Pregnancy Risks by Age: A Chart and Explanation

Age shifts the odds of almost every pregnancy complication, but it works like a slope, not a switch. Risks are lowest around the late 20s, climb slowly through the 30s, and rise faster after 40. The youngest mothers face their own set of higher risks, so the overall pattern is closer to a U than a straight line.1PubMed Central. Maternal age and severe maternal morbidity: A population-based retrospective cohort study For most women in their late 30s and early 40s, the more likely outcome is still an uncomplicated pregnancy and a healthy baby.

Pregnancy Risks by Age at a Glance

Doctors call pregnancy at 35 or older “advanced maternal age,” and you may see that phrase on your chart or in referrals. It marks a point on a gradual curve, not a sudden jump in risk.2PubMed. Advanced maternal age: delayed childbearing is rarely a conscious choice a qualitative study of women’s views and experiences

A risk that doubles or quadruples can still be small in absolute terms. “4 times the risk” means little until you know the starting risk. A stillbirth risk of 1 in 267 means about 266 of every 267 pregnancies at 40 and over reach full term without stillbirth. When you talk with your doctor, ask for your odds as “X in 1,000” rather than as a percentage increase.

The exact figures differ between countries and studies because researchers studied different groups of women. The direction of the pattern is the same across all of them.

A chart also averages everyone in an age group. Your own risk depends on your health, such as blood pressure, diabetes or weight, and on whether this is your first pregnancy. The chart is a starting point for a conversation with your care team.

Chromosomal Conditions and Why Egg Age Matters

Every egg a woman will have is present from before birth, so eggs age along with her. Over the years, the proteins that hold paired chromosomes together wear down.10PubMed Central. Meiosis and Maternal Aging: Insights from Aneuploid Oocytes and Trisomy Births When an older egg divides, it more often ends up with an extra or missing chromosome.11PubMed. Mechanisms of oocyte aneuploidy associated with advanced maternal age

An egg with an extra or missing chromosome produces an embryo with the same imbalance in every cell, which is why the condition cannot be treated later in pregnancy. Many such embryos do not survive, so some chromosomal errors end as early miscarriages and never reach a screening test.

Trisomies 21, 18 and 13 all become more common after 35.12PubMed Central. Maternal age and the risk of fetal aneuploidy: A nationwide cohort study of more than 500 000 singleton pregnancies in Denmark from 2008 to 2017 Monosomy X (Turner syndrome) and triploidy do not rise with age.13PubMed Central. Maternal age and the risk of fetal aneuploidy: A nationwide cohort study of more than 500 000 singleton pregnancies in Denmark from 2008 to 2017 Much of the increase in Down syndrome births across Europe comes from mothers being older.14PubMed Central. Twenty-year trends in the prevalence of Down syndrome and other trisomies in Europe: impact of maternal age and prenatal screening Most extra or missing chromosomes in a baby come from the egg, which is why the mother’s age is the main factor in these figures.

The cell-free DNA blood test (NIPT) checks the baby’s DNA in the mother’s blood.15PubMed. Analysis of the results of non-invasive prenatal testing (NIPT) in 545 pregnant women in advanced maternal age In one group of women over 35, every high-risk result for trisomy 21 or 18 was confirmed, while high-risk results for sex chromosome conditions and rarer conditions turned out to be false alarms.16PubMed. Analysis of the results of non-invasive prenatal testing (NIPT) in 545 pregnant women in advanced maternal age So any high-risk result should be confirmed with a diagnostic test, amniocentesis or CVS, before you make decisions.

A screening test gives the odds of a condition; a diagnostic test gives a yes or no answer. CVS is usually done at about 10–13 weeks and amniocentesis from about 15 weeks. Both carry a small miscarriage risk, which is why many people start with screening.

After a high-risk result, most clinics offer genetic counseling. Counselors explain how likely the result is to be correct for that specific condition, and you have time to decide before taking any action.

Miscarriage Risk Through the 30s and 40s

The lowest miscarriage risk is at about age 27, around 9.5%.17PubMed Central. Role of maternal age and pregnancy history in risk of miscarriage: prospective register based study Among women having fertility treatment, risk rose about 2% per year before 33 and about 10% per year after 33.18PubMed Central. Association between Age and Miscarriage in an Assisted Reproductive Technology Population: A 10-Year Cohort Study The change speeds up in the mid-30s rather than at exactly 35. At the other end, mothers under 20 have a risk of about 16%.19PubMed Central. Role of maternal age and pregnancy history in risk of miscarriage: prospective register based study

These figures count pregnancies that were recognized, not very early losses that happen before a pregnancy is noticed. Once a heartbeat is seen, the risk falls, though it stays higher in older women.

