Pregnancy Week by Week : Week 29 (part 1) - Premature Labor and Premature Birth

Premature Labor and Premature Birth

Many babies born in the United States are born before their due date. Statistics show nearly 13% of all babies are premature—that’s over half a million babies each year! The rate of premature births has increased by over 30% since 1980.

Today, we classify premature babies into categories. The most commonly used classifications are:

• micropreemie—born before 27 weeks of pregnancy

• very premature—born between 27 and 32 weeks of pregnancy

• premature—born between 32 and 37 weeks of pregnancy

• late premature—born after 37 weeks of pregnancy

Premature birth increases the risk of problems in a baby. In 1950, the neonatal death rate was about 20 per 1000 live births. Today, the rate is less than 10 per 1000 live births. Nearly twice the number of preterm infants survive today than 60 years ago.

The higher survival rate applies mainly to babies delivered after 27 weeks or more of gestation, who weigh at least 2¾ pounds (1kg), with no birth defects. When gestational age and birthweight are below these levels, the death rate increases.

Better methods of caring for premature babies have contributed to higher survival statistics. Today, infants born as early as 25 weeks of pregnancy may survive, but long-term survival and quality of life for these babies remains to be seen as they grow older. In the lower-birthweight range, many babies had disabilities. Higher-weight babies also had disabilities, but statistics for this group were much lower. Premature babies with low birth weights are at highest risk.

It’s usually best for the baby to remain in the uterus as long as possible, so it can grow and develop fully. Occasionally it’s best for the baby to be delivered early, such as when baby is not receiving adequate nutrition. Nearly 25% of preterm births are a result of pregnancy complications—a baby needs to be delivered early for its health and safety.

How will you know if you are experiencing preterm labor? Signs that preterm labor may begin include the following:

• change in type of vaginal discharge (watery, mucus or bloody)

• menstruallike cramps (cramps that feel like your period)

• low, dull backache

• pelvic or lower-abdominal pressure—the feeling that your baby is pushing down hard

• unusual vaginal discharge

• increase in amount of discharge

• abdominal cramps with or without diarrhea

• ruptured membranes

• contractions every 10 minutes or more often

• bleeding

There are some actions that may help stop premature labor. Stop what you’re doing and rest on your left side for 1 hour. Drink 2 to 3 glasses of water or juice. If symptoms get worse or don’t go away after an hour, call your healthcare provider or go to the hospital. If symptoms go away, relax for the rest of the day. If the symptoms stop but come back, call your healthcare provider or go to the hospital.

Causes of Premature Labor and Premature Birth. In most cases, we don’t know the cause of premature labor and premature birth, and finding a cause may be difficult. An attempt is always made to determine what causes it so treatment may be more effective. Half of the women who go into preterm labor have no known risk factors.

The list below contains risk factors for preterm labor. Your risk for preterm labor increases if you:

• had preterm labor or preterm birth in a previous pregnancy

• smoke cigarettes or use cocaine

• are carrying more than one baby

• have an abnormal cervix or uterus

• had abdominal surgery during this pregnancy

• had an infection while pregnant, such as a UTI or gum problems

• had any bleeding in the second or third trimester of this pregnancy

• are underweight

• have a mother or a grandmother who took DES (diethylstilbestrol; medication given to many pregnant women in the 1950s, 1960s and 1970s)

• have had little or no prenatal care

• are carrying a child with chromosomal disorders

Other risk factors have been identified, including giving birth at an older age, carrying a baby conceived from in-vitro fertilization, quickly getting pregnant after a previous birth (less than 9 months), you are Black/African-American or you are under 17 or over 35. Research shows if it took you longer than 1 year to get pregnant, you may have a slightly higher chance of giving birth prematurely.

Premature baby (born at 29 weeks of pregnancy) shown with fetal monitors attached to it. Note size of adult hand in comparison.

Some experts believe up to half of all premature births may be tied to infections. Iron deficiency has also been linked to an increased risk. Some researchers believe taking your prenatal vitamin every day may help cut your risk by as much as 50%!

Low HDL cholesterol and elevated homocysteine levels in a mother-to-be have been shown to be key factors associated with preterm birth. When found together, the risk of premature delivery was twice as high.

One study indicates a link between preterm delivery and a mother’s future risk of heart disease and stroke. The factors we know lead to stroke and heart disease were elevated in the second trimester in mothers who delivered babies prematurely.

Tests Your Healthcare Provider May Do. One test, called SalEst, can help determine if a woman might go into labor too early. The test measures levels of the hormone estriol in a woman’s saliva. Research has shown there is often a surge in this chemical several weeks before early labor. A positive result means a woman has a 7 times greater chance of delivering her baby before the 37^th week of pregnancy. Another test is fetal fibronectin (fFN).

Some difficult questions that must be answered when premature labor begins include those below.

• Is it better for the infant to be inside the uterus or to be delivered?

• Are the dates of the pregnancy correct?

• Is this really labor?