When Something's Wrong: Second Trimester Complications

Overview | Overview

The second trimester is often when women feel their best during pregnancy. Nausea and vomiting generally resolve, the risk of miscarriage is very small, and the aches and pains of the ninth month are far away. Even so, there are a few complications that can occur.

Bleeding | Bleeding

Although a miscarriage is much less common in the second trimester, it can still occur. Vaginal bleeding is usually the first warning sign. Miscarriages in the second trimester (before 20 weeks) may be caused by several different factors, which can include:

  • uterine septum (a wall, or septum, inside the uterus that divides it into two separate parts)
  • incompetent cervix (when the cervix opens too soon, causing early birth)
  • autoimmune diseases, such as lupus or scleroderma (these diseases can occur when your immune system attacks healthy cells)
  • chromosomal abnormalities of the fetus (when something is wrong with the baby’s chromosomes, which are cells that are made up of DNA)

Other causes of bleeding in the second trimester include:

  • early labor
  • problems with the placenta, such as placenta previa (placenta covering the cervix)
  • placental abruption (placenta separating from the uterus)

These problems are more common in the third trimester, but they can also occur late in the second trimester.

Women who have Rh-negative blood should get an injection of immunoglobulin (RhoGAM) if they experience bleeding during pregnancy. Immunoglobulin is an antibody. An antibody is a protein your immune system produces that recognizes and fights harmful substances, such as bacteria and viruses. Getting a shot of immunoglobulin will help prevent the development of Rh antibodies, which will attack the fetus if it has an Rh-positive blood type.

You may feel scared when you experience vaginal bleeding, but it’s important to remember that not all bleeding is a bad sign. Bleeding is common in pregnancy.

Preterm Labor | Preterm Labor

When labor occurs before the ninth month or 37th week of pregnancy, it’s considered “preterm." Various conditions may cause preterm labor such as bladder infection, smoking, or a long-term medical disease (like diabetes or kidney disease). It’s more common in women who have experienced any of these conditions:

  • a previous preterm birth
  • twin pregnancies
  • multiple pregnancies
  • extra amniotic fluid (the fluid surrounding the fetus)
  • infection of the amniotic fluid or amniotic membranes


The signs and symptoms of preterm labor may be subtle and can include:

  • vaginal pressure
  • low-back pain
  • frequent urination
  • diarrhea
  • increased vaginal discharge
  • tightness in the lower abdomen

In other cases, the symptoms of preterm labor are more obvious, causing painful contractions, leakage of fluid from the vagina, and vaginal bleeding.

Call your doctor if you have these symptoms and are worried about being in labor. Depending on your symptoms, your doctor may tell you to go to the hospital right away.


Each additional day a woman doesn’t go into preterm labor offers a chance for fewer complications when the baby is born. Several medications can be helpful in stopping preterm labor. These include:

  • magnesium sulfate
  • corticosteroids
  • tocolytics

A steroid medication is often given to the mother if preterm labor can’t be stopped. It helps develop the baby's lungs and reduces the severity of lung disease. It’s most effective two days after the first dose, so your doctor will try to prevent delivery for at least two days.

Preterm Premature Rupture of Membranes (PPROM) | Preterm Premature Rupture of Membranes (PPROM)

It’s normal for your membranes to rupture (break) during labor. People often refer to it as “your water breaking.” This occurs when the amniotic sac surrounding your baby breaks, allowing the amniotic fluid to flow out.

While your water is supposed to break when you go into labor, it can cause serious problems for your baby when it happens too early. This is called preterm premature rupture of membranes, or PPROM. The exact cause of PPROM isn’t clear, but in many cases, the source of the problem is an infection of the membranes.

PPROM in the second trimester is a big concern because it can lead to a preterm delivery. Infants born between the 24th and 28th weeks of pregnancy are at the greatest risk for developing serious long-term medical problems, particularly lung disease. The good news is that with the appropriate intensive care nursery services, most preterm infants tend to do very well.


Treatment for PPROM varies. Women are often hospitalized and given antibiotics, steroids (such as betamethasone), or medications that can stop labor (such as terbutaline). If there are signs of an infection, labor must be induced to avoid serious complications.

