The second trimester is often when people feel their best during pregnancy. Nausea and vomiting usually resolve, the risk of miscarriage has dropped, and the aches and pains of the ninth month are far away.

Even so, there are a few complications that can occur. Read on to learn what to watch for and how to prevent complications from occurring in the first place.


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 divides it into two separate parts.
  • Incompetent cervix. When the cervix opens too soon, causing early birth.
  • Autoimmune diseases. Examples include lupus or scleroderma. These diseases can occur when your immune system attacks healthy cells.
  • Chromosomal abnormalities of the fetus. This is 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:

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

If you have have Rh-negative blood, get an injection of immunoglobulin (RhoGAM) if you 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 if you experience vaginal bleeding, but it’s important to remember that not all bleeding means pregnancy loss.

Seek immediate care if you’re bleeding in pregnancy, but try to stay calm while the doctor understands why you’re bleeding. You may be put on bed rest until the bleeding stops.

Preterm labor

When labor occurs before the 38th week of pregnancy, it’s considered preterm. Various conditions may cause preterm labor, such as:

Risk factors for preterm labor include:

  • 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. They 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, such as:

  • painful contractions
  • leakage of fluid from the vagina
  • 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 you don’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

If preterm labor can’t be stopped, your doctor will give you a steroid medication. Doing so 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)

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 the baby breaks, allowing the amniotic fluid to flow out. That bag protects the baby from bacteria. Once it’s broken, there’s a concern of the baby getting an infection.

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 (PPROM).

The exact cause of PPROM isn’t always clear. In many cases, though, the source of the problem is an infection of the membranes.

PPROM in the second trimester is a big concern, as 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. It can often include:

If there are signs of an infection, labor may be induced to avoid serious complications. Antibiotics will be started to prevent infection.

Many babies are born within two days of rupture, and most will deliver within a week. In rare cases, especially with a slow leak, the amniotic sac can reseal itself. Preterm labor can be avoided, and the baby is born closer to their due date.

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. 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 uterus at that point, the pregnancy often can’t 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
  • a cervical cone biopsy
  • 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 cervical incompetence 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.


You can prevent cervical incompetence. If you have a history of it, you 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 occurs when you develop:

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 for first-time pregnancies, some people 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).

Your doctor will also evaluate you for conditions that can increase the likelihood of developing early preeclampsia, such as blood clotting disorders and molar pregnancy. That’s 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 acetaminophen (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


You’re more prone to injury during pregnancy. 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 you don’t slip. Consider adding grab bars or rails in your shower, too. Also check your house for other hazards that could cause you to fall.


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!