When Something's Wrong: Second Trimester Complications

Written by the Healthline Editorial Team | Published on March 15, 2012
Medically Reviewed by Joan K. Lingen, MD


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 pain of the ninth month are far away. However, there are a few complications that can occur.


Although miscarriage is much less common in the second trimester, it can occur and bleeding is the most common sign. Miscarriages in the second trimester (before 20 weeks) often are caused by factors other than the chromosomal ones that are frequent in the first trimester. Pregnancy loss in the second trimester may be caused by malformations of the uterus such as a uterine septum, problems with premature opening of the cervix (insufficient cervix), autoimmune diseases such as lupus or anti-phospholipid syndrome, and chromosomal abnormalities of the fetus. Autopsy of the fetus may be recommended to help determine the cause of the loss.

Other causes of bleeding in the second trimester include problems with the placenta, such as placenta previa (placenta covering the cervix), abruption (placenta separating from the uterus), and premature labor. These are more common problems in the third trimester, but can also occur in the late second trimester.

Women who have Rh-negative blood should receive an injection of immunoglobulin (RhoGAM) if they experience bleeding during pregnancy. This helps prevent the development of antibodies against the fetus if the fetus has an Rh-positive blood type. It is important to remember that not all bleeding is an ominous sign. Bleeding can be a normal part of pregnancy.

Preterm Labor

When labor occurs before the ninth month or 37th week of pregnancy, it is considered "preterm". Preterm labor is more common in women with a previous preterm birth, with twin pregnancies (or multiple pregnancies), with excess amniotic fluid, or with infection of the amniotic membranes or amniotic fluid.


The signs and symptoms of preterm labor may be subtle and include vaginal pressure, low back pain, frequent urination, diarrhea, increased vaginal discharge, and tightness in the lower stomach. In other cases, the onset of preterm labor is more obvious, causing regular painful contractions, leakage of fluid from the vagina, and vaginal bleeding.

If you have these symptoms and are worried about being in labor, call your health care provider. Depending on your symptoms, your provider may have you drink lots of fluid and lie down, or may instruct you to go to the office or hospital right away.


Premature infants are at risk for numerous health problems, lung disease in particular. These risks are much higher for the very preterm infant (24 to 28 weeks of gestation). Several strong medications, such as magnesium sulfate, can be helpful in stopping preterm labor and delaying delivery. Each day gained offers a chance for fewer complications when the baby is born.

A steroid medication is often given to the mother to help mature the fetus's lungs and reduce the severity of lung disease should labor not be stopped. This medication has its peak effect within two days, so the minimum goal is to prevent delivery for at least two days.

Preterm Premature Rupture of Membranes (PPROM)

Rupture of membranes is a normal part of giving birth. It is another way of saying "your water broke." Technically, what this means is that the amniotic sac surrounding your baby has broken, allowing the amniotic fluid to flow out.

While it is normal for the sac to break during labor, if it happens too early it can cause serious problems for your baby. This is called preterm premature rupture of membranes, or PPROM. Although the cause of PPROM is not clear, it is thought that infection of the amniotic membranes is an underlying problem in many cases.

PPROM in the second trimester is a serious concern because it hastens preterm delivery. Extremely preterm infants (24to 28 weeks gestation) are at the greatest risk of serious long-term problems. However, with improved intensive care nursery services, most preterm infants born after 28 weeks do very well.


Treatment for PPROM varies. Women are often hospitalized and administered antibiotics, steroids (betamethasone or dexamethasone), and drugs to stop labor (tocolytics-for example, terbutaline or Brethine). If there are signs of infection, labor must be induced to avoid serious complications.

Many women will deliver within two days of rupture. Within a week, almost all women will deliver their babies. Occasionally, a woman with PPROM will experience resealing of the membranes. In these rare cases, she may continue her pregnancy to near term with close surveillance for signs of infection.

Cervical Incompetence (Increasingly Referred to as Cervical Insufficiency)

This is an uncommon but serious cause of miscarriage and preterm delivery in the second trimester, occurring in about 1 to 2% of pregnancies. In this condition, the cervix begins to open and thin long before the ninth month, and the cervix is not able to withstand the pressure of the growing uterus.

The opening and thinning cervix eventually leads to rupture of membranes and delivery of a very premature fetus. Because this most often occurs around 20 weeks of pregnancy, it is uncommon to save the pregnancy, since the fetus is too premature to survive outside the womb.

Women at higher risk for cervical insufficiency include those who have had a previous cervical trauma such as a laceration during delivery, cervical cone biopsy, or other operation on the cervix. Women with a history of DES exposure are also at higher risk.


Unlike preterm labor, during which contractions are often felt, cervical insufficiency generally does not cause pain or contractions. Vaginal bleeding or discharge are often noted.


Treatment for insufficient cervix is limited. Once the diagnosis is made, an emergency cerclage (stitch around the cervix) can be considered. If the cervix is very dilated, the risk of rupturing the membranes is higher. Extended bedrest is necessary after the cerclage is placed. If the membranes have already ruptured and the fetus is old enough to survive outside the uterus, then induction of labor to promote delivery is common.

The best treatment is prevention. If a woman has a history of insufficient cervix, then she can receive a cerclage with future pregnancies at about 14 weeks of gestation. This will reduce, but not eliminate, the risk of losing the pregnancy and also reduce the chance of very preterm delivery.


Though preeclampsia primarily occurs during the third trimester in women delivering their first baby, some women develop preeclampsia during the second trimester. This condition is diagnosed when a women develops hypertension (high blood pressure), proteinuria (protein in the urine), and pathologic or excessive edema (swelling). Preeclampsia affects every system in the body, including the placenta, which is responsible for providing the baby with nutrients.

If you develop preeclampsia in the second trimester, you will be evaluated for other conditions that may be confused with preeclampsia, such as lupus, anti-phospholipid syndrome, idiopathic thrombocytopenic purpura (ITP), and epilepsy. You will also be evaluated for conditions that can increase the likelihood of developing early preeclampsia, such as hypercoagulable conditions, twins, and molar pregnancy.

Symptoms of preeclampsia include rapid swelling of your lower extremities, hands, or face. If you experience this swelling, or any of the following symptoms, call your provider:

  • headache that does not go away with acetaminophen (Tylenol);
  • loss of vision;
  • "floaters" in your vision;
  • severe pain on your right side or in your stomach area; or
  • easy bruising.


Use common sense and be safe during pregnancy because you are more susceptible to injury. Your center of gravity changes with pregnancy, which means it's easier to lose your balance and harder to see your feet. In the car, fasten your seatbelt and tilt the steering wheel at least 10 inches away from your chest. Be careful in the bathroom, and add nonskid surfaces to your shower if you don't have them. Check your house for other hazards that could cause you to fall.

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