Sorokin Y. The Preterm Prediction Study: association between maternal body mass index and spontaneous and indicated preterm birth. Am J Obstet Gynecol. 2005;192(3):882-6.

8. Mercer BM, Goldenberg RL, Moawad AH, et al. The preterm prediction study: effect of gestational age and cause of preterm birth on subsequent obstetric outcome. National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Am J Obstet Gynecol 1999; 181: 1216–21.

9. DeFranco EA, Lewis DF, Odibo AO. Improving the screening accuracy for preterm labor: is the combination of fetal fibronectin and cervical length in symptomatic patients a useful predictor of preterm birth? A systematic review. Am J Obstet Gynecol. 2013;208(3):233.e1-6.

10. Gomez R, Romero R, Medina L, Nien JK, Chaiworapongsa T, Carstens M, Gonzalez R, Espinoza J, Iams JD, Edwin S, Rojas I. Cervicovaginal fibronectin improves the prediction of preterm delivery based on sonographic cervical length in patients with preterm uterine contractions and intact membranes. Am J Obstet Gynecol. 2005;192:350-9

11. Sanchez-Ramos L, Delke I, Zamora J, Kaunitz AM. Fetal fibronectin as a short-term predictor of preterm birth in symptomatic patients: a meta-analysis. Obstet Gynecol 2009; 114(3):631-640

12. McPheeters ML, Miller WC, Hartmann KE, Savitz DA, Kaufman JS, Garrett JM et al. The epidemiology of threatened preterm labor: a prospective cohort study. Am J Obstet Gynecol 2005; 192(4):1325-1329

13. Honest H, Bachmann LM, Coomarasamy A, Gupta JK, Kleijnen J, Khan KS. Accuracy of cervical transvaginal sonography in predicting preterm birth: a systematic review. Ultrasound Obstet Gynecol. 2003;22:305-22

14. Sotiriadis A, Papatheodorou S, Kavvadias A, Makrydimas G. Transvaginal cervical length measurement for prediction of preterm birth in women with threatened preterm labor: a meta-analysis. Ultrasound Obstet Gynecol 2010; 35(1):54-64.

15. Wiegerinck MM, Vis JY, Mol BW. Re: Transvaginal cervical length measurement for prediction of preterm birth in women with threatened preterm labor: a meta-analysis. Ultrasound Obstet Gynecol 2010; 35(6):756-757.

16. Goldenberg RL, Mercer BM, Meis PJ, Copper Rl, Das A, McNellis D. The preterm prediction study: fetal fibronectin testing and spontaneous preterm birth. NICHD Maternal fetal medicine units network. Obstet Gynecol 1996;87:643-8

17. Honest H, Bachmann LM, Gupta JK, Kleijnen J, Khan KS. Accuracy of cervicovaginal fetal fibronectin test in predicting risk of spontaneous preterm birth: systematic review. BMJ. 2002;325:301

18. Schmitz T, Maillard F, Bessard-Bacquaert S, Kayem G, Fulla Y, Cabrol D, Goffinet F. Selective use of fetal fibronectin detection after cervical length measurement to predict spontaneous preterm delivery in women with preterm labor. Am J Obstet Gynecol. 2006;194:138-43.

19. Ness A. Prevention of preterm birth based on short cervix: symptomatic women with preterm labor or premature prelabor rupture of membranes. Semin. Perinatol. 2009;33:343-351

20. Tsoi E, Akmal S, Geerts L, Jeffery B, Nicolaides KH, Sonographic measurement of cervical length and fetal fibronectin testing in threatened preterm labour. Ultrasound Obs Gyn 2006;27:368-72

21. McKenna DS, Chung K, Iams JD. Effect of digital cervical examination on the expression of fetal fibronectin. J Reprod Med. 1999;44:796-800.

28712 Wilms.indd 16 30-03-14 12:54

1

Introduction

17

22. Institute of Medicine (US) Committee on Understanding Premature Birth and Assuring Healthy Out-comes; Behrman RE, Butler AS, editors. Preterm Birth: Causes, Consequences, and Prevention. Wash-ington (DC): National Academies Press (US); 2007. 10, Mortality and Acute Complications in Preterm Infants. Available from: http://www.ncbi.nlm.nih.gov/books/NBK11385

23. Bonanno C, Wapner RJ. Antenatal corticosteroid treatment: what’s happened since Drs Liggins and Howie? Am J Obstet Gynecol. 2009;200(4):448-57.

24. Iams JD. Prediction and early detection of preterm labor. Obstet Gynecol 2003;101:402-41225. King JF, Flenady VG, Papatsonis DN, Dekker JA, Carbonne B. Calcium channel blocker for inhibiting

preterm labour. Cochrane Database Systematic Review 2003: CD00225526. Papatsonis D, Flenady V, Cole S, Liley H. Oxytocin receptor antagonists for inhibiting preterm labour.

