Geriatric Pregnancy: What Changes After 35 and 40

What does geriatric pregnancy mean?

"Geriatric pregnancy" is a label for being pregnant at 35 or older. The clinical term behind it is advanced maternal age, which ACOG says "has been defined as women who are 35 years or older at estimated date of delivery". So the age that counts is your age on your due date, not when you conceived.

This page is about being pregnant at 35 or over. If you are still trying, see trying to conceive at 35 and at 40.

Why the term is outdated, and what replaced it

Thirty-five is a convention, not a cliff edge. ACOG's 2022 Obstetric Care Consensus, written with the Society for Maternal-Fetal Medicine, says 35 "is an arbitrary threshold" and that some age-related risks "may not influence outcomes until later ages (ie, 40 years and older)". It describes risk as rising "on a continuum" rather than switching on at a birthday.

There is no single official new name. To be more precise, ACOG now uses phrasing such as "pregnancy with anticipated delivery at [a specific age or age range] or older", and notes that recent studies split risk into five-year bands: 35–39, 40–44, 45–49 and 50 or older. NHS pages simply say "aged 35 or over" where age matters.

You are also far from unusual. ACOG reports that in the US in 2020, nearly 19% of all pregnancies were in women aged 35 and older.

Is a geriatric pregnancy high risk?

Not automatically. ACOG suggests that age 35 or over be "recognized as a risk factor" when counselling and planning care, adding that "nuanced counseling will be dependent on specific age and comorbidities". Several of the extra steps it recommends start at 40 rather than 35.

What rises with age, according to ACOG, is the chance of gestational diabetes, pre-eclampsia, labour that slows down, caesarean birth, preterm birth and low birth weight. In a US study of nearly 34 million births, the risk of pregnancy-related complications compared with women aged 25–29 was 1.36 times higher at 35–39, 1.83 times at 40–44 and 3.33 times at 45–54. Part of this is that conditions such as high blood pressure and type 2 diabetes are more common with age, but ACOG says older women "remained at significant risk" of pre-eclampsia and gestational diabetes even after allowing for them.

What actually changes with age: the numbers

Chromosome conditions

The chance of a chromosome condition such as Down's syndrome rises with age. ACOG gives the chance of a pregnancy being affected by Down's syndrome as:

Screening is not reserved for older mothers. The NHS says screening for Down's, Edwards' and Patau's syndromes "is offered to everyone who's pregnant", and that whether to have it is your choice. ACOG likewise recommends that screening and diagnostic tests be offered to all pregnant people "regardless of age". Our pages on NIPT and screening in the UK explain the options.

Miscarriage

The NHS lists being aged 35 or over among the things that may increase the chance of miscarriage. The RCOG puts the risk of miscarriage at one in five (20%) at age 30 and one in two (50%) over the age of 40.

Stillbirth

Stillbirth is uncommon at any age, but the risk late in pregnancy rises with age. Using US data on nearly 5.5 million pregnancies, ACOG reports the cumulative risk of stillbirth by 41 weeks:

In the same data, the risk at 37 to 41 weeks was 1 in 382 ongoing pregnancies for women aged 35–39 and 1 in 267 for women aged 40 and over.

Twins

Twins become more common with age. ACOG cites US figures of 17.1 twin births per 1,000 births under age 20, against 51.1 per 1,000 at 40–54, partly because of fertility treatment. For this reason it suggests a first-trimester scan for everyone 35 or over.

Extra monitoring if you are 40 or over

ACOG's recommendations are graded by age:

• 35 or over: a first-trimester scan and a detailed anatomy scan.
• 40 or over: a third-trimester growth scan, and extra checks of the baby's wellbeing towards the end of pregnancy, which it says it is reasonable to start between 32 and 36 weeks.

ACOG is open that "there are no robust data evaluating whether" these extra checks reduce stillbirth, and that for women aged 35–39 without other risk factors there is not enough evidence to recommend them routinely. If you are in the UK, ask your maternity team what monitoring your plan includes and why.

Induction at 39 weeks if you are 40 or over

In the US, ACOG recommends birth between 39+0 and 39+6 weeks for well-dated pregnancies when you will be 40 or over at delivery, because neonatal complications and stillbirth increase beyond that point. Its patient guidance says your ob-gyn "may recommend that you give birth at 39 weeks to reduce the risk of stillbirth".

In the UK, NICE's induction guideline (NG207) says to discuss with all women that induction from 41+0 weeks may reduce the risks of a pregnancy continuing beyond that point; its recommendations on prolonged pregnancy contain no separate age-based recommendation. The RCOG's Scientific Impact Paper No. 34 on older mothers, published in 2013, discusses the possible benefits of induction at 39–40 weeks for women aged 40 and over. Ask your obstetrician which approach your unit follows. Our page on induction of labour explains what is involved.

Induction does not appear to raise the chance of a caesarean in this group. ACOG cites a trial of more than 600 women aged 35 or over that found caesarean rates of 32% with induction at 39 weeks and 33% when waiting.

Pre-eclampsia and aspirin

NICE lists being 40 or over as a moderate risk factor for pre-eclampsia, and advises low-dose aspirin from 12 weeks for women with more than one moderate risk factor. In the US, ACOG recommends low-dose aspirin for those aged 35 or over with at least one other moderate risk factor. The two thresholds differ, so ask your midwife or doctor whether it applies to you. NICE notes that in England, aspirin for this purpose must be prescribed.

Does age mean a caesarean?

No. ACOG is explicit: "Advancing patient age alone is not an indication for cesarean delivery." It suggests telling patients that vaginal birth "is safe and appropriate" when there are no other reasons for a caesarean. Caesarean rates are higher in older mothers, but ACOG notes the reason for this remains unknown.

Frequently asked questions

What age is a geriatric pregnancy?

The term usually means you will be 35 or older on your due date. That is the definition of advanced maternal age that ACOG describes. ACOG calls 35 an arbitrary threshold, and several of its extra recommendations, such as growth scans and earlier birth, apply from 40 rather than 35.

What is the new name for geriatric pregnancy?

There is no single official replacement. "Advanced maternal age" is the clinical term, and ACOG now prefers precise wording such as "pregnancy with anticipated delivery at age 35 years or older", or a specific age band. NHS pages simply refer to being aged 35 or over.

Does a geriatric pregnancy increase the chance of Down's syndrome?

Yes, the chance rises with age. ACOG gives it as 1 in 714 at 30, 1 in 294 at 35 and 1 in 86 at 40. In the UK, screening for Down's, Edwards' and Patau's syndromes is offered to everyone, whatever their age, and having it is your choice.

Is a pregnancy at 40 high risk?

Some risks rise more clearly from 40, including pre-eclampsia, gestational diabetes and stillbirth late in pregnancy. That is why ACOG recommends a growth scan, extra monitoring and birth at 39 weeks from 40. ACOG also stresses that advice should depend on your specific age and any other health conditions, not on age alone.