Key messages
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Planned early birth leads to fewer complications for the woman, with no increase in the risk of caesarean section.
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Planned early birth probably reduces the risk of stillbirth and probably results in little to no difference in the risk of neonatal unit admission (special care baby unit). The effect on neonatal death is unclear.
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Further studies are needed to understand the effect of planned early birth on the longer-term health of women and children.
What is high blood pressure during pregnancy?
High blood pressure affects 1 in 10 pregnancies. Women who have high blood pressure during pregnancy are more at risk of developing complications. Pre-eclampsia (high blood pressure with protein in the urine or affecting other organs) is the most serious type of high blood pressure problem during pregnancy and is caused when there is a problem affecting the placenta.
If high blood pressure is not detected and treated early, complications can develop. These can include seizures (eclampsia), stroke, abnormal blood and liver function (HELLP syndrome), difficulty breathing because of fluid in the lungs (pulmonary oedema), detachment of the placenta (placental abruption), liver failure and kidney failure. The baby may also be affected, as it may not grow as well. This may lead to the baby needing more support after birth and a higher chance of admission to the special care baby unit. Sadly, it can also cause the baby to be stillborn.
How is high blood pressure during pregnancy treated?
For women who have high blood pressure in pregnancy, careful monitoring is advised, which may include regular blood pressure and urine checks as well as blood tests and ultrasound scans. Some women may need to take medication to help keep their blood pressure in a safe range.
Planned early birth is the only treatment that has been shown to reduce the risk of serious complications developing, but the timing of birth depends on what stage of pregnancy is reached and whether there are signs or symptoms of complications, as well as the type of blood pressure problem.
For women who have high blood pressure early in pregnancy (less than 34 weeks), careful monitoring is advised unless serious complications develop, because of the risks to the baby associated with early preterm birth. Later in pregnancy (after 34 weeks), the balance of risks and benefits is less certain.
What did we want to find out?
We wanted to find out if planned early birth for women who have high blood pressure in pregnancy after 34 weeks was better than careful monitoring (expectant management) at reducing complications for women and babies. We also wanted to find out if planned early birth was associated with any unwanted effects.
What did we do?
We searched for studies that looked at planned early birth compared with careful monitoring for women with any type of high blood pressure problem during pregnancy, after 34 weeks. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found six studies that involved 3491 women with high blood pressure during pregnancy conducted between 2002 and 2022. Five of these studies took place in high-income countries (UK, The Netherlands, USA). One of these studies took place in two countries classified as low income (Zambia) and lower-middle income (India). The timing of planned early birth varied between the trials, depending on the time that the trial took place and the type of high blood pressure problem that was evaluated.
Main results
Planned early birth reduces complications for women with high blood pressure in pregnancy after 34 weeks. Planned early birth after 34 weeks did not increase the risk of caesarean section. Planned early birth may result in little to no difference in the risk of maternal death.
For the baby, planned early birth likely results in a large reduction in the risk of stillbirth, but likely results in little to no difference in the risk of neonatal unit admission. Planned early birth may result in little to no difference in the overall risk of serious complications after birth, including neonatal death, but we are very uncertain about the results.
What are the limitations of the evidence?
We are confident in our results for the effect of planned early birth on the overall risk of complications for women and the risk of caesarean section. We are less confident in our results for the effect on the babies, because of the low number of unwanted effects reported.
How up to date is this evidence?
This review updates our previous review. The evidence is up to date to 16 January 2026.
Read the full abstract
Hypertensive disorders in pregnancy are significant contributors to maternal and perinatal morbidity and mortality. These disorders include well-controlled chronic hypertension, gestational hypertension (pregnancy-induced hypertension) and mild pre-eclampsia. The definitive treatment for these disorders is planned early delivery and the alternative is to manage the pregnancy expectantly if severe uncontrolled hypertension is not present, with close maternal and fetal monitoring. There are benefits and risks associated with both, so it is important to establish the safest option.
Objectives
To assess the benefits and risks of planned early birth versus expectant management in pregnant women with hypertensive disorders, from 34 weeks' gestation onwards.
