When the Placenta Grows Too Deeply Into the Womb: What Families Should Know About Accreta and Their Baby

Four studies published in 2026 on predicting the condition before birth, controlling bleeding safely during the operation, and caring for the newborn afterwards

A condition that begins with a scar

Placenta accreta spectrum is a condition in which the placenta grows too deeply into the wall of the womb and cannot separate normally after birth. It is nearly always linked to a previous caesarean scar, and it makes delivery a carefully planned operation with a real risk of heavy bleeding. Four studies published in 2026 look at how it can be predicted, how the bleeding can be controlled, and what the baby needs after birth.

To understand why this happens, it helps to know how a pregnancy normally ends. The placenta — the organ that supplies the baby with oxygen and nutrients — attaches to the inner lining of the womb, and after the baby is born it peels away cleanly. That clean separation depends on a healthy lining. Where the womb has been cut and repaired before, as during a caesarean section, that lining can be thin or absent, and a placenta implanting over such an area may grow into the muscle of the womb instead of resting on top of it. When delivery arrives, it does not let go.

Doctors describe three depths. In accreta, the placenta is attached too firmly but has not grown far into the muscle. In increta, it has grown into the muscle. In percreta, it has grown through the wall and may reach nearby organs such as the bladder. Because these depths blend into one another and can appear in the same womb, they are grouped together as a spectrum [1].

How this became a common problem

Two generations ago this condition was a rarity that most obstetricians saw only a handful of times in a career. It became more common for a simple reason: caesarean sections became more common. A large study published in 2006 followed women having repeat caesarean deliveries and found that the chance of the placenta growing in abnormally rose with each additional operation, and rose sharply when the placenta also lay low in the womb, covering the cervix — a situation called placenta praevia [2]. Expert groups later described the same pattern across many countries [3]. Pooled figures put the condition at roughly 1 to 2 pregnancies in every 1,000, though the true number varies with how carefully it is looked for [4].

Before ultrasound could reliably show the problem, families found out at the worst possible moment. The baby would be born, the placenta would not come away, and the bleeding that followed could be sudden and severe. Emergency hysterectomy — removal of the womb — was often the only way to stop it, ending both the bleeding and the possibility of future pregnancies. Modern care is built around never letting that happen. Guidance now recommends that when abnormal attachment is suspected, the woman is cared for at an experienced hospital and delivery is planned in advance, usually a few weeks early and always before labour begins, with blood ready and a full surgical team present [5]. Pooled studies show that women whose condition is recognised before delivery lose less blood and suffer fewer complications than those in whom it is discovered unexpectedly [6].

That is why families in this situation often meet a neonatal team before they meet their baby. Delivery is typically scheduled at around 34 to 37 weeks — earlier than nature would choose, but a deliberate trade: a slightly early baby in exchange for a controlled operation rather than an emergency.

What researchers learned about the baby

The first of the 2026 studies speaks most directly to families [7]. Researchers at a hospital in Kielce, Poland, reviewed 82 women who had a low-lying placenta and delivered by caesarean section between 2014 and 2021. Afterwards, every placenta was examined under a microscope. In 37 cases it had grown into the womb wall; in 45 it had not. That comparison is what makes the study useful: both groups had the same underlying problem and both delivered at almost the same point in pregnancy — a median of 34 to 35 weeks — so differences between them were unlikely to be explained by prematurity alone.

The babies whose mothers had the deeper form of the condition needed more help breathing. Just under three-quarters (72%) needed breathing support given by mask in the delivery room, compared with 43% of the others. Around 86% needed non-invasive breathing support in the neonatal unit — the kind delivered through soft prongs in the nose rather than a tube in the windpipe — compared with 55%. And 81% needed extra oxygen during their stay, compared with 48%. When the researchers accounted statistically for how early each baby was born, the differences in delivery-room support and extra oxygen remained; the difference in non-invasive support became too uncertain to call.

It is worth being clear about what this does and does not mean. These were 80 babies at one hospital. The study cannot prove the placenta caused the extra breathing difficulty, and the researchers were careful to call their explanation — that the transition of the baby's lung circulation may be affected — a hypothesis they could not test. What it does support is a practical adjustment: when this condition is expected, the team receiving the baby should be ready to help with breathing straight away.

