Doctors warn that pregnancy risks double for women aged 45 and up

In most countries around the world, many women are diving into pregnancy at older ages to start or expand a family. The choice offers career flexibility, yet the newest data show the baby may shoulder extra risk when the mother’s age passes forty.

That warning comes from a study of more than 300,000 births led by intern physician Sofia Voss at Uppsala University.

Her team compared infants born to mothers aged 35‑39, 40‑44, and 45 and older, looking for trouble at the delivery‑room door.

Why pregnancy age keeps rising

The average age at first birth across the European Union climbed from 29 years in 2001 to 31 years in 2021. Career planning, reliable contraception, and better fertility treatments all help women delay parenthood.

In the United States, the provisional 2023 birth rate for mothers 40‑44 was 12.5 births per 1,000 women, more than double the rate in 1990.  Older parenthood is no longer a fringe choice.

The Swedish Medical Birth Register confirmed that serious complications remain rare at every age. Even so, the odds of stillbirth doubled for mothers 45 and older compared with those 35‑39.

Preterm delivery, defined as fewer than 37 weeks of gestation, struck 8.4 percent of babies in the oldest group versus 4.8 percent in the reference group.

That translates into one extra premature baby for roughly every 25 very‑advanced‑age pregnancies.

“The highest risks of all were to babies born to mothers 45 years and older,” said Voss. Low birth weight relative to gestational age and newborn low blood sugar also crept upward with each five‑year step in maternal age. 

Risky business babies’ health

Researchers have long known that advanced maternal age raises the likelihood of placental problems and pregnancy disorders such as preeclampsia. These conditions can cut oxygen and nutrients to the fetus, raising stillbirth risk.

Egg quality drops steadily after the mid‑thirties, increasing chromosomal errors and triggering early miscarriage or growth restriction.

Age‑related vascular stiffness may further limit blood flow to the uterus, setting the stage for preterm birth.

Cesarean delivery rates also rise with maternal age, partly because older mothers carry more chronic conditions. Surgery itself can lead to short‑term breathing trouble for the newborn.

Reproductive tech adds another layer

About 18 percent of Swedish mothers 45 plus conceived with assisted reproductive technology, triple the share in the 35‑39 group.

ACOG reviews show ART singletons carry roughly a 30 percent higher risk of birth defects than naturally conceived peers.

Separate Australian registry work links ART to a significantly higher preterm rate even after adjusting for parental age and health. The reasons range from embryo culture effects to higher twin loss before birth.

A U.S. analysis of 14 million births echoed those worries, reporting a clear preterm signal in fertility‑treatment pregnancies. When older age and ART stack together, clinicians need to watch even more closely.

Medical advances are helping

Medical advances have softened many dangers once tied to late pregnancy.

Most infants born to mothers over 40 leave the hospital healthy, and some studies show developmental benefits when parents are older and more financially secure.

Still, the Swedish data remind couples that odds shift as the clock ticks. A baby born at 32 weeks may face weeks in neonatal intensive care and a lifelong risk of breathing and learning difficulties.

Families weighing egg freezing or career delays should factor those possibilities into their timeline.

What doctors recommend next

Clinicians already offer extra ultrasounds and glucose screening to older mothers of advanced age. Voss hopes her findings will sharpen that approach so the most intensive surveillance targets pregnancies when the mother’s age is past 44.

Simple steps help too. Maintaining a healthy body mass index, controlling blood pressure, and spacing pregnancies at least 12 months apart all cut complications regardless of age.

A low Apgar score at five minutes, even in the 7‑8 range, has been linked to a higher risk of cerebral palsy and epilepsy.

Because the Swedish cohort showed slightly lower scores in older‑age births, delivery teams may err on the side of closer neonatal monitoring.

The demographic trend toward later motherhood is unlikely to reverse soon. With clear statistics in hand, public‑health planners can steer prenatal programs, and prospective parents can make informed decisions.

Rising pregnancy age and healthcare

As more women give birth later in life, public health systems must rethink how they allocate resources.

Targeted screenings, flexible prenatal care, and specialized delivery protocols may reduce complications linked to advanced maternal age.

Countries with universal health systems, like Sweden, are positioned to integrate this kind of age-stratified care more easily.

In nations without guaranteed maternity coverage, however, uneven access may widen health gaps between age groups.

The study is published in Acta Paediatrica.

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