Skip to main content

Table 1 Characteristics of the included studies, N = 14

From: Immediate versus delayed induction of labour in hypertensive disorders of pregnancy: a systematic review and meta-analysis

S.No Author and year Country Study Design Inclusion criteria Sample size in early induction arm Sample size in delayed induction arm Gestational age of onset Severity of pre-eclampsia Intervention
1. Bhageerathy et al. 2016 [22] India Randomized Controlled Trial All women with a singleton pregnancy, aged 18 to 35 years, with cephalic presentation at 37 to 40 weeks of gestation, with mild gestational hypertension. Systolic BP between 140 and 159 mm of Hg and a diastolic BP between 90 and 100 mm of Hg (Korotkoff Phase V) repeated after 4 h were recruited 49 51 37–39.5 weeks (late onset) Mild Experimental intervention: For those in the immediate induction arm (group 1), a vaginal examination was done to assess the Bishop’s score. If the score was 6 or more, artificial rupture of membranes with or without oxytocin augmentation was done within 12 h of randomization. If the score was less than 6, cervical ripening was done with PGE1 (25 microgram 6th hourly for 2 doses) as is the routine for induction of labour in our hospital.
Comparison/control intervention: For those allocated to the conservative management arm (group 2), pregnancy induced hypertension (PIH) work up which included platelet count, serum creatinine, serum transaminases (SGOT, SGPT), lactate dehydrogenase (LDH) and blood picture was done. They were advised daily home blood pressure (BP) monitoring by a local doctor or nurse who recorded it.
2. Boers et al. 2010 [15] Netherlands Randomized Controlled Trial Pregnant women between 36 + 0 and 41 + 0 weeks’ gestation who had a singleton fetus in cephalic presentation, suspected intrauterine growth restriction, and who were under specialised obstetric care were recruited. 321 329 36 weeks (Late onset) Mild Experimental intervention: Participants allocated to the induction of labour group were induced within 48 h of randomisation. If the Bishop score at randomisation was greater than 6, labour was induced with amniotomy and, if necessary, augmented with oxytocin
Comparison/Control intervention: Participants allocated to the expectant monitoring group were monitored until the onset of spontaneous labour with daily fetal movement counts and twice weekly heart rate tracings, ultrasound examination, maternal blood pressure measurement, assessment of proteinuria, laboratory tests of liver and kidney function, and full blood count.
3. Broekhuijsen et al. 2015 [23] Netherlands Randomized controlled trial Women were eligible if they had gestational hypertension, pre-eclampsia, deteriorating pre-existing hypertension, or superimposed pre-eclampsia, and had a gestational age of 34 weeks up to and including 36 weeks.
Gestational hypertension: diastolic blood pressure of 100 mmHg or more, on at least two occasions, 6 h apart, in women without pre-existing hypertension (defined as a blood pressure ≥ 140/90 mmHg before 20 weeks of gestation).
Pre-eclampsia: diastolic blood pressure of 90 mmHg or more on at least two occasions, 6 h apart, combined with proteinuria, also in women without pre-existing hypertension.
352 351 34–37 weeks (Late onset) Mild Experimental intervention: planned early delivery with an induction of labour started within 24 h after randomisation
Control/Comparison intervention: expectant monitoring until 37 weeks of GA
4. Chappell et al. 2019 [24] United Kingdom Randomized controlled trial Pregnant woman was eligible if she had a diagnosis of pre-eclampsia or superimposed pre-eclampsia (as defined by the International Society for the Study of Hypertension in Pregnancy) with a singleton or dichorionic diamniotic twin pregnancy and at least one viable fetus, was aged 18 years or older, and was able to give written informed consent. Women with any other comorbidity (including pre-existing hypertension or diabetes) or with a previous caesarean section or any foetal position were eligible. 471 475 Early onset Severe Experimental intervention: induction of labour
Control/Comparison intervention: expectant management
5. Duvekot et al. 2015 [25] Netherlands Randomized controlled Trial Women between 28 + 0 and 34 + 0 weeks of gestation after admission for severe preeclampsia with or without HELLP syndrome 25 30 28–34 weeks (Early onset) Severe Experimental intervention: induction of labour
Control/Comparison intervention: expectant management
6. GRIT study group 2013 [26] 13 European countries Randomized controlled trial Singleton or multiple pregnancies where the responsible clinician was uncertain whether to deliver the baby immediately, the gestational age was between 24 and 36 weeks and the umbilical artery Doppler waveform had been recorded 273 274 24–36 weeks (Early onset) Mild Experimental intervention: induction of labour
Control/Comparison intervention: expectant management
7. Hamed et al. 2014 [16] Saudi Arabia and Egypt Randomized controlled Trial Mild to moderate essential chronic hypertension without proteinuria, singleton pregnancy, and gestational age at recruitment of 24–36 weeks.
Mild to moderate chronic hypertension was diagnosed if diastolic blood pressure was between 90 and 110 mmHg and/or systolic pressure was between 140 and 160 mmHg on two occasions at least 6 h apart in the first half of pregnancy, or if the patient was known to be hypertensive before pregnancy
38 38 24–36 weeks (early onset) Mild Experimental intervention: delivery at 37 completed weeks, provided that no maternal or fetal complications demanded elective preterm labour