Search strategy
An Information Specialist within the Cochrane Central Executive Team searched CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov and WHO ICTRP. The searches were run from 1 January 2016 to 16 January 2026 with no language restrictions. Reference lists of retrieved studies were also searched.
Selection criteria
Randomised trials of a policy of planned early delivery (by induction of labour or by caesarean section) compared with a policy of delayed delivery ("expectant management") for women with hypertensive disorders from 34 weeks' gestation. Cluster-randomised trials would have been eligible for inclusion in this review, but we found none.
Studies using a quasi-randomised design are not eligible for inclusion in this review. Similarly, studies using a cross-over design are not eligible for inclusion, because they are not a suitable study design for investigating hypertensive disorders in pregnancy.
Data collection and analysis
Two review authors independently assessed eligibility and risks of bias. Two review authors independently extracted data. Data were checked for accuracy.
Main results
We included five studies (involving 1819 women) in this review.
There was a lower risk of composite maternal mortality and severe morbidity for women randomised to receive planned early delivery (risk ratio (RR) 0.69, 95% confidence interval (CI) 0.57 to 0.83, two studies, 1459 women (evidence graded high)). There were no clear differences between subgroups based on our subgroup analysis by gestational age, gestational week or condition. Planned early delivery was associated with lower risk of HELLP syndrome (RR 0.40, 95% CI 0.17 to 0.93, 1628 women; three studies) and severe renal impairment (RR 0.36, 95% CI 0.14 to 0.92, 100 women, one study).
There was not enough information to draw any conclusions about the effects on composite infant mortality and severe morbidity. We observed a high level of heterogeneity between the two studies in this analysis (two studies, 1459 infants, I2 = 87%, Tau2 = 0.98), so we did not pool data in meta-analysis. There were no clear differences between subgroups based on our subgroup analysis by gestational age, gestational week or condition. Planned early delivery was associated with higher levels of respiratory distress syndrome (RR 2.24, 95% CI 1.20 to 4.18, three studies, 1511 infants), and NICU admission (RR 1.65, 95% CI 1.13 to 2.40, four studies, 1585 infants).
There was no clear difference between groups for caesarean section (RR 0.91, 95% CI 0.78 to 1.07, 1728 women, four studies, evidence graded moderate), or in the duration of hospital stay for the mother after delivery of the baby (mean difference (MD) -0.16 days, 95% CI -0.46 to 0.15, two studies, 925 women, evidence graded moderate) or for the baby (MD -0.20 days, 95% CI -0.57 to 0.17, one study, 756 infants, evidence graded moderate).
Two fairly large, well-designed trials with overall low risk of bias contributed the majority of the evidence. Other studies were at low or unclear risk of bias. No studies attempted to blind participants or clinicians to group allocation, potentially introducing bias as women and staff would have been aware of the intervention and this may have affected aspects of care and decision-making.
The level of evidence was graded high (composite maternal mortality and morbidity), moderate (caesarean section, duration of hospital stay after delivery for mother, and duration of hospital stay after delivery for baby) or low (composite infant mortality and morbidity). Where the evidence was downgraded, it was mostly because the confidence intervals were wide, crossing both the line of no effect and appreciable benefit or harm.
Authors' conclusions
For women with hypertensive disorders of pregnancy beyond 34 weeks' gestation, planned early birth is associated with a lower risk of maternal complications, and probably a reduced risk of fetal death (stillbirth), with no increased risk of caesarean section and probably no clear differences in the rate of neonatal unit admission or short-term neonatal morbidity.
It is important that the timing of delivery takes into account the woman's preferences, the type of hypertensive disorder and the presence or absence of severe features.
Further information is needed to establish the longer-term infant outcomes associated with late preterm birth and longer-term maternal cardiovascular health.
Funding
This Cochrane review had no dedicated funding.
Registration
The original review and review protocol can be accessed via the following links.
Protocol (2011): DOI: 10.1002/14651858.CD009273
Original review (2017): DOI: 10.1002/14651858.CD009273.pub2
