- Hypertensive disorders of pregnancy are fairly common, affecting
nearly 10 percent pregnancies.
- Women with hypertension disorders during pregnancy have an
increased risk of post-pregnancy hypertension, heart disease and stroke.
- Current study suggests that these women should have regular blood
pressure monitoring, starting immediately postpartum to prevent
(PIH) have a significantly higher risk of
developing hypertension during their life and regular blood pressure checks,
starting post-delivery, are important to prevent complications such as heart
disease and strokes, according to a recent nationwide study in Denmark
published in the British Medical Journal
Hypertension Risk in Women With PIH -
What Is New In Current Study
The research team feels that existing research to determine
future hypertension risk in women
with PIH does not clearly outline exactly when the
risk of hypertension appears postpartum and how the risk changes over time
These answers would provide valuable evidence based on which recommendations
for blood pressure checks and appropriate interventions post-delivery can be
The study team set out to answer these
questions in their study.
‘Women who suffer from pregnancy-induced hypertension should begin blood pressure monitoring starting immediately postpartum to prevent long-term heart disease risk.’
Risk Post-delivery in PIH - The Study
For the study, the team used two cohorts,
conducted among pregnant women nationwide across Denmark.
Findings of The Study - Cumulative
Incidences of Post-pregnancy Hypertension
- All pregnancies,
more than 20 weeks ending in live or stillbirths from 1995-2012 to estimate the cumulative
risk of post-pregnancy hypertension. This study included 482972
- All women who had at least one
pregnancy more than 20 weeks ending in live or stillbirths between 1978-2012 who were living in
Denmark at some point during the followup from 1995-2012. This group was
used for hazard ratio (relative
risk) estimation of post-pregnancy hypertension and included 1025118
Relative Risk of
- In the first cohort, 22,235
(4.8%) were diagnosed with hypertension in their first pregnancy, and
16 611 (3.4%) developed hypertension subsequent during follow-up.
- Women who were normotensive during first pregnancy in their 20s, 30s, or 40s
had cumulative incidences of hypertension of 4.0%, 5.7%, and 11.3%, respectively, in the 10 years (decade)
- The corresponding cumulative
incidences for women whose first pregnancy was complicated by a hypertension were 13.7%, 20.3%, and 32.4%, respectively.
- A similar pattern was noted in the
decade following a second pregnancy in women with two pregnancies, where
either pregnancy could have been complicated by hypertensive disorder.
- In the second cohort of 1025118
women, 59 319 (5.8%) had one or more pregnancies complicated by
hypertensive disorders between 1978 and 2012; 183 423 developed
hypertension during follow-up (1995-2012).
- In the first year post-delivery incidence of post-pregnancy hypertension
was 12-fold to 25-fold higher in women with a hypertensive disorder of
pregnancy than in women who had normal blood pressure during pregnancy
to five years postpartum, hypertension
rates were four to 10-fold higher in
women with a hypertensive disorder of pregnancy following the most recent
- Subsequently, the hazard ratios decreased in
women with PIH,
but even after 20 years their
hypertension rates were twice as
higher compared to women with normotensive pregnancies.
Interestingly for women aged more than 30
years into their first pregnancy, gestational
hypertension was associated with an increased risk of post-delivery
hypertension than preeclampsia
(a more severe hypertensive disorder of
pregnancy) suggesting that the pathophysiology of gestational and essential
hypertension might be similar.
Sequence Of Hypertension In Women With Two Pregnancies -
How It Affects Post-delivery Hypertension
Takeaway From The Study
- Having a hypertensive disorder of
pregnancy in the first pregnancy but not in the second was associated with
a doubling of the rate of post-pregnancy hypertension, compared to having
- The risks were even higher in women with a normotensive first
pregnancy and a hypertensive disorder in the second pregnancy.
- The largest (hazard ratio range
2.6-7.8) in women with hypertensive disorders affecting both pregnancies.
The important takeaway from the study is
that increased risk of post-delivery
hypertension appears immediately
after a hypertensive pregnancy.
risk is in the first year,
gradually decreasing but still persists even after 20 years
when the risk of post-delivery
hypertension is twice as much in women who have had hypertensive pregnancies
than those with normal pregnancies.
of blood pressure
in women with PIH should begin immediately postpartum
and continue longterm. This
would ensure early diagnosis and putting in place appropriate measures to
reduce or prevent complications such as heart disease later in life.
Hypertensive Disorders of Pregnancy
Hypertensive disorders during pregnancy
are common, occurring in up to 10
percent of all pregnancies
, and include gestational hypertension, preeclampsia
(which is a combination of high
blood pressure and proteinuria), and eclampsia, which comprises seizures in
women with preeclampsia. High blood pressure develops after 20 weeks gestation and becomes normal following delivery
Women with hypertensive disorders
associated with pregnancy are at increased
risk of developing essential hypertension, ischemic heart disease and stroke
, prompting the American Heart
Association and the European Society of Cardiology to add hypertensive
disorders of pregnancy as risk factors for cardiovascular disease in women
In conclusion, women diagnosed with
hypertensive disorder during pregnancy should discuss periodic checking of their blood pressure following delivery
with their physicians
. Further research is needed to determine whether
regular followup and treatment indeed reduces or prevents future cardiovascular
disease risk in these women.
- Ida Behrens, Saima Basit, Mads Melbye, Jacob A Lykke, Jan Wohlfahrt, Henning Bundgaard, Baskaran Thilaganathan, Heather A Boyd. Risk of post-pregnancy hypertension in women with a history of hypertensive disorders of pregnancy: nationwide cohort study. The British Medical Journal (2017). doi: https:doi.org/10.1136/bmj.j3078