Many women will deliver their babies within two days of rupture, and almost all will deliver within a week. In rare cases, the amniotic sac can reseal itself, and preterm labor can be avoided.

Cervical Incompetence (Cervical Insufficiency) | Cervical Incompetence (Cervical Insufficiency)

The cervix is a tissue that connects the vagina and the uterus. Sometimes, the cervix is unable to withstand the pressure of the growing uterus during pregnancy. The increased pressure can weaken the cervix and cause it to open before the ninth month. This condition is known as cervical incompetence, or cervical insufficiency. According to the American Pregnancy Association, an incompetent cervix only occurs in about 1 to 2 percent of pregnancies. While it’s an uncommon condition, it can cause serious complications.

The opening and thinning of the cervix eventually leads to the rupture of membranes and delivery of a very premature fetus. This usually occurs around the 20th week of pregnancy. Since the fetus is too premature to survive outside the womb at that point, the pregnancy often cannot be saved.

Women are at a higher risk for cervical incompetence if they’ve had a previous cervical trauma (such as a tear during delivery), cervical cone biopsy, or other operation on the cervix.


Unlike preterm labor, cervical incompetence typically doesn’t cause pain or contractions. There may be vaginal bleeding or discharge.


Treatment for an incompetent cervix is limited. An emergency cerclage (stitch around the cervix) is a possibility if the membranes haven’t ruptured yet. The risk of rupturing the membranes is higher if the cervix is very dilated (wide). Extended bed rest is necessary after the placement of a cerclage.

In other cases, when the membranes have already ruptured and the fetus is old enough to survive, your doctor will likely induce labor.


Luckily, an incompetent cervix is preventable. If a woman has a history of cervical incompetence, she can receive a cerclage with future pregnancies at about 14 weeks. This will lower, but not eliminate, the risk of having a preterm delivery and losing the baby.

Preeclampsia | Preeclampsia

Preeclampsia occurs when a woman develops hypertension (high blood pressure), proteinuria (a large amount of protein in the urine), or excessive edema (swelling). Preeclampsia affects every system in the body, including the placenta. The placenta is responsible for providing nutrients to the baby. Though preeclampsia typically occurs during the third trimester in women who are pregnant with their first baby, some women develop preeclampsia during the second trimester.

Before making a diagnosis, your doctor will evaluate you for other conditions that may be confused with preeclampsia, such as lupus (which causes inflammation throughout the body) and epilepsy (a seizure disorder). You’ll also be evaluated for conditions that can increase the likelihood of developing early preeclampsia, such as hypercoagulable conditions (blood clotting disorders) and molar pregnancy (a noncancerous tumor that forms in the uterus).


Symptoms of preeclampsia include rapid swelling of your legs, hands, or face. Call your doctor right away if you experience this type of swelling or any of the following symptoms:

  • headache that doesn’t go away after taking an acetaminophen (such as Tylenol)
  • loss of vision
  • "floaters" in your eye (specks or spots in your vision)
  • severe pain on your right side or in your stomach area
  • easy bruising

Injury | Injury

Be safe during your pregnancy because you’re more prone to injury. Your center of gravity changes when you’re pregnant, which means it's easier to lose your balance. In the bathroom, be careful when stepping into the shower or tub. You may want to add nonskid surfaces to your shower so that you don’t slip. You should also check your house for other hazards that could cause you to fall.

Outlook | Outlook

If you’re experiencing any of the symptoms described in this article, contact your doctor. They’ll be able to determine the cause and get you started on the right treatment, which means a happy and healthy pregnancy for you!

Your Week-by-Week Pregnancy Calendar

Read This Next

What Exercises are Safe in the Second Trimester?
The Second Trimester: What Have You Never Read Before?
The Second Trimester of Pregnancy: The Pregnant Father
12 Food Allergy-Friendly Holiday Recipes
The Essential Stretches for Every Level of Gymnast

Want information? Want to take action?
We want to help.

We've got all the information you need to help ensure a healthy pregnancy and delivery. Sign up for Healthline's pregnancy newsletter and you'll receive:
  • the latest pregnancy and parenting news
  • recipes and practical tips to keep you and
    baby healthy
  • advice on everything from preconception
    to delivery

Thanks very much! You’ll receive a confirmation email soon!