Which of the following is not associated with Intrauterine Growth Retardation?
Correct Answer B: Intrauterine growth restriction (IUGR) is a term used to describe a condition in which the fetus is smaller than expected for the number of weeks of pregnancy. Another term for IUGR is fetal growth restriction. Newborn babies with IUGR are often described as small for gestational age (SGA). A fetus with IUGR often has an estimated fetal weight less than the 10th percentile.
Maternal factors associated with IUGR are:
Factors involving the uterus and placenta are:
Factors related to the developing fetus are:
A 25-year-old primigravida at 34 weeks gestation is thought to be small for dates by her physician and is sent for a sonographic evaluation. The ultrasound shows the biparietal diameter to be appropriate for 30 weeks gestation. The abdominal circumference is appropriate for 26 weeks gestation. The head:abdominal circumference ratio is > 1. The estimated fetal weight is < 10th percentile for 34 weeks gestation. The amniotic fluid is decreased.
Which of the following is the most likely diagnosis?
Correct Answer B: Intrauterine growth retardation (IUGR) is where a baby fails to grow as normal in the womb. These babies are smaller than they should be for their age and their weight is below what it should be for that stage of the pregnancy (below the 10th weight percentile for the baby’s age). Babies with IUGR are prone to a variety of problems before and after birth.
IUGR can be classified into:
In symmetrical IUGR, the baby's head and body are proportionately small. This usually occurs when IUGR begins in early pregnancy. Head circumference, length and weight are all decreased proportionately. These infants are more likely to have significant intrinsic fetal problems than babies where the IUGR begins later.
In asymmetrical IUGR, growth restriction is due to problems in late pregnancy (such as maternal renal disease or preeclampsia). These babies have a relatively normal head circumference but a small abdominal circumference, some reduction in length, and a marked reduction in weight.
The most common maternal cause of fetal growth restriction is:
Correct Answer A: The most common cause of Fetal Growth Restriction (FGR) is maternal chronic hypertension. Moreover, infants of hypertensive mothers have a threefold increase in perinatal mortality compared to infants with FGR who are born to normotensive mothers.
Maternal causes of FGR include the following:
→ Fetal genetic abnormalities account for 5 to 20% of FGR. Genetic abnormalities include: aneuploidy (choice D) (including triploidy), uniparental disomy, single gene mutations, partial deletions or duplications, ring chromosome, and aberrant genomic imprinting.
→ Multiple gestation (choice E) is considered a uteroplacental cause of FGR.
A 34-year-old white primigravida in her first trimester had established moderate hypertension before becoming pregnant. She currently has a blood pressure of 168/108 mm Hg. You are considering how to best manage her hypertension during the pregnancy.
Which one of the following is associated with the greatest risk of fetal growth retardation if used for hypertension throughout pregnancy?
Correct Answer A: Atenolol and propranolol are associated with intrauterine growth retardation when used for prolonged periods during pregnancy. They are class D agents during pregnancy. Other beta-blockers may not share this risk.
Methyldopa, hydralazine, and calcium channel blockers have not been associated with intrauterine growth retardation. They are generally acceptable agents to use for established, significant hypertension during pregnancy.
A 25-year-old woman, gravida 2, para 1, with chronic hypertension, is at 38 weeks gestation. Ultrasound examination shows an amniotic fluid index of 4 cm and an estimated fetal weight below the 10th percentile. A nonstress test (NST) is nonreactive with absent variability, and a subsequent contraction stress test (CST) is positive. Her Bishop score is 4.
Which of the following should be the next step in managing this patient?
Correct Answer D: Late deceleration as a rule generally indicate uteroplacental insufficiency. A positive CST indicates that late deceleration are present on at least 50% of the contractions. This, along with the absence of variability, as well as other measures consistent with chronic growth restriction (oligohydramnios and weight <10th percentile), is an indication for immediate delivery. Since the Bishop score indicates an unripe cervix, this would be best done by performing a cesarean section.
→ Fetal karyotype is important for the workup of a symmetrical IUGR fetus. This is the picture of uteroplacental insufficiency.
→ Fetal blood pH will not aid in the management of this patient. Immediate delivery is the answer.
→ A positive CST with an unripe cervix and IUGR at 38 weeks is managed by immediate delivery. Further fetal testing is not warranted.
→ This fetus needs delivery today. Further delay may lead to stillbirth or other serious sequelae.
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