Maternal and neonatal outcomes of pregnancy in women with chronic hypertension: a retrospective analysis of a national register.
BACKGROUND
Pregnancies complicated by chronic hypertension are at increased risk of adverse pregnancy outcomes. To assess whether planned early delivery might prevent some of these adverse outcomes, we studied maternal and neonatal outcomes of pregnancy in women with chronic hypertension, including gestational-age-specific outcomes.


METHODS
We performed a retrospective, population-based cohort study, using data from the Netherlands Perinatal Register. We included women with chronic hypertension and normotensive controls who delivered a singleton without congenital anomalies in 2002-2007. We calculated crude and adjusted odds ratios (OR) with 95% CI, compared delivery and ongoing pregnancy using moving averages, and used multiple Cox regression to adjust for differences in baseline characteristics and to examine adverse neonatal outcomes across subgroups of hypertensive disorder. Main outcome measures were composite adverse maternal and neonatal outcomes.


RESULTS
We included 3457 (0.3%) women with chronic hypertension and 984 932 normotensive controls. Women with chronic hypertension had adverse maternal outcomes more often (28.7% vs. 6.6%, adjusted OR 5.7, 95% CI 5.3-6.2). Their offspring had an increased rate of neonatal morbidity (17.4% vs. 13.2%, adjusted OR 1.2, 95% CI 1.1-1.4) but not of severe adverse neonatal outcomes (2.5% vs. 2.2%, adjusted OR 0.8, 95% CI 0.6-1.0). The increased risk of adverse maternal outcomes for ongoing pregnancy remained stable around 17% at term. The risk of severe adverse neonatal outcomes for birth was at its lowest between 38 and 40 weeks, mainly in women with iatrogenic onset of delivery.


CONCLUSIONS
Women with chronic hypertension are at increased risk of adverse maternal and neonatal outcomes compared with controls throughout pregnancy, including at term. Our results suggest that the optimal timing of delivery might be between 38 and 40 weeks of gestation, but prospective randomized studies should confirm this.
Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
Kim
http://orcid.org/0000-0002-0441-7108
K
Broekhuijsen
Department of Medical Informatics, Academic Medical Center, Amsterdam, the Netherlands.
Anita C J
http://orcid.org/0000-0002-3447-8286
AC
Ravelli
Department of Obstetrics and Gynecology, Atrium Medical Center, Heerlen, the Netherlands.
Josje
http://orcid.org/0000-0003-0107-2332
J
Langenveld
Department of Obstetrics and Gynecology, Onze Lieve Vrouwe Gasthuis Hospital, Amsterdam, the Netherlands.
Mariëlle G
http://orcid.org/0000-0002-3020-8908
MG
van Pampus
Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
Paul P
http://orcid.org/0000-0003-2241-3001
PP
van den Berg
Department of Obstetrics and Gynecology, University of Amsterdam, Academic Medical Center, Amsterdam, the Netherlands.
Ben W J
http://orcid.org/0000-0001-8337-550X
BW
Mol
Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
Maureen T M
http://orcid.org/0000-0001-6887-0262
MT
Franssen
D000328:Adult; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007231:Infant, Newborn; D009426:Netherlands; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000503:physiopathology*; D011256:Pregnancy Outcome; D012042:Registries; D012189:Retrospective Studies
Hypertension in pregnancy; eclampsia; morbidity; mortality; neonatology; preeclampsia