Call your care team for heavy bleeding or bleeding with cramps. After two or more miscarriages, ask about testing to look for a cause.

Blood Pressure, Diabetes and Placenta Problems

The risk of gestational diabetes, diabetes that starts in pregnancy, rises about 8% with each year of age.20PubMed. Maternal age and the risk of gestational diabetes mellitus: A systematic review and meta-analysis of over 120 million participants At any age from 25 on, Asian women have a higher risk than European women.21PubMed. Maternal age and the risk of gestational diabetes mellitus: A systematic review and meta-analysis of over 120 million participants Early glucose testing may therefore be offered to some women, especially Asian women over 35. Gestational diabetes often causes no symptoms, which is why it is found by testing and not by how you feel. The usual check is a glucose drink test at 24–28 weeks. Untreated, high blood sugar can lead to a larger baby and a harder delivery, and it is usually managed with diet, activity and sometimes medicine.

Preeclampsia, a dangerous rise in blood pressure during pregnancy, is most common at the youngest and oldest ages.22PubMed Central. Pre-eclampsia rates in the United States, 1980-2010: age-period-cohort analysis Among women with preeclampsia, those 35 and over had serious complications 60% of the time, compared with 33% of younger women.23PubMed Central. Maternal Perinatal Outcomes Related to Advanced Maternal Age in Preeclampsia Pregnant Women Blood pressure and urine are checked at every visit, and it helps to know the warning signs: severe headache, vision changes, swelling of the face or hands, and pain under the ribs.

Doctors often recommend low-dose aspirin from 12 weeks for women with risk factors for preeclampsia, and being over 35 counts as one. Don’t start aspirin without your provider’s advice. Care for preeclampsia means closer monitoring, blood pressure medicine when needed, and sometimes delivery earlier than planned, since delivery is the definitive treatment.

In placenta previa, the placenta sits low and covers the cervix.24PubMed. Effect of maternal age and parity on the risk of uteroplacental bleeding disorders in pregnancy Women over 40 have about nine times the risk of women under 20.25PubMed. Effect of maternal age and parity on the risk of uteroplacental bleeding disorders in pregnancy It usually shows up on the mid-pregnancy ultrasound and often moves up on its own later. Placental abruption, where the placenta separates early, rises only a little with age.26PubMed. Advanced maternal age and its association with placenta praevia and placental abruption: a meta-analysis

Preterm Birth, Stillbirth and Timing of Delivery

Very preterm birth, before 32 weeks, is about twice as likely at 40 and over, whether or not it’s a first baby.27PubMed. Advanced maternal age increases the risk of very preterm birth, irrespective of parity: a population-based register study Teens and women under 24 also have a higher risk of preterm birth.28PubMed Central. Effect of maternal age on the risk of preterm birth: A large cohort study Babies born before 37 weeks may need time in a neonatal unit, and the earlier the birth the more help they usually need.

For women 35 and over, stillbirth risk doubles from 5 per 10,000 at 39 weeks to 10 per 10,000 at 40 weeks.29PubMed Central. The risk of stillbirth and infant death by each additional week of expectant management stratified by maternal age In women 39 and older, the risk starts to climb at 40 weeks.30PubMed. Gestational age-specific risk of stillbirth during term pregnancy according to maternal age After 40 weeks the placenta may supply oxygen and nutrients less well, and this effect appears to be stronger in older mothers. Stillbirth at this stage is still uncommon, and the point of timing delivery is to lower an already small risk further.

If you are 40 or older, ask your provider about planning induction around 39 weeks. In studies of healthy women, inducing labor at 39 weeks did not raise the chance of a cesarean, and it’s worth discussing the timing well before your due date.

Late in pregnancy, some women are offered extra growth scans, and non-stress tests check the baby’s heart rate. Counting your baby’s movements each day helps you notice changes. Report reduced movement the same day.

Labor, Delivery and the Mother’s Own Health

The chance of labor slowing or stalling roughly doubles at 35–39 compared with age 25 and under.31PubMed. Risk of labor dystocia increases with maternal age irrespective of parity: a population-based register study The uterus may contract less efficiently in older mothers, though the exact reasons are not fully settled. Labor-speeding drugs, assisted births and cesareans during labor all become more common with age.32PubMed. Dystocia increases with advancing maternal age

Women 45 and over have nearly three times the cesarean rate, but fewer emergency cesareans.33PubMed Central / Elsevier. Pregnancy outcomes at maternal age over 45 years: a systematic review and meta-analysis A planned cesarean is scheduled in advance, often for a medical reason, while an emergency cesarean happens when a problem arises during labor.

