Induction of labour versus expectant monitoring for gestational hypertension or mild pre-eclampsia after 36 weeks' gestation (HYPITAT): a multicentre, open-label randomised controlled trial.
BACKGROUND
Robust evidence to direct management of pregnant women with mild hypertensive disease at term is scarce. We investigated whether induction of labour in women with a singleton pregnancy complicated by gestational hypertension or mild pre-eclampsia reduces severe maternal morbidity.


METHODS
We undertook a multicentre, parallel, open-label randomised controlled trial in six academic and 32 non-academic hospitals in the Netherlands between October, 2005, and March, 2008. We enrolled patients with a singleton pregnancy at 36-41 weeks' gestation, and who had gestational hypertension or mild pre-eclampsia. Participants were randomly allocated in a 1:1 ratio by block randomisation with a web-based application system to receive either induction of labour or expectant monitoring. Masking of intervention allocation was not possible. The primary outcome was a composite measure of poor maternal outcome--maternal mortality, maternal morbidity (eclampsia, HELLP syndrome, pulmonary oedema, thromboembolic disease, and placental abruption), progression to severe hypertension or proteinuria, and major post-partum haemorrhage (>1000 mL blood loss). Analysis was by intention to treat and treatment effect is presented as relative risk. This study is registered, number ISRCTN08132825.


RESULTS
756 patients were allocated to receive induction of labour (n=377 patients) or expectant monitoring (n=379). 397 patients refused randomisation but authorised use of their medical records. Of women who were randomised, 117 (31%) allocated to induction of labour developed poor maternal outcome compared with 166 (44%) allocated to expectant monitoring (relative risk 0.71, 95% CI 0.59-0.86, p<0.0001). No cases of maternal or neonatal death or eclampsia were recorded.


CONCLUSIONS
Induction of labour is associated with improved maternal outcome and should be advised for women with mild hypertensive disease beyond 37 weeks' gestation.


BACKGROUND
ZonMw.
Koopmans
Corine M
CM
University Medical Centre, Groningen, Netherlands. Electronic address: c.m.koopmans@og.umcg.nl.
Bijlenga
Denise
D
Academic Medical Centre, Amsterdam, Netherlands.
Groen
Henk
H
University Medical Centre, Groningen, Netherlands.
Vijgen
Sylvia Mc
SM
Academic Medical Centre, Amsterdam, Netherlands.
Aarnoudse
Jan G
JG
University Medical Centre, Groningen, Netherlands.
Bekedam
Dick J
DJ
Onze Lieve Vrouwe Gasthuis, Amsterdam, Netherlands.
van den Berg
Paul P
PP
University Medical Centre, Groningen, Netherlands.
de Boer
Karin
K
Hospital Rijnstate, Arnhem, Netherlands.
Burggraaff
Jan M
JM
Scheper Hospital, Emmen, Netherlands.
Bloemenkamp
Kitty Wm
KW
Leiden University Medical Centre, Netherlands.
Drogtrop
Addy P
AP
Twee Steden Hospital, Tilburg, Netherlands.
Franx
Arie
A
Sint Elisabeth Hospital, Tilburg, Netherlands.
de Groot
Christianne Jm
CJ
Medical Centre Haaglanden, Den Haag, Netherlands.
Huisjes
Anjoke Jm
AJ
Gelre Hospital, Apeldoorn, Netherlands.
Kwee
Anneke
A
University Medical Centre, Utrecht, Netherlands.
van Loon
Aren J
AJ
Martini Hospital, Groningen, Netherlands.
Lub
Annemiek
A
Spaarne Hospital, Hoofddorp, Netherlands.
Papatsonis
Dimitri Nm
DN
Amphia Hospital, Breda, Netherlands.
van der Post
Joris Am
JA
Academic Medical Centre, Amsterdam, Netherlands.
Roumen
Frans Jme
FJ
Atrium Medical Centre, Heerlen, Netherlands.
Scheepers
Hubertina Cj
HC
University Medical Centre St Radboud, Nijmegen, Netherlands.
Willekes
Christine
C
University Hospital Maastricht, Netherlands.
Mol
Ben Wj
BW
Academic Medical Centre, Amsterdam, Netherlands; Maxima Medical Centre, Veldhoven, Netherlands.
van Pampus
Maria G
MG
University Medical Centre, Groningen, Netherlands.
D000037:Abruptio Placentae / Q000453:epidemiology; D000328:Adult; D004461:Eclampsia / Q000453:epidemiology; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D005865:Gestational Age; D017359:HELLP Syndrome / Q000453:epidemiology; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology / Q000628:therapy*; D007751:Labor, Induced / Q000379:methods*; D016015:Logistic Models; D008428:Maternal Mortality; D009426:Netherlands / Q000453:epidemiology; D018579:Patient Selection; D006473:Postpartum Hemorrhage / Q000453:epidemiology; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000628:therapy*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology; D011654:Pulmonary Edema / Q000453:epidemiology; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013923:Thromboembolism / Q000453:epidemiology