Blood pressure is the commonest serious thing
Roughly one in eight hospital deliveries carries a high blood pressure diagnosis, and the number has been rising fast.
If you are going to worry about one thing in pregnancy, the data say worry about blood pressure. It is also the thing most likely to be caught, because it is measured at every visit.
From hospital records. CDC reported that across 2017 to 2019, the prevalence of HDP among delivery hospitalizations increased from 13.3% to 15.9%
, with the three years combined at 14.6%. That grouping is broad: CDC defines it as chronic high blood pressure, pregnancy-associated high blood pressure (gestational hypertension, preeclampsia, eclampsia and chronic hypertension with superimposed preeclampsia) and unspecified maternal hypertension. In unweighted terms that was 319,913 cases.
Broken into its parts. The CDC study of 6,892,304 hospital deliveries in 2018 and 2019 separates them. The five rows beginning "of those" are subcategories of the first row, not additions to it, so adding them up double-counts women and overshoots the total.
| Condition | Deliveries | Share of hospital deliveries |
|---|---|---|
| Any high blood pressure disorder of pregnancy | 864,665 | 12.5% |
| Of those, gestational hypertension | 443,780 | 6.4% |
| Of those, preeclampsia | 370,105 | 5.4% |
| Of those, chronic hypertension with superimposed preeclampsia | 71,920 | 1.0% |
| Of those, HELLP syndrome | 18,815 | 0.3% |
| Of those, eclampsia | 4,710 | 0.1% |
| Chronic hypertension, a separate condition group | 249,995 | 3.6% |
So about one in eight hospital deliveries carries a high blood pressure code of some kind, and about one in eighteen carries a preeclampsia code.
From birth certificates, which give a lower number and a longer trend. The birth certificate cannot separate gestational hypertension from preeclampsia; it has one box covering both. On that measure, per live births, the rate went from 5.98% in 2016 (235,693 births) to 10.42% in 2024 (377,267 births). That is a 74% relative rise, and in plain counts an extra 141,574 births affected, in a year with about 317,000 fewer births overall. Chronic high blood pressure nearly doubled over the same period, from 1.73% (68,378) to 3.35% (121,339).
Two numbers, two systems, and they do not match. That is expected, not a contradiction: one counts live births with a checkbox, the other counts hospital deliveries with diagnosis codes, and they draw the category boundaries differently. They agree on the shape and disagree on the level.
ACOG's 2020 guidance states that it has been estimated that preeclampsia complicates 2-8% of pregnancies globally
. Note the two labels in that sentence: globally, and per pregnancies. It is not a US population figure, and its background data are those of the original 2020 publication.
"What is my blood pressure today, and what is my own normal?"
"What number would make you call me in early?"