Control/Comparison intervention: expectant management until the spontaneous onset of labour or 41 gestational weeks
8. Koopmans et al. 2009 [27] Netherlands Randomized controlled Trial Women with a singleton pregnancy and a fetus in cephalic presentation at a gestational age of between 36 (0 days) and 41 weeks (0 days), and who had gestational hypertension or mild pre-eclampsia.
Pre-eclampsia: diastolic BP > 90 mm on two occasions at least 6 h apart; proteinuria (two or more occurrences of protein on a dipstick, > 300 mg total protein within a 24-h urine collection, or ratio of protein to creatinine > 30 mg/mmol)
Gestational hypertension: diastolic BP 95 mmHg, on two occasions at least 6 h apart
377 379 36 weeks (late onset) Mild to moderate Experimental intervention: induction of labour within 24 h of randomisation
Control/Comparison intervention: expectant monitoring. They were monitored until the onset of spontaneous delivery, in hospital or outpatient setting, depending on the condition of the woman with frequent blood pressure measurements and testing of urine for protein of the mother.
9. Owens et al. 2014 [28] United States of America Randomized controlled Trial Late preterm patients with preeclampsia without severe features assigned to immediate delivery/ expectant management until 37 weeks gestation or earlier if severe features develop 94 75 34–37 weeks (late onset) Mild Experimental intervention: planned early delivery via induction of labour or caesarean delivery within 12 h of randomisation. All study participants were treated with magnesium sulphate prophylaxis intrapartum and immediately postpartum. 97 women were randomised, 3 were subsequently excluded for not meeting the inclusion criteria
Control/Comparison intervention: inpatient expectant management, to 37 weeks’ gestation unless there was spontaneous onset of labour or rupture of membranes, suspected placental abruption, development of severe PE of fetal compromise.
10. Majeed et al. 2014 [29] India Randomized controlled Trial Pregnant women at 36 - 40 weeks’ gestation, with mild pre-eclampsia/ gestational hypertension without proteinuria
Gestational Hypertension: systolic blood pressure ≥ 140 or diastolic blood pressure ≥ 90 mmHg for the first time during pregnancy without proteinuria. Mild pre-eclampsia: systolic blood pressure was 140–159 mmHg and diastolic blood pressure is 90–109 mmHg accompanied by proteinuria of > 0.3 g to < 5 g/24 h
50 50 36–40 weeks (late onset) Mild Experimental intervention: induction of labour
Control/Comparison intervention: expectant management
11. Mesbah EMM 2003 [30] Egypt Randomized controlled trial Pregnant women with severe PE between 28 and 33 + 6 days gestation. Severe PE was defined as a BP > 180/120 mmHg on 2 occasions, 30 min apart; or a BP between 160 to 180/110 to 120 mmHg on 2 occasions, 6 h apart. All participants had > 500 mg of proteinuria on a 24 h urine collection measure 15 15 32 weeks (Early onset) Severe Experimental Intervention: Administered dexamethasone phosphate; 48 h to lapse before either an induction of labour was attempted (50 μ, vaginal misoprostol) or caesarean section after 24 h
Control/Comparison Intervention:
Administered dexamethasone phosphate then managed conservatively with bed rest, observations and nifedipine to control BP. Indications for delivery were imminent eclampsia, deteriorating renal function, spontaneous preterm labour, absent EDF or a non-reassuring CTG reaching 34 weeks
12. Odendaal HJ et al. 1990 [32] Africa Randomized controlled trial Women with severe PE at 28 to 34 weeks’ gestation. Severe PE defined in 4 ways, depending on BP, proteinuria, and symptoms. Women were either already admitted for bedrest and later met criteria, or admitted because of severe PE, and after 48 h stabilisation met entry criteria 20 18 28–34 weeks (Early onset) Severe Experimental Intervention: Delivery by induction or caesarean section depending on obstetric circumstances 48 h after betamethasone. If cervix not favourable, prostaglandin E2 tablets. If still not favourable after 24 h, caesarean section
Control/Comparison intervention: Bed rest on high-risk obstetric ward; maternal and fetal condition monitored intensively; BP controlled with prazosin; delivery at 34 weeks unless indicated earlier
13. Sibai BM et al. 1994 [33] United States of America Randomized controlled trial Women with severe PE at 28 to 32 weeks’ gestation. Severe PE defined as a persistent elevation of BP ≥ 160/110 mmHg, proteinuria > 500 mg in 24 h, and uric acid > 5 mg/dL. 46 49 32 weeks (Early onset) Severe Experimental Intervention: Delivery by caesarean section or by induction of labour, on the basis of obstetric condition, 48 h after first dose of betamethasone
Control/Comparison intervention: Maternal and fetal monitoring on an antenatal ward. If either condition deteriorated, or reached 34 weeks’ gestation, delivery using the ‘most appropriate method’
15. Vigil De Gracia et al. 2013 [31] Latin America Randomized controlled trial Pregnant women between 28 and 33 weeks’ gestation with severe PE, severe gestational hypertension, and super-imposed PE 133 131 32 weeks (Early onset) Severe Experimental intervention: Prompt delivery’: glucocorticoid therapy followed by delivery in 24–72 h, magnesium sulphate continued until 24 h after delivery
Control/Comparison intervention: Treated expectantly: glucocorticoid therapy followed by delivery only for specific maternal/ fetal indications or reaching 34 weeks of gestation