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Risk Factors for High-Risk Pregnancy


Raul Artal-Mittelmark

, MD, Saint Louis University School of Medicine

Reviewed/Revised Sep 2022 | Modified Nov 2023
Topic Resources

Some risk factors are present before women become pregnant. These risk factors include

Physical Characteristics

The following characteristics of women affect risk during pregnancy.


About 13% of all pregnancies occur in adolescents. Adolescents are at increased risk of having the following:

Part of the reason for these risks is that adolescents are less likely to get medical care during pregnancy. Thus, they may not understand what activities and behaviors (such as smoking, drinking alcohol, and having sex without using a condom) can put their pregnancy at risk. Many adolescents smoke. They also have a higher risk of getting a sexually transmitted infection Overview of Sexually Transmitted Infections (STIs) Sexually transmitted infection (STI) refers to an infection that is passed through blood, semen, vaginal fluids, or other body fluids during oral, anal, or genital sex with an infected partner... read more Overview of Sexually Transmitted Infections (STIs) . Using condoms can help prevent sexually transmitted infections.

Women aged 35 and older are at increased risk of having the following:


  • Small, underweight babies

Overweight women (with a BMI of 25 to 29.9 before pregnancy) and obese women (with a BMI of more than 30) are more likely to have the following problems:

Doctors encourage overweight and obese women to exercise at least 3 times a week for a total of 150 minutes a week. These women should talk to their doctor about what exercises are appropriate for them. Changes to a healthier diet may be recommended.


Reproductive abnormalities

Structural abnormalities in the uterus or cervix increase the risk of the following:

Problems in a Previous Pregnancy

Women who have had a problem in one pregnancy are more likely to have a problem, often the same one, in subsequent pregnancies. Such problems include having had any of the following:

Women may have a condition that tends to make the same problem recur. For example, women with diabetes are more likely to have babies that weigh more than 10 pounds at birth.

Having had five or more pregnancies increases the risk of very rapid labor and excessive bleeding after delivery.

Having had twins or more fetuses in one pregnancy increases the risk of the following:

Disorders Present Before Pregnancy

Before becoming pregnant, women may have a disorder that can increase the risk of problems during pregnancy. These disorders include

Women who have one of these disorders should talk with a doctor and try to get in the best physical condition possible before they become pregnant. After they become pregnant, they may need special care, often from an interdisciplinary team. The team may include an obstetrician (who may also be a specialist in the disorder), a specialist in the disorder, and other health care practitioners (such as nutritionists).

Disorders During Pregnancy

During pregnancy, a problem may occur or a disorder may develop to make the pregnancy high risk.

Some disorders that occur during pregnancy are related to (are complications of) pregnancy. Other disorders are not directly related to pregnancy (see Pregnancy Complicated by Disease Overview of Disease During Pregnancy During pregnancy, having a medical condition can increase the risk of pregnancy complications for the pregnant woman or the fetus. The disorder may be one that A woman had before she became... read more ). Certain disorders are more likely to occur during pregnancy because of the many changes pregnancy causes in a woman's body.

Other pregnancy complications include

Exposures During Pregnancy

During pregnancy, being exposed to the following can increase the risk of having a baby with a birth defect:

These substances and conditions are called teratogens.

Infections that are particularly dangerous during pregnancy include

Drugs that may increase the risk of birth defects include

Mercury in seafood

Consuming too much mercury in seafood may harm the fetus. However, seafood contains nutrients that are important for growth and development of the fetus and breastfed infants. Thus, the Food and Drug Administration (FDA) recommends the following for women who are pregnant, who may become pregnant, or who are breastfeeding:

  • Do not eat tilefish from the Gulf of Mexico, shark, swordfish, big-eye tuna, marlin, orange roughy, and king mackerel.

  • Limit the amount of albacore tuna eaten to 4 ounces (one average meal) a week.

  • Before eating fish caught in local lakes, rivers, and coastal areas, check local advisories about the safety of such fish, and if mercury levels in the fish are not known to be low or if no advice is available, limit the amount eaten to 4 ounces (one average meal) a week and do not eat other high-mercury seafood during that week.

  • Each week, eat 8 to 12 ounces (2 or 3 average meals) of a variety of seafood that is lower in mercury.

Tilefish from the Gulf of Mexico have the highest levels of mercury of all fish (as tested by the U.S. Food and Drug Administration (FDA), but tilefish from the Atlantic Ocean can be safely eaten.

Seafood that is lower in mercury includes flounder, shrimp, canned light tuna, salmon, pollock, tilapia, cod, and catfish (see Advice about Eating Fish For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1–11 Years). Some authorities (Consumer Reports: Choose the Right Fish To Lower Mercury Risk Exposure) advise against eating any tuna during pregnancy.

More Information

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Eskalith, Eskalith CR, Lithobid
Azasite, Zithromax, Zithromax Powder, Zithromax Single-Dose , Zithromax Tri-Pak, Zithromax Z-Pak, Zmax, Zmax Pediatric
A/T/S, Akne-mycin, E.E.S., Emcin Clear , EMGEL, E-Mycin, ERYC, Erycette, Eryderm , Erygel, Erymax, EryPed, Ery-Tab, Erythra Derm , Erythrocin, Erythrocin Lactobionate, Erythrocin Stearate, Ilosone, Ilotycin, My-E, PCE, PCE Dispertab , Romycin, Staticin, T-Stat
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