A major international review has found that planning an early birth for pregnant women suffering from high blood pressure can dramatically reduce life-threatening complications for mothers and may also lower the risk of stillbirth without increasing the chances of a caesarean section — a finding experts say could help doctors and families make faster and safer decisions during complicated pregnancies.

The evidence comes from a new review by Cochrane, led by researchers from King’s College London, which analysed six randomised clinical trials involving 3,491 pregnant women across India, Zambia, the United Kingdom, the United States, and the Netherlands.

The study focused on hypertensive disorders during pregnancy—a group of conditions that includes pre-eclampsia, gestational hypertension, and chronic high blood pressure. Doctors say these disorders are among the leading causes of maternal deaths worldwide and can rapidly become fatal if not treated in time.

Pre-eclampsia, one of the most feared pregnancy complications, happens when blood pressure rises dangerously during pregnancy and causes damage to organs such as the liver, kidneys, and brain. In severe cases, it can trigger seizures, strokes, organ failure or death for both mother and baby. The condition is linked to the placenta, meaning it only fully resolves once the baby and placenta are delivered.

The review found strong evidence that planning an early birth after 34 weeks of pregnancy nearly halved serious maternal complications compared to “watchful waiting”, where doctors continue monitoring the mother while delaying delivery in the hope of extending the pregnancy safely.

Researchers also found that planned early birth likely reduced the risk of stillbirth by around 75 per cent. However, the authors cautioned that this finding was mainly driven by one trial conducted in India and Zambia, where stillbirth rates remain significantly higher than in many richer countries. The trials conducted in high-income nations reported no stillbirths.

Importantly, the review found no rise in neonatal intensive care admissions among babies delivered early. It also found no increased risk of caesarean delivery — an issue that often worries expectant mothers when doctors discuss early induction.

“These findings give clinicians and women clearer guidance about the timing of birth when high blood pressure develops in pregnancy,” said Prof. Catherine Cluver of Stellenbosch University and Tygerberg Hospital. “For women with pre-eclampsia in particular, the evidence supports offering planned early birth from 34 weeks and no later than 37 weeks.”

Doctors involved in the review said the findings reflect a difficult reality seen daily inside maternity wards. Women who initially appear stable can deteriorate suddenly within hours.

“Judging when to offer birth is the question that we battle with clinically every day,” said Dr Alice Beardmore-Grey.

The review noted that in two of the trials, more than half the women assigned to watchful waiting eventually required emergency delivery before reaching 37 weeks — often only three to five days later than women who underwent planned early birth, but with more complications already developing.

“A common misconception is that by waiting longer, mum and baby are gaining more time, but often what you are doing is just delaying an inevitable emergency birth, when both may be in a worse condition,” Dr Beardmore-Grey explained.

Researchers said one of the most reassuring findings was the absence of increased caesarean risk.

“That is the first question anyone asks when you offer them an early induction: won't it increase my risk of a C-section?” Dr Beardmore-Grey said. “Being able to clearly answer 'no' is a really important piece of information to give women when counselling them about the timing of their birth.”

Global health agencies, including the World Health Organization, have repeatedly warned that high blood pressure during pregnancy remains a major but often under-recognised maternal health threat, especially in low- and middle-income countries where access to emergency obstetric care can be uneven.

The authors said treatment decisions should still consider the severity of the condition and the woman’s preferences. They added that more research is needed to understand the long-term health effects on babies born slightly early and the future cardiovascular risks faced by mothers who develop hypertension during pregnancy.