Other medical complications
Hypertensive diseases in pregnancy
- Chronic hypertension complicating pregnancy is associated with an 8-15% risk of fetal growth restriction and a 12-34% risk of preterm birth. Placental abruption and perinatal death are 2- and 2 to 4-fold more common in pregnancies complicated by chronic hypertension.
- Hypertension in pregnancy is the 2nd leading cause of maternal death in the United States, accounting for 15% of all deaths.
- One in four women with chronic hypertension will also develop preeclampsia.
- Some serious complications of preeclampsia include pulmonary edema (2-5%), kidney failure (1-2%), cerebral hemorrhage (<1%), and eclampsia (seizures: <1%).
- In the developed world, the risk of maternal death in cases of eclampsia is 1-2%, and the risk of perinatal mortality is 6-12%.
Diabetes in pregnancy
- Over 8 million women in the United States have pregestational diabetes. It complicates 1% of all pregnancies.
- Major birth defects are the leading cause of perinatal mortality in pregnancies complicated by pregestational diabetes, with the risk being proportionate to 1st trimester control of blood sugar as reflected by hemoglobin A1c values. With very high levels, the risk of major birth defects can be as high as 20% or more.
- Diabetic ketoacidosis occurs in 5-10% of pregnant women with type 1 diabetes, and stillbirth can occur in up to 10% of cases when this occurs.
- Up to 200,000 pregnancies are affected by gestational diabetes each year.
- Approximately 50% of women with gestational diabetes will develop diabetes later in life.
Cesarean delivery
- In 2007, the cesarean delivery rate increased to 32%, marking the 11th annual increase. This rate has climbed by more than 50% since 1996.
- The risk of an abnormally adherent placenta (placenta accreta) increases with the number of prior cesarean deliveries: from 3% to 11% to 40% for women with one, two, and three prior cesarean deliveries, respectively. This condition can result in severe hemorrhage and usually requires hysterectomy.
- Hysterectomy is needed in 10%, 45%, and 67% of women with placenta previa when they have had 1, 2, or 4 or more prior cesarean deliveries, respectively.
- The rate of primary cesarean delivery was 21 per 100 live births in the United States in 2006. During the same time period, 92.4% of women with a prior cesarean underwent a repeat cesarean delivery.
- Of women who attempt a vaginal birth after cesarean delivery, 75% will be successful. Uterine rupture will complicate only 0.7 to 1% of attempts.
Fetal and infant mortality
- Stillbirths account for 58% of all perinatal deaths before 28 days of life, and 48% of all deaths in the first year of life in the United States.
- One in six stillbirths (17.5%) occurs at term.
- The rate of stillbirth equals the rate of death due to preterm birth and sudden infant death syndrome combined.
- The 10 leading causes of infant death (death in the first year of life) in the United States in 2006 were birth defects, preterm birth and low birth weight (absent another cause), sudden infant death syndrome (SIDS), maternal complications, accidents, umbilical cord and placental complications, newborn respiratory distress, newborn sepsis, neonatal hemorrhage, and circulatory system diseases. Birth defects account for about 1 in 5 infant deaths.
- In 2009 the CIA World FactBook ranked the United States 45th among 224 countries for infant mortality, a higher rate than in most developed countries. Much of this is because of the high rate of preterm birth, which is responsible for about one-third of
Fetal growth and well-being
- Infants born small for gestational age at term have a 5-fold higher risk of death than normal-weight infants.
- Intrauterine growth restriction (IUGR) accounts for 50% of stillbirths and 20% of neonatal deaths.
- There is a 10-30% increase in minor and major birth defects among IUGR fetuses.
- Fetal infection (e.g., cytomegalovirus, rubella, and toxoplasmosis) accounts for 5-10% of IUGR cases.
- Maternal vascular disease and subsequent utero-placental insufficiency accounts for 25-30% of IUGR cases.
- Use of antenatal fetal surveillance decreases the rate of perinatal mortality from 8.8 to 1.3 deaths per 1,000 births.
Maternal mortality
- Maternal mortality declined 50-fold in the United States between 1915 and 2006, from 608 to 13 deaths per 100,000 live births. In 2006, one maternal death complicated every 7,500 live births.
- The leading causes of maternal death in the United States are hemorrhage, hypertension, thrombosis and thromboembolism, infection, stroke, amniotic infection, stroke, amniotic fluid embolism, and cardiac disease.
- Black women have a substantially higher risk of maternal death than white or Hispanic women (32.7 deaths per 100,000 live births in 2006 for black women, versus 9.5 and 10.2 for white and Hispanic women)
U.S. infant deaths
- Infant mortality is over two times more common among non-Hispanic black infants than non-Hispanic white or Hispanic infants (13.6 versus 5.8 and 5.6 per 1,000 live births, respectively).
Multiple gestations
- Preterm birth complicates 95%, 93%, and 60% of quadruplet, triplet, and twin pregnancies, respectively. Early preterm birth (before 32 weeks’ gestation) affects 1 in 63 singleton, 1 in 8 twin (12%), 1 in 3 triplet (36%), and 4 in 5 quadruplet (79%) pregnancies.
- Intrauterine growth restriction complicates up to 25% of twin and 50–60% of triplet and quadruplet pregnancies.
- One-fourth of twin, three-fourths of triplet, and virtually all quadruplet newborns require neonatal intensive care unit (NICU) admission, with average NICU stays of 18, 30, and 58 days, respectively.
- The infant mortality rate for twins and higher-order multiples is 5-fold higher than for singletons (32 versus 6 per 1,000).
- Matched for gestational age at birth, twin and multifetal pregnancy infants have a nearly 3-fold higher risk of cerebral palsy than do singleton infants.
Preterm birth
- The rate of preterm birth (before 37 weeks) in the United States has steadily increased over the last two decades; reaching 1 in 8 babies in 2007 (12.7%). There are over 500,000 preterm births each year in the United States.
- African American women are almost twice as likely to deliver preterm (18.3%) com-pared with white (11.6%) and Hispanic (12.1%) women, regardless of socioeconomic status and education level.
- The annual cost to society (medical, educational, and lost productivity) of preterm birth in the United States is at least $26 billion (in 2005 dollars).
- The average first-year inpatient and outpatient medical care cost for a preterm infant is 10 times more than for a term infant ($32,325 vs. $3,325 in 2005 dollars).
- The 34-week human brain is one-third smaller and significantly less developed than that of a term infant. Late preterm infants, born at 34-36 weeks, are 3.4 times more likely to develop cerebral palsy and 1.3 times more likely to have cognitive impairment than are term babies.
- Severe neuro-developmental disability including cerebral palsy occurs in approximately 34% of infants surviving after birth at 23-25 weeks (the threshold of viability).
- Intramuscular 17 alpha-hydroxyprogesterone caproate, given weekly from 16-20 weeks through 36 weeks has been found to decrease recurrent preterm birth by one-third in women with a prior spontaneous preterm birth.
- To date, there is no treatment that consistently prevents preterm birth once preterm labor occurs.
- A single course of antenatal corticosteroids (betamethasone or dexamethasone) before preterm birth offers significant neonatal health benefits, including reduction of neonatal death, respiratory distress syndrome, cerebroventricular hemorrhage, and necrotizing enterocolitis.
- Antenatal magnesium sulfate is associated with a 31% decrease in the rate of cerebral palsy in surviving infants when given to women at risk of delivering preterm.