A 38-year-old G4P3 at 33 weeks’ gestation presents for a routine OB visit, and is noted to have a fundal height of 29 cm. An ultrasound is performed, and demonstrates an EFW in the 5 percentile for the gestational age. The biparietal diameter and abdominal circumference are concordant in size.
Which of the following is associated with symmetric growth restriction?
Intrauterine growth restriction (IUGR) is diagnosed when the estimated weight of the fetus falls below the 10 percentile for a given age. By the use of ultrasonography, IUGR can be classified as either symmetric or asymmetric. In asymmetric IUGR, the abdominal circumference is low, but the biparietal diameter may be at or near normal. In cases of symmetric IUGR, all fetal structures (including both head and body size) are proportionately diminished in size. Fetal infections, chromosome abnormalities, and congenital anomalies usually result in symmetric IUGR. Asymmetric IUGR is seen in cases where fetal access to nutrients is compromised, such as with severe maternal nutritional deficiencies or hypertension causing utero-placental insufficiency.
Which of the following factors would indicate that this fetus needs to be delivered?
The timing of deliver depends on many factors, including the underlying etiology of the growth restriction (if known), and the gestational age. Typically, growth restricted fetuses will be monitored with antenatal testing, serial ultrasounds for growth, and Doppler studies. The EFW alone is not necessarily an indication for delivery if other factors are favorable. There is no evidence that early delivery improves outcomes in fetuses with aneuploidy. A BPP of 8/10 and normal umbilical artery dopplers are reassuring. Absence of interval growth would indicate that the fetus should be delivered. Ultrasound measurements for growth should not be performed more frequently than every 2 weeks, because the inherent user error associated with ultrasound measurements can preclude an accurate assessment of interval growth.
A 26-year-old G1 at 37 weeks presents to the hospital in active labor. She has no medical problems and has a normal prenatal course except for fetal growth restriction. She undergoes an uncomplicated vaginal delivery of a female infant weighing 1950 g.
The infant is at risk for which of the following complications?
Fetuses that are growth-restricted often have difficulty transitioning to the extrauterine environment. Therefore, it is critical that neonatologists be involved in such deliveries. Growth-restricted fetuses more commonly pass meconium, and are more likely to develop meconium aspiration syndrome. In addition, growth-restricted fetuses compensate for poor placental oxygen transfer by developing polycythemia, which can then result in multiorgan thrombosis at or after birth. At the time of delivery, growth restricted infants may suffer from hypoxia caused by uteroplacental insufficiency. Infants with IUGR have less subcutaneous fat deposition; therefore, hypothermia and hypoglycemia are a potential concern.
A 38-year-old G2P1 comes to see you for her first prenatal visit at 10 weeks’ gestation. She had a previous term vaginal delivery without any complications. You detect fetal heart tones at this visit, and her uterine size is consistent with dates. You also order routine prenatal laboratory tests, which return showing that her blood type is A-, and she has a positive antibody screen, with an anti-D antibody titer of 1:4.
Which of the following is the most appropriate next step in the management of this patient?
During the first prenatal visit, all pregnant women are screened for the ABO blood group and the Rh group, which includes the D antigen. If the woman is Rh-negative, antibody screening is performed. If the antibody D titer is positive, the woman is considered sensitized because she has produced antibodies against the D antigen. Sensitization occurs as a result of exposure to blood from an Rh-positive fetus in a prior pregnancy. A fetus that is Rh-positive possesses red blood cells that express the D antigen. Therefore, the maternal anti-D antibodies can cross the placenta and cause fetal hemolysis. Once the antibody screen is positive for isoimmunization, the titer should be followed at regular intervals (about every 4 weeks). A titer of 1:16 or greater is usually indicative of the possibility of severe hemolytic disease of the fetus. Once this critical titer is reached, further evaluation is done by amniotic fluid assessment or analysis of fetal blood via PUBS. In the presence of fetal hemolysis, the amniotic fluid contains elevated levels of bilirubin that can be determined via spectrophotometric analysis. Cordocentesis, or percutaneous umbilical blood sampling, involves obtaining a blood sample from the umbilical cord under ultrasound guidance. The fetal blood sample can then be analyzed for hematocrit and determination of fetal blood type. Cordocentesis also allows the fetus with anemia to undergo a blood transfusion.
A 23-year-old G3P1011 at 6 weeks presents for routine prenatal care. She had a cesarean delivery 3 years ago for breech presentation after a failed external cephalic version. Her daughter is Rh-negative. She also had an elective termination of pregnancy 1 year ago. She is Rh-negative and is found to have a positive anti-D titer of 1:8 on routine prenatal laboratory findings.
Failure to administer RhoGAM at which time is the most likely cause of her sensitization?
To prevent maternal Rh sensitization, pregnant women who are Rh-negative should receive RhoGAM or Rh immune globulin (antibody to the D antigen) in the following situations: after a spontaneous or induced abortion, after an ectopic pregnancy, at the time of an amniocentesis/CVS/PUBS, at 28 weeks’ gestation (prophylactically), within 3 days of a delivery of an Rh-positive fetus, at the time of external cephalic version, with second- or third-trimester antenatal bleeding, and in the setting of abdominal trauma.
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