Cochrane Database Syst Rev. 2005:CD00445227. Liggins GC, Howie RN, A controlled trial of antepartum glucocorticoid treatment for prevention of the

respiratory distress syndrome in premature infants. Pediatrics 1972;50:515-25 28. Crowley P, Chalmers I, Keirse MJ. The effects of corticosteroid administration before preterm delivery: an

overview of the evidence from controlled trials. Br J Obstet Gynaecol 1990;97(1):11-2529. Crowley PA. Antenatal corticosteroid therapy: A meta-analysis of the randomized trials, 1972 to 1994.

Am J Obstet Gynecol 1995;175:322-35.30. Roberts D, Dalziel S. Antenatal corticosteroids for accelerating fetal lung maturation for women at risk

of preterm birth. Cochrane Database of Systematic Reviews 2006, Issue 3.31. Liggins GC. Premature delivery of foetal lambs infused with glucocorticoids. J Endocrinol 1969;45:515-

23.32. Leviton LC, Baker S, Hassol A, Goldenberg RL. An exploration of opinion and practice patterns affecting

low use of antenatal corticosteroids. Am J Obstet Gynecol 1995;173:312-6. 33. NIH consensus development panel on the effect of corticosteroids for fetal maturation on perinatal

outcomes. Effect of corticosteroids for fetal maturation on perinatal outcome. JAMA 1995;273:413-8. 34. Vermillion ST, Soper DE, Newman RB. Is betamethasone effective longer than 7 days after treatment?

Obstet Gynecol 2001;97:491-3.35. Peaceman AM, Bajaj K, Kumar P, Grobman WA. The interval between a single course of antenatal

steroids and delivery and its association with neonatal outcomes. Am J Obstet Gynecol 2005;193:1165-9.

36. Sehdev HM, Abbasi S, Robertson P, et al. The effects of the time interval from antenatal corticosteroid exposure to delivery on neonatal outcome of very low birth weight infants. Am J Obstet Gynecol 2004;191:1409-13.

37. Ring AM, Garland JS, Stafeil BR, et al. The effect of a prolonged time interval between antenatal corticosteroid administration and delivery on outcomes in preterm neonates: a cohort study. Am J Obstet Gynecol 2007;196:457.e1-6.

38. Planer B. Antenatal corticosteroid (ANCS) use in preterm labor in the USA. Pediatr Res 1996;39:110A.39. Quinlivan JA, Evans SF, Dunlop SA, Beazley LD,NewnhamJP. Use of corticosteroids by Australian

obstetricians—a survey of clinical practice. Aust N Z J Obstet Gynaecol 1998;38:1-740. Brocklehurst P, Gates S, McKenzie-McHarg K, Alfirevic Z, Chamberlain G. Are we prescribing multiple

courses of antenatal corticosteroids? A survey of practice in the UK. BJOG 1999;106:977-9.41. NIH consensus development conference statement. Antenatal corticosteroids revisited: repeat courses.

Obstet Gynecol 2001;98:144-50. 42. Crowther CA, Haslam RR, Hiller JE, Doyle LW, Robinson JS. Neonatal respiratory distress syndrome after

repeat exposure to antenatal corticosteroids: a randomised controlled trial. Lancet 2006;367:1913-9. 43. Wapner RJ, Sorokin Y, Thom EA, et al. Single versus weekly courses of antenatal corticosteroids:

evaluation of safety and efficacy. Am J Obstet Gynecol 2006;195:633-42.44. Crowther CA, Harding JE. Repeat doses of prenatal corticosteroids for women at risk of preterm birth

for preventing neonatal respiratory disease. Cochrane Database Syst Rev 2007;3: CD003935. 45. Murphy KE, Hannah ME, Willan AR, et al. Multiple courses of antenatal corticosteroids for preterm birth

(MACS): a randomised controlled trial. Lancet 2008;372:2143-51.

46. Crowther CA, Doyle LW, Haslam RR, Hiller JE, Harding JE, Robinson JS. Outcomes at 2 years of age after repeat doses of antenatal corticosteroids.N Engl J Med 2007;357:1179-89.

47. Wapner RJ, Sorokin Y, Mele L, et al. Longterm outcomes after repeat doses of antenatal corticosteroids. N Engl J Med 2007;357:1190-8.

48. ACOG Committee on Obstetric Practice. ACOG Committee Opinion No. 475: Antenatal corticosteroid therapy for fetal maturation. Obstet Gynecol. 2011;117(2 Pt 1):422-4

28712 Wilms.indd 17 30-03-14 12:54

49. Garite TJ, Kurtzman J, Maurel K, et al. Impact of a ‘rescue course’ of antenatal corticosteroids: a multi-center randomized placebo-controlled trial. Am J Obstet Gynecol 2009;200:248.e1-248.e9.

50. McEvoy C, Schilling D, Peters D, et al. Respiratory compliance in preterm infants after a single rescue course of antenatal steroids: a randomized controlled trial. Am J Obstet Gynecol 2010;202:544.e1-9.

51. NVOG richtlijn “dreigende vroeggeboorte” 2011 http://nvog-documenten.nl/uploaded/docs/Dreigende%20vroeggeboorte.

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