Rates of serious complications for the mother are low in the 20s and early 30s and rise sharply after 39.34PubMed Central. Maternal age and severe maternal morbidity: A population-based retrospective cohort study At 40–44, the risk of heart problems is about four times higher.35PubMed Central. Maternal age and severe maternal morbidity: A population-based retrospective cohort study Death is rare, about 6 per 100,000 births in Canada, but the risk is roughly three times higher at 40–44.36PubMed Central. Association of Maternal Age With Severe Maternal Morbidity and Mortality in Canada Other health conditions and having a low income also raise the risk.37PubMed Central. Association of Maternal Age With Severe Maternal Morbidity and Mortality in Canada

If you are over 40, choose a hospital that can handle complications. Talk through your cesarean preferences ahead of time, and ask your provider how they manage labor that stalls. After the birth, get urgent care for chest pain, shortness of breath or heavy bleeding, and keep your blood pressure checks in the weeks after delivery.

Risks for Teenage Mothers

Teen pregnancies have higher rates of preterm birth, low birth weight and anemia.38PubMed Central. Prevalence, determinants, and complications of adolescent pregnancy: an umbrella review of systematic reviews and meta-analyses Babies of teen mothers weighed about 330 grams less on average in one study.39PubMed Central. Adolescent Pregnancy Outcomes and Risk Factors Most babies born to teen mothers are healthy, and the averages describe groups, not individual babies.

A teenager’s body may still be growing, and some of the extra risk is linked to late or little prenatal care and to nutrition. Social factors such as income and support also play a part, so age is not the whole explanation. Once other factors are taken into account, teens are not at higher risk for most serious complications.40PubMed Central. Maternal age and severe maternal morbidity: A population-based retrospective cohort study They do have a higher risk of sepsis, a serious infection.41PubMed Central. Maternal age and severe maternal morbidity: A population-based retrospective cohort study Starting prenatal care early helps, as does taking iron, eating well, and getting signs of infection checked quickly.

Getting Pregnant at Older Ages, Including IVF

After six IVF cycles, women under 35 had a 65–86% chance of a baby.42PubMed. Cumulative live-birth rates after in vitro fertilization At 40 and over, the chance after six cycles was about 23–42%.43PubMed. Cumulative live-birth rates after in vitro fertilization At 40 and over, success stopped improving after about four cycles.44PubMed Central. Cumulative Live-Birth Rates by Maternal Age after One or Multiple In Vitro Fertilization Cycles: An Institutional Experience IVF cannot change the age of the egg, so the same chromosomal changes that affect natural pregnancy also lower the chance that an embryo will implant and continue. Each cycle is also less likely to produce usable embryos as the woman gets older.

Because of that plateau, a clinic may discuss other options once those cycles have not worked. They can include donor eggs, which come from a younger woman and carry the odds of that younger age.

If you are over 35, see a specialist after six months of trying. Freezing eggs at a younger age preserves those younger eggs for later, and embryos made from them carry the chromosomal risks of the age at which the eggs were collected.

How to Lower Your Risk at Any Age

Conditions that are new or poorly controlled carry the highest risk in pregnancy.45PubMed Central. A Balancing Act: Navigating Hypertensive Disorders of Pregnancy at Very Advanced Maternal Age, from Preconception to Postpartum A visit before pregnancy can screen for diabetes and high blood pressure and adjust medicines.46PubMed Central. Preconception Care: A Strategic Intervention for the Prevention of Neonatal and Birth Disorders It usually covers a review of the medicines you take, checks on your blood pressure, blood sugar and weight, vaccines you may need, and genetic carrier screening. Taking folic acid starting before pregnancy lowers the risk of neural tube defects.

Having a first baby at an older age is linked with higher heart disease risk later in life.47PubMed. Advanced maternal age at first delivery as a risk factor for long-term cardiovascular disease Complications such as preeclampsia are an early warning sign for heart risk.48PubMed Central. Pregnancy History at 40 Years of Age as a Marker of Cardiovascular Risk Share your pregnancy history with your doctor in the years after the birth.

Depression after the birth was more common at 40–44 in one study, though overall findings on mood and age are mixed.49PubMed. The association between maternal age and depression Whatever your age, get screened for postpartum depression.