Preeclampsia reduces blood flow to the placenta, which can limit the oxygen and nutrients reaching your baby. This can lead to slower growth, early delivery, and in some cases, lasting effects on your child’s health. The severity and timing of preeclampsia matter enormously: earlier onset generally carries greater risk.
How Preeclampsia Restricts Blood Flow
During a healthy pregnancy, the blood vessels supplying the placenta remodel themselves into wide, low-resistance channels that allow a generous flow of blood to the baby. In preeclampsia, this remodeling is incomplete. Some vessels retain their muscular walls, and others never remodel at all. The result is a narrower pipeline delivering less blood, less oxygen, and fewer nutrients to the placenta and, by extension, to your baby.
This reduced blood supply is the root cause of most complications preeclampsia creates for the baby. It explains why growth slows, why the placenta can become unstable, and why doctors sometimes need to deliver the baby early to protect both mother and child.
Fetal Growth Restriction
When the placenta can’t deliver enough nutrition, babies grow more slowly than expected. In a study of over 2,700 women with preeclampsia, about 1 in 5 with severe preeclampsia (22.4%) had a baby diagnosed with fetal growth restriction. Early-onset preeclampsia, which develops before 34 weeks, carried a higher rate (18.4%) than late-onset cases (14.0%).
Growth restriction doesn’t just mean a smaller baby at birth. It signals that the baby has been under chronic stress in the womb, and these infants are more likely to need intensive monitoring and support after delivery.
Preterm Birth and NICU Stays
Preeclampsia is one of the leading reasons doctors deliver babies early. When the condition becomes severe or progresses rapidly, delivery is often the only effective treatment for the mother, even if the baby hasn’t reached full term. This medically initiated preterm birth is sometimes called iatrogenic prematurity, meaning it’s a deliberate decision rather than spontaneous labor.
Premature babies face their own set of challenges: underdeveloped lungs, difficulty regulating body temperature, feeding problems, and higher vulnerability to infection. Infants born to mothers with preeclampsia are roughly three times more likely to be admitted to a neonatal intensive care unit (NICU) compared to babies from uncomplicated pregnancies, at a rate of about 28% versus 10%. Those admitted also tend to stay twice as long, averaging six days compared to three.
Stillbirth and Fetal Mortality Risk
Preeclampsia does increase the risk of stillbirth, though the overall numbers remain relatively low. Across all gestational ages, the stillbirth rate in preeclamptic pregnancies is about 5.2 per 1,000, compared to 3.6 per 1,000 overall. That translates to roughly a 45% higher relative risk.
The risk is most concentrated early in pregnancy. At 26 weeks, pregnancies with preeclampsia had a stillbirth rate of 11.6 per 1,000, compared to just 0.14 per 1,000 without it. That’s an 86-fold difference. By 34 weeks, the gap narrows significantly but remains about sevenfold higher than in unaffected pregnancies. This steep decline over time is one reason doctors closely monitor preeclamptic pregnancies and weigh the timing of delivery so carefully.
Placental Abruption
Preeclampsia raises the risk of placental abruption, where the placenta partially or fully separates from the uterine wall before delivery. This is an emergency because it cuts off the baby’s blood supply suddenly rather than gradually. When abruption occurs alongside preeclampsia, outcomes tend to be worse than abruption alone: rates of stillbirth, neonatal death, and fetal distress are all significantly higher, and birth weights tend to be lower.
Effects on Brain Development
Research has uncovered a broader pattern of neurological risk in children born to mothers with preeclampsia. A large population-based study published in JAMA Psychiatry found increased rates of autism spectrum disorder, ADHD, epilepsy, and intellectual disability in these children. Earlier research had already established a link to cerebral palsy.
What makes these findings particularly notable is that the association persisted even after researchers accounted for preterm delivery. That suggests preeclampsia itself, likely through reduced oxygen and blood flow during critical periods of brain development, may directly affect the developing nervous system rather than all the risk coming from being born early.
Long-Term Cardiovascular Risk
The effects of preeclampsia can extend well beyond childhood. A population-based study tracking offspring into adulthood found that children born from pregnancies with high blood pressure disorders had a 50% higher risk of developing high blood pressure themselves. By age 30, about 8.9% of these offspring had been diagnosed with chronic hypertension, compared to 5.5% of those from normotensive pregnancies. By age 40, the gap widened to 22.5% versus 15.7%.
The risk was greatest when preeclampsia occurred in a mother who also went on to develop chronic high blood pressure herself. In that combined scenario, offspring faced more than double the risk of hypertension compared to unexposed children. Beyond blood pressure, offspring from preeclamptic pregnancies also show higher rates of type 2 diabetes and changes in heart structure.
Researchers aren’t certain whether this happens because of shared genetics, shared environmental factors like weight, or a direct effect of the in-utero environment on the baby’s developing cardiovascular system. It’s likely some combination of all three. What it means practically is that children born from preeclamptic pregnancies may benefit from earlier and more consistent cardiovascular screening as they grow into adulthood.
Why Timing and Severity Matter
Nearly every risk preeclampsia poses to a baby scales with how early the condition develops and how severe it becomes. Early-onset preeclampsia (before 34 weeks) is associated with higher rates of growth restriction, greater stillbirth risk, and more extreme prematurity if delivery becomes necessary. Late-onset preeclampsia, which develops closer to term, still carries risks but generally allows the baby more time to develop before delivery.
Mild preeclampsia that’s caught early and managed with close monitoring can often continue safely for weeks, giving the baby crucial additional time in the womb. Severe preeclampsia, particularly when it involves very high blood pressure or signs of organ damage in the mother, may require prompt delivery regardless of gestational age. In those cases, the risks of continuing the pregnancy outweigh the risks of prematurity. This is the core tradeoff doctors navigate: every additional day in the womb benefits the baby’s development, but only if the placental blood supply and the mother’s health can sustain it.