After a woman gives birth, the baby’s well-being usually becomes the focus of family attention, and the mother’s health often recedes as a priority. Many busy new mothers don’t make it to their postpartum visit with an obstetrician or midwife, even though recent medical guidelines say they should do so within three weeks of the delivery.

But new research has highlighted the frequency with which serious pregnancy-related medical complications emerge after childbirth — often well after the mother is discharged from the hospital.

Here’s what you need to know.

When are postpartum complications most likely to occur?

The first six weeks after delivery are the most dangerous; women and their partners or support teams should be particularly vigilant during the first week. But complications related to pregnancy can emerge up to a year after childbearing.

“That whole first year is a vulnerable time,” said Dr. Cheryl Franklin, an assistant professor of obstetrics and gynecology at Morehouse School of Medicine in Atlanta.

Who is at greatest risk?

Black women are almost twice as likely as white women to have serious complications during the postpartum period. Native American women are at even higher risk of complications, both during and after pregnancy.

But all mothers who are 35 and older are more likely to experience complications after being discharged from the hospital, regardless of race and ethnicity. Women who had a cesarean section and those who had a stillbirth also have higher odds of complications, as do obese women and those with underlying conditions like heart disease. Women in the South have higher complication rates than those in the Northeast.

What are the most common warning signs?

A number of symptoms after childbearing may indicate very serious medical complications and should prompt women to seek care immediately. They include:

• a headache that doesn’t go away or gets worse;

• dizziness or fainting;

• changes in vision;

• a fever of 100.4 degrees or higher;

• extreme swelling of the face or hands;

• trouble breathing;

• chest pain or fast-beating heart;

• severe nausea and vomiting;

• severe belly pain;

• severe swelling and redness or pain in an arm or leg;

• heavy vaginal bleeding or discharge;

• and overwhelming fatigue.

If you can’t reach your usual health provider, go to the emergency room and make sure you say you were pregnant within the last year.

The C.D.C. offers a useful quiz that helps familiarize women with the warning signs during and after pregnancy.

Is a difficult pregnancy or delivery more likely than an uneventful one to prompt postpartum complications?

Yes — but anyone can develop a medical complication after childbearing, even someone who had a smooth and easy pregnancy.

Some medical conditions that emerge during pregnancy, like hypertensive disorders and diabetes, may increase the risks during the postpartum period, and require close follow-up and monitoring. Women with hypertension or a family history of it may want to have a cuff at home to track their blood pressure, or to use a remote blood pressure monitoring program.

Certain birth outcomes also raise red flags. Cesarean sections may lead to infections and potentially life-threatening blood clots. Having a preterm birth, or having a baby who is small for his or her gestational age, should prompt close monitoring of the mother’s health in addition to the baby’s.

A traumatic birthing experience may lead to depression, anxiety and post-traumatic stress disorder, said Katayune Kaeni, a psychologist. All women should be screened for depression during their postpartum checkups.

Are there precautions I can take to lessen my risk?

If you are not pregnant and are planning a pregnancy, schedule a preconception visit with your doctor and your partner, if you have one (that person’s medical history may also be significant).

“Optimize your health prior to pregnancy, with heart-healthy nutrition, fitness, cancer screenings and immunizations,” Dr. Franklin said. “Optimize chronic conditions such as high blood pressure, diabetes, obesity and cardiovascular disease, and understand your family history and your own risk factors.”

Once you are pregnant, start prenatal care early and don’t skip appointments.

After childbirth, make sure to go back to your OB-GYN or midwife for checkups, preferably within the first two to three weeks after being discharged from the hospital. If you had difficulty during your pregnancy, or you have underlying conditions like hypertension, diabetes or obesity, talk to your provider about an earlier check-in, more frequent calls or visits and transitioning to doctors who can manage your postnatal care.

If you have concerns, call your doctor. If providers dismiss your concerns but you don’t feel right, go to an emergency room.

Is it normal to feel weepy immediately after childbirth? What psychological symptoms should prompt immediate medical care?

Some new mothers may feel sad after childbearing, but this is usually a transient phenomenon. Seek help if feelings of sadness and hopelessness continue, or you think that you aren’t a good mother, or feel you have no control over your life and are constantly worried.

Get help immediately if you have thoughts of hurting yourself or your baby, or if intrusive thoughts pop into your head and you can’t get rid of them. Your regular health provider should be able to provide a referral; you can get more information at Postpartum Support International.