Of all the types of multiple births, twins normally face the fewest medical problems and complications. Each additional baby a woman carries during her pregnancy increases the possibility of developing pregnancy complications.
What are the most common complications associated with multiples?
- Preterm Labor/Delivery
- Low birth weight
- Intrauterine Growth Restriction (IUGR)
- Gestational Diabetes
- Placental Abruption
- Fetal Demise/Loss
Preterm labor/delivery is defined as delivery before 37 completed weeks of pregnancy. The length of gestation typically decreases with each additional baby. On average most single pregnancies last 39 weeks, twin pregnancies 36 weeks, triplets 32 weeks, quadruplets 30 weeks, and quintuplets 29 weeks.
Almost 60% of twins are delivered preterm, while 90% of triplets are preterm.
Higher order pregnancies are almost always preterm. Many times premature labor is a result of preterm premature rupture of the membranes (PPROM). PPROM is rupture of the membranes prior to the onset of labor in a patient who is less than 37 weeks of gestation.
Low Birth Weight
Low birth weight is almost always related to preterm delivery. Low birth weight is less than 5.5 pounds (2,500 grams). Babies born before 32 weeks and weighing less than 3.3 pounds (1,500 grams) have an increased risk of developing complications as newborns.
They are at increased risk for having long-term problems such as mental retardation, cerebral palsy, vision loss, and hearing loss.
Intrauterine Growth Restriction (IUGR)
Multiple pregnancies grow at approximately the same rate as single pregnancies up to a certain point. The growth rate of twin pregnancies begins to slow at 30 to 32 weeks.
Triplet pregnancies begin slowing at 27 to 28 weeks, and quadruplet pregnancies begin slowing at 25 to 26 weeks.
IUGR seems to occur because the placenta cannot handle any more growth and because the babies are competing for nutrients. Your doctor will monitor the growth of your babies by ultrasound and by measuring your abdomen.
Preeclampsia, Pregnancy Induced Hypertension (PIH), Toxemia, and high blood pressure are all synonymous terms. Twin pregnancies are twice as likely to develop preeclampsia as single pregnancies. Half of triplet pregnancies develop preeclampsia.
Frequent prenatal care increases the chance of detecting and treating preeclampsia. Adequate prenatal care also decreases the risk of developing a serious problem from preeclampsia for both the babies and the mother.
The increased risk for gestational diabetes in a multiples pregnancy appears to be a result of the two placentas increasing the resistance to insulin, increased placental size, and an elevation in placental hormones.
The risk of occurrence of gestational diabetes in a multiples pregnancy is still being researched at this time. In one study, an increased risk of gestational diabetes did seem to be apparent, but the doctors involved recommended that further testing be conducted.
Placental abruption is three times more likely to occur in a multiples pregnancy. This may be linked to the fact that there is an increased risk of developing preeclampsia. It most often occurs in the third trimester, but the risk significantly increases once the first baby has been delivered vaginally.
Fetal Demise or Loss
Intrauterine fetal demise is extremely uncommon. Your healthcare provider will determine whether it is best to expose the other baby(ies) to the fetus that has died or to proceed with delivery.
If the pregnancy is dichorionic (two chorions present), then intervention may not be necessary. (The chorion is a membrane that forms the fetal portion of the placenta. Fraternal twins always have two chorions while identical twins can have one or two chorions.)
If the pregnancy has a single chorion, fetal maturity will be assessed to see if immediate delivery is recommended. In this situation it would be necessary to weigh the risks between having a premature baby and the risks of remaining in utero.
If you are pregnant with multiples it does not necessarily mean that you will have a cesarean birth. The typical recommendation for the delivery of triplets and higher order multiples is a cesarean, but twins are often delivered vaginally.
The vaginal delivery of twins depends on the presentation of the babies.
Twins can be delivered vaginally when:
- The gestation is greater than 32 weeks
- Twin A (the baby closest to the cervix) is the largest
- Twin A is head down
- Twin B is head down, Breech, or sideways
- Twin B is smaller than twin A
- There is no evidence of fetal distress
- There is no cephalopelvic disproportion (CPD)
Last Updated: 07/2015