Predicting the problem before birth

A second study, from a specialist referral centre in Houston, Texas, asked whether an extra ultrasound measurement could help identify the condition earlier [8]. Between December 2021 and June 2025, 177 women referred with suspicion of abnormal placental attachment had the blood flow in their uterine arteries — the two main vessels supplying the womb — measured with Doppler ultrasound, a technique that shows how fast blood is moving. In the 108 women whose condition was later confirmed, blood was flowing faster through those arteries.

The measurement was helpful but not decisive. Fast flow made the diagnosis about five times more likely, but normal flow did not rule it out, and it could not tell doctors how deeply the placenta had grown. Its most interesting result came in a small group of women who did not have a low-lying placenta — the group hardest to assess with the usual ultrasound signs — where it performed much better. Only ten women in that group turned out to have the condition, so this is a promising lead rather than a finished answer.

Controlling the bleeding safely

Two further studies tackled the bleeding itself, from opposite directions. In Astana, Kazakhstan, at the national referral centre for this condition, researchers ran a randomised trial — the most reliable kind of study, in which chance decides which treatment each participant receives [9]. Of 150 women, 65 had a small balloon threaded into the main artery of the abdomen and inflated to slow blood flow to the womb, and 75 had standard surgery. Crucially for parents to know, the balloon was inflated only after the baby was born, so it did not affect the baby's blood supply.

The balloon cut blood loss by roughly a third — a median of 1,000 millilitres compared with 1,600 — and sharply reduced the amount of donated blood needed. It did not significantly reduce the chance of needing a hysterectomy, and it did not change anything about the babies: Apgar scores, time in the neonatal unit and outcomes were the same in both groups. It also carried its own risk: five women in the balloon group developed blood clots in the vessels of the leg or pelvis, and none did in the comparison group. This is a maternal treatment with maternal benefits and risks, not something done to the baby.

The fourth study shows a different philosophy [10]. At Mersin University in Turkey, a single experienced surgeon operated on 324 women with a low-lying placenta over thirteen years, using no balloon but a stepwise series of techniques to stop bleeding: a temporary tourniquet around the lower womb, stitches into the bleeding area, tying off the pelvic arteries, an inflatable balloon inside the womb itself, and, if necessary, cutting away and rebuilding the affected part of the wall. Hysterectomy was kept as a last resort. The womb was saved in 89% of women, use of these techniques rose from none in the first year to over 90% recently, and the hysterectomy rate fell by half. No mother died in thirteen years.

There is an honest trade-off here that matters to families: saving the womb takes longer. Operations using four preserving techniques lasted a median of two hours, compared with one hour when none was needed. That is more time before a mother can be reunited with her baby, and it is worth knowing in advance. Expert guidance emphasises that this kind of surgery depends heavily on the experience of the team and is not right for every case [11].

What this means for families, and what comes next

If you are pregnant and have been told the placenta may be growing too deeply, several things follow. Your delivery will be planned rather than left to chance, and that planning is itself protective. Your baby will probably arrive a few weeks early, a well-recognised consequence of any placenta that sits abnormally in the womb [12]. Babies born by caesarean section before labour begins are more likely to need help with breathing [13], because the squeeze and hormonal signals of labour help clear fluid from the lungs [14] — and the Polish study suggests the deeper forms of this condition may add something further.

None of this is cause for alarm. Needing breathing support in the first hours is common among babies born a few weeks early and is usually short-lived. What the research supports is preparation rather than worry: a neonatal team ready at your delivery, steroid injections beforehand to help mature your baby's lungs where timing allows, and a frank conversation about how long the operation may take.

What researchers are working on next is the question these four studies raise but cannot answer: whether the condition itself affects the newborn's lungs, or whether the extra breathing support simply reflects being born early. Answering it needs a much larger study following the same pregnancies from the scan, through the operation, into the neonatal unit — with the baby's outcome as the main question rather than an afterthought. Until then, families can reasonably expect their care team to plan for a baby who may need a little more help, and to be pleasantly surprised when one does not.

References

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  2. Silver RM, Landon MB, Rouse DJ, et al. Maternal morbidity associated with multiple repeat cesarean deliveries. Obstet Gynecol. 2006;107(6):1226–1232. doi:10.1097/01.AOG.0000219750.79480.84